P1.02 In Vivo Quantification of Carotid Artery Wall Dimensions: 3.0 Tesla Mri Versus B-Mode Ultrasound Imaging

Abstract

Background

We compared 3.0 Tesla MRI (3T MRI)common carotid Mean Wall Thickness (MWT) to B-mode ultrasound (US) common carotid intima-media thickness (CCIMT) measurements.

Methods and Results

3T MRI and B-mode US scans of the left and right common carotid arteries were performed three times in 15 healthy younger volunteers (aged 26±2.6 years), 15 healthy older volunteers (aged 57±3.2 years) and 15 subjects with CVD and carotid atherosclerosis (aged 63 ± 9.8 years). MWT was 0.711(SD 0.229) mm; CCIMT was 0.800 (SD0.206)mm. MWT and CCIMT were highly correlated (r =0.89, p<0.001). ICC’s for inter-scan and inter- and intraobserver agreements of MRI MWT measurements were >0.95 with small confidence intervals. Power calculations indicated that 89 subjects per group are required to detect 4% difference in MRI MWT, compared to 469 subjects per group for a similar CCIMT change.

Conclusion

Carotid MRI MWT and ultrasound CCIMT measurements showed strong agreements. MRI showed smaller variability that may allow sample sizes and potentially shorter study duration in cardiovascular prevention trials.