Ghanbari Fahime, Schulz Alexander, Morales Manuel A, Rodriguez Jennifer, Street Jordan A, Arcand Kathryn, Johnson Scott, Pierce Patrick, Hoeger Christopher W, Tsao Connie W, Manning Warren J, Nezafat Reza
Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA; Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
J Cardiovasc Magn Reson. 2025;27(1):101901. doi: 10.1016/j.jocmr.2025.101901. Epub 2025 Apr 30.
Exercise cardiovascular magnetic resonance (Ex-CMR) can reveal pathophysiologies not evident at rest by quantifying biventricular volume and function during or immediately after exercise. However, achieving reproducible Ex-CMR measurements is challenging due to limited spatial and temporal resolution. This study aimed to develop and evaluate a free-breathing, high-spatiotemporal-resolution single-beat Ex-CMR cine enhanced by generative artificial intelligence. We assessed image analysis reproducibility, scan-rescan reproducibility, and impact of the reader's experience on the analysis.
Imaging was performed on a 3T CMR system using a free-breathing, highly accelerated, multi-slice, single-beat cine sequence (in-plane spatiotemporal resolution of 1.9 × 1.9 mm² and 37 ms, respectively). High acceleration was achieved by combining compressed sensing reconstruction with a resolution-enhancement generative adversarial inline neural network. Ex-CMR was performed using a supine ergometer positioned immediately outside the magnet bore. Single-beat cine images were acquired at rest and immediately post-exercise. In a prospective study, the protocol was evaluated in 141 subjects. A structured image analysis workflow was implemented. Four expert readers, with or without prior training in single-beat Ex-CMR, independently rated all images for diagnostic and image quality. The subjective assessment used two 3-point Likert scales. Biventricular parameters were calculated. Inter- and intra-observer reproducibility were assessed. Fifteen healthy subjects were re-imaged 1 year later for scan-rescan reproducibility. Reproducibility was assessed using intraclass correlation coefficient (ICC), with agreement evaluated via Bland-Altman analysis, linear regression, and Pearson correlation.
Free-breathing, single-beat Ex-CMR cine enabled imaging of the beating heart within 30 ± 6 s, with technically successful scans in 96% (136/141) of subjects. Post-exercise single-beat cine images were assessed as diagnostic in 98% (133/136), 96% (131/136), 82% (112/136), and 65% (89/136) of cases by four readers (ordered by descending years of Ex-CMR experience). Good image quality was reported in 74% (100/136) to 80% (109/136) of subjects. Biventricular parameters were successfully measured in all subjects, demonstrating good to excellent inter-observer reproducibility. Scan/rescan reproducibility over 1 year, assessed by two independent readers, showed excellent inter-visit ICCs (0.96-1.0) and strong correlations (R² ≥ 0.92, p < 0.001 for left ventricle; R² ≥ 0.95, p < 0.001 for right ventricle).
Single-beat Ex-CMR enabled evaluation of biventricular volumetric and functional indices with excellent reproducibility.
运动心血管磁共振成像（Ex-CMR）通过在运动期间或运动后立即量化双心室容积和功能，能够揭示静息时不明显的病理生理情况。然而，由于空间和时间分辨率有限，实现可重复的Ex-CMR测量具有挑战性。本研究旨在开发并评估一种通过生成式人工智能增强的自由呼吸、高时空分辨率单节拍Ex-CMR电影成像。我们评估了图像分析的可重复性、扫描-重扫描的可重复性以及阅片者经验对分析的影响。
在3T磁共振成像系统上进行成像，使用自由呼吸、高度加速、多层、单节拍电影序列（平面内时空分辨率分别为1.9×1.9平方毫米和37毫秒）。通过将压缩感知重建与分辨率增强生成对抗内联神经网络相结合实现高加速。使用直接置于磁体孔外的仰卧式测力计进行Ex-CMR检查。在静息时和运动后立即采集单节拍电影图像。在一项前瞻性研究中，对141名受试者进行了该方案的评估。实施了结构化的图像分析工作流程。四名专家阅片者，无论是否有单节拍Ex-CMR的先前培训，都独立对所有图像的诊断和图像质量进行评分。主观评估使用两个3级李克特量表。计算双心室参数。评估观察者间和观察者内的可重复性。15名健康受试者在1年后重新成像以评估扫描-重扫描的可重复性。使用组内相关系数（ICC）评估可重复性，通过布兰德-奥特曼分析、线性回归和皮尔逊相关性评估一致性。
自由呼吸单节拍Ex-CMR电影成像能够在30±6秒内对跳动的心脏进行成像，96%（136/141）的受试者扫描技术成功。运动后单节拍电影图像在四名阅片者（按Ex-CMR经验年限降序排列）评估的病例中，诊断率分别为98%（133/136）、96%（131/136）、82%（（112/）136）和65%（89/136）。74%（100/136）至（80%（109/136）的受试者报告图像质量良好。所有受试者均成功测量了双心室参数，显示出良好至优秀的观察者间可重复性。由两名独立阅片者评估的1年扫描/重扫描可重复性显示出极好的访间ICC（0.96 - 1.0）和强相关性（左心室R²≥0.92，p<0.001；右心室R²≥0.95，p<0.001）。
单节拍Ex-CMR能够以优异的可重复性评估双心室容积和功能指标。
