文档介绍：: .
s golden angle variable density spiral trajectory, parallel imaging and homotopic l0
minimization-based compressed sensing. Golden angle variable density spiral trajectory, which has the advantages of high data
acquisition efficiency and motion insensitivity, was used to acquire k-space data. In the reconstruction algorithm, multicoil
sparsity constrain was applied in the temporal total variation domain and l0 minimization, instead of traditional l1 minimization,
was adopted, which could further increase the undersampling rate. Simulations and in vivo experiments demonstrated that high
spatial resolution and temporal resolution can be achieved by the proposed method while maintaining the image quality. This
study also suggested the advantages of homotopic l0 norm-based 3D dynamic MRI reconstruction and its clinical potential.
Key words: 3D dynamic magnetic resonance imaging, golden angle spiral, l0 minimization, high spatiotemporal resolution,
motion-insensitive
收稿日期: 2021-04-26; 在线发表日期: 2021-05-17
基金项目: 国家自然科学基金资助项目(61801026, 62071049).
通讯联系人(Corresponding author): * Tel: **********, E-mail: ******@ 1 期 李嫣嫣等：基于同伦 l 0 范数最小化重建的三维动态磁共振成像 21
引 言
时空分辨率和运动不敏感对于三维动态磁共振成像（Magnetic Resonance Imaging，MRI）[1-7]
至关重要，如在肝脏三维动态对比增强磁共振成像（Dynamic Contrast Enhancement-MRI，DCE-MRI）
中[4,8-14]，高空间分辨率有助于发现微小病灶，高时间分辨率有助于可视化整个对比度增强过程．在
动态功能磁共振成像（Functional MRI，fMRI）中，高时空分辨率还可以较好的定位激活区域．而
在采集过程中结合了运动不敏感性的成像技术则有助于提高成像质量．
高时空分辨率 MRI 的实现依赖基于欠采样的信号重建技术，特别是在欠采样率较高时，需要使
用特殊的数据采集策略和相应的重建算法．随着磁共振技术的发展，越来越多的方法可用以提高成
像效率．例如基于 SENSE（Sensitivity encoding）[15]和 GRAPPA（GeneRalized Autocalibrating Partia