Kerri Wachter

WASHINGTON — When refractory hypertension rears its head, it might be time to look for problems in the renin-aldosterone system, according to one expert who spoke at a meeting sponsored by the National Kidney Foundation.

In patients with hypertension, the prevalence of primary aldosteronism ranges from 5% to 30%, and the rate is especially high among older patients, said J. Howard Pratt, M.D., professor of medicine at Indiana University in Indianapolis.

Aldosterone works on the collecting duct of the distal nephron to increase the activity of the epithelial sodium channels. The resulting increase in the sodium level promotes hypertension.

There are two types of primary aldosteronism: adenoma and bilateral adrenal hyperplasia. “Adrenal hyperplasia is much more common than the adenomas,” Dr. Pratt said. According to many textbooks, adenomas are three times more likely to be the cause of hypertension than hyperplasia. “It's probably the reverse. It's probably much more than three times more common to have hyperplasia than adenoma.”

Classically, this disorder presented with a low serum potassium level. Current thinking is that most of these patients have a normal potassium level because of hyperplasia, he said. Serum sodium is usually greater than 140 μmol/L. Renal cysts are present in about 40% of patients. Left ventricular hypertrophy is also common.

“The work-up for primary aldosteronism is very simple, and I think this is one of the reasons that we see so much of it today,” Dr. Pratt said. The key is to measure plasma renin and aldosterone levels. Patients can be on any kind of medication to treat hypertension when these tests are performed, with the exception of spironolactone, which blocks the action of aldosterone.

For the diagnosis of primary aldosteronism, plasma aldosterone levels should be greater than 15–20 ng/dL with suppressed renin activity. The ratio of aldosterone to renin also should be greater than 20:30. Urine aldosterone excretion also can be measured; a 24-hour level of 12 μg or greater can indicate the disorder.

Once moderately severe primary aldosteronism has been diagnosed through lab tests, it can be useful to get a CT scan or MRI to check for adrenal tumors, Dr. Pratt said.

Adrenal vein catheterization—a technically difficult procedure—should be considered when the adrenal glands appear normal on CT imaging, but there is still a high suspicion of primary aldosteronism—low potassium level and high plasma aldosterone level. “These are the people who typically have adenomas,” he said.

If the patient has a distinct tumor on CT imaging and is older than 40 years, Dr. Pratt performs adrenal vein catheterization because “at that age they could have an incidental adrenal tumor.”

Treatment for an adenoma is laparoscopic removal. Bilateral adrenal hyperplasia is treated medically. “The approach that I take is to use a small dose of spironolactone (25 mg/day) with a small dose of a thiazide diuretic (12.5 mg/day hydrochlorothiazide). This is usually all that is needed for many patients,” Dr. Pratt said.

A calcium channel blocker, ACE inhibitor, or angiotensin II receptor blocker can be added if necessary. “Once you've given spironolactone, you've sort of revved up the renin-angiotensin system, and there's something for these drugs to work on,” he said.

Some patients with refractory hypertension can have low-renin hypertension instead. In this disorder, patients have low renin levels but normal aldosterone levels. These patients are resistant to antihypertensive therapy but do respond to spironolactone (25–50 mg/day) or amiloride (5–10 mg/day), in combination with a diuretic, Dr. Pratt said.

WASHINGTON — When refractory hypertension rears its head, it might be time to look for problems in the renin-aldosterone system, according to one expert who spoke at a meeting sponsored by the National Kidney Foundation.

In patients with hypertension, the prevalence of primary aldosteronism ranges from 5% to 30%, and the rate is especially high among older patients, said J. Howard Pratt, M.D., professor of medicine at Indiana University in Indianapolis.

Aldosterone works on the collecting duct of the distal nephron to increase the activity of the epithelial sodium channels. The resulting increase in the sodium level promotes hypertension.

There are two types of primary aldosteronism: adenoma and bilateral adrenal hyperplasia. “Adrenal hyperplasia is much more common than the adenomas,” Dr. Pratt said. According to many textbooks, adenomas are three times more likely to be the cause of hypertension than hyperplasia. “It's probably the reverse. It's probably much more than three times more common to have hyperplasia than adenoma.”

Classically, this disorder presented with a low serum potassium level. Current thinking is that most of these patients have a normal potassium level because of hyperplasia, he said. Serum sodium is usually greater than 140 μmol/L. Renal cysts are present in about 40% of patients. Left ventricular hypertrophy is also common.

“The work-up for primary aldosteronism is very simple, and I think this is one of the reasons that we see so much of it today,” Dr. Pratt said. The key is to measure plasma renin and aldosterone levels. Patients can be on any kind of medication to treat hypertension when these tests are performed, with the exception of spironolactone, which blocks the action of aldosterone.

For the diagnosis of primary aldosteronism, plasma aldosterone levels should be greater than 15–20 ng/dL with suppressed renin activity. The ratio of aldosterone to renin also should be greater than 20:30. Urine aldosterone excretion also can be measured; a 24-hour level of 12 μg or greater can indicate the disorder.

Once moderately severe primary aldosteronism has been diagnosed through lab tests, it can be useful to get a CT scan or MRI to check for adrenal tumors, Dr. Pratt said.

Adrenal vein catheterization—a technically difficult procedure—should be considered when the adrenal glands appear normal on CT imaging, but there is still a high suspicion of primary aldosteronism—low potassium level and high plasma aldosterone level. “These are the people who typically have adenomas,” he said.

If the patient has a distinct tumor on CT imaging and is older than 40 years, Dr. Pratt performs adrenal vein catheterization because “at that age they could have an incidental adrenal tumor.”

Treatment for an adenoma is laparoscopic removal. Bilateral adrenal hyperplasia is treated medically. “The approach that I take is to use a small dose of spironolactone (25 mg/day) with a small dose of a thiazide diuretic (12.5 mg/day hydrochlorothiazide). This is usually all that is needed for many patients,” Dr. Pratt said.

A calcium channel blocker, ACE inhibitor, or angiotensin II receptor blocker can be added if necessary. “Once you've given spironolactone, you've sort of revved up the renin-angiotensin system, and there's something for these drugs to work on,” he said.

Some patients with refractory hypertension can have low-renin hypertension instead. In this disorder, patients have low renin levels but normal aldosterone levels. These patients are resistant to antihypertensive therapy but do respond to spironolactone (25–50 mg/day) or amiloride (5–10 mg/day), in combination with a diuretic, Dr. Pratt said.

WASHINGTON — When refractory hypertension rears its head, it might be time to look for problems in the renin-aldosterone system, according to one expert who spoke at a meeting sponsored by the National Kidney Foundation.

In patients with hypertension, the prevalence of primary aldosteronism ranges from 5% to 30%, and the rate is especially high among older patients, said J. Howard Pratt, M.D., professor of medicine at Indiana University in Indianapolis.

Aldosterone works on the collecting duct of the distal nephron to increase the activity of the epithelial sodium channels. The resulting increase in the sodium level promotes hypertension.

There are two types of primary aldosteronism: adenoma and bilateral adrenal hyperplasia. “Adrenal hyperplasia is much more common than the adenomas,” Dr. Pratt said. According to many textbooks, adenomas are three times more likely to be the cause of hypertension than hyperplasia. “It's probably the reverse. It's probably much more than three times more common to have hyperplasia than adenoma.”

Classically, this disorder presented with a low serum potassium level. Current thinking is that most of these patients have a normal potassium level because of hyperplasia, he said. Serum sodium is usually greater than 140 μmol/L. Renal cysts are present in about 40% of patients. Left ventricular hypertrophy is also common.

“The work-up for primary aldosteronism is very simple, and I think this is one of the reasons that we see so much of it today,” Dr. Pratt said. The key is to measure plasma renin and aldosterone levels. Patients can be on any kind of medication to treat hypertension when these tests are performed, with the exception of spironolactone, which blocks the action of aldosterone.

For the diagnosis of primary aldosteronism, plasma aldosterone levels should be greater than 15–20 ng/dL with suppressed renin activity. The ratio of aldosterone to renin also should be greater than 20:30. Urine aldosterone excretion also can be measured; a 24-hour level of 12 μg or greater can indicate the disorder.

Once moderately severe primary aldosteronism has been diagnosed through lab tests, it can be useful to get a CT scan or MRI to check for adrenal tumors, Dr. Pratt said.

Adrenal vein catheterization—a technically difficult procedure—should be considered when the adrenal glands appear normal on CT imaging, but there is still a high suspicion of primary aldosteronism—low potassium level and high plasma aldosterone level. “These are the people who typically have adenomas,” he said.

If the patient has a distinct tumor on CT imaging and is older than 40 years, Dr. Pratt performs adrenal vein catheterization because “at that age they could have an incidental adrenal tumor.”

Treatment for an adenoma is laparoscopic removal. Bilateral adrenal hyperplasia is treated medically. “The approach that I take is to use a small dose of spironolactone (25 mg/day) with a small dose of a thiazide diuretic (12.5 mg/day hydrochlorothiazide). This is usually all that is needed for many patients,” Dr. Pratt said.

A calcium channel blocker, ACE inhibitor, or angiotensin II receptor blocker can be added if necessary. “Once you've given spironolactone, you've sort of revved up the renin-angiotensin system, and there's something for these drugs to work on,” he said.

Some patients with refractory hypertension can have low-renin hypertension instead. In this disorder, patients have low renin levels but normal aldosterone levels. These patients are resistant to antihypertensive therapy but do respond to spironolactone (25–50 mg/day) or amiloride (5–10 mg/day), in combination with a diuretic, Dr. Pratt said.

ORLANDO, FLA. – Neuroimaging is key to diagnosing relatively rare secondary headaches, one expert said at the annual meeting of the American Society of Neuroimaging.

“Secondary headaches are where neuroimaging is of paramount importance,” said Laszlo L. Mechtler, M.D., director of the headache center at Dent Neurologic Institute in Buffalo, N.Y.

Secondary headaches represent a symptom of a pathologic organic process and are associated with more than 316 disorders and illnesses, posing a diagnostic challenge. The causes of these headaches can be serious and life threatening. Secondary headaches account for up to 16% of annual emergency department visits that are attributable to headaches, according to Dr. Mechtler.

Physicians should rely on several red flags to trigger an imaging study to investigate the possibility of secondary headache, he pointed out.

Dr. Mechtler discussed the use of neuroimaging in diagnosing several types of secondary headaches.

Subarachnoid hemorrhage is classically described as the “worst headache of my life,” but be careful when patients say that. Only 12% of the patients who present to the emergency department with this type of headache actually have subarachnoid hemorrhage, if the neurologic examination is normal. The percentage jumps to 25% if the neurologic examination is abnormal, Dr. Mechtler said. “So even with the worst headache of your life, we're still talking primary headaches.”

For a patient presenting with “the worst headache of my life,” in the first 24 hours, CT is the study of choice, Dr. Mechtler said. According to the literature, the probability of recognizing a subarachnoid hemorrhage on CT during the first 24 hours is 95%. At 1 week post onset, that probability drops to 50%.

