Wassenaar Nienke P M, Gurney-Champion Oliver J, van Schelt Anne-Sophie, Bruijnen Tom, van Laarhoven Hanneke W M, Stoker Jaap, Nederveen Aart J, Runge Jurgen H, Schrauben Eric M
Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.
Imaging and Biomarkers, Cancer Center Amsterdam, Amsterdam, The Netherlands.
Magn Reson Med. 2024 Nov;92(5):2051-2064. doi: 10.1002/mrm.30213. Epub 2024 Jul 14.
For reliable DCE MRI parameter estimation, k-space undersampling is essential to meet resolution, coverage, and signal-to-noise requirements. Pseudo-spiral (PS) sampling achieves this by sampling k-space on a Cartesian grid following a spiral trajectory. The goal was to optimize PS k-space sampling patterns for abdomin al DCE MRI.
The optimal PS k-space sampling pattern was determined using an anthropomorphic digital phantom. Contrast agent inflow was simulated in the liver, spleen, pancreas, and pancreatic ductal adenocarcinoma (PDAC). A total of 704 variable sampling and reconstruction approaches were created using three algorithms using different parametrizations to control sampling density, halfscan and compressed sensing regularization. The sampling patterns were evaluated based on image quality scores and the accuracy and precision of the DCE pharmacokinetic parameters. The best and worst strategies were assessed in vivo in five healthy volunteers without contrast agent administration. The best strategy was tested in a DCE scan of a PDAC patient.
The best PS reconstruction was found to be PS-diffuse based, with quadratic distribution of readouts on a spiral, without random shuffling, halfscan factor of 0.8, and total variation regularization of 0.05 in the spatial and temporal domains. The best scoring strategy showed sharper images with less prominent artifacts in healthy volunteers compared to the worst strategy. Our suggested DCE sampling strategy also showed high quality DCE images in the PDAC patient.
Using an anthropomorphic digital phantom, we identified an optimal PS sampling strategy for abdominal DCE MRI, and demonstrated feasibility in a PDAC patient.
为了实现可靠的动态对比增强磁共振成像（DCE MRI）参数估计，k空间欠采样对于满足分辨率、覆盖范围和信噪比要求至关重要。伪螺旋（PS）采样通过在笛卡尔网格上沿螺旋轨迹对k空间进行采样来实现这一点。目标是优化腹部DCE MRI的PS k空间采样模式。
使用拟人化数字体模确定最佳PS k空间采样模式。在肝脏、脾脏、胰腺和胰腺导管腺癌（PDAC）中模拟对比剂流入。使用三种算法并采用不同参数设置来控制采样密度、半扫描和压缩感知正则化，共创建了704种可变采样和重建方法。基于图像质量评分以及DCE药代动力学参数的准确性和精确性对采样模式进行评估。在五名未注射对比剂的健康志愿者体内评估最佳和最差策略。在一名PDAC患者的DCE扫描中测试最佳策略。
发现最佳的PS重建基于PS-扩散，读出数据在螺旋上呈二次分布，无随机混洗，半扫描因子为0.8，并在空间和时间域中采用0.05的总变差正则化。与最差策略相比，最佳评分策略在健康志愿者中显示出图像更清晰且伪影不那么明显。我们建议的DCE采样策略在PDAC患者中也显示出高质量的DCE图像。
使用拟人化数字体模，我们确定了腹部DCE MRI的最佳PS采样策略，并在一名PDAC患者中证明了其可行性。
