|Front Page||NIH To Evaluate Role of MRI in Emergency Diagnosis of Heart
NIH and Suburban Hospital recently announced the start of a unique study to evaluate whether advanced magnetic resonance imaging (MRI) technology will improve the emergency diagnosis of heart attack and stroke, ultimately saving patients' lives.
"This is the first time that an MRI scanner will be used to diagnose heart disease soon after patients are admitted to a hospital emergency room," said NHLBI director Dr. Claude Lenfant, the lead NIH sponsor of the study. "We hope to learn whether this technology can more quickly and accurately identify heart attacks and strokes so patients can benefit from earlier treatment such as clot-busters."
The 4-year study is a collaborative research program between three NIH components NHLBI, NINDS and the Clinical Center and Suburban Hospital. The core tools of the new research program will be two specially designed MRI scanners, which will be housed in a new imaging facility at Suburban Hospital called the NIH-Suburban MRI Center, a Heart and Stroke Research and Care Program. The study will involve magnetic resonance imaging of approximately 75 percent of the several hundred patients admitted to Suburban's ER with chest pain or symptoms of possible stroke.
"This is the dawn of a wonderfully beneficial interaction between a government research institution and a private community hospital," said Dr. Gerald Fischbach, NINDS director. "This collaboration offers us a chance to deliver care and to reduce the burden of stroke and cardiovascular disease."
MRI scanners are noninvasive yet they create clear, detailed images of internal organs and structures and can rapidly evaluate blood flow/supply.
Of all the patients coming into a hospital emergency room with chest pain, only about 40 percent can be immediately diagnosed with heart attack using standard testing. The majority of patients must undergo a number of tests or further hospitalization to reach a conclusive diagnosis. MRI may shorten the time needed to evaluate cardiac patients accurately.
The timing of stroke diagnosis is equally critical. "The new MRI technology will allow us to immediately see the stroke as it is occurring in the brain, while the damage is potentially reversible," said Fischbach. "This offers us more hope of intervention and, with better understanding of the causes of stroke, we may ultimately learn ways to prevent stroke."
The three groups of cardiac patients who will receive MRIs include:
Patients with a definite heart attack. These patients will be treated with current state-of-the-art therapies such as a clot-busting drug or balloon angioplasty. MRI evaluation of these patients will occur after stabilization.
The stroke component of the study will be fully operational in fall 1999. Until that time, a pilot phase will be in effect. Dr. Steve Warach, chief of the NINDS section on stroke diagnostics and therapeutics, said the new program will help researchers address the many unanswered questions about stroke causes, diagnosis and treatment.
The NINDS research team will investigate the factors that cause brain damage in stroke as well as study promising new treatment approaches to see if brain damage can be reduced.
Currently, there is only one proven medicine to help victims of acute stroke, t-PA, a clot-dissolving drug that must be delivered to a patient in the hospital within 3 hours of the onset of stroke symptoms.
In order to determine whether patients are eligible for t-PA treatment, they must first have a CT scan, to see whether the stroke is ischemic (caused by a blockage) or hemorrhagic (caused by bleeding in the brain). If the stroke is ischemic, the patient may be eligible for treatment, but if the stroke is hemorrhagic, delivery of t-PA is dangerous because it can cause more bleeding. NINDS scientists will compare the effectiveness of MRI with CT scans in detecting acute hemorrhages. If MRI proves to be as good or better than CT for seeing blood, MRI alone will replace both tests in most stroke patients.
Another study will involve the development and testing of strategies to extend the "window of opportunity" for optimal stroke treatment beyond 3 hours. One strategy involves direct administration of medication into damaged brain tissue.
Scanned images from both the heart and stroke studies will be archived into a database along with clinical, laboratory and other information to keep track of patient results. This will yield a rich source of clinical information for future studies.
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