Carotid IMT variability (IMTV) and its validation in symptomatic versus asymptomatic Italian population: can this be a useful index for studying symptomaticity?

The carotid intima-media thickness (IMT) is a validated marker of cerebrovascular disease risk. This paper presents a new parameter, the IMT variability (IMTV), and compares it between symptomatic and asymptomatic patients taken from a cohort of Italian population. One hundred forty-two patients were analyzed (age 59 ± 112 years, 59% males), 42 of these patients suffered from TIA or minor stroke. The lumen-intima (LI) and media-adventitia (MA) interfaces of the far wall were manually traced by a Reader. We also used a computer-based automated system (called AutoEdge) to obtain the LI/MA interfaces. The LI/MA interfaces were used to measure the IMT and the IMTV along the distal wall of the common carotid artery. Wilcoxon and Pearson correlation analyses were performed. The agreement between the Reader's IMT and the AutoEdge IMT values was 98.7% for the symptomatic (0.83 ± 0.44 mm for Reader, 0.82 ± 0.35 mm for AutoEdge) and 94.9% for the asymptomatic patients (0.78 ± 0.45 mm for Reader, 0.74 ± 0.30 mm for AutoEdge). Correlation was 65% for symptomatic and 68% for asymptomatic patients, respectively. The IMT measured using AutoEdge was 1.2% lower compared to manual measurements in symptomatic population, while 5.12% lower in asymptomatic. The IMTV was 11% higher in symptomatic patients compared to asymptomatic when using manual delineations, 8% higher when using AutoEdge. There was no statistical difference between the manual and automated IMTV measurements (Wilcoxon signed rank, P > 0.7). We conclude that the IMT and IMTV values were very similar between Reader and AutoEdge software when studying symptomatic and asymptomatic patients in Italian population.