Intravascular thrombosis: definitive detection by quantitative tissue characterization in vitro.

To improve the sensitivity and reliability of the ultrasonic detection of intravascular thrombosis, we employed quantitative ultrasonic techniques for the analysis of thrombi induced in vitro. Citrated human blood or platelet-rich plasma was added to sections of canine thoracic aorta mounted vertically in a saline bath. CaCl2 and thrombin were then added to induce thrombosis. Ultrasonic integrated backscatter measured sequentially with a 10-MHz focused transducer exhibited more than a 10 dB increase in integrated backscatter when either whole blood or platelet-rich plasma was clotted (-61.7 dB to -47.4 dB whole blood; less than -70 dB to -52.8 dB platelet-rich plasma). Thus, large significant changes in integrated backscatter measured from structures within the arterial lumen were readily detectable and indicative of thrombosis in situ.