Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University School of Medicine, Beijing, China.
Department of Radiology, Beijing Anzhen Hospital, Beijing, China.
Med Phys. 2022 Feb;49(2):854-864. doi: 10.1002/mp.15436. Epub 2022 Jan 18.
Many diseases can simultaneously involve renal arteries and the adjacent abdominal aorta. This study proposed a free-breathing three-dimensional (3D) isotropic-resolution magnetic resonance sequence for simultaneous vessel wall imaging (VWI) of bilateral renal arteries and adjacent abdominal aorta.
A respiratory-triggered isotropic-resolution sequence that combined the improved motion-sensitized driven-equilibrium (iMSDE) preparation with the spoiled gradient recalled (SPGR) readout (iMSDE-SPGR) was proposed for simultaneous VWI of renal arteries and abdominal aorta. The proposed iMSDE-SPGR sequence was optimized by positioning spatial saturation pulses (i.e., REST slabs) elaborately to further alleviate respiratory and gastrointestinal motion artifacts and selecting appropriate first-order gradient moment (m ) of the iMSDE preparation. Thirteen healthy subjects and 13 patients with renal artery stenosis underwent simultaneous VWI with the optimized iMSDE-SPGR sequence at 3.0 T. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and morphology of renal arterial wall and aortic wall were measured. Reproducibility of intra-observer, inter-observer, and scan-rescan (n = 13 healthy subjects) in measuring SNR, CNR, and morphology was evaluated. For the reproducibility test, the agreement was determined using intraclass correlation coefficients (ICC), and the differences were compared using paired t-test or nonparametric Wilcoxon test when appropriate. Bland-Altman plots were used to calculate the bias between observers and between scans.
The proposed iMSDE-SPGR sequence was feasible for simultaneous VWI both in the healthy subjects and the patients. The sequence showed good to excellent inter-observer (ICC: 0.615-0.999), excellent intra-observer (ICC: 0.801-0.998), and scan-rescan (ICC: 0.768-0.998) reproducibility in measuring morphology, SNR, and CNR. There were no significant differences in SNR, CNR, and morphology measurements between observers and between scans (all p > 0.05). Bland-Altman plots showed small bias in assessing SNR, CNR, and morphology.
The proposed free-breathing 3D isotropic-resolution iMSDE-SPGR technique is feasible and reproducible for simultaneous VWI of bilateral renal arteries and adjacent abdominal aorta.
许多疾病可同时累及肾动脉及其毗邻的腹主动脉。本研究提出了一种自由呼吸三维（3D）各向同性分辨率磁共振序列，用于同时进行双侧肾动脉和毗邻腹主动脉的血管壁成像（VWI）。
提出了一种结合改良运动敏感驱动平衡（iMSDE）准备和扰相梯度回波（SPGR）读出的呼吸触发各向同性分辨率序列（iMSDE-SPGR），用于同时进行肾动脉和腹主动脉的 VWI。通过精心定位空间饱和脉冲（即 REST 板）进一步减轻呼吸和胃肠道运动伪影，并选择适当的 iMSDE 准备的一阶梯度矩（m），对所提出的 iMSDE-SPGR 序列进行优化。13 名健康受试者和 13 名肾动脉狭窄患者在 3.0T 上进行了优化的 iMSDE-SPGR 序列的同时 VWI。测量了肾动脉壁和主动脉壁的信噪比（SNR）、对比噪声比（CNR）和形态。评估了观察者内、观察者间和扫描-再扫描（n=13 名健康受试者）在测量 SNR、CNR 和形态方面的重复性。对于重复性测试，使用组内相关系数（ICC）确定一致性，并在适当情况下使用配对 t 检验或非参数 Wilcoxon 检验比较差异。Bland-Altman 图用于计算观察者之间和扫描之间的偏差。
所提出的 iMSDE-SPGR 序列可用于健康受试者和患者的同时 VWI。该序列在测量形态、SNR 和 CNR 方面表现出良好到极好的观察者间（ICC：0.615-0.999）、极好的观察者内（ICC：0.801-0.998）和扫描-再扫描（ICC：0.768-0.998）的可重复性。观察者之间和扫描之间的 SNR、CNR 和形态测量值无显著差异（均 p>0.05）。Bland-Altman 图显示 SNR、CNR 和形态评估的偏差较小。
所提出的自由呼吸 3D 各向同性分辨率 iMSDE-SPGR 技术可用于同时进行双侧肾动脉和毗邻腹主动脉的 VWI，具有可行性和可重复性。
