The National Institutes of Health (NIH) and Suburban Hospital in Bethesda, MD today 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 Dr. Claude Lenfant, director of the National Heart, Lung, and Blood Institute (NHLBI), 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," added Dr. Lenfant.
"The benefits to the health of our community will be extraordinary," said Dr. William Minogue, senior vice president for medical affairs at Suburban. "Suburban Hospital will be the only community hospital, and one of a small number of facilities in the world, with this level of imaging technology," he added.
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 accurately evaluate cardiac patients.
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 Dr. Gerald Fischbach, Director of the National Institute of Neurological Disorders and Stroke (NINDS), a co-sponsor of the study. "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 4-year study is a collaborative research program between three NIH components -- NHLBI, NINDS, and the Warren Grant Magnuson Clinical Center (CC) -- 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.
According to Dr. Robert Balaban, chief of NHLBI's Laboratory of Cardiac Energetics and Dr. Andrew Arai, NHLBI's lead investigator on the chest pain studies, three groups of cardiac patients will receive MRIs:
- Patients with a definite heart attack 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.
- For patients without a definite explanation for their chest pain, scientists hope to use the high quality image of MRI to rapidly identify which of these patients has unstable angina or a heart attack.
- Patients with a milder chest pain--possibly angina-- will be evaluated with MRI and traditional clinical evaluation.
The stroke component of the study will be fully operational in the fall of 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 stroke 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.