Qiu Wenyuan, Li Dongxiao, Jin Xinyu, Liu Fan, Nguyen Thanh D, Prince Martin R, Wang Yi, Spincemaille Pascal
College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, China.
College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, China.
Magn Reson Imaging. 2019 May;58:56-66. doi: 10.1016/j.mri.2019.01.012. Epub 2019 Jan 15.
Liver dynamic contrast-enhanced MRI (DCE-MRI) requires high spatiotemporal resolution and large field of view to clearly visualize all relevant enhancement phases and detect early-stage liver lesions. The low-rank plus sparse (L + S) reconstruction outperforms standard sparsity-only-based reconstruction through separation of low-rank background component (L) and sparse dynamic components (S). However, the L + S decomposition is sensitive to respiratory motion so that image quality is compromised when breathing occurs during long time data acquisition. To enable high quality reconstruction for free-breathing liver 4D DCE-MRI, this paper presents a novel method called SMC-LS, which incorporates Sliding Motion Compensation into the standard L + S reconstruction. The global superior-inferior displacement of the internal abdominal organs is inferred directly from the undersampled raw data and then used to correct the breathing induced sliding motion which is the dominant component of respiratory motion. With sliding motion compensation, the reconstructed temporal frames are roughly registered before applying the standard L + S decomposition. The proposed method has been validated using free-breathing liver 4D MRI phantom data, free-breathing liver 4D DCE-MRI phantom data, and in vivo free breathing liver 4D MRI dataset. Results demonstrated that SMC-LS reconstruction can effectively reduce motion blurring artefacts and preserve both spatial structures and temporal variations at a sub-second temporal frame rate for free-breathing whole-liver 4D DCE-MRI.
肝脏动态对比增强磁共振成像（DCE-MRI）需要高时空分辨率和大视野，以清晰显示所有相关增强阶段并检测早期肝脏病变。低秩加稀疏（L+S）重建通过分离低秩背景分量（L）和稀疏动态分量（S），优于基于标准稀疏性的重建方法。然而，L+S分解对呼吸运动敏感，因此在长时间数据采集过程中发生呼吸时，图像质量会受到影响。为了实现自由呼吸肝脏4D DCE-MRI的高质量重建，本文提出了一种名为SMC-LS的新方法，该方法将滑动运动补偿纳入标准L+S重建中。直接从欠采样的原始数据中推断出腹部内部器官的全局上下位移，然后用于校正作为呼吸运动主要成分的呼吸诱导滑动运动。通过滑动运动补偿，在应用标准L+S分解之前，对重建的时间帧进行大致配准。所提出的方法已使用自由呼吸肝脏4D MRI体模数据、自由呼吸肝脏4D DCE-MRI体模数据和体内自由呼吸肝脏4D MRI数据集进行了验证。结果表明，SMC-LS重建可以有效减少运动模糊伪影，并在自由呼吸全肝4D DCE-MRI的亚秒级时间帧速率下保留空间结构和时间变化。
