Diagnostic Imaging "In Review" Supplement
January 2000

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Power Doppler helps manage sickle cell cases

Power Doppler ultrasound is a valuable, cost-effective tool in assessing risk of stroke in patients with sickle cell anemia, offering a highly visual way to evaluate blood flow and arteries, according to research presented at the RSNA meeting.

Previous studies have shown that use of pulsed Doppler is valuable in detecting abnormal blood flow in children with sickle cell disease. Those with the most abnormal blood flows, characterized as 200 cm per second or higher, carry a 40% risk of stroke. Once those patients are identified, monthly blood transfusions can decrease that risk by 90%. But because the transfusions themselves can cause complications in young patients, it’s important to ensure that only those at highest risk are selected to receive them.

Power Doppler offers a higher edge of diagnostic confidence, according to Dr. Abe Malouf, an assistant professor of radiology at the University of Mississippi.

“Power Doppler is a quick, noninvasive test that can be easily learned,” he said. “The visual nature of the images means we have something we can show clinicians that demonstrates the abnormal flow. And that’s important, because they don’t want to start transfusing someone they don’t have to.”

In 126 pediatric sickle cell patients studied to date, with follow-up ranging between six and 18 months, 10 patients exhibited abnormalities. Eight of those patients underwent a subsequent MR angiography study that confirmed the power Doppler findings, and began a blood transfusion regime. Two patients suffered stroke, one of which was nonclinical.

“Percentages of patients with abnormal flow and risk of stroke are comparable to other, larger studies, so we know we are on the right track,” Malouf said. “What’s really important is that we are following these patients. So if we are wrong in terms of identifying flow, we are going to see a higher rate of stroke than we expect. We’ll just have to wait and see.”

—By Deborah R. Dakins