Accelerated contrast-enhanced whole-heart coronary MRI using low-dimensional-structure self-learning and thresholding.

We sought to evaluate the efficacy of prospective random undesampling and LOw-dimensional-structure Self-learning and Thresholding (LOST) reconstruction for highly accelerated contrast-enhanced whole-heart coronary MRI. A prospective random undersampling scheme was implemented using phase ordering to minimize artifacts due to gradient switching, and was compared to a randomly undersampled acquisition with no profile ordering. This profile ordering technique was then used to acquire contrast-enhanced whole-heart coronary MRI in 10 healthy subjects with 4-fold acceleration. Reconstructed images and the acquired zerofilled images were compared for depicted vessel length, vessel sharpness, and subjective image quality on a scale of 1 (poor) to 4 (excellent). In a pilot study, contrast-enhanced whole-heart coronary MRI was also acquired in 4 patients with suspected coronary artery disease with 3-fold acceleration. The undersampled images were reconstructed using LOST, which showed significant improvement over the zerofilled images in both objective and subjective measures, with an overall score of 3.6±0.5. Reconstructed images in patients were all diagnostic. LOST reconstruction allows contrast-enhanced whole-heart coronary MRI with acceleration as high as 4-fold using clinically available 5-channel phased-array coil.