(Movie of cranial vasculature)
Intracranial Vascular Disease is a major cause of death and disability throughout the world. Until the early 1990s, the only method for diagnosing disease in the intracranial arteries was the placement of a catheter through the skin, deep into an artery, passing the catheter into the arteries that feed blood into the head, and then injecting a mildly toxic contrast agent into the arteries to highlight the blood vessels in the head in a set of X-ray images. This procedure, when necessary, is considered to be relatively safe, having major adverse events (stroke, death, etc.) in only about 1 in 100 patients. However, even without a major event, the technique is invasive and often results in substantial patient discomfort including headaches and nausea.
Dennis L. Parker, Ph.D., (current director of UCAIR and holder of the Mark H. Huntsman Presidential Chair in diagnostic imaging) has been doing research in magnetic resonance imaging (MRI) since about 1980 when he was the first to try to use MRI to make images of temperature non-invasively. At a scientific meeting in about 1986, he remembers talking with two other MRI researchers about whether MRI would ever be used to image blood vessels and possibly replace the more dangerous and invasive X-ray techniques. Each agreed it highly unlikely. Yet, each turned their focus to the problem and within 3 years each, unaware of the work of the others, had developed their own novel techniques for MR angiography.
Paul Keller became a developer of a technique known as 2 dimensional time-of-flight (TOF) imaging. Petra Schmalbroch developed the complementary technique of 3D TOF imaging. And Dennis Parker developed a hybrid of the 2D and 3D techniques, known as Multiple Overlapping Thin Slab Acquisition or MOTSA, which he recognized would not suffer from problems inherent in 2D TOF and 3D TOF techniques. MOTSA has become a mainstay of head and neck blood vessel imaging at MRI centers throughout the world. Since that time Dr. Parker and his team of radiologists, graduate students, engineers, and technologists have continued his work to improve the quality of MR angiography. Since 1992 his group has received over $3 million in funding from the National Institutes of Health to study these techniques. Because of the work of this group, the University of Utah is known throughout the world as a center for the development of novel blood vessel imaging techniques. More importantly, these techniques are used on a daily basis to help radiologists detect and monitor intracranial blood vessel disease. Because these techniques do not require the injection of contrast agents or ionizing radiation, they are considered to be much safer than conventional X-ray angiography. This research led to a collaborative research project with Lisa Cannon-Albright , Ph.D., a professor medical informatics and a well known population geneticist. Dr. Cannon-Albright has been a pioneer in the use of genetic studies based upon family pedigrees. From her linking of death certificates and family pedigrees, Dr. Cannon-Albright was able to demonstrate that intracranial aneurysms have a strong genetic predisposition. Using the high resolution MRA techniques at the University, Dr. Cannon-Albright was able to study nearly 400 individuals in high risk families (individuals with close relatives with aneurysms). Intracranial aneurysms were found in 10% of those studied, compared to about 1 to 2% in the general public. From these studies, Dr. Cannon-Albrights group has identified a suspicious gene, but many more volunteers are needed to complete the localization of the genetic factors.