Mukherjee Tanmay, Keshavarzian Maziyar, Fugate Elizabeth M, Naeini Vahid, Darwish Amr, Ohayon Jacques, Myers Kyle J, Shah Dipan J, Lindquist Diana, Sadayappan Sakthivel, Pettigrew Roderic I, Avazmohammadi Reza
Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843, USA.
Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
bioRxiv. 2024 Jun 3:2024.05.31.596322. doi: 10.1101/2024.05.31.596322.
The quantification of cardiac motion using cardiac magnetic resonance imaging (CMR) has shown promise as an early-stage marker for cardiovascular diseases. Despite the growing popularity of CMR-based myocardial strain calculations, measures of complete spatiotemporal strains (i.e., three-dimensional strains over the cardiac cycle) remain elusive. Complete spatiotemporal strain calculations are primarily hampered by poor spatial resolution, with the rapid motion of the cardiac wall also challenging the reproducibility of such strains. We hypothesize that a super-resolution reconstruction (SRR) framework that leverages combined image acquisitions at multiple orientations will enhance the reproducibility of complete spatiotemporal strain estimation. Two sets of CMR acquisitions were obtained for five wild-type mice, combining short-axis scans with radial and orthogonal long-axis scans. Super-resolution reconstruction, integrated with tissue classification, was performed to generate full four-dimensional (4D) images. The resulting enhanced and full 4D images enabled complete quantification of the motion in terms of 4D myocardial strains. Additionally, the effects of SRR in improving accurate strain measurements were evaluated using an in-silico heart phantom. The SRR framework revealed near isotropic spatial resolution, high structural similarity, and minimal loss of contrast, which led to overall improvements in strain accuracy. In essence, a comprehensive methodology was generated to quantify complete and reproducible myocardial deformation, aiding in the much-needed standardization of complete spatiotemporal strain calculations.
利用心脏磁共振成像（CMR）对心脏运动进行量化已显示出作为心血管疾病早期标志物的潜力。尽管基于CMR的心肌应变计算越来越受欢迎，但完整的时空应变测量（即心动周期中的三维应变）仍然难以实现。完整的时空应变计算主要受到空间分辨率差的阻碍，心脏壁的快速运动也对这种应变的可重复性提出了挑战。我们假设，一个利用多个方向的联合图像采集的超分辨率重建（SRR）框架将提高完整时空应变估计的可重复性。对五只野生型小鼠进行了两组CMR采集，将短轴扫描与径向和正交长轴扫描相结合。进行了与组织分类相结合的超分辨率重建，以生成完整的四维（4D）图像。由此产生的增强型全4D图像能够根据4D心肌应变对运动进行完整量化。此外，使用计算机模拟心脏模型评估了SRR在改善精确应变测量方面的效果。SRR框架显示出接近各向同性的空间分辨率、高结构相似性和最小的对比度损失，这导致应变准确性的整体提高。本质上，生成了一种全面的方法来量化完整且可重复的心肌变形，有助于对完整时空应变计算进行急需的标准化。
