Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.
J Magn Reson Imaging. 2017 Nov;46(5):1389-1399. doi: 10.1002/jmri.25691. Epub 2017 Mar 13.
Hemodynamic atlases can add to the pathophysiological understanding of cardiac diseases. This study proposes a method to create hemodynamic atlases using 4D Flow magnetic resonance imaging (MRI). The method is demonstrated for kinetic energy (KE) and helicity density (H ).
Thirteen healthy subjects underwent 4D Flow MRI at 3T. Phase-contrast magnetic resonance cardioangiographies (PC-MRCAs) and an average heart were created and segmented. The PC-MRCAs, KE, and H were nonrigidly registered to the average heart to create atlases. The method was compared with 1) rigid, 2) affine registration of the PC-MRCAs, and 3) affine registration of segmentations. The peak and mean KE and H before and after registration were calculated to evaluate interpolation error due to nonrigid registration.
The segmentations deformed using nonrigid registration overlapped (median: 92.3%) more than rigid (23.1%, P < 0.001), and affine registration of PC-MRCAs (38.5%, P < 0.001) and affine registration of segmentations (61.5%, P < 0.001). The peak KE was 4.9 mJ using the proposed method and affine registration of segmentations (P = 0.91), 3.5 mJ using rigid registration (P < 0.001), and 4.2 mJ using affine registration of the PC-MRCAs (P < 0.001). The mean KE was 1.1 mJ using the proposed method, 0.8 mJ using rigid registration (P < 0.001), 0.9 mJ using affine registration of the PC-MRCAs (P < 0.001), and 1.0 mJ using affine registration of segmentations (P = 0.028). The interpolation error was 5.2 ± 2.6% at mid-systole, 2.8 ± 3.8% at early diastole for peak KE; 9.6 ± 9.3% at mid-systole, 4.0 ± 4.6% at early diastole, and 4.9 ± 4.6% at late diastole for peak H . The mean KE and H were not affected by interpolation.
Hemodynamic atlases can be obtained with minimal user interaction using nonrigid registration of 4D Flow MRI.
2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017;46:1389-1399.
血流动力学图谱可以增加对心脏疾病病理生理学的理解。本研究提出了一种使用 4D Flow 磁共振成像（MRI）创建血流动力学图谱的方法。该方法用于展示动能（KE）和螺旋密度（H）。
13 名健康受试者在 3T 下进行 4D Flow MRI。创建并分割相位对比磁共振心血管造影术（PC-MRCAs）和平均心脏。将 PC-MRCAs、KE 和 H 非刚性地注册到平均心脏以创建图谱。该方法与 1）刚性、2）PC-MRCAs 的仿射注册和 3）分割的仿射注册进行了比较。计算注册前后的峰值和平均 KE 和 H，以评估由于非刚性注册引起的插值误差。
使用非刚性注册的分割变形（中位数：92.3%）比刚性（23.1%，P < 0.001）和 PC-MRCAs 的仿射注册（38.5%，P < 0.001）以及分割的仿射注册（61.5%，P < 0.001）更多地重叠。使用所提出的方法和分割的仿射注册的峰值 KE 为 4.9 mJ（P = 0.91），使用刚性注册为 3.5 mJ（P < 0.001），使用 PC-MRCAs 的仿射注册为 4.2 mJ（P < 0.001）。使用所提出的方法的平均 KE 为 1.1 mJ，使用刚性注册为 0.8 mJ（P < 0.001），使用 PC-MRCAs 的仿射注册为 0.9 mJ（P < 0.001），使用分割的仿射注册为 1.0 mJ（P = 0.028）。峰值 KE 的插值误差为中收缩期 5.2±2.6%，早期舒张期 2.8±3.8%；中期收缩期 9.6±9.3%，早期舒张期 4.0±4.6%，晚期舒张期 4.9±4.6%，峰值 H。平均 KE 和 H 不受插值影响。
使用 4D Flow MRI 的非刚性注册，可以最少的用户交互获得血流动力学图谱。
2 技术功效：第 1 阶段 J. Magn. Reson. Imaging 2017;46:1389-1399.
