Precision and accuracy of cross‐sectional area measurements used to measure coronary endothelial function with spiral MRI

Abstract

Current CEF spiral MRI with in vivo SNR allows detection of a 4-5% area change and Fourier interpolation improves precision several-fold to sub-voxel dimensions.

Phase contrast coronary blood velocity mapping with both high temporal and spatial resolution using triggered Golden Angle rotated Spiral k‐t Sparse Parallel imaging (GASSP) with shifted binning

“…However, the vessel areas were measured larger with the proposed method than either of the other two, and PDV was measured lower compared to the high‐temporal sequence. With regards to the area, it has been shown that a larger voxel size, such as in the high‐temporal sequence, in combination with Fourier interpolation (used to improve precision) leads to area measurement underestimation 13 . Therefore, the larger area compared to the high‐temporal sequence was expected.…”

“…A semi‐automatic flow analysis software was implemented in MATLAB (Mathworks, Natick, MA, USA) that included vessel segmentation and correction for background phase and through‐plane motion. All images were Fourier‐interpolated to 0.1 mm spatial resolution for more precise segmentation 13 . First, the vessel area A v was semi‐automatically computed from three consecutive end‐diastolic frames by full‐width‐half‐maximum thresholding.…”

“…All images were Fourier-interpolated to 0.1 mm spatial resolution for more precise segmentation. 13 (1) V = V enc arg I + I * − .…”

“…High spatial resolution Δx ≤ 1 mm is needed for accurate assessment of the mean flow, 12 which includes the determination of cross-sectional areas that may benefit from even smaller voxel sizes. 13 Furthermore, high temporal resolution is needed due to fast cardiac motion and to resolve temporal detail, especially for the right coronary artery (RCA), which is twice as mobile as the left anterior descending artery (LAD). 14 According to Marcus et al the temporal resolution τ should be ≤58 ms and ≤23 ms for LAD and RCA, respectively.…”

“…Coronary PC MRI is challenging because the coronary arteries are small in diameter (<3‐4 mm) and move due to cardiac contraction and respiration. High spatial resolution Δx ≤ 1 mm is needed for accurate assessment of the mean flow, 12 which includes the determination of cross‐sectional areas that may benefit from even smaller voxel sizes 13 . Furthermore, high temporal resolution is needed due to fast cardiac motion and to resolve temporal detail, especially for the right coronary artery (RCA), which is twice as mobile as the left anterior descending artery (LAD) 14 .…”