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Enhanced Computed Tomography Scan Can Bring Precision to Stroke Evaluation in Hospitals

BOSTON, MA -- September 7, 2001 -- Researchers at Massachusetts General Hospital (MGH) have found a new way to evaluate acute strokes.

The imaging technique will allow physicians to quickly administer the appropriate treatment to a patient who has suffered a stroke or "brain attack." It will also help doctors better predict a patient's clinical outcome. The work, published in the September issue of Stroke, results from a collaboration between the Massachusetts General Hospital (MGH) neuroradiology and neurology departments.

"People are always looking for imaging tests to fine tune the selection of which patients get which treatments," says lead author Michael Lev, MD, of the MGH Department of Radiology. "Right now, there are very good magnetic resonance imaging, or MRI techniques, such as diffusion imaging. However, MRI is not universally available, and it's expensive."

The MGH-led group found that a special procedure using a computed tomography (CT) scan could be performed instead of MRI. "The beauty of this technique is that it can be done on a helical CT scanner, which most emergency rooms already have," says senior author Lee Schwamm, MD, associate director of the MGH Acute Stroke Service.

The procedure involves a type of contrast-enhanced head examination called a perfusion-weighted CT scan that allows physicians to simultaneously look at blood vessels and blood flow to tissues in the brain. "The scan gives us information about the physiology of what's going on during a stroke," says Dr. Lev.

The current study consisted of twenty-two patients who each had a stroke and appeared in the emergency room within six hours of symptom onset. The researchers performed perfusion-weighted CT scans of the brain prior to therapeutic angiography and found that the technique allowed them to accurately predict the final size of the stroke and the clinical outcome of each patient. "In the past, people thought of CT scans as being insensitive to the early changes seen in stroke," says Dr. Schwamm. "We've demonstrated here that, with subtle changes to current methods, the sensitivity of CT can be increased and we can anticipate the minimum size of the final stroke."

Dr. Schwamm adds that the technique may help physicians decide on the proper course of treatment for different stroke victims. Either a ruptured blood vessel or a clot can produce symptoms of a stroke, and there are different subtypes of stroke that are seen when a vessel is blocked by a clot.

Accurate diagnosis is of utmost importance, because current medications can cause more harm than good to patients who suffer a stroke due to a ruptured blood vessel or to those with vessel blockage who already have extensive brain injury at the time of treatment.

In addition, administering treatment as soon as possible is extremely important, because earlier medical intervention is associated with better clinical recovery. The earlier the medical intervention, the better chance of recovery. The new CT scanning technique will now allow emergency room physicians to treat stroke victims quickly and appropriately.

SOURCE: Massachusetts General Hospital

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