June 28, 2013
An arteriovenous malformation (AVM) in the brain is a relatively rare condition – occurring in less that 1 percent of the population. It can, however, be neurologically morbid in young adults ages 15 to 20, who are at the greatest risk for hemorrhage and least likely to exhibit symptoms. About 2 to 4 percent of all AVMs each year hemorrhage.
An AVM’s tangled mass of blood vessels, which forms in utero, produces multiple direct connections between arteries and veins without the normal, intervening capillaries. Symptoms often are not present until later in life or until after the AVM ruptures.
A small number of congenital syndromes, such as Sturge-Weber, Rendu-Osler-Weber, ataxia telangiectasia, and Wyburn-Mason, are associated with AVMs. Once formed, extrinsic factors, such as arterial shunting, growth factors and intracranial hemorrhage, may alter the size and shape of an AVM.
The most common types of AVMs are:
January 26, 2012
In September, I co-authored this cover article in the Journal of Neurosurgery on the results of a study using ultrasound for the treatment of brain hemorrhage. The study involved 33 patients with spontaneous intracerebral hemorrhage who were screened for inclusion in a SNI clinical study known as “SLEUTH” (Safety of Lysis with Ultrasound in the Treatment of Intracerebral and Intraventricular Hemorrhage). You can the abstract and full text of the article or see background information on the study, and watch a related video on WebMD.
March 14, 2011
Since its introduction in 1982, transcranial doppler ultrasound (TCD) has evolved into a portable, multimodality, noninvasive method for real-time imaging of intracranial vasculature.
The detection of cerebral microemboli is among the more remarkable capabilities of TCD. Emboli create countable signals in the ultrasound display due to the higher reflection of sound waves compared to the blood cells. Experimental models have shown a high sensitivity and specificity for detection of a variety of substrates, including thrombotic, platelet and atheromatous emboli.
Microembolic signals (MES) within the intracranial vasculature are most frequently identified in patients with large-vessel atherosclerotic disease, such as carotid stenosis. They have also been reported in intracranial arterial stenosis, arterial dissection, cardiac disease and atheroaortic plaque. Additionally, they have been...