D. Recchia et Sa. Wickline, ULTRASONIC TISSUE CHARACTERIZATION OF BLOOD DURING STASIS AND THROMBOSIS WITH A REAL-TIME LINEAR-ARRAY BACKSCATTER IMAGING-SYSTEM, Coronary artery disease, 4(11), 1993, pp. 987-994
Background: The use of B-mode ultrasound in the diagnosis of thrombosi
s is still limited by problems that include transducer-related artifac
ts, the influence of system electronics on image formation, and the su
bjective nature of image interpretation. In this study we used a novel
quantitative vascular imaging method based on the measurement of ultr
asonic integrated backscatter to detect changes in the scattering from
blood under conditions of stasis and coagulation. Methods: Thrombi we
re created in excised sections of porcine aortae and imaged in a water
tank over 2 h with a clinical integrated backscatter imaging system e
quipped with a 7.5 MHz linear-array transducer. Similar backscatter im
aging was performed on anticoagulated whole blood that was allowed to
remain quiescent for 2 h. Imaging was also performed on anticoagulated
blood to which hetastarch was added to accelerate red cell aggregatio
n. Results: The integrated backscatter from thrombus increased by 19.4
+/- 2.1 dB from baseline. Blood that remained static but did not clot
showed an increase in integrated backscatter of 12.6 +/- 0.9 dB; this
increase was immediately and completely reversed by restirring. The a
ddition of hetastarch produced a marked increase in scattering of 29.0
+/- 1.6 dB, and this value also returned to baseline after the blood
was restirred. The increase in integrated backscatter after the additi
on of hetastarch was significantly greater than that observed for thro
mbosis, which in turn was greater than that for static blood. Conclusi
on: Quantitative integrated backscatter imaging of blood during stasis
and coagulation is feasible using a clinically applicable real-time i
ntegrated backscatter imager. Ultrasonic tissue characterization of th
rombi may provide data on thrombus age, composition, and stability, wh
ich may assist diagnosis and treatment.