Inter-study reproducibility of 3D volume selective fast spin echo sequence for quantifying carotid artery wall volume in asymptomatic subjects.

PURPOSE To determine, in asymptomatic subjects, the inter-study reproducibility of a three-dimensional (3D) volume selective fast spin echo (FSE) cardiovascular magnetic resonance sequence for the assessment of carotid artery wall volume as a measure of atheroma burden. METHODS Inter-study reproducibility was evaluated in 16 asymptomatic volunteers (10 male, 6 female). Both carotid arteries were scanned twice with a median inter-scan time of 5 days. The images were acquired in cross-section, and the total carotid arterial wall volume (TWV) was calculated by subtraction of the total carotid lumen volume from the total outer carotid vessel volume. RESULTS The mean carotid T1-weighted TWV for the first and second scans was 828 and 821 mm(3), respectively (mean difference 7 mm(3), p=0.45). The standard deviation (S.D.) of the differences between the measurements was 38 mm(3) yielding an inter-study coefficient of variation of 4.6%. The time for each study was approximately 30 min. For the longitudinal evaluation of carotid atheroma burden with pharmacological intervention versus placebo, 32 subjects would enable a difference of 38 mm(3) to be detected with a significance level of 5% with 80% power. CONCLUSION Volumetric analysis with carotid CMR in asymptomatic subjects using a 3D volume-selective FSE is time-efficient with good inter-study reproducibility, and is well suited for longitudinal studies of carotid atheroma with reasonable sample sizes.