IN-VIVO DETECTION OF CAROTID PLAQUE THROMBUS BY ULTRASONIC TISSUE CHARACTERIZATION

The purpose of the study was to determine whether ultrasonic tissue ch aracterization could detect carotid plaque thrombus in, vivo. Patients undergoing carotid endarterectomy were examined preoperatively and th e ultrasonic tissue characterization findings were compared to those o f optical microscopy of the removed plaque specimens. Ten of 15 patien ts studied had plaque thrombus. Ultra-ultrasonic tissue characterizati on entailed an analysis of parameters obtained from the power spectrum of backscattered ultrasound signals. Data were obtained with a nomina l 10 MHz sector scanning transducer with an effective bandwidth of 3 t o 13 MHz. The parameters were the slope and intercept derived from the linear regression of the normalized spectrum and total power (log of the integrated power of the normalized spectrum over the effective ban dwidth). The combined effect of the three parameters was determined by discriminant function analysis and showed a significant difference (P < 0.05) between nonthrombus and plaque thrombus in a small sample of patients with advance carotid atherosclerosis. These parameters applie d singly could not provide such a distinction. Correct classification of carotid plaque thrombus using the multiple-parameter analysis revea led a sensitivity of 90%, specificity of 80%, and accuracy of 86.7%. T his study demonstrates that analysis utilizing a combination of multip le spectral parameters was able to detect carotid plaque thrombus in v ivo.