Blood clot characterization by ultrasound Nakagami imaging

Abstract

Detection of blood clotting by ultrasound has been widely explored. Many ultrasonic quantitative parameters have been demonstrated to have the ability to characterize clot. This study proposes the ultrasound Nakagami image as a tool to visually characterize the properties of blood clot. Whole blood samples with a hematocrit of 40% were made. A 10-mL whole blood was placed in a tube and 1 mL of 0.2 mol/L CaCl2 solution was added to induce clotting. A 35-MHz focused transducer was used to scan the tube filled with blood before and after blood clot formation for Nakagami imaging. The results showed that whole blood and clot have similar textures in their B-scans, but the Nakagami image behaved well in distinguishing between blood and clot. The Nakagami image before clot formation is based on red-blue-interlaced shading, corresponding to Rayleigh distribution (the Nakagami parameter m approaches 1). However, the clot has more blue shadings in the Nakagami image, representing that the backscattered statistics of blood clot tends to be pre-Rayleigh distributed (m < 1). This study suggests that the Nakagami image may be used to characterize blood and clot for clinical studies and diagnosis.