“Interestingly, FLAIR [fluid-attenuated inversion recovery] MRI has really changed our perception of subarachnoid hemorrhage,” he said. Recent studies have shown that FLAIR MRI is as sensitive as CT between 1 and 7 days. “After 4 or 5 days, FLAIR is probably even more sensitive than CT itself.”

Neuroimaging is very important in the diagnosis of carotid/vertebral arterial dissections, in which headache is the most common symptom. “But this headache has no classic symptoms,” Dr. Mechtler said.

This condition is relatively rare, occurring in only 3 of 100,000 carotid dissections and 1.5 of 100,000 vertebral dissections. There are multiple causes, which include an underlying arteriopathy (Ehlers-Danlos and Marfan syndromes); fibromuscular dysplasia; minor trauma, hyperextension, or rotation of the neck; major trauma or sports injuries; and possibly even chiropractic manipulations.

In vertebral dissections, the headache usually precedes neurologic symptoms by about 15 hours. Neck pain is also common in these patients, and there is the possibility of a brain stem infarct, as well. “Any time you have neck pain [or] headaches, and the patient might have a risk factor, consider dissection in your differential diagnosis,” Dr. Mechtler said.

MRI of possible dissections involves the use of special fat-suppression protocols that allow visualization of the double lumen. Magnetic resonance angiography has been very useful in the diagnosis of dissections, particularly vertebral artery dissections, he said.

Cerebral venous thrombosis can have several variations. The classic CT scan sign is the empty delta sign, Dr. Mechtler said. The sign consists of a triangular area of enhancement or high attenuation with a relatively low-attenuating center on multiple contiguous transverse CT images obtained in the region of the superior sagittal sinus.

It's not uncommon for the findings to consist of an atypical arterial distribution vascular event. Often, this type of case is sent on to a neurooncologist for evaluation of a possible glioblastoma multiforme.

Most adult patients with intracranial neoplasms don't have headaches initially. “It's a myth that brain tumors cause headaches often,” Dr. Mechtler said. Headache is present in only about 50% of cases of intracranial neoplasm.

Headache frequently does occur when there is a mass in the posterior fossa or around the meninges, he said.

In children, though, headaches are associated with intracranial neoplasms–two-thirds of childhood tumors are intratentorial.

When a glioblastoma multiforme spreads across the corpus callosum to the contralateral side, a butterfly shape can be seen on a coronal view MRI. Dr. Mechtler also noted that headaches are associated with glioblastoma multiforme when subependymal spread can be seen on MRI.

To diagnose subarachnoid hemorrhage, CT imaging (A) done within 24 hours of headache is the study of choice, compared with MR T1- (B) and T2- (C) weighted images. Red arrow points to blood within the sylvian fissure. FLAIR image (D) is as sensitive as CT between 24 and 72 hours and more sensitive after 72 hours. Yellow arrow points to blood. Normal FLAIR (E) also shown. Courtesy Dr. Laszlo L. Mechtler

ORLANDO, FLA. – Neuroimaging is key to diagnosing relatively rare secondary headaches, one expert said at the annual meeting of the American Society of Neuroimaging.

“Secondary headaches are where neuroimaging is of paramount importance,” said Laszlo L. Mechtler, M.D., director of the headache center at Dent Neurologic Institute in Buffalo, N.Y.

Secondary headaches represent a symptom of a pathologic organic process and are associated with more than 316 disorders and illnesses, posing a diagnostic challenge. The causes of these headaches can be serious and life threatening. Secondary headaches account for up to 16% of annual emergency department visits that are attributable to headaches, according to Dr. Mechtler.

Physicians should rely on several red flags to trigger an imaging study to investigate the possibility of secondary headache, he pointed out.

Dr. Mechtler discussed the use of neuroimaging in diagnosing several types of secondary headaches.

Subarachnoid hemorrhage is classically described as the “worst headache of my life,” but be careful when patients say that. Only 12% of the patients who present to the emergency department with this type of headache actually have subarachnoid hemorrhage, if the neurologic examination is normal. The percentage jumps to 25% if the neurologic examination is abnormal, Dr. Mechtler said. “So even with the worst headache of your life, we're still talking primary headaches.”

For a patient presenting with “the worst headache of my life,” in the first 24 hours, CT is the study of choice, Dr. Mechtler said. According to the literature, the probability of recognizing a subarachnoid hemorrhage on CT during the first 24 hours is 95%. At 1 week post onset, that probability drops to 50%.

“Interestingly, FLAIR [fluid-attenuated inversion recovery] MRI has really changed our perception of subarachnoid hemorrhage,” he said. Recent studies have shown that FLAIR MRI is as sensitive as CT between 1 and 7 days. “After 4 or 5 days, FLAIR is probably even more sensitive than CT itself.”

Neuroimaging is very important in the diagnosis of carotid/vertebral arterial dissections, in which headache is the most common symptom. “But this headache has no classic symptoms,” Dr. Mechtler said.

This condition is relatively rare, occurring in only 3 of 100,000 carotid dissections and 1.5 of 100,000 vertebral dissections. There are multiple causes, which include an underlying arteriopathy (Ehlers-Danlos and Marfan syndromes); fibromuscular dysplasia; minor trauma, hyperextension, or rotation of the neck; major trauma or sports injuries; and possibly even chiropractic manipulations.

In vertebral dissections, the headache usually precedes neurologic symptoms by about 15 hours. Neck pain is also common in these patients, and there is the possibility of a brain stem infarct, as well. “Any time you have neck pain [or] headaches, and the patient might have a risk factor, consider dissection in your differential diagnosis,” Dr. Mechtler said.

MRI of possible dissections involves the use of special fat-suppression protocols that allow visualization of the double lumen. Magnetic resonance angiography has been very useful in the diagnosis of dissections, particularly vertebral artery dissections, he said.

Cerebral venous thrombosis can have several variations. The classic CT scan sign is the empty delta sign, Dr. Mechtler said. The sign consists of a triangular area of enhancement or high attenuation with a relatively low-attenuating center on multiple contiguous transverse CT images obtained in the region of the superior sagittal sinus.

It's not uncommon for the findings to consist of an atypical arterial distribution vascular event. Often, this type of case is sent on to a neurooncologist for evaluation of a possible glioblastoma multiforme.

Most adult patients with intracranial neoplasms don't have headaches initially. “It's a myth that brain tumors cause headaches often,” Dr. Mechtler said. Headache is present in only about 50% of cases of intracranial neoplasm.

Headache frequently does occur when there is a mass in the posterior fossa or around the meninges, he said.

In children, though, headaches are associated with intracranial neoplasms–two-thirds of childhood tumors are intratentorial.

When a glioblastoma multiforme spreads across the corpus callosum to the contralateral side, a butterfly shape can be seen on a coronal view MRI. Dr. Mechtler also noted that headaches are associated with glioblastoma multiforme when subependymal spread can be seen on MRI.

To diagnose subarachnoid hemorrhage, CT imaging (A) done within 24 hours of headache is the study of choice, compared with MR T1- (B) and T2- (C) weighted images. Red arrow points to blood within the sylvian fissure. FLAIR image (D) is as sensitive as CT between 24 and 72 hours and more sensitive after 72 hours. Yellow arrow points to blood. Normal FLAIR (E) also shown. Courtesy Dr. Laszlo L. Mechtler

ORLANDO, FLA. – Neuroimaging is key to diagnosing relatively rare secondary headaches, one expert said at the annual meeting of the American Society of Neuroimaging.

“Secondary headaches are where neuroimaging is of paramount importance,” said Laszlo L. Mechtler, M.D., director of the headache center at Dent Neurologic Institute in Buffalo, N.Y.

Secondary headaches represent a symptom of a pathologic organic process and are associated with more than 316 disorders and illnesses, posing a diagnostic challenge. The causes of these headaches can be serious and life threatening. Secondary headaches account for up to 16% of annual emergency department visits that are attributable to headaches, according to Dr. Mechtler.

Physicians should rely on several red flags to trigger an imaging study to investigate the possibility of secondary headache, he pointed out.

Dr. Mechtler discussed the use of neuroimaging in diagnosing several types of secondary headaches.

Subarachnoid hemorrhage is classically described as the “worst headache of my life,” but be careful when patients say that. Only 12% of the patients who present to the emergency department with this type of headache actually have subarachnoid hemorrhage, if the neurologic examination is normal. The percentage jumps to 25% if the neurologic examination is abnormal, Dr. Mechtler said. “So even with the worst headache of your life, we're still talking primary headaches.”

For a patient presenting with “the worst headache of my life,” in the first 24 hours, CT is the study of choice, Dr. Mechtler said. According to the literature, the probability of recognizing a subarachnoid hemorrhage on CT during the first 24 hours is 95%. At 1 week post onset, that probability drops to 50%.

“Interestingly, FLAIR [fluid-attenuated inversion recovery] MRI has really changed our perception of subarachnoid hemorrhage,” he said. Recent studies have shown that FLAIR MRI is as sensitive as CT between 1 and 7 days. “After 4 or 5 days, FLAIR is probably even more sensitive than CT itself.”

Neuroimaging is very important in the diagnosis of carotid/vertebral arterial dissections, in which headache is the most common symptom. “But this headache has no classic symptoms,” Dr. Mechtler said.

This condition is relatively rare, occurring in only 3 of 100,000 carotid dissections and 1.5 of 100,000 vertebral dissections. There are multiple causes, which include an underlying arteriopathy (Ehlers-Danlos and Marfan syndromes); fibromuscular dysplasia; minor trauma, hyperextension, or rotation of the neck; major trauma or sports injuries; and possibly even chiropractic manipulations.

In vertebral dissections, the headache usually precedes neurologic symptoms by about 15 hours. Neck pain is also common in these patients, and there is the possibility of a brain stem infarct, as well. “Any time you have neck pain [or] headaches, and the patient might have a risk factor, consider dissection in your differential diagnosis,” Dr. Mechtler said.

MRI of possible dissections involves the use of special fat-suppression protocols that allow visualization of the double lumen. Magnetic resonance angiography has been very useful in the diagnosis of dissections, particularly vertebral artery dissections, he said.

Cerebral venous thrombosis can have several variations. The classic CT scan sign is the empty delta sign, Dr. Mechtler said. The sign consists of a triangular area of enhancement or high attenuation with a relatively low-attenuating center on multiple contiguous transverse CT images obtained in the region of the superior sagittal sinus.

It's not uncommon for the findings to consist of an atypical arterial distribution vascular event. Often, this type of case is sent on to a neurooncologist for evaluation of a possible glioblastoma multiforme.

Most adult patients with intracranial neoplasms don't have headaches initially. “It's a myth that brain tumors cause headaches often,” Dr. Mechtler said. Headache is present in only about 50% of cases of intracranial neoplasm.

Headache frequently does occur when there is a mass in the posterior fossa or around the meninges, he said.

