“Most standard ultrasound machines are at hospitals or a lab, and they are expensive to operate,” says Ulf Schminke, M.D., lead author of the study and research fellow at Wake Forest University in Winston-Salem, North Carolina. “So it’s not a convenient screening tool if you have to send patients to a private laboratory or a hospital for an examination.”
The portable device Schminke’s team used, SonoSite 180, is commercially available and costs about $18,000 to $20,000. Schminke estimates that stationary laboratory ultrasound machines cost more than $100,000.
Researchers investigated how to make ultrasonography cheaper and faster to screen carotid arteries with ultrasound for stroke prevention. The lightweight ultrasound is commonly used for abdominal examinations rather than vascular screening.
Researchers screened 102 carotid arteries in 51 patients. While a normal laboratory ultrasound measured the speed of blood flow in the arteries, the portable device was used to take two different views of the arteries: a diameter measurement and a cross-sectional view. The average examination time with the portable device was 8.8 minutes. A standard laboratory ultrasound may take 30 minutes or longer, says Schminke.
They compared the accuracy of the portable device to that of a laboratory ultrasound and found that the portable ultrasound was 89.7 percent accurate in detecting stenoses (blockages) greater than 75 percent of the vessel. The portable device was also accurate (83.8 percent) at detecting stenoses of 50 percent or greater. Overall, the device’s accuracy was considered excellent for use as a primary prevention tool.
“If a patient is determined to have a high degree of stenosis with this device, they could then be referred for further testing and possibly surgery to unclog their carotid arteries,” says Schminke. “The idea of this type of screening is to find out which people are normal and which people may need a further workup.”