Diagnostic accuracy of gray-scale analysis on B-mode ultrasound for identifying intraplaque hemorrhage and lipid-rich necrotic core in carotid plaques.

BACKGROUND

Intraplaque hemorrhage (IPH) and lipid-rich necrotic core (LRNC) are key markers of carotid plaque vulnerability and stroke risk. Though magnetic resonance imaging (MRI) can detect both, duplex ultrasound is more accessible and may identify echolucent plaque areas that correlate with IPH or LRNC. This study investigated whether quantitative ultrasound can predict the presence of IPH or LRNC in atherosclerotic carotid artery stenosis (CS).

METHODS

In this prospective single-center study, patients with moderate to severe asymptomatic or symptomatic CS underwent MR plaque imaging and quantitative ultrasound with color mapping. Echolucency was measured in various plaque areas using several gray-scale thresholds. IPH was defined as part of the LRNC. Receiver operating characteristic (ROC) curve analysis assessed the predictive value of ultrasound for MRI-detected IPH or LRNC.

RESULTS

Among 113 enrolled patients, 75 patients (mean age 75 years; 69% men; 40% with symptomatic CS) were included in the analysis. On MRI, 43 patients (57%) had LRNC, and 32 patients (43%) showed IPH in the index artery. In the group without IPH, LRNC status could not be scored for 19 index arteries. Echolucency of the plaque surface with a gray-scale value < 20 showed the strongest association with IPH, with an area under the ROC curve (AUC) of 0.58 (95% CI 0.43, 0.71) and a negative predictive value of 0.64 (95% CI 0.50, 0.69) for the presence of IPH (sensitivity 0.50, specificity 0.65). For LRNC without IPH, several thresholds yielded the best-performing AUC of 0.48 (95% CI 0.23, 0.73/0.74)

Conclusion

Quantitative ultrasound does not reliably predict the presence of IPH or LRNC, as detected by MRI, in patients with atherosclerotic internal CS.