In children, though, headaches are associated with intracranial neoplasms–two-thirds of childhood tumors are intratentorial.

When a glioblastoma multiforme spreads across the corpus callosum to the contralateral side, a butterfly shape can be seen on a coronal view MRI. Dr. Mechtler also noted that headaches are associated with glioblastoma multiforme when subependymal spread can be seen on MRI.

To diagnose subarachnoid hemorrhage, CT imaging (A) done within 24 hours of headache is the study of choice, compared with MR T1- (B) and T2- (C) weighted images. Red arrow points to blood within the sylvian fissure. FLAIR image (D) is as sensitive as CT between 24 and 72 hours and more sensitive after 72 hours. Yellow arrow points to blood. Normal FLAIR (E) also shown. Courtesy Dr. Laszlo L. Mechtler

ORLANDO, FLA. — Neuroimaging can make a big difference in the care of AIDS patients, who are vulnerable to several opportunistic diseases, one expert said at the annual meeting of the American Society of Neuroimaging.

James G. Smirniotopoulos, M.D., chairman of radiology at the Uniformed Services University of the Health Sciences in Bethesda, Md., noted that AIDS patients are vulnerable to both infectious and neoplastic opportunistic diseases. Neuroimaging is indicated in any AIDS patients who manifest:

▸ Mental status changes.

▸ Neurologic deficits.

▸ Seizures (focal or generalized).

▸ Headaches.

▸ Meningeal signs.

There are some cautions, though. AIDS patients typically have depression and other psychological conditions as a result of their situation; these should be separated out from genuinely neurologic causes.

In addition, in a substance-abuse population, seizures can be the result of substance withdrawal. Lastly, when AIDS patients complain of headaches, their immune status can determine the type of imaging used. For patients with very suppressed CD4 counts (less than 200 cells/μL), get a CT scan. If the count is mildly suppressed (greater than 200 cells/μL), get an MRI.

Once AIDS patients have been imaged, Dr. Smirniotopoulos and his colleagues triage them based on whether they have normal imaging results, atrophy, lesions without mass effect, or mass lesions.

He warned that several conditions can spuriously give an appearance of atrophy, including malnutrition, dehydration, steroid use, and long-term renal dialysis.

AIDS encephalopathy can also appear as atrophy. On images, this condition typically appears as bilateral white matter volume loss that can be symmetrical or not. “This is a disease process that is destructive of the parenchyma, but there's a lot of debate about what's really going on,” Dr. Smirniotopoulos said.

Progressive multifocal leukoencephalopathy (PML) is a lesion that has geographic signal and density abnormalities but without a mass effect. This lesion usually does not show any effect when enhanced using gadolinium. PML is a demyelinating white matter disease. On images, look for big geographic lesions that come right up to the gray matter and stop, Dr. Smirniotopoulos said.

The lesions are the result of infection with the ubiquitous JC papovavirus. As many as 70% of adults have antibodies to this virus, and almost 20% of patients with AIDS express antigens. PML is responsible for about 4% of AIDS deaths. Mortality is high in these patients. In the past, most patients with PML died within 4–6 months of diagnosis. Zidovudine and other antiretroviral drugs have improved survival only somewhat.

The two most common mass lesions seen on images in patients with AIDS are from primary infections and CNS lymphomas—with toxoplasmosis being the most common of the infections. “Toxoplasmosis is still probably what we think about first and foremost when an AIDS patient has a mass lesion,” Dr. Smirniotopoulos said.

If toxoplasmosis is suspected, try empiric therapy for 3 weeks. If any of the lesions fail to respond, it's time to get a biopsy, he said. The infection results primarily in paracentral brain abscesses. “Abscesses in toxoplasmosis tend to be relatively deep rather than being peripheral,” he said. The abscesses can be in gray or white matter. Abscesses are round, uniformly convex with smooth, thin walls and are often multifocal.

It can be difficult to distinguish between a toxoplasmosis infection and lymphoma. “Lesions that involve the deep white matter and the deep gray matter at the same time might be CNS lymphoma or toxoplasmosis, and the problem is that both of these diseases occur in immunosuppressed patients,” Dr. Smirniotopoulos said.

The good news is that in most cases—roughly five out of six—primary CNS lymphoma has distinguishing features on imaging that allow diagnosis. Lymphoma is a small round tumor with densely packed cells that result in hyperattenuation on a noncontrast scan.

CNS lymphomas are usually primary, non-Hodgkin's, and B cell. Primary lymphoma is usually paracentral, hugging the ventricles. “Very commonly, [CNS lymphomas are] going to be hypointense to gray matter on multiple pulse sequences,” Dr. Smirniotopoulos said.

ORLANDO, FLA. — Neuroimaging can make a big difference in the care of AIDS patients, who are vulnerable to several opportunistic diseases, one expert said at the annual meeting of the American Society of Neuroimaging.

James G. Smirniotopoulos, M.D., chairman of radiology at the Uniformed Services University of the Health Sciences in Bethesda, Md., noted that AIDS patients are vulnerable to both infectious and neoplastic opportunistic diseases. Neuroimaging is indicated in any AIDS patients who manifest:

▸ Mental status changes.

▸ Neurologic deficits.

▸ Seizures (focal or generalized).

▸ Headaches.

▸ Meningeal signs.

There are some cautions, though. AIDS patients typically have depression and other psychological conditions as a result of their situation; these should be separated out from genuinely neurologic causes.

In addition, in a substance-abuse population, seizures can be the result of substance withdrawal. Lastly, when AIDS patients complain of headaches, their immune status can determine the type of imaging used. For patients with very suppressed CD4 counts (less than 200 cells/μL), get a CT scan. If the count is mildly suppressed (greater than 200 cells/μL), get an MRI.

Once AIDS patients have been imaged, Dr. Smirniotopoulos and his colleagues triage them based on whether they have normal imaging results, atrophy, lesions without mass effect, or mass lesions.

He warned that several conditions can spuriously give an appearance of atrophy, including malnutrition, dehydration, steroid use, and long-term renal dialysis.

AIDS encephalopathy can also appear as atrophy. On images, this condition typically appears as bilateral white matter volume loss that can be symmetrical or not. “This is a disease process that is destructive of the parenchyma, but there's a lot of debate about what's really going on,” Dr. Smirniotopoulos said.

Progressive multifocal leukoencephalopathy (PML) is a lesion that has geographic signal and density abnormalities but without a mass effect. This lesion usually does not show any effect when enhanced using gadolinium. PML is a demyelinating white matter disease. On images, look for big geographic lesions that come right up to the gray matter and stop, Dr. Smirniotopoulos said.

The lesions are the result of infection with the ubiquitous JC papovavirus. As many as 70% of adults have antibodies to this virus, and almost 20% of patients with AIDS express antigens. PML is responsible for about 4% of AIDS deaths. Mortality is high in these patients. In the past, most patients with PML died within 4–6 months of diagnosis. Zidovudine and other antiretroviral drugs have improved survival only somewhat.

The two most common mass lesions seen on images in patients with AIDS are from primary infections and CNS lymphomas—with toxoplasmosis being the most common of the infections. “Toxoplasmosis is still probably what we think about first and foremost when an AIDS patient has a mass lesion,” Dr. Smirniotopoulos said.

If toxoplasmosis is suspected, try empiric therapy for 3 weeks. If any of the lesions fail to respond, it's time to get a biopsy, he said. The infection results primarily in paracentral brain abscesses. “Abscesses in toxoplasmosis tend to be relatively deep rather than being peripheral,” he said. The abscesses can be in gray or white matter. Abscesses are round, uniformly convex with smooth, thin walls and are often multifocal.

It can be difficult to distinguish between a toxoplasmosis infection and lymphoma. “Lesions that involve the deep white matter and the deep gray matter at the same time might be CNS lymphoma or toxoplasmosis, and the problem is that both of these diseases occur in immunosuppressed patients,” Dr. Smirniotopoulos said.

The good news is that in most cases—roughly five out of six—primary CNS lymphoma has distinguishing features on imaging that allow diagnosis. Lymphoma is a small round tumor with densely packed cells that result in hyperattenuation on a noncontrast scan.

CNS lymphomas are usually primary, non-Hodgkin's, and B cell. Primary lymphoma is usually paracentral, hugging the ventricles. “Very commonly, [CNS lymphomas are] going to be hypointense to gray matter on multiple pulse sequences,” Dr. Smirniotopoulos said.

ORLANDO, FLA. — Neuroimaging can make a big difference in the care of AIDS patients, who are vulnerable to several opportunistic diseases, one expert said at the annual meeting of the American Society of Neuroimaging.

James G. Smirniotopoulos, M.D., chairman of radiology at the Uniformed Services University of the Health Sciences in Bethesda, Md., noted that AIDS patients are vulnerable to both infectious and neoplastic opportunistic diseases. Neuroimaging is indicated in any AIDS patients who manifest:

▸ Mental status changes.

▸ Neurologic deficits.

▸ Seizures (focal or generalized).

▸ Headaches.

▸ Meningeal signs.

There are some cautions, though. AIDS patients typically have depression and other psychological conditions as a result of their situation; these should be separated out from genuinely neurologic causes.

In addition, in a substance-abuse population, seizures can be the result of substance withdrawal. Lastly, when AIDS patients complain of headaches, their immune status can determine the type of imaging used. For patients with very suppressed CD4 counts (less than 200 cells/μL), get a CT scan. If the count is mildly suppressed (greater than 200 cells/μL), get an MRI.

Once AIDS patients have been imaged, Dr. Smirniotopoulos and his colleagues triage them based on whether they have normal imaging results, atrophy, lesions without mass effect, or mass lesions.

He warned that several conditions can spuriously give an appearance of atrophy, including malnutrition, dehydration, steroid use, and long-term renal dialysis.

AIDS encephalopathy can also appear as atrophy. On images, this condition typically appears as bilateral white matter volume loss that can be symmetrical or not. “This is a disease process that is destructive of the parenchyma, but there's a lot of debate about what's really going on,” Dr. Smirniotopoulos said.

Progressive multifocal leukoencephalopathy (PML) is a lesion that has geographic signal and density abnormalities but without a mass effect. This lesion usually does not show any effect when enhanced using gadolinium. PML is a demyelinating white matter disease. On images, look for big geographic lesions that come right up to the gray matter and stop, Dr. Smirniotopoulos said.

The lesions are the result of infection with the ubiquitous JC papovavirus. As many as 70% of adults have antibodies to this virus, and almost 20% of patients with AIDS express antigens. PML is responsible for about 4% of AIDS deaths. Mortality is high in these patients. In the past, most patients with PML died within 4–6 months of diagnosis. Zidovudine and other antiretroviral drugs have improved survival only somewhat.

The two most common mass lesions seen on images in patients with AIDS are from primary infections and CNS lymphomas—with toxoplasmosis being the most common of the infections. “Toxoplasmosis is still probably what we think about first and foremost when an AIDS patient has a mass lesion,” Dr. Smirniotopoulos said.

