Denoising using deep-learning-based reconstruction for whole-heart coronary MRA with sub-millimeter isotropic...

PURPOSE The aim of this study was to assess the usefulness of denoising deep-learning-based reconstruction (dDLR) to improve image quality and vessel delineation in noncontrast 3-T wholeheart coronary magnetic resonance angiography (WHCMRA) with sub-millimeter isotropic resolution (Sub-mm) compared with a standard resolution without dDLR (Standard). METHODS For 10 healthy volunteers, we acquired the WHCMRA with Sub-mm with and without dDLR and Standard to quantify signal- (SNR) and contrast-to-noise ratio (CNR) and vessel edge signal response (VESR) in all the 3 image types. Two independent readers subjectively graded vessel sharpness and signal homogeneity of 8 coronary segments in each patient. We used Kruskal- Wallis test with Bonferroni correction to compare SNR, CNR, VESR, and the subjective evaluation scores among the 3 image types and weighted kappa test to evaluate inter-reader agreement on the scores. RESULTS SNR was significantly higher with Sub-mm with dDLR (P < .001) and Standard (P=.005) than with Sub-mm without dDLR and was comparable between Sub-mm with dDLR and Standard (P=.511). CNR was significantly higher with Sub-mm with dDLR (P < .001) and Standard (P=.005) than with Sub-mm without dDLR and was comparable between Sub-mm with dDLR and Standard (P=.560). VESR was significantly greater with Sub-mm with (P=.001) and without dDLR (P=.017) than with Standard and was comparable between Sub-mm with and without dDLR (P=1.000). In the proximal, middle, distal, and all the coronary segments, the subjective vessel sharpness was significantly better with Sub-mm with dDLR than Sub-mm without dDLR and Standard (P < .001, for all) and was comparable between Sub-mm without dDLR and Standard (P > .05); the subjective signal homogeneity was significantly improved from Sub-mm without dDLR to Standard to Sub-mm with dDLR (P < .001). The inter-reader agreement was excellent (kappa=0.84). CONCLUSION Application of dDLR is useful for improving image quality and vessel delineation in the WHCMRA with Sub-mm compared with Standard.