Purpose: Ferumoxytal-enhanced 5D free-running whole heart CMR provides image quality comparable to CTA, but requires hours-long reconstruction time, preventing clinical usage. This study developed a variable projection augmented Lagrangian (VPAL) method for 5D motion-resolved image reconstruction and compared it with alternating direction method of multipliers (ADMM) in five numerical simulations and 15 in-vivo pediatric data set. Approach: Relative error of the reconstructed images against the ground-truth images was assessed in numerical simulations. In-vivo analysis compared reconstruction time, mid-short axis (SA) blood-myocardium sharpness, left ventricular ejection fraction (LVEF), and a radiologist's image quality ratings between VPAL and ADMM. A paired t-test (p<0.05) was used to determine statistical significance, while linear regression and Bland-Altman analysis for agreement assessments. Results: VPAL and ADMM had similar relative errors compared to the ground truth, p = 0.07. In in-vivo datasets, VPAL reduced the reconstruction time from 16.3 +/- 3.6 hours (ADMM) to 4.7 +/- 1.1 hours (VPAL), p=1e-10. Blood-myocardium border sharpness in VPAL closely correlates to ADMM , R^2 = 0.97. The LVEFs values measured by VPAL and ADMM reconstructions are largely similar, 56 +/- 6 % in ADMM and 56 +/- 6 % in VPAL, p=0.55. Both VPAL and ADMM reconstructions have good to excellent diagnostic ratings (VPAL vs. ADMM: 3.9 +/- 0.3 vs. 3.8 +/- 0.4 in 2-chamber; 3.9 +/- 0.4 vs. 3.9 +/- in 4-chamber; 3.7 +/- 0.5 vs. 3.7 +/- 0.5 in mid-SA reformatted views. Conclusion: VPAL enables faster reconstruction than ADMM while maintaining equivalent image quality for functional assessments, supporting its potential for clinical use.

翻译：目的：菲立磁增强的5D自由运行全心心脏磁共振成像（CMR）提供的图像质量可与计算机断层扫描血管造影（CTA）相媲美，但需要数小时的重建时间，阻碍了其临床应用。本研究开发了一种用于5D运动分辨图像重建的变量投影增广拉格朗日（VPAL）方法，并在五个数值模拟和15个体内儿科数据集中，将其与交替方向乘子法（ADMM）进行了比较。方法：在数值模拟中，评估了重建图像相对于真实图像的相对误差。体内分析比较了VPAL与ADMM的重建时间、中短轴（SA）血-心肌边界锐利度、左心室射血分数（LVEF）以及放射科医生的图像质量评分。使用配对t检验（p<0.05）确定统计学显著性，同时使用线性回归和Bland-Altman分析进行一致性评估。结果：与真实图像相比，VPAL和ADMM具有相似的相对误差，p = 0.07。在体内数据集中，VPAL将重建时间从16.3 +/- 3.6小时（ADMM）减少到4.7 +/- 1.1小时（VPAL），p=1e-10。VPAL的血-心肌边界锐利度与ADMM高度相关，R^2 = 0.97。通过VPAL和ADMM重建测量的LVEF值基本相似，ADMM为56 +/- 6 %，VPAL为56 +/- 6 %，p=0.55。VPAL和ADMM重建均获得良好至优秀的诊断评分（VPAL vs. ADMM：两腔心切面为3.9 +/- 0.3 vs. 3.8 +/- 0.4；四腔心切面为3.9 +/- 0.4 vs. 3.9 +/- 0.4；中短轴重建切面为3.7 +/- 0.5 vs. 3.7 +/- 0.5）。结论：VPAL能够实现比ADMM更快的重建，同时保持用于功能评估的同等图像质量，支持了其临床应用的潜力。