If toxoplasmosis is suspected, try empiric therapy for 3 weeks. If any of the lesions fail to respond, it's time to get a biopsy, he said. The infection results primarily in paracentral brain abscesses. “Abscesses in toxoplasmosis tend to be relatively deep rather than being peripheral,” he said. The abscesses can be in gray or white matter. Abscesses are round, uniformly convex with smooth, thin walls and are often multifocal.

It can be difficult to distinguish between a toxoplasmosis infection and lymphoma. “Lesions that involve the deep white matter and the deep gray matter at the same time might be CNS lymphoma or toxoplasmosis, and the problem is that both of these diseases occur in immunosuppressed patients,” Dr. Smirniotopoulos said.

The good news is that in most cases—roughly five out of six—primary CNS lymphoma has distinguishing features on imaging that allow diagnosis. Lymphoma is a small round tumor with densely packed cells that result in hyperattenuation on a noncontrast scan.

CNS lymphomas are usually primary, non-Hodgkin's, and B cell. Primary lymphoma is usually paracentral, hugging the ventricles. “Very commonly, [CNS lymphomas are] going to be hypointense to gray matter on multiple pulse sequences,” Dr. Smirniotopoulos said.

LAKE BUENA VISTA, FLA. — Endovenous saphenous-vein obliteration with a 1,320-nm laser produces results comparable to those of radiofrequency, the preferred method, and better than those of 810-nm laser treatment, Girish Munavalli, M.D., said at the annual meeting of the American Society for Laser Medicine and Surgery.

Treatment with an 810-nm-diode laser uses that wavelength's hemoglobin specificity to essentially boil blood and transfer the heat to the vein wall, shrinking it. Radiofrequency (RF) treatment works by heating the vein wall to contract collagen. The 1,320-nm laser uses the water specificity of that wavelength to heat water and collagen in the vein wall to cause contraction, said Dr. Munavalli, a dermatologic surgeon affiliated with Johns Hopkins University, Baltimore.

In this retrospective study, 36 patients were treated with the 810-nm EVLT system (Diomed Inc.), 98 were treated with the 1,320-nm CTEV system (CoolTouch Inc.), and 224 were treated with RF using fast pullback at 90° C. The Closure Plus catheter (VNUS Medical Technologies Inc.) was used to facilitate closure in RF procedures. Endovenous occlusion was performed with single puncture under Duplex-guided tumescent anesthesia.

The 810-nm-laser procedure was performed using manual pullback; the 1,320-nm-laser procedure was performed using automatic pullback (1 mm/sec); and the RF procedure was guided by temperature feedback from the embedded thermocouple feedback loop. CoolTouch, Diomed, and VNUS provided discounted use of equipment for the study. Lead author Robert A. Weiss, M.D., receives consulting fees from CoolTouch and VNUS.

All treatments were evaluated using Duplex ultrasound at 1 day, 6 weeks, and 6 months post treatment.

Using the 810-nm laser, "we saw thickened vein walls on Duplex ultrasound," said Dr. Munavalli, also of the University of Maryland, Baltimore. With RF, "we frequently saw a double wall within the vein." With the 1,320-nm laser, "we actually observed complete retraction of the vein wall and disappearance of the lumen."

At 1-year follow-up, occlusion rates were 86%, 98%, and 92% for the 810-nm laser, 1,320-nm laser, and RF procedures, respectively. At 2 years, the rates were 82%, 96%, and 90%.

LAKE BUENA VISTA, FLA. — Endovenous saphenous-vein obliteration with a 1,320-nm laser produces results comparable to those of radiofrequency, the preferred method, and better than those of 810-nm laser treatment, Girish Munavalli, M.D., said at the annual meeting of the American Society for Laser Medicine and Surgery.

Treatment with an 810-nm-diode laser uses that wavelength's hemoglobin specificity to essentially boil blood and transfer the heat to the vein wall, shrinking it. Radiofrequency (RF) treatment works by heating the vein wall to contract collagen. The 1,320-nm laser uses the water specificity of that wavelength to heat water and collagen in the vein wall to cause contraction, said Dr. Munavalli, a dermatologic surgeon affiliated with Johns Hopkins University, Baltimore.

In this retrospective study, 36 patients were treated with the 810-nm EVLT system (Diomed Inc.), 98 were treated with the 1,320-nm CTEV system (CoolTouch Inc.), and 224 were treated with RF using fast pullback at 90° C. The Closure Plus catheter (VNUS Medical Technologies Inc.) was used to facilitate closure in RF procedures. Endovenous occlusion was performed with single puncture under Duplex-guided tumescent anesthesia.

The 810-nm-laser procedure was performed using manual pullback; the 1,320-nm-laser procedure was performed using automatic pullback (1 mm/sec); and the RF procedure was guided by temperature feedback from the embedded thermocouple feedback loop. CoolTouch, Diomed, and VNUS provided discounted use of equipment for the study. Lead author Robert A. Weiss, M.D., receives consulting fees from CoolTouch and VNUS.

All treatments were evaluated using Duplex ultrasound at 1 day, 6 weeks, and 6 months post treatment.

Using the 810-nm laser, "we saw thickened vein walls on Duplex ultrasound," said Dr. Munavalli, also of the University of Maryland, Baltimore. With RF, "we frequently saw a double wall within the vein." With the 1,320-nm laser, "we actually observed complete retraction of the vein wall and disappearance of the lumen."

At 1-year follow-up, occlusion rates were 86%, 98%, and 92% for the 810-nm laser, 1,320-nm laser, and RF procedures, respectively. At 2 years, the rates were 82%, 96%, and 90%.

LAKE BUENA VISTA, FLA. — Endovenous saphenous-vein obliteration with a 1,320-nm laser produces results comparable to those of radiofrequency, the preferred method, and better than those of 810-nm laser treatment, Girish Munavalli, M.D., said at the annual meeting of the American Society for Laser Medicine and Surgery.

Treatment with an 810-nm-diode laser uses that wavelength's hemoglobin specificity to essentially boil blood and transfer the heat to the vein wall, shrinking it. Radiofrequency (RF) treatment works by heating the vein wall to contract collagen. The 1,320-nm laser uses the water specificity of that wavelength to heat water and collagen in the vein wall to cause contraction, said Dr. Munavalli, a dermatologic surgeon affiliated with Johns Hopkins University, Baltimore.

In this retrospective study, 36 patients were treated with the 810-nm EVLT system (Diomed Inc.), 98 were treated with the 1,320-nm CTEV system (CoolTouch Inc.), and 224 were treated with RF using fast pullback at 90° C. The Closure Plus catheter (VNUS Medical Technologies Inc.) was used to facilitate closure in RF procedures. Endovenous occlusion was performed with single puncture under Duplex-guided tumescent anesthesia.

The 810-nm-laser procedure was performed using manual pullback; the 1,320-nm-laser procedure was performed using automatic pullback (1 mm/sec); and the RF procedure was guided by temperature feedback from the embedded thermocouple feedback loop. CoolTouch, Diomed, and VNUS provided discounted use of equipment for the study. Lead author Robert A. Weiss, M.D., receives consulting fees from CoolTouch and VNUS.

All treatments were evaluated using Duplex ultrasound at 1 day, 6 weeks, and 6 months post treatment.

Using the 810-nm laser, "we saw thickened vein walls on Duplex ultrasound," said Dr. Munavalli, also of the University of Maryland, Baltimore. With RF, "we frequently saw a double wall within the vein." With the 1,320-nm laser, "we actually observed complete retraction of the vein wall and disappearance of the lumen."

At 1-year follow-up, occlusion rates were 86%, 98%, and 92% for the 810-nm laser, 1,320-nm laser, and RF procedures, respectively. At 2 years, the rates were 82%, 96%, and 90%.

LAKE BUENA VISTA, FLA. — Treatment with an erbium:glass laser can safely reduce moderate to severe acne lesions by as much as 80% up to 1 year after therapy, according to the results of two studies presented at the annual meeting of the American Society for Laser Medicine and Surgery.

In the first study, 18 patients (15 women) had a baseline total of 275 lesions—77 comedones, 173 pustules and papules, and 25 nodules, said Sylvie Angel, M.D., of the Cabinet de Dermatologie in Paris. At 12 months' follow-up, only 20% of the baseline lesions remained (55 total lesions—24 comedones, 28 pustules and papules, and 3 nodules). At 6 months' follow-up, there were 87 total lesions—32 comedones, 52 pustules and papules, and 3 nodules.

"All patients observed that their skin was less prone to oiliness and reported quicker healing when new lesions appeared after the treatments," she said.

All the patients had acne—severity greater than 2 on the Burton scale—on the back (10 patients) or face (8 patients). All the patients had received standard acne therapies but were not satisfied by the results. Antibiotic and Accutane (isotretinoin) treatments were stopped 6 and 12 months, respectively, prior to this study. No other therapies were used during the study.

Dr. Angel and her colleagues used a 1,540-nm erbium:glass laser (Aramis, Quantel Medical) in combination with contact cooling set at 5° C. The protocol involved four pulses at 10 J/cm

On average, the patients rated pain during treatments at 1.4, based on a scale of 1-4. There were no adverse events, except for some transient edema and erythema.

Dr. Angel and her colleagues say they believe that the laser induces a thermal injury in the upper- to mid-dermis. Penetration depth has been shown to range between 200 and 900 μm—sebaceous gland depth. Contact cooling protects the dermis from thermal injury.

She suggested future studies be designed to find the ideal number of treatments.

In the second study, 15 patients with moderate to severe inflammatory acne of the face—grade 3 or higher on the Burton scale—were treated with an erbium:glass laser (Aramis, Quantel Medical), which has a 4-mm spot size and 3.3-ms pulse duration. Contact cooling was also used. Quantel Medical provided equipment and funding for the study.

"The treatment worked well for all types of inflammatory lesions," said Melissa A. Bogle, M.D., a practicing dermatologist in Chestnut Hill, Mass. As the treatment course progressed, patients had a steady decline in the total number of lesions. At 6 months, only 20% of the baseline lesions remained. There was essentially no change in sebum production, even though the patients reported that their skin felt less oily.

The patients were treated four times at 2-week intervals. The protocol consisted of first treating the active lesions using bursts of six pulses (10 J/cm

At the 6-month follow-up, improvement was more than 80%, as subjectively determined by the investigator. Patients felt their acne had improved by 70%.

Patients rated treatment on average at 2.25 on a scale of 1-4. Dr. Bogle noted that there was some minimal erythema that resolved in 5-10 minutes.

"I think the most exciting thing about it is that it's a relatively painless device," Dr. Bogle said.

A patient with inflammatory acne is shown prior to treatment with an erbium:glass laser.

The same patient is shown 1 month after receiving four laser treatments at 2-week intervals. Photos courtesy Dr. Melissa A. Bogle

LAKE BUENA VISTA, FLA. — Treatment with an erbium:glass laser can safely reduce moderate to severe acne lesions by as much as 80% up to 1 year after therapy, according to the results of two studies presented at the annual meeting of the American Society for Laser Medicine and Surgery.

