Diagnostic accuracy of gray-scale analysis on B-mode ultrasound for identifying intraplaque hemorrhage and lipid-rich necrotic core in carotid plaques.
Level 3 - non-randomized controlled study
Prospective diagnostic cohort study comparing index test against MRI reference standard
PubMed 41739643 · doi:10.1177/1358863X251410527
What was done
This prospective single-center diagnostic study evaluated whether quantitative gray-scale B-mode ultrasound can identify vulnerable carotid plaque features. Among 113 enrolled patients with moderate-to-severe symptomatic or asymptomatic carotid artery stenosis, 75 were included in the final analysis (mean age 75 years; 69% male; 40% symptomatic). Patients underwent carotid MR plaque imaging to identify intraplaque hemorrhage (IPH) and lipid-rich necrotic core (LRNC), alongside quantitative ultrasound with color mapping across several gray-scale thresholds and plaque regions. Diagnostic accuracy was determined via receiver operating characteristic (ROC) analysis.
What was found
On MRI, LRNC was present in 57% (43/75) and IPH in 43% (32/75) of analyzed arteries; LRNC could not be scored in 19 non-IPH arteries. Plaque surface echolucency with a gray-scale value < 20 had the highest association with IPH, producing an area under the ROC curve (AUC) of 0.58 (95% CI 0.43, 0.71), sensitivity of 0.50, specificity of 0.65, and a negative predictive value of 0.64 (95% CI 0.50, 0.69). For LRNC without IPH, the top-performing threshold achieved an AUC of 0.48 (95% CI 0.23, 0.73/0.74).
Why it matters
Quantitative gray-scale ultrasound metrics perform near chance level for identifying IPH and LRNC, confirming that standard B-mode echolucency cannot substitute for MRI in evaluating vulnerable carotid plaque features.
Limits
The sample size was small with substantial attrition (38 of 113 enrolled patients excluded), and 19 index arteries lacked interpretable LRNC status on MRI. The study was conducted at a single center and validated ultrasound against MRI rather than surgical histology.
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