Biomedical Frontiers: Winter 1995, Vol.2, No.2
Neurointerventional Radiology

In the late 1960s, Dr. Sadek Hilal pioneered the use of catheters and dyes to detect and treat problems in the brain's vasculature. Through a shaft in the femoral artery of the leg, he placed a catheter containing a contrast dye and navigated north through the torso's blood vessels and up into the brain's circulation. X-rays of the dye during the voyage guided him.

Since March of 1992, Dr. John Pile-Spellman, associate professor of radiology and neurosurgery, has continued the tradition begun by Dr. Hilal, professor of radiology in neurological surgery. As director of one of the top four neurointerventional radiology centers in the country, Dr. Pile-Spellman coordinates a multidisciplinary team of physicians and nurses who perform around 300 to 350 neurointerventional procedures each year. Using the most advanced methods, the team treats a variety of complex cerebral vascular diseases including arteriovenous malformations and aneurysms, atherosclerotic diseases, tumors, and embolic or clotting diseases.

The team's largest proportion of cases, around 150 a year, involve rare AVMs. An AVM is an abnormal formation of blood vessels that can occur in the brain, spine, face, foot, and arms. Normally, arteries feed into a capillary bed that deposits the blood's nutrients and oxygen into tissues. Deoxygenated blood from the tissues then goes into the capillaries and veins. AVMs lack the capillary bed. Arterial blood flows directly into the veins at a high pressure causing the veins to enlarge and sometimes to bleed.

Unfortunately, doctors often cannot detect an AVM unless a vein bursts or if it causes symptoms such as a seizure. But sometimes AVMs are caught during an MRI of the brain.

AVMs are treated by stopping blood flow from the artery to the vein. The methods include surgery, radiation, embolization (a neurointerventional radiological method that uses glue or coils to block the blood flow), or a combination of procedures. When embolization is indicated, the procedure usually must be repeated two to three times, often followed by surgery to remove the occluded vasculature.

During the procedure, physicians find the region of the AVM through angiography and they inject a material that temporarily blocks blood flow in the brain. They perform neuropsychological tests to see if blood flow stoppage in the area affects mental function. If the patient isn't affected, Dr. Pile-Spellman uses a more permanent blocker, such as a glue or a coil. The glue part of the procedure requires split-second timing. After he applies the glue, an X-ray determines where the glue stuck to the vascular wall. Another series of neuropsychological tests measure mental function.

Neurointerventional procedures generally are done on an investigational basis. Part of Dr. Pile-Spellman's work is devoted to clinical research that continues to search for better glues, contrast dyes, catheters, and coils, as well as treating patients in the first few hours after of stroke.