In the first study, 18 patients (15 women) had a baseline total of 275 lesions—77 comedones, 173 pustules and papules, and 25 nodules, said Sylvie Angel, M.D., of the Cabinet de Dermatologie in Paris. At 12 months' follow-up, only 20% of the baseline lesions remained (55 total lesions—24 comedones, 28 pustules and papules, and 3 nodules). At 6 months' follow-up, there were 87 total lesions—32 comedones, 52 pustules and papules, and 3 nodules.

"All patients observed that their skin was less prone to oiliness and reported quicker healing when new lesions appeared after the treatments," she said.

All the patients had acne—severity greater than 2 on the Burton scale—on the back (10 patients) or face (8 patients). All the patients had received standard acne therapies but were not satisfied by the results. Antibiotic and Accutane (isotretinoin) treatments were stopped 6 and 12 months, respectively, prior to this study. No other therapies were used during the study.

Dr. Angel and her colleagues used a 1,540-nm erbium:glass laser (Aramis, Quantel Medical) in combination with contact cooling set at 5° C. The protocol involved four pulses at 10 J/cm

On average, the patients rated pain during treatments at 1.4, based on a scale of 1-4. There were no adverse events, except for some transient edema and erythema.

Dr. Angel and her colleagues say they believe that the laser induces a thermal injury in the upper- to mid-dermis. Penetration depth has been shown to range between 200 and 900 μm—sebaceous gland depth. Contact cooling protects the dermis from thermal injury.

She suggested future studies be designed to find the ideal number of treatments.

In the second study, 15 patients with moderate to severe inflammatory acne of the face—grade 3 or higher on the Burton scale—were treated with an erbium:glass laser (Aramis, Quantel Medical), which has a 4-mm spot size and 3.3-ms pulse duration. Contact cooling was also used. Quantel Medical provided equipment and funding for the study.

"The treatment worked well for all types of inflammatory lesions," said Melissa A. Bogle, M.D., a practicing dermatologist in Chestnut Hill, Mass. As the treatment course progressed, patients had a steady decline in the total number of lesions. At 6 months, only 20% of the baseline lesions remained. There was essentially no change in sebum production, even though the patients reported that their skin felt less oily.

The patients were treated four times at 2-week intervals. The protocol consisted of first treating the active lesions using bursts of six pulses (10 J/cm

At the 6-month follow-up, improvement was more than 80%, as subjectively determined by the investigator. Patients felt their acne had improved by 70%.

Patients rated treatment on average at 2.25 on a scale of 1-4. Dr. Bogle noted that there was some minimal erythema that resolved in 5-10 minutes.

"I think the most exciting thing about it is that it's a relatively painless device," Dr. Bogle said.

A patient with inflammatory acne is shown prior to treatment with an erbium:glass laser.

The same patient is shown 1 month after receiving four laser treatments at 2-week intervals. Photos courtesy Dr. Melissa A. Bogle

LAKE BUENA VISTA, FLA. — Treatment with an erbium:glass laser can safely reduce moderate to severe acne lesions by as much as 80% up to 1 year after therapy, according to the results of two studies presented at the annual meeting of the American Society for Laser Medicine and Surgery.

In the first study, 18 patients (15 women) had a baseline total of 275 lesions—77 comedones, 173 pustules and papules, and 25 nodules, said Sylvie Angel, M.D., of the Cabinet de Dermatologie in Paris. At 12 months' follow-up, only 20% of the baseline lesions remained (55 total lesions—24 comedones, 28 pustules and papules, and 3 nodules). At 6 months' follow-up, there were 87 total lesions—32 comedones, 52 pustules and papules, and 3 nodules.

"All patients observed that their skin was less prone to oiliness and reported quicker healing when new lesions appeared after the treatments," she said.

All the patients had acne—severity greater than 2 on the Burton scale—on the back (10 patients) or face (8 patients). All the patients had received standard acne therapies but were not satisfied by the results. Antibiotic and Accutane (isotretinoin) treatments were stopped 6 and 12 months, respectively, prior to this study. No other therapies were used during the study.

Dr. Angel and her colleagues used a 1,540-nm erbium:glass laser (Aramis, Quantel Medical) in combination with contact cooling set at 5° C. The protocol involved four pulses at 10 J/cm

On average, the patients rated pain during treatments at 1.4, based on a scale of 1-4. There were no adverse events, except for some transient edema and erythema.

Dr. Angel and her colleagues say they believe that the laser induces a thermal injury in the upper- to mid-dermis. Penetration depth has been shown to range between 200 and 900 μm—sebaceous gland depth. Contact cooling protects the dermis from thermal injury.

She suggested future studies be designed to find the ideal number of treatments.

In the second study, 15 patients with moderate to severe inflammatory acne of the face—grade 3 or higher on the Burton scale—were treated with an erbium:glass laser (Aramis, Quantel Medical), which has a 4-mm spot size and 3.3-ms pulse duration. Contact cooling was also used. Quantel Medical provided equipment and funding for the study.

"The treatment worked well for all types of inflammatory lesions," said Melissa A. Bogle, M.D., a practicing dermatologist in Chestnut Hill, Mass. As the treatment course progressed, patients had a steady decline in the total number of lesions. At 6 months, only 20% of the baseline lesions remained. There was essentially no change in sebum production, even though the patients reported that their skin felt less oily.

The patients were treated four times at 2-week intervals. The protocol consisted of first treating the active lesions using bursts of six pulses (10 J/cm

At the 6-month follow-up, improvement was more than 80%, as subjectively determined by the investigator. Patients felt their acne had improved by 70%.

Patients rated treatment on average at 2.25 on a scale of 1-4. Dr. Bogle noted that there was some minimal erythema that resolved in 5-10 minutes.

"I think the most exciting thing about it is that it's a relatively painless device," Dr. Bogle said.

A patient with inflammatory acne is shown prior to treatment with an erbium:glass laser.

The same patient is shown 1 month after receiving four laser treatments at 2-week intervals. Photos courtesy Dr. Melissa A. Bogle

LAKE BUENA VISTA, FLA. — An experimental light technique using pneumatic pressure treats unwanted hair, photodamage, and pigmented and vascular lesions with greater efficacy and safety than do comparable techniques, according to research presented at the annual meeting of the American Society for Laser Medicine and Surgery.

Photopneumatic pixilation combines vacuum pneumatic energy with a broadband light source, allowing four to five times the energy of other laser and light source techniques to be transmitted to the target area, said Vic A. Narurkar, M.D., a dermatologist practicing in San Francisco. As a result, lower wavelengths can be used.

The investigational device was provided by Aesthera Inc. Dr. Narurkar has equity in the company and is also on its medical advisory board.

The device works by switching from positive to negative pressure once in contact with the skin, essentially sucking the skin closer to the light source. "During this 2-second phase of vacuum application, the blood concentration and melanin concentrations are reduced. So theoretically, every skin type behaves as what I like to call skin type zero," Dr. Narurkar said.

In the instant that light is applied, fluences are about one-tenth what would be used with competitive technologies. As a result, there is very selective destruction of the targets. Finally the skin is released.

The treatment area is fairly large and the technique rapid, allowing treatment of the back in about 15 minutes and a hand in 2-3 minutes, Dr. Narurkar explained.

Dr. Narurkar said he has completed a 60-patient trial with promising results. Beta testing of the device is ongoing.

LAKE BUENA VISTA, FLA. — An experimental light technique using pneumatic pressure treats unwanted hair, photodamage, and pigmented and vascular lesions with greater efficacy and safety than do comparable techniques, according to research presented at the annual meeting of the American Society for Laser Medicine and Surgery.

Photopneumatic pixilation combines vacuum pneumatic energy with a broadband light source, allowing four to five times the energy of other laser and light source techniques to be transmitted to the target area, said Vic A. Narurkar, M.D., a dermatologist practicing in San Francisco. As a result, lower wavelengths can be used.

The investigational device was provided by Aesthera Inc. Dr. Narurkar has equity in the company and is also on its medical advisory board.

The device works by switching from positive to negative pressure once in contact with the skin, essentially sucking the skin closer to the light source. "During this 2-second phase of vacuum application, the blood concentration and melanin concentrations are reduced. So theoretically, every skin type behaves as what I like to call skin type zero," Dr. Narurkar said.

In the instant that light is applied, fluences are about one-tenth what would be used with competitive technologies. As a result, there is very selective destruction of the targets. Finally the skin is released.

The treatment area is fairly large and the technique rapid, allowing treatment of the back in about 15 minutes and a hand in 2-3 minutes, Dr. Narurkar explained.

Dr. Narurkar said he has completed a 60-patient trial with promising results. Beta testing of the device is ongoing.

LAKE BUENA VISTA, FLA. — An experimental light technique using pneumatic pressure treats unwanted hair, photodamage, and pigmented and vascular lesions with greater efficacy and safety than do comparable techniques, according to research presented at the annual meeting of the American Society for Laser Medicine and Surgery.

Photopneumatic pixilation combines vacuum pneumatic energy with a broadband light source, allowing four to five times the energy of other laser and light source techniques to be transmitted to the target area, said Vic A. Narurkar, M.D., a dermatologist practicing in San Francisco. As a result, lower wavelengths can be used.

The investigational device was provided by Aesthera Inc. Dr. Narurkar has equity in the company and is also on its medical advisory board.

The device works by switching from positive to negative pressure once in contact with the skin, essentially sucking the skin closer to the light source. "During this 2-second phase of vacuum application, the blood concentration and melanin concentrations are reduced. So theoretically, every skin type behaves as what I like to call skin type zero," Dr. Narurkar said.

In the instant that light is applied, fluences are about one-tenth what would be used with competitive technologies. As a result, there is very selective destruction of the targets. Finally the skin is released.

The treatment area is fairly large and the technique rapid, allowing treatment of the back in about 15 minutes and a hand in 2-3 minutes, Dr. Narurkar explained.

Dr. Narurkar said he has completed a 60-patient trial with promising results. Beta testing of the device is ongoing.

LAKE BUENA VISTA, FLA. — Laser lipolysis without fat suction appears safe and effective for the removal of small volumes of focal fat, according to data presented at the annual meeting of the American Society for Laser Medicine and Surgery.

Based on MRI, patients who underwent laser lipolysis alone showed an average of 17% reduction in fat, said Karen H. Kim, M.D., a dermatologist in New York. Those treated under the chin showed the greatest average loss (25%); other areas averaged a 13% reduction.

In this study, 10 patients were treated with laser lipolysis using a Nd-YAG laser (Cynosure Inc.), and 12 were treated with laser lipolysis and the Tri-Active therapeutic laser massage device (12 treatments). There were also 10 control volunteers. The patients had unwanted fat less than 120 cc in volume. Cynosure provided equipment and funding for the study.

