Interventional neuroradiologists in West Virginia University School of Medicine and Hospitals have carried out one of the largest studies involving 372 stroke patients on the utility of computed tomography (CT) perfusion imaging of the brain in determining and predicting stroke outcomes. The results of the study will help in identifying patients suited for treatment with either clot busting medicines or clot retrieval devices. The research assumes significance because it allows doctors to customise stroke treatments based on the degree of brain death, instead of relying solely on how soon or late a patient comes to the hospital after having stroke symptoms. According to the existing National Institutes of Health stroke guidelines, hospitals typically administer tPA (a clot-busting drug) to patients within a three-hour window of stroke onset. After six hours, it becomes too risky to administer even interarterial clot busting medicines, due to the risk of potentially deadly hemorrhage. But according to the research carried out by interventional neuroradiologists Jeff Carpenter and Ansaar Rai, assistant professors at the Department of Neurological Surgery of West Virginia University School of Medicine, the use of qualitative and quantitative imaging techniques such as CT perfusion and CT angiography could lead to saving of more lives and also minimise side effects--compared to the generalised application of arbitrary time windows of three hours to six hours. Speaking to Technical Insights about the technology, Jeff Carpenter explains, "The idea and technology behind this study are exactly the same as a normal CT scan using IV [intravenous] contrast dye. Basically, the CT scan gets brighter if there is contrast getting to the brain. The rate at which it gets brighter is linearly related to the blood flow. If no or little blood flow gets to an area of the brain it is either dead or miserable (alive but unable to function electrically as a normal brain cell). Using different parameters we believe that we can tell the difference." Elaborating further on its applications, Carpenter says, "The applications for this are innumerable. Primarily, it can allow stroke physicians to treat stroke victims confidently. They know it's a stroke. They also know the size of the stroke and if there is penumbra to save. Seeing the problem and having confidence in the diagnosis goes a long way in getting a physician to treat with clot busters. Knowing how much blood flow there is also allows for treatment decisions not based solely on the clock." The study is very accurate in determining the patients who would best benefit from treatment and who should not receive clot-busting drugs. It also allows radiologists to determine which portions of a stroke patient's brain are dead, and which portions are dying but capable of being salvaged, for them to decide the best course of treatment. "It is in most emergency departments in the [United States]. It uses existing CT scanners and most hospitals have special personnel that operate the CT in the hospital 24 hours a day. Other techniques such as MRI or PET [positron emission tomography] scanners either are not in all emergency departments or hospitals, or aren't staffed 24 hours a day, or are always busy. It's faster. It's already incorporated into all stroke treatment protocols (head CT) to exclude bleeding," says Carpenter explaining its utility and advantages over other technologies. CT perfusion imaging has been available for about five years, and Carpenter has been specifically working with GE and Siemens perfusion packages in this time frame. Details: Dr. Jeff Carpenter, M. D., Assistant Professor, Director, Interventional Neuroradiology, West Virginia University Department of Radiology PO Box 9235, Morgantown, WV 26506 Phone: 304-293-3091 Fax: 304-293-3899 E-mail: jcarpenter@hsc.wvu.edu To comment on this article, write to us at tiresearch@frost.com
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