Correlation of Cerebrovascular Symptoms and Microembolic Signals With the Stratified Gray-Scale Median Analysis and Color Mapping of the Carotid Plaque

Background and Purpose—To determine whether a stratified gray-scale median (GSM) analysis of the carotid plaque combined with color mapping correlated better with the presence of neurological symptoms and microembolic signals (MES) than a whole plaque measurement. Methods—A total of 131 patients presenting 167 carotid stenoses between 30% and 99% were analyzed by ultrasound. Emboli detection was performed by transcranial Doppler. For each plaque, the GSM values at depth 0 mm (surface) and at one third (30) and one half (50) of the plaque thickness were compared with the values obtained for the whole plaque. The plaque pixels were mapped into 3 colors: red, yellow and green, depending on their GSM value. Results—Mean GSM values were lower among symptomatic plaques, but a statistically significant difference between values of the whole plaque and those of the surface was obtained only for MES stenoses (P0.01). In a proportional odds logistic regression model based on 4 subgroups with an increasing clinical risk (MES/symptoms; MES/ symptoms; MES/symptoms; ; MES/symptoms), low mean GSM values and the predominant red color at the surface were independent factors associated with the presence of symptoms or MES (P0.0005). Furthermore, compared with a whole plaque measurement, analysis of the surface values predicted systematically with a greater sensitivity and specificity (receiver operating characteristic curves) each one of these 4 subgroups. Conclusions—Low mean GSM values and predominance of the red color at the surface correlated with most of the symptomatic or MES stenoses. This combined approach should be further investigated in a longitudinal study. (Stroke. 2006;37:824-829.)