Treatment involves the use of a 1,064-nm Nd:YAG laser with a 100-μm optic fiber and 1-mm microcannula. The low-power laser produces a photothermal effect when in contact with fat, Dr. Kim said. Treated fat was allowed to drain naturally in the patients. The Tri-Active device was used on 10 patients to facilitate drainage.

Of the 30 patients enrolled, 29 completed treatment. The area under the chin was the most commonly treated area. Total energy ranged from 758 J to more than 7,000 J. Greater energy was used at larger treatment sites, Dr. Kim said.

At 3 months, patients who received treatment considered the treated area to have improved 37% on average, based on observation.

For those treated with the Tri-Active device and for the laser lipolysis only group, the figures were 47% and 33%, respectively. The most common side effects were bruising, swelling, and tenderness.

The technique seems to be well suited for the treatment of focal areas of excess fat, Dr. Kim said. She and her colleagues are planning a larger multicenter trial using the technique.

This technique has been used in South America, Europe, and Japan. Previous studies have shown that it destroys more adipocytes than cannulation alone.

LAKE BUENA VISTA, FLA. — Laser lipolysis without fat suction appears safe and effective for the removal of small volumes of focal fat, according to data presented at the annual meeting of the American Society for Laser Medicine and Surgery.

Based on MRI, patients who underwent laser lipolysis alone showed an average of 17% reduction in fat, said Karen H. Kim, M.D., a dermatologist in New York. Those treated under the chin showed the greatest average loss (25%); other areas averaged a 13% reduction.

In this study, 10 patients were treated with laser lipolysis using a Nd-YAG laser (Cynosure Inc.), and 12 were treated with laser lipolysis and the Tri-Active therapeutic laser massage device (12 treatments). There were also 10 control volunteers. The patients had unwanted fat less than 120 cc in volume. Cynosure provided equipment and funding for the study.

Treatment involves the use of a 1,064-nm Nd:YAG laser with a 100-μm optic fiber and 1-mm microcannula. The low-power laser produces a photothermal effect when in contact with fat, Dr. Kim said. Treated fat was allowed to drain naturally in the patients. The Tri-Active device was used on 10 patients to facilitate drainage.

Of the 30 patients enrolled, 29 completed treatment. The area under the chin was the most commonly treated area. Total energy ranged from 758 J to more than 7,000 J. Greater energy was used at larger treatment sites, Dr. Kim said.

At 3 months, patients who received treatment considered the treated area to have improved 37% on average, based on observation.

For those treated with the Tri-Active device and for the laser lipolysis only group, the figures were 47% and 33%, respectively. The most common side effects were bruising, swelling, and tenderness.

The technique seems to be well suited for the treatment of focal areas of excess fat, Dr. Kim said. She and her colleagues are planning a larger multicenter trial using the technique.

This technique has been used in South America, Europe, and Japan. Previous studies have shown that it destroys more adipocytes than cannulation alone.

LAKE BUENA VISTA, FLA. — Laser lipolysis without fat suction appears safe and effective for the removal of small volumes of focal fat, according to data presented at the annual meeting of the American Society for Laser Medicine and Surgery.

Based on MRI, patients who underwent laser lipolysis alone showed an average of 17% reduction in fat, said Karen H. Kim, M.D., a dermatologist in New York. Those treated under the chin showed the greatest average loss (25%); other areas averaged a 13% reduction.

In this study, 10 patients were treated with laser lipolysis using a Nd-YAG laser (Cynosure Inc.), and 12 were treated with laser lipolysis and the Tri-Active therapeutic laser massage device (12 treatments). There were also 10 control volunteers. The patients had unwanted fat less than 120 cc in volume. Cynosure provided equipment and funding for the study.

Treatment involves the use of a 1,064-nm Nd:YAG laser with a 100-μm optic fiber and 1-mm microcannula. The low-power laser produces a photothermal effect when in contact with fat, Dr. Kim said. Treated fat was allowed to drain naturally in the patients. The Tri-Active device was used on 10 patients to facilitate drainage.

Of the 30 patients enrolled, 29 completed treatment. The area under the chin was the most commonly treated area. Total energy ranged from 758 J to more than 7,000 J. Greater energy was used at larger treatment sites, Dr. Kim said.

At 3 months, patients who received treatment considered the treated area to have improved 37% on average, based on observation.

For those treated with the Tri-Active device and for the laser lipolysis only group, the figures were 47% and 33%, respectively. The most common side effects were bruising, swelling, and tenderness.

The technique seems to be well suited for the treatment of focal areas of excess fat, Dr. Kim said. She and her colleagues are planning a larger multicenter trial using the technique.

This technique has been used in South America, Europe, and Japan. Previous studies have shown that it destroys more adipocytes than cannulation alone.

LAKE BUENA VISTA, FLA. — Potassium titanyl phosphate laser treatment can provide results comparable to and perhaps even better than intense pulsed light that is now considered the preferred method for treatment of photoaging, according to data presented at the annual meeting of the American Society for Laser Medicine and Surgery.

In a study designed to compare the two treatments, a 532-nm potassium titanyl phosphate (KTP) "green" laser (Gemini, made by Laserscope) with a 10-mm spot size was used to treat one side of the face, and intense pulsed light (Quantum SR, made by Lumenis) was used to treat the other side, said Girish Munavalli, M.D., a dermatologic surgeon at Johns Hopkins University in Baltimore. A total of 16 patients with diffuse redness and photoaging pigmentation (Fitzpatrick skin types I-IV) were treated.

The emission profile of the 532-nm KTP laser predicts very good absorption by hemoglobin and melanin. "In addition to the absorption spectrum, as you increase the spot size to 10 mm you get deeper penetration of this wavelength," Dr. Munavalli explained.

Treatment with the KTP laser lasted for 90-120 seconds at 7-9 J/cm

Dr. Munavalli has no financial interest in either of the devices used in this study.

Patients were evaluated at 1 week and at 1 month using a standardized scale (1-10) by the treating physician. Canfield stereotactic imaging was performed, and a physician blinded to the study evaluated these images.

At 1 week, physician evaluation rated the KTP treatment as producing an overall improvement in vascularity and pigmentation of 64%, compared with a 50% improvement for IPL. Patients rated the two treatments as producing overall improvements of 56% and 40%, respectively.

At 1 month, both sides were rated as producing an improvement of 50%. However, 14 of 16 patients opted for the KTP laser for subsequent treatments, preferring its efficacy, treatment times, and comfort. KTP induced slightly more erythema and edema at 10 and 24 hours posttreatment.

Stereotactic imaging resulted in equivalent if not slightly better reduction of the components of photoaging (lentigines, telangiectasias) with KTP, compared with IPL alone.

The Gemini laser can also be set for spot sizes between 1 and 5 mm, in 0.1-mm increments. In addition the KTP laser can be switched out with a 1,064-nm Nd:YAG laser.

The system has received Food and Drug Administration clearance for the treatment of acne, wrinkles, vascular and pigmented lesions, and hair removal.

LAKE BUENA VISTA, FLA. — Potassium titanyl phosphate laser treatment can provide results comparable to and perhaps even better than intense pulsed light that is now considered the preferred method for treatment of photoaging, according to data presented at the annual meeting of the American Society for Laser Medicine and Surgery.

In a study designed to compare the two treatments, a 532-nm potassium titanyl phosphate (KTP) "green" laser (Gemini, made by Laserscope) with a 10-mm spot size was used to treat one side of the face, and intense pulsed light (Quantum SR, made by Lumenis) was used to treat the other side, said Girish Munavalli, M.D., a dermatologic surgeon at Johns Hopkins University in Baltimore. A total of 16 patients with diffuse redness and photoaging pigmentation (Fitzpatrick skin types I-IV) were treated.

The emission profile of the 532-nm KTP laser predicts very good absorption by hemoglobin and melanin. "In addition to the absorption spectrum, as you increase the spot size to 10 mm you get deeper penetration of this wavelength," Dr. Munavalli explained.

Treatment with the KTP laser lasted for 90-120 seconds at 7-9 J/cm

Dr. Munavalli has no financial interest in either of the devices used in this study.

Patients were evaluated at 1 week and at 1 month using a standardized scale (1-10) by the treating physician. Canfield stereotactic imaging was performed, and a physician blinded to the study evaluated these images.

At 1 week, physician evaluation rated the KTP treatment as producing an overall improvement in vascularity and pigmentation of 64%, compared with a 50% improvement for IPL. Patients rated the two treatments as producing overall improvements of 56% and 40%, respectively.

At 1 month, both sides were rated as producing an improvement of 50%. However, 14 of 16 patients opted for the KTP laser for subsequent treatments, preferring its efficacy, treatment times, and comfort. KTP induced slightly more erythema and edema at 10 and 24 hours posttreatment.

Stereotactic imaging resulted in equivalent if not slightly better reduction of the components of photoaging (lentigines, telangiectasias) with KTP, compared with IPL alone.

The Gemini laser can also be set for spot sizes between 1 and 5 mm, in 0.1-mm increments. In addition the KTP laser can be switched out with a 1,064-nm Nd:YAG laser.

The system has received Food and Drug Administration clearance for the treatment of acne, wrinkles, vascular and pigmented lesions, and hair removal.

LAKE BUENA VISTA, FLA. — Potassium titanyl phosphate laser treatment can provide results comparable to and perhaps even better than intense pulsed light that is now considered the preferred method for treatment of photoaging, according to data presented at the annual meeting of the American Society for Laser Medicine and Surgery.

In a study designed to compare the two treatments, a 532-nm potassium titanyl phosphate (KTP) "green" laser (Gemini, made by Laserscope) with a 10-mm spot size was used to treat one side of the face, and intense pulsed light (Quantum SR, made by Lumenis) was used to treat the other side, said Girish Munavalli, M.D., a dermatologic surgeon at Johns Hopkins University in Baltimore. A total of 16 patients with diffuse redness and photoaging pigmentation (Fitzpatrick skin types I-IV) were treated.

The emission profile of the 532-nm KTP laser predicts very good absorption by hemoglobin and melanin. "In addition to the absorption spectrum, as you increase the spot size to 10 mm you get deeper penetration of this wavelength," Dr. Munavalli explained.

Treatment with the KTP laser lasted for 90-120 seconds at 7-9 J/cm

Dr. Munavalli has no financial interest in either of the devices used in this study.

Patients were evaluated at 1 week and at 1 month using a standardized scale (1-10) by the treating physician. Canfield stereotactic imaging was performed, and a physician blinded to the study evaluated these images.

At 1 week, physician evaluation rated the KTP treatment as producing an overall improvement in vascularity and pigmentation of 64%, compared with a 50% improvement for IPL. Patients rated the two treatments as producing overall improvements of 56% and 40%, respectively.

At 1 month, both sides were rated as producing an improvement of 50%. However, 14 of 16 patients opted for the KTP laser for subsequent treatments, preferring its efficacy, treatment times, and comfort. KTP induced slightly more erythema and edema at 10 and 24 hours posttreatment.

