Carotid IMT variability (IMTV): its design and validation in symptomatic vs. asymptomatic 142 Italian population

The carotid intima-media thickness (IMT) is a validated marker of cerebrovascular disease risk. This work presents a new parameter, the IMT variability (IMTV), and compares the IMT and IMTV in symptomatic and asymptomatic Italian patients. 142 patients were analyzed (age 59±11.2 years, 59% males), 42 of which suffered from TIA (transient ischemic attack) or minor stroke. The lumen-intima (LI) and media-adventitia (MA) interfaces were manually traced by a Reader, and automatically traced by an automated system (AutoEdge). These interfaces were then used to measure the IMT and IMTV along the carotid wall. Wilcoxon and Pearson correlation analyses were performed. There was about a 65% correlation between the manual and automated measurements of IMT. There was no statistical difference between the manual and automated IMTV measurements (Wilcoxon signed rank, p>0.7). The observed mean IMT for symptomatic patients (0.83±0.44 mm for Reader vs. 0.82±0.35 mm for AutoEdge) was higher compared to asymptomatic patients (0.78±0.45 mm for Reader vs. 0.74±0.30 mm for AutoEdge). The symptomatic IMTV was about 11% higher than the asymptomatic IMTV when using Reader tracings and 8% higher when using AutoEdge. AutoEdge was very accurate in measuring the IMT and IMTV both for symptomatic and asymptomatic patients. Results showed that the symptomatic subjects had comparable IMT with respect to asymptomatic subjects, but a higher IMTV value.