High field carotid vessel wall imaging: A study on reproducibility.

PURPOSE: Currently, a multi-contrast protocol, including a combination of five MR-sequences is used as reference standard for morphologic imaging and quantitative measurements of the carotid artery vessel wall. The purpose of this study is to investigate the scan-rescan reproducibility together with intra- and inter-observer reproducibility of each of the five MR-sequences. METHODS: Twenty healthy volunteers (55% male, mean age=26 years) underwent repeated MR-examinations (3T-Philips-MRI) of the left carotid artery vessel wall with five sequences; T1-TFE, T2-TSE, PD-TSE, T1-TSE and 3D TOF. A standard phased-array coil with two flexible elements of 14cmx17cm was used to obtain nine transverse imaging sections of the left carotid artery with identical in-plane resolution (0.46mmx0.46mm). Reproducibility analysis was performed in 3 slices of the common carotid artery for all sequences. RESULTS: For, scan-rescan reproducibility, intra class correlation coefficients (ICC) were excellent for all sequences and ranged from 0.79 to 0.95. The intra-observer ICC ranged from 0.89 to 0.98 and the inter-observer ICC ranged from 0.84 to 0.96, for both lumen and vessel wall assessment. CONCLUSIONS: By high field MR imaging, vessel wall and lumen area of the carotid artery can be assessed with excellent scan-rescan, intra- and inter-observer reproducibility for all five sequences.