Combination of tissue harmonic sonography, real-time spatial compound sonography and adaptive image processing technique for the detection of carotid plaques and intima-medial thickness.

BACKGROUND AND PURPOSE

Conventional sonography (CS) had many unwanted artifacts, which obscured the carotid artery lesions. We try to explore whether the combination of tissue harmonic imaging (THI), real-time spatial compound sonography (SCS), and adaptive image processing (AIP) techniques (CTX) could be a better way to reduce the artifacts in the carotid artery and enhance the visualization of its plaques and intima-medial thickness (IMT) than CS.

METHODS

Eighty-three patients who harbored IMT (73) and carotid plaques (19) with variable degrees of stenosis underwent scanning for which five different ultrasound techniques were performed for overall image quality, lesion conspicuity, and elimination of artifacts. Two observers, who were blinded to the imaging techniques, graded the different images. A Friedman test was used for multiple statistical comparisons between the five techniques. To make paired comparisons between different imaging modes, Wilcoxon's signed-rank test was used.

RESULTS

The mean Kappa score for the two independent observers was 0.812 (standard error, 0.021), and reflected moderate-to-high interobserver agreement. Combining SCS+THI+AIP (CTX) provided the best for overall image quality, lesion conspicuity, and elimination of undesired artifacts of carotid plaques whereas CS produced the worst quality (p<0.001). There were significant differences among the five techniques (p<0.001); however, there were no differences between SCS and THI on either image quality (p=0.417), lesion conspicuity (p=0.594), or elimination of artifact (p=0.064).

CONCLUSIONS

The combined technique of SCS, THI, and AIP may represent the optimal ultrasonic technique for the evaluation of the IMT and carotid plaque echomorphology.