Journal of Ultrasound in Medicine, Vol 16, Issue 2 107-111, Copyright © 1997 by American Institute of Ultrasound in Medicine
In vivo detection of carotid plaque thrombus by ultrasonic tissue characterization
T. Noritomi, B. Sigel, V. Gahtan, V. Swami, J. Justin, E. Feleppa and K. Shirouzu
Department of Surgery, Allegheny University of the Health Sciences, Philadelphia, Pennsylvania 19129, USA.
The purpose of the study was to determine whether ultrasonic tissue
characterization could detect carotid plaque thrombus in vivo. Patients
undergoing carotid endarterectomy were examined preoperatively and the
ultrasonic tissue characterization findings were compared to those of
optical microscopy of the removed plaque specimens. Ten of 15 patients
studied had plaque thrombus. Ultra-ultrasonic tissue characterization
entailed an analysis of parameters obtained from the power spectrum of
backscattered ultrasound signals. Data were obtained with a nominal 10 MHz
sector scanning transducer with an effective bandwidth of 3 to 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 bandwidth). 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 applied singly could not provide such a
distinction. Correct classification of carotid plaque thrombus using the
multiple-parameter analysis revealed a sensitivity of 90%, specificity of
80%, and accuracy of 86.7%. This study demonstrates that analysis utilizing
a combination of multiple spectral parameters was able to detect carotid
plaque thrombus in vivo.