Stereotactic imaging resulted in equivalent if not slightly better reduction of the components of photoaging (lentigines, telangiectasias) with KTP, compared with IPL alone.

The Gemini laser can also be set for spot sizes between 1 and 5 mm, in 0.1-mm increments. In addition the KTP laser can be switched out with a 1,064-nm Nd:YAG laser.

The system has received Food and Drug Administration clearance for the treatment of acne, wrinkles, vascular and pigmented lesions, and hair removal.

NEW ORLEANS — Of all the factors that contribute to bone strength, the rate of turnover may be most clinically relevant, David Dempster, Ph.D., said at the annual meeting of the International Society for Clinical Densitometry.

At the same time, several recent advances may soon transform the way bone is assessed.

Bone turnover affects each and every one of the other variables that factor into bone strength, including structural factors and material properties, said Dr. Dempster, professor of clinical pathology at Columbia University, New York.

High bone turnover increases remodeling space, accelerates bone loss, disrupts the trabecular microarchitecture, increases mechanical stress concentration, decreases mineralization density, and increases cortical porosity, each of which can undermine bone strength, Dr. Dempster said.

When osteoclast activity exceeds osteoblast activity, there's a deficit on the surface of the trabeculae and within the cortex. “This may not amount to much in terms of bone mass … but I think that a small amount of missing bone may be important.” As bone mass declines, there is an exponential increase in fracture risk. “Simply by preventing a small amount of bone loss, you will prevent that patient from going up a steep slope in terms of fracture risk,” he said.

Another consequence of high turnover is the increase in the destruction of the trabecular microarchitecture. As bone turnover increases, there is a preferential loss of the horizontal trabeculae known as cross-ties, Dr. Dempster said.

“I'm talking about high turnover in a catabolic sense … where resorption exceeds formation.” This type of turnover occurs shortly after menopause or shortly after the introduction of glucocorticoids, said Dr. Dempster, who is also the director of the Regional Bone Center at the Helen Hayes Hospital in West Haverstraw, N.Y.

After menopause, a confluence of three phenomena can occur: a greater number of osteoclasts gather on the bone surface, osteoclasts become more efficient at breaking bone down, and the plates may become thinner. The result is that instead of sweeping across the trabecular surface—as with normal bone turnover—the osteoclasts tend to penetrate through the trabecular plate, leaving osteoblasts without a template for creating new bone. Supportive horizontal trabecular rods eventually become disconnected.

Mechanical stress concentration is another important element of bone strength. Osteoclast resorption cavities are the mechanical stress points. Without these cavities, intact trabeculae bend in response to stress but don't break. When resorption cavities are present, the same force will cause the trabeculae to break.

With high bone turnover, mineral density declines. While measuring bone mineral density (BMD) captures large-scale information on mineralization density, it doesn't provide information on the local distribution of minerals. Nor do conventional BMD measures provide information on the collagen-to-mineral ratio. Too much mineral makes bones brittle; too much collagen makes them weak.

So far, markers of bone turnover have been shown to be useful in the research setting, but they aren't ready for clinical use. Still, once they are ready, “I think that a BMD test coupled with a good measure of bone turnover in an individual patient would give you much more information than you currently have,” he said.

Improvements to turnover measurement are imminent, as more of these tests are incorporated into auto-analyzer formats. In addition, progress is being made in defining what the normal premenopausal range is for these markers.

“We [also] have some very good research going on looking at how we can assess microarchitecture noninvasively,” he said. Quantitative CT is starting to be used to assess bone strength in hip structural analysis. This technique not only measures BMD but also assesses the structural geometry of cross sections at specific locations of the hip. The evaluation of bone microarchitecture has benefited from the use of new techniques such as peripheral quantitative CT and high-resolution micro MRI.

In the past, bone microarchitecture has been hampered by the need to extract bone samples from volunteers and look at these samples under a powerful microscope. These new technologies give researchers an easier way to study a larger pool of volunteers.

NEW ORLEANS — Of all the factors that contribute to bone strength, the rate of turnover may be most clinically relevant, David Dempster, Ph.D., said at the annual meeting of the International Society for Clinical Densitometry.

At the same time, several recent advances may soon transform the way bone is assessed.

Bone turnover affects each and every one of the other variables that factor into bone strength, including structural factors and material properties, said Dr. Dempster, professor of clinical pathology at Columbia University, New York.

High bone turnover increases remodeling space, accelerates bone loss, disrupts the trabecular microarchitecture, increases mechanical stress concentration, decreases mineralization density, and increases cortical porosity, each of which can undermine bone strength, Dr. Dempster said.

When osteoclast activity exceeds osteoblast activity, there's a deficit on the surface of the trabeculae and within the cortex. “This may not amount to much in terms of bone mass … but I think that a small amount of missing bone may be important.” As bone mass declines, there is an exponential increase in fracture risk. “Simply by preventing a small amount of bone loss, you will prevent that patient from going up a steep slope in terms of fracture risk,” he said.

Another consequence of high turnover is the increase in the destruction of the trabecular microarchitecture. As bone turnover increases, there is a preferential loss of the horizontal trabeculae known as cross-ties, Dr. Dempster said.

“I'm talking about high turnover in a catabolic sense … where resorption exceeds formation.” This type of turnover occurs shortly after menopause or shortly after the introduction of glucocorticoids, said Dr. Dempster, who is also the director of the Regional Bone Center at the Helen Hayes Hospital in West Haverstraw, N.Y.

After menopause, a confluence of three phenomena can occur: a greater number of osteoclasts gather on the bone surface, osteoclasts become more efficient at breaking bone down, and the plates may become thinner. The result is that instead of sweeping across the trabecular surface—as with normal bone turnover—the osteoclasts tend to penetrate through the trabecular plate, leaving osteoblasts without a template for creating new bone. Supportive horizontal trabecular rods eventually become disconnected.

Mechanical stress concentration is another important element of bone strength. Osteoclast resorption cavities are the mechanical stress points. Without these cavities, intact trabeculae bend in response to stress but don't break. When resorption cavities are present, the same force will cause the trabeculae to break.

With high bone turnover, mineral density declines. While measuring bone mineral density (BMD) captures large-scale information on mineralization density, it doesn't provide information on the local distribution of minerals. Nor do conventional BMD measures provide information on the collagen-to-mineral ratio. Too much mineral makes bones brittle; too much collagen makes them weak.

So far, markers of bone turnover have been shown to be useful in the research setting, but they aren't ready for clinical use. Still, once they are ready, “I think that a BMD test coupled with a good measure of bone turnover in an individual patient would give you much more information than you currently have,” he said.

Improvements to turnover measurement are imminent, as more of these tests are incorporated into auto-analyzer formats. In addition, progress is being made in defining what the normal premenopausal range is for these markers.

“We [also] have some very good research going on looking at how we can assess microarchitecture noninvasively,” he said. Quantitative CT is starting to be used to assess bone strength in hip structural analysis. This technique not only measures BMD but also assesses the structural geometry of cross sections at specific locations of the hip. The evaluation of bone microarchitecture has benefited from the use of new techniques such as peripheral quantitative CT and high-resolution micro MRI.

In the past, bone microarchitecture has been hampered by the need to extract bone samples from volunteers and look at these samples under a powerful microscope. These new technologies give researchers an easier way to study a larger pool of volunteers.

NEW ORLEANS — Of all the factors that contribute to bone strength, the rate of turnover may be most clinically relevant, David Dempster, Ph.D., said at the annual meeting of the International Society for Clinical Densitometry.

At the same time, several recent advances may soon transform the way bone is assessed.

Bone turnover affects each and every one of the other variables that factor into bone strength, including structural factors and material properties, said Dr. Dempster, professor of clinical pathology at Columbia University, New York.

High bone turnover increases remodeling space, accelerates bone loss, disrupts the trabecular microarchitecture, increases mechanical stress concentration, decreases mineralization density, and increases cortical porosity, each of which can undermine bone strength, Dr. Dempster said.

When osteoclast activity exceeds osteoblast activity, there's a deficit on the surface of the trabeculae and within the cortex. “This may not amount to much in terms of bone mass … but I think that a small amount of missing bone may be important.” As bone mass declines, there is an exponential increase in fracture risk. “Simply by preventing a small amount of bone loss, you will prevent that patient from going up a steep slope in terms of fracture risk,” he said.

Another consequence of high turnover is the increase in the destruction of the trabecular microarchitecture. As bone turnover increases, there is a preferential loss of the horizontal trabeculae known as cross-ties, Dr. Dempster said.

“I'm talking about high turnover in a catabolic sense … where resorption exceeds formation.” This type of turnover occurs shortly after menopause or shortly after the introduction of glucocorticoids, said Dr. Dempster, who is also the director of the Regional Bone Center at the Helen Hayes Hospital in West Haverstraw, N.Y.

After menopause, a confluence of three phenomena can occur: a greater number of osteoclasts gather on the bone surface, osteoclasts become more efficient at breaking bone down, and the plates may become thinner. The result is that instead of sweeping across the trabecular surface—as with normal bone turnover—the osteoclasts tend to penetrate through the trabecular plate, leaving osteoblasts without a template for creating new bone. Supportive horizontal trabecular rods eventually become disconnected.

Mechanical stress concentration is another important element of bone strength. Osteoclast resorption cavities are the mechanical stress points. Without these cavities, intact trabeculae bend in response to stress but don't break. When resorption cavities are present, the same force will cause the trabeculae to break.

With high bone turnover, mineral density declines. While measuring bone mineral density (BMD) captures large-scale information on mineralization density, it doesn't provide information on the local distribution of minerals. Nor do conventional BMD measures provide information on the collagen-to-mineral ratio. Too much mineral makes bones brittle; too much collagen makes them weak.

So far, markers of bone turnover have been shown to be useful in the research setting, but they aren't ready for clinical use. Still, once they are ready, “I think that a BMD test coupled with a good measure of bone turnover in an individual patient would give you much more information than you currently have,” he said.

Improvements to turnover measurement are imminent, as more of these tests are incorporated into auto-analyzer formats. In addition, progress is being made in defining what the normal premenopausal range is for these markers.

“We [also] have some very good research going on looking at how we can assess microarchitecture noninvasively,” he said. Quantitative CT is starting to be used to assess bone strength in hip structural analysis. This technique not only measures BMD but also assesses the structural geometry of cross sections at specific locations of the hip. The evaluation of bone microarchitecture has benefited from the use of new techniques such as peripheral quantitative CT and high-resolution micro MRI.

In the past, bone microarchitecture has been hampered by the need to extract bone samples from volunteers and look at these samples under a powerful microscope. These new technologies give researchers an easier way to study a larger pool of volunteers.

NEW ORLEANS — Of all the factors that contribute to bone strength, the rate of turnover may be most clinically relevant, David Dempster, Ph.D., said at the annual meeting of the International Society for Clinical Densitometry.

At the same time, several recent advances may soon transform the way bone is assessed.

