MRI Combined with Echocardiography Improves Care and Helps Prevent Strokes

Using both magnetic resonance imaging (MRI) and echocardiography to image the heart significantly enhances the detection of the cause and selection of the best treatment of cardioembolic strokes, the deadliest type of stroke.

A cardioembolic stroke occurs when a thrombus (clot) dislodges from the heart, travels through the cardiovascular system and lodges in the brain, first cutting off the blood supply and then frequently causing a hemorrhagic bleed--a one-two punch of both types of stroke, ischemic first and then hemorrhagic.

The study revealed that MRI detected almost twice as many sources of stroke in the heart than echocardiogram alone. It also demonstrated the ability of MRI to show more heart disease disorders that contribute to clot formation in the first place. Echocardiography, however, was strong in the detection of heart valve lesions. Combined, these imaging systems can more clearly identify underlying causes of future stroke, helping clinicians decide the best initial therapy and the best treatment to prevent a secondary stroke. The study's results were presented on March 5, 2007, at the Society of Interventional Radiology's 32nd annual scientific meeting, held in Seattle, WA, USA.

"This can revolutionize patient care because we can detect the underlying cause of the stroke and prevent it from occurring again,” stated lead investigator John Sheehan, M.D., an interventional radiologist at Northwestern University (Evanston, IL, USA) and Northwestern Memorial Hospital (Chicago, IL, USA).

In the study, of the 93 patients who had an MRI and echocardiogram of their heart after a stroke, MRI detected nearly twice as many potential causes of stroke originating from the heart compared to echocardiography. MRI also detected significant heart conditions that predispose a patient to stroke in 30% of patients compared to echocardiography. These additional findings included acute myocardial infarction, myocardial scarring, and left ventricular aneurysms. Echocardiography was, however, more sensitive in detecting potential embolic lesions on prosthetic cardiac valves and strokes related to a hole in the heart.

There are two basic types of stroke: ischemic (blockage of an artery) or hemorrhagic (rupture of an artery). Approximately 80% of strokes are ischemic strokes. They occur when blood clots, plaque, or vegetation block arteries to the brain and result in damage. Ischemic strokes are either embolic or thrombotic.

The combination of MRI and echocardiography of the heart provides the optimal imaging assessment of stroke patients, according to the researchers, leading to improved detection of not only the potential source of the stroke, but the underlying cause.


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