Retrospective slice prescription compensation improves coronary cross-sectional area measurement by MRI

Background Measurements of coronary cross-sectional area are utilized in vasomotor tone and endothelial function studies, which typically employ breath-held, 2-D multi-slice imaging protocols wherein slices are prescribed orthogonally to a linear vessel segment (Fig 1a) [1],[2]. An ovoid template is then manually fitted to the transverse vessel images (Fig 1b) to measure cross-sectional area. Projection through the slice leads to dependencies between the measured area and the prescription angle (between the slice and the vessel–ideally 0°). This adds bias and reduces repeatability, which is problematic when detecting subtle dilations [3].