Abstract: Objective To assess the reproducibility of 3.0 T high-resolution magnetic resonance imaging (HR MRI) for evaluation
of atherosclerotic stenosis in the middle cerebral artery (MCA). Methods From February, 2011 to December, 2013, 66
consecutive patients with MCA-M1 atherosclerotic stenosis (50%-99%) confirmed by digital subtractive angiography (DSA)
received examinations with 3.0 T HR MRI for measurement of the vessel area (VA) and lumen area (LA) at the maximum
narrow site (VAnarrow and LAnarrow) and the reference site (VAreference and LAreference) as well as the plaque distribution (ventral, dorsal,
superior, and inferior). Two independent readers reviewed all the images and one reader reevaluated these images 4 weeks
later. The inter- and intra-observer reproducibility was evaluated using the intraclass correlation coefficient (ICC). Results The
measurements of VAnarrow, VAreference, and LAreference using HR MRI showed excellent inter- (ICC=0.801, 0.843, and 0.808,
respectively) and intra-observer reproducibility (ICC=0.811, 0.916, and 0.958, respectively), but the measurement of LAnarrow had
only moderate inter- and intra-observer reproducibility (ICC=0.584 and 0.625, respectively). For plaque distribution analysis
(ventral, dorsal, superior, and inferior plaques), HR MRI also showed excellent inter- (ICC=0.856, 0.836, 0.791, and 0.905,
respectively) and intra-observer reproducibility (ICC=0.876, 0.827, 0.825, and 0.950, respectively). Conclusion HR MRI shows
good inter- and intra-observer reproducibility in identifying MCA-M1 atherosclerotic plaque distribution and vessel and
lumen measurements, but its reliability for lumen area measurement at the maximum narrowing site needs to be improved.