Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Munich, Germany; Department of Diagnostic Radiology, Oregon Health and Science University, Oregon, USA.
Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Munich, Germany.
Magn Reson Imaging. 2022 Apr;87:1-6. doi: 10.1016/j.mri.2021.11.009. Epub 2021 Nov 19.
To prospectively evaluate an L1 regularized iterative SENSE reconstruction (L1-R SENSE) to eliminate band-like artifacts frequently seen with parallel imaging (SENSE) at high acceleration factors in high resolution diffusion weighted magnetic resonance imaging of the pancreas.
Fourteen patients with pancreatic ductal adenocarcinoma (PDAC) underwent respiratory triggered DWI ss-EPI at a resolution of 2.5 × 2.5 × 3 mm3 with uniform undersampling in the phase encoding direction (AP axis) with an acceleration factor of 4. Data were reconstructed using the standard SENSE reconstruction routine of the vendor and an iterative SENSE reconstruction employing L1 regularization after a wavelet sparsifying transformation (L1-R SENSE). Retrospective reconstruction of the data with a lower number of averages was performed using both reconstruction methods. Two radiologists independently assessed noise artifacts, anatomical details and image quality (IQ) subjectively with a 4-point scale. Apparent diffusion coefficient (ADC) and covariance (CV) of ADC estimated from images reconstructed at a different number of averages for PDAC and the normal pancreas were assessed.
L1-R SENSE resulted in higher IQ and less noise artifacts than SENSE. Anatomical details were significantly higher for SENSE in one reader. Mean ADC of PDAC and normal pancreas were significantly higher for L1-R SENSE than SENSE. L1-R SENSE revealed lower CV of ADC for normal pancreas compared to SENSE, whereas no difference was noted for PDAC.
Compared with traditional SENSE reconstruction, L1-R SENSE effectively reduces band-like noise and improves the robustness of the ADC estimation from acquisitions using single-shot DW-EPI of the pancreas.
前瞻性评估 L1 正则化迭代 SENSE 重建（L1-R SENSE），以消除在胰腺高分辨率扩散加权磁共振成像中使用并行成像（SENSE）在高加速因子下经常出现的带条状伪影。
14 例胰腺导管腺癌（PDAC）患者接受呼吸触发 DWI ss-EPI，分辨率为 2.5×2.5×3mm3，在相位编码方向（AP 轴）进行均匀欠采样，加速因子为 4。数据使用供应商的标准 SENSE 重建程序和采用小波稀疏变换的迭代 SENSE 重建（L1-R SENSE）进行重建。使用两种重建方法对数据进行回顾性重建，减少平均次数。两位放射科医生独立使用 4 分制对噪声伪影、解剖细节和图像质量（IQ）进行主观评估。从不同平均次数重建的图像中评估 PDAC 和正常胰腺的表观扩散系数（ADC）和 ADC 协方差（CV）。
L1-R SENSE 重建的 IQ 更高，噪声伪影更少，优于 SENSE。一位读者认为 SENSE 的解剖细节明显更高。L1-R SENSE 重建的 PDAC 和正常胰腺的平均 ADC 明显高于 SENSE。L1-R SENSE 重建的正常胰腺 ADC 的 CV 明显低于 SENSE，而 PDAC 则无差异。
与传统的 SENSE 重建相比，L1-R SENSE 可有效减少带条状噪声，并提高单次激发 DW-EPI 采集的胰腺 ADC 估计的稳健性。
