Carotid magnetic resonance imaging for monitoring atherosclerotic plaque progression: a multicenter reproducibility study

Abstract

This study sought to determine the multicenter reproducibility of magnetic resonance imaging (MRI) and the compatibility of different scanner platforms in assessing carotid plaque morphology and composition. A standardized multi-contrast MRI protocol was implemented at 16 imaging sites (GE: 8; Philips: 8). Sixty-eight subjects (61 ± 8 years; 52 males) were dispersedly recruited and scanned twice within 2 weeks on the same magnet. Images were reviewed centrally using a streamlined semiautomatic approach. Quantitative volumetric measurements on plaque morphology (lumen, wall, and outer wall) and plaque tissue composition [lipid-rich necrotic core (LRNC), calcification, and fibrous tissue] were obtained. Inter-scan reproducibility was summarized using the within-subject standard deviation, coefficient of variation (CV) and intraclass correlation coefficient (ICC). Good to excellent reproducibility was observed for both morphological (ICC range 0.98-0.99) and compositional (ICC range 0.88-0.96) measurements. Measurement precision was related to the size of structures (CV range 2.5-4.9 % for morphology, 36-44 % for LRNC and calcification). Comparable measurement variability was found between the two platforms on both plaque morphology and tissue composition. In conclusion, good to excellent inter-scan reproducibility of carotid MRI can be achieved in multicenter settings with comparable measurement precision between platforms, which may facilitate future multicenter endeavors that use serial MRI to monitor atherosclerotic plaque progression.

Trial registration: ClinicalTrials.gov NCT00880178 NCT01178320.

Fig. 1

First and repeat scans on different scanner platforms. a A plaque with calcification (short arrows) and LRNC (long arrows) was scanned twice on GE platform. b A plaque with ulceration (short arrows) and LRNC (long arrows) was scanned twice on Philips platform. Primary weightings are presented to highlight specific features. The last image in each panel illustrates contour-based measurements (yellow contours indicate LRNC). CE-T1W contrast-enhanced T1-weighted, LRNC lipid-rich necrotic core, T1W T1-weighted, T2W T2-weighted, TOF time-of-flight

Fig. 2

Bland–Altman plots on plaque morphology. Bland–Altman plots are shown for lumen volume (a), wall volume (b) and total vessel volume (c). A logarithmic scale is used for the x-axis to aid visualization as the measurements spanned a wide range. Note that the actual values shown are on the original scale. Dashed lines indicate the mean difference and dotted lines indicate 95 % limits of agreement

Fig. 3

Bland–Altman plots on plaque composition. Bland–Altman plots are shown for LRNC volume (a), CA volume (b) and fibrous tissue volume (c). A logarithmic scale is used for the x-axis to aid visualization as the measurements spanned a wide range. Note that the actual values shown are on the original scale. Dashed lines indicate the mean difference and dotted lines indicate 95 % limits of agreement