Bone turnover affects each and every one of the other variables that factor into bone strength, including structural factors and material properties, said Dr. Dempster, professor of clinical pathology at Columbia University, New York.

High bone turnover increases remodeling space, accelerates bone loss, disrupts the trabecular microarchitecture, increases mechanical stress concentration, decreases mineralization density, and increases cortical porosity—each of which can undermine the strength of the bone, Dr. Dempster explained.

When osteoclast activity exceeds osteoblast activity, there's a deficit on the surface of the trabeculae and within the cortex. “This may not amount to much in terms of bone mass … but I think that a small amount of missing bone may be important.”

As bone mass declines, there is an exponential increase in fracture risk. “Simply by preventing a small amount of bone loss, you will prevent that patient from going up a steep slope in terms of fracture risk,” Dr. Dempster said.

Another consequence of high turnover is the increase in the destruction of the trabecular microarchitecture. As bone turnover increases, there is a preferential loss of the horizontal trabeculae known as cross-ties, Dr. Dempster said.

“I'm talking about high turnover in a catabolic sense … where resorption exceeds formation.” This type of turnover occurs shortly after menopause or shortly after the introduction of glucocorticoids, said Dr. Dempster, who is also the director of the Regional Bone Center at the Helen Hayes Hospital in West Haverstraw, N.Y.

After menopause, a confluence of three phenomena can occur: a greater number of osteoclasts gather on the bone surface, osteoclasts become more efficient at breaking bone down, and the plates may become thinner. The result is that instead of sweeping across the trabecular surface—as with normal bone turnover—the osteoclasts tend to penetrate through the trabecular plate, leaving osteoblasts without a template for creating new bone. Supportive horizontal trabecular rods eventually become disconnected.

Mechanical stress concentration is another important element of bone strength. Osteoclast resorption cavities are the mechanical stress points. Without these cavities, intact trabeculae bend in response to stress but do not break. When resorption cavities are present, the same force will cause the trabeculae to break.

With high bone turnover, mineral density declines. While measuring bone mineral density (BMD) captures large-scale information on mineralization density, it doesn't provide information on the local distribution of minerals. Nor do conventional BMD measures provide information on the collagen-to-mineral ratio. Too much mineral makes bones brittle; too much collagen makes them weak.

So far, markers of bone turnover have been shown to be useful in the research setting, but they aren't ready for clinical use. Still, once they are ready, “I think that a BMD test coupled with a good measure of bone turnover in an individual patient would give you much more information than you currently have,” Dr. Dempster said.

Improvements to turnover measurement are imminent, as more of these tests are incorporated into auto-analyzer formats. In addition, progress is being made in defining what the normal premenopausal range is for these markers.

“We [also] have some very good research going on looking at how we can assess microarchitecture noninvasively,” he said. Quantitative CT is starting to be used to assess bone strength in hip structural analysis. This technique not only measures BMD but it also assesses the structural geometry of cross-sections at specific locations of the hip. The evaluation of bone microarchitecture has benefited from the use of new techniques such as peripheral quantitative CT and high-resolution micro MRI.

In the past, bone microarchitecture has been hampered by the need to extract bone samples from volunteers and look at these samples under a powerful microscope. These new technologies give researchers an easier way to study a larger pool of volunteers.

The BMD scores for patient A (top) and patient B (bottom) are identical. But three-dimensional composites of the area from which structural biomarkers are derived (left) and axial MRI slices of the distal radius (right) reveal that patient A requires aggressive treatment, while patient B does not. Photos courtesy Dr. Felix Wehrli/University of Pennsylvania

NEW ORLEANS — Of all the factors that contribute to bone strength, the rate of turnover may be most clinically relevant, David Dempster, Ph.D., said at the annual meeting of the International Society for Clinical Densitometry.

At the same time, several recent advances may soon transform the way bone is assessed.

Bone turnover affects each and every one of the other variables that factor into bone strength, including structural factors and material properties, said Dr. Dempster, professor of clinical pathology at Columbia University, New York.

High bone turnover increases remodeling space, accelerates bone loss, disrupts the trabecular microarchitecture, increases mechanical stress concentration, decreases mineralization density, and increases cortical porosity—each of which can undermine the strength of the bone, Dr. Dempster explained.

When osteoclast activity exceeds osteoblast activity, there's a deficit on the surface of the trabeculae and within the cortex. “This may not amount to much in terms of bone mass … but I think that a small amount of missing bone may be important.”

As bone mass declines, there is an exponential increase in fracture risk. “Simply by preventing a small amount of bone loss, you will prevent that patient from going up a steep slope in terms of fracture risk,” Dr. Dempster said.

Another consequence of high turnover is the increase in the destruction of the trabecular microarchitecture. As bone turnover increases, there is a preferential loss of the horizontal trabeculae known as cross-ties, Dr. Dempster said.

“I'm talking about high turnover in a catabolic sense … where resorption exceeds formation.” This type of turnover occurs shortly after menopause or shortly after the introduction of glucocorticoids, said Dr. Dempster, who is also the director of the Regional Bone Center at the Helen Hayes Hospital in West Haverstraw, N.Y.

After menopause, a confluence of three phenomena can occur: a greater number of osteoclasts gather on the bone surface, osteoclasts become more efficient at breaking bone down, and the plates may become thinner. The result is that instead of sweeping across the trabecular surface—as with normal bone turnover—the osteoclasts tend to penetrate through the trabecular plate, leaving osteoblasts without a template for creating new bone. Supportive horizontal trabecular rods eventually become disconnected.

Mechanical stress concentration is another important element of bone strength. Osteoclast resorption cavities are the mechanical stress points. Without these cavities, intact trabeculae bend in response to stress but do not break. When resorption cavities are present, the same force will cause the trabeculae to break.

With high bone turnover, mineral density declines. While measuring bone mineral density (BMD) captures large-scale information on mineralization density, it doesn't provide information on the local distribution of minerals. Nor do conventional BMD measures provide information on the collagen-to-mineral ratio. Too much mineral makes bones brittle; too much collagen makes them weak.

So far, markers of bone turnover have been shown to be useful in the research setting, but they aren't ready for clinical use. Still, once they are ready, “I think that a BMD test coupled with a good measure of bone turnover in an individual patient would give you much more information than you currently have,” Dr. Dempster said.

Improvements to turnover measurement are imminent, as more of these tests are incorporated into auto-analyzer formats. In addition, progress is being made in defining what the normal premenopausal range is for these markers.

“We [also] have some very good research going on looking at how we can assess microarchitecture noninvasively,” he said. Quantitative CT is starting to be used to assess bone strength in hip structural analysis. This technique not only measures BMD but it also assesses the structural geometry of cross-sections at specific locations of the hip. The evaluation of bone microarchitecture has benefited from the use of new techniques such as peripheral quantitative CT and high-resolution micro MRI.

In the past, bone microarchitecture has been hampered by the need to extract bone samples from volunteers and look at these samples under a powerful microscope. These new technologies give researchers an easier way to study a larger pool of volunteers.

The BMD scores for patient A (top) and patient B (bottom) are identical. But three-dimensional composites of the area from which structural biomarkers are derived (left) and axial MRI slices of the distal radius (right) reveal that patient A requires aggressive treatment, while patient B does not. Photos courtesy Dr. Felix Wehrli/University of Pennsylvania

NEW ORLEANS — Of all the factors that contribute to bone strength, the rate of turnover may be most clinically relevant, David Dempster, Ph.D., said at the annual meeting of the International Society for Clinical Densitometry.

At the same time, several recent advances may soon transform the way bone is assessed.

Bone turnover affects each and every one of the other variables that factor into bone strength, including structural factors and material properties, said Dr. Dempster, professor of clinical pathology at Columbia University, New York.

High bone turnover increases remodeling space, accelerates bone loss, disrupts the trabecular microarchitecture, increases mechanical stress concentration, decreases mineralization density, and increases cortical porosity—each of which can undermine the strength of the bone, Dr. Dempster explained.

When osteoclast activity exceeds osteoblast activity, there's a deficit on the surface of the trabeculae and within the cortex. “This may not amount to much in terms of bone mass … but I think that a small amount of missing bone may be important.”

As bone mass declines, there is an exponential increase in fracture risk. “Simply by preventing a small amount of bone loss, you will prevent that patient from going up a steep slope in terms of fracture risk,” Dr. Dempster said.

Another consequence of high turnover is the increase in the destruction of the trabecular microarchitecture. As bone turnover increases, there is a preferential loss of the horizontal trabeculae known as cross-ties, Dr. Dempster said.

“I'm talking about high turnover in a catabolic sense … where resorption exceeds formation.” This type of turnover occurs shortly after menopause or shortly after the introduction of glucocorticoids, said Dr. Dempster, who is also the director of the Regional Bone Center at the Helen Hayes Hospital in West Haverstraw, N.Y.

After menopause, a confluence of three phenomena can occur: a greater number of osteoclasts gather on the bone surface, osteoclasts become more efficient at breaking bone down, and the plates may become thinner. The result is that instead of sweeping across the trabecular surface—as with normal bone turnover—the osteoclasts tend to penetrate through the trabecular plate, leaving osteoblasts without a template for creating new bone. Supportive horizontal trabecular rods eventually become disconnected.

Mechanical stress concentration is another important element of bone strength. Osteoclast resorption cavities are the mechanical stress points. Without these cavities, intact trabeculae bend in response to stress but do not break. When resorption cavities are present, the same force will cause the trabeculae to break.

With high bone turnover, mineral density declines. While measuring bone mineral density (BMD) captures large-scale information on mineralization density, it doesn't provide information on the local distribution of minerals. Nor do conventional BMD measures provide information on the collagen-to-mineral ratio. Too much mineral makes bones brittle; too much collagen makes them weak.

So far, markers of bone turnover have been shown to be useful in the research setting, but they aren't ready for clinical use. Still, once they are ready, “I think that a BMD test coupled with a good measure of bone turnover in an individual patient would give you much more information than you currently have,” Dr. Dempster said.

Improvements to turnover measurement are imminent, as more of these tests are incorporated into auto-analyzer formats. In addition, progress is being made in defining what the normal premenopausal range is for these markers.

“We [also] have some very good research going on looking at how we can assess microarchitecture noninvasively,” he said. Quantitative CT is starting to be used to assess bone strength in hip structural analysis. This technique not only measures BMD but it also assesses the structural geometry of cross-sections at specific locations of the hip. The evaluation of bone microarchitecture has benefited from the use of new techniques such as peripheral quantitative CT and high-resolution micro MRI.

In the past, bone microarchitecture has been hampered by the need to extract bone samples from volunteers and look at these samples under a powerful microscope. These new technologies give researchers an easier way to study a larger pool of volunteers.

The BMD scores for patient A (top) and patient B (bottom) are identical. But three-dimensional composites of the area from which structural biomarkers are derived (left) and axial MRI slices of the distal radius (right) reveal that patient A requires aggressive treatment, while patient B does not. Photos courtesy Dr. Felix Wehrli/University of Pennsylvania