Medgadget was invited to the University of California, San Francisco Medical Center to witness a minimally invasive procedure to help a man with hereditary hemorrhagic telangiectasia (HHT). The disease causes irregular formation of blood vessels within the body, including the brain, which leads to a bunch of unusual symptoms ranging from nose bleeds to poor neurological function.
The patient, in his early 30’s, has suffered from symptoms of HHT since his late teens. Since then he’s had a number of surgeries, including the removal of a large part of his skull that became infected. Recently new symptoms, such as frequent and debilitating seizures, have appeared that have taken a toll on him. To further diagnose the problem he was referred to the specialists at the HHT Center of Excellence at UCSF, one of the few places in the U.S. that specializes in HHT.
Dr. Steven Hetts, an Associate Professor of Radiology at UCSF and Chief of Neuroradiology at San Francisco General Hospital, as well as a member of the Society of NeuroInterventional Surgery, was suspecting that the patient may have developed an arteriovenous malformation (AVM) within the brain. AVMs are large defects that connect arteries to veins directly, bypassing the capillary system and causing any of a series of problems. These lesions typically happen in larger organs in HHT patients (lungs, brain), and have been known to cause symptoms similar to what the patient was experiencing.
X-ray angiograms of the brain are often used to look for AVMs and actually spotting them requires high-end equipment, meticulous and steady procedural discipline, teamwork, and a keen eye when repeatedly looking at the images. Most importantly, years of experience develop a sense of what to look for and the associated intuition to spot abnormalities within a complex picture.
When we arrived into the catheterization lab the patient was already under anesthesia. Because the angiograms required the patient to hold his breath during image capture, he was kept under controlled MAC sedation. This lets the patient hear what’s going around him and to follow the frequent repeat instructions of “keep your eyes closed and hold your breath”.
Following sedation, a catheter is inserted at the groin and guided up the femoral artery toward the brain. It is used to deliver an X-ray contrast agent into the vasculature within the head. Snaking it up different branches of the vasculature allows for imaging of different parts of the brain. A dual C-arm fluoroscopy system from Siemens was used for imaging in two planes at the same time, which lets one understand the 3D nature of the vasculature being examined.
The process of navigating the catheter around, injecting the contrast agent, and taking images was done repeatedly by the surgical team that included Dr. Hetts at the helm, two radiologists in training, and a surgical tech. The anesthesiologist meanwhile kept the patient cruising, nearly asleep, but not quite, but neither really awake. About every ten minutes the patient was asked to not blink and to do a breath hold for about ten seconds as the contrast was injected and X-ray shots were taken.
The surgical team working directly on the patient standed behind a leaded glass shield and wore leaded suits as they guided the catheter around, keeping them safe from stray radiation coming off the X-ray source. For additional safety, during the imaging process they stepped out of the operating room as the X-ray made a series of high resolution exposures.
After each imaging process, Dr. Hetts reviewed the shots taken, looking for any signs of AVM lesions, changing contrast, zooming in and out, and considering where to look next. For better or worse, there were no AVMs discovered during this angiogram and there will have to be further studies done to diagnose the cause of the patient’s latest seizures and other medical troubles.
We spoke with patient’s parents who were hopeful about what doctors at UCSF will be able to do for him, and having struggled with managing the disease understand there are further challenges ahead.
We’re glad to see that doctors today have the capability of navigating through the brain using extremely narrow, flexible, slick, and strong guidewires and catheters while imaging the organ with impressive quality using advanced fluoroscopes. This being essentially a new field, we’re confident that there will be a lot more progress in the coming years in neuroradiology for addressing strokes, cancers, and other debilitating conditions. We’re glad to see the folks at UCSF are helping to lead that effort.
We’d like to thank the Society of NeuroInterventional Surgery for helping to organize this tour. According to the society, it was founded in 1992 as the American Society of Interventional and Therapeutic Neuroradiology (ASITN), the Society of NeuroInterventional Surgery (SNIS) is a scientific and educational association with over 600 members worldwide. The SNIS is dedicated to advancing the specialty of neurointerventional surgery in order to provide the highest quality of patient care to the public. SNIS draws its membership from three areas – interventional neuroradiology, endovascular neurosurgery and interventional neurology. It’s the bringing together of these three subspecialties under one umbrella that gives SNIS its diversity and strength.