Relation between B-mode Gray-scale Median and Clinical Features of Carotid Stenosis Vulnerability

Background: Vulnerability of the carotid plaque might be useful as a predictor for ischemic stroke risk. The gray-scale median (GSM) of the carotid plaque at B-mode imaging has been described as an objective tool to quantify vulnerability. However, its use is disputed in the published literature. This study sought to validate the GSM as a predictor for carotid plaque vulnerability. Methods: We included 89 consecutive patients (64 men; mean +/- SD age: 68 +/- 1 years) who were evaluated for carotid endarterectomy. The GSM was derived from preoperative B-mode images and related to the presence of clinical symptoms, the presence of ipsilateral infarction on neuroimaging, and to the number of intraoperative ipsilateral microemboli (ME) detected by transcranial Doppler ultrasonography. In addition, we combined the GSM with its standard deviation (GSM-SD), which we hypothesized to be a measure for plaque heterogeneity and thereby vulnerability. Results: B-mode imaging revealed a wide variety in GSM among all plaques (median: 36; range: 6-89). The GSM could not be related to cardiovascular risk factors and was not different between symptomatic and asymptomatic patients (37.8 +/- 8.9 vs 37.6 +/- 17.1; P = 0.97). The GSM of plaques in patients with ipsilateral ischemic lesions on neuroimaging did also not differ from plaques in patients without (36.0 +/- 14.6 vs 37.8 +/- 16.9; P = 0.64). Finally, no relation between GSM and the presence of intraoperative ME (Spearman correlation; n = 73; rho = 0.039; P = 0.75) was found. Combining GSM with its GSM-SD also could not identify more vulnerable plaques. Conclusions: No relation was found between the GSM and any clinical, radiologic, or intra-and postoperative neurologic phenomena. These data showed no additional value of the use of GSM in evaluating plaque vulnerability.