This paper presents a prospective study evaluating the impact on image quality and quantitative dynamic contrast-enhanced (DCE)-MRI perfusion parameters when varying the number of respiratory motion states when using an eXtra-Dimensional Golden-Angle Radial Sparse Parallel (XD-GRASP) MRI sequence. DCE acquisition was performed using a 3D stack-of-stars gradient-echo golden-angle radial acquisition in free-breathing with 100 spokes per motion state and temporal resolution of 6 s/volume, and using a non-rigid motion compensation to align different motion states. Parametric analysis was conducted using a dual-input single-compartment model. Nonparametric analysis was performed on the time-intensity curves. A total of 22 hepatocellular carcinomas (size: 11-52 mm) were evaluated. XD-GRASP reconstructed with increasing number of spokes for each motion state increased the signal-to-noise ratio (SNR) (p < 0.05) but decreased temporal resolution (0.04 volume/s vs 0.17 volume/s for one motion state) (p < 0.05). A visual scoring by an experienced radiologist show no change between increasing number of motion states with same number of spokes using the Likert score. The normalized maximum intensity time ratio, peak enhancement ratio and tumor arterial fraction increased with decreasing number of motion states (p < 0.05) while the transfer constant from the portal venous plasma to the surrounding tissue significantly decreased (p < 0.05). These same perfusion parameters show a significant difference in case of tumor displacement more than 1 cm (p < 0.05) whereas in the opposite case there was no significant variation. While a higher number of motion states and higher number of spokes improves SNR, the resulting lower temporal resolution can influence quantitative parameters that capture rapid signal changes. Finally, fewer displacement compensation is advantageous with lower number of motion state due to the higher temporal resolution. XD-GRASP can be used to perform quantitative perfusion measures in the liver, but the number of motion states may significantly alter some quantitative parameters.

中文翻译：

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时间分辨率和运动校正对肝脏动态对比度增强MRI的影响（使用加速的金角放射状序列）。

本文提出了一项前瞻性研究，评估了使用超尺寸金角径向稀疏平行（XD-GRASP）改变呼吸运动状态数量时，对图像质量和定量动态对比度增强（DCE）-MRI灌注参数的影响MRI序列。DCE采集使用3D星空梯度梯度回声金角径向采集进行，自由呼吸，每个运动状态100条辐条，时间分辨率为6 s /体积，并使用非刚性运动补偿来对齐运动状态。使用双输入单隔室模型进行参数分析。对时间强度曲线进行非参数分析。总共评估了22种肝细胞癌（大小：11-52 mm）。XD-GRASP在每个运动状态下以增加的轮辐数量进行重建，从而提高了信噪比（SNR）（p <0.05），但在时间分辨率上却有所降低（0.04体积/秒与0.17体积/秒，一种运动状态）（p <0.05）。经验丰富的放射科医生的视觉评分显示，在使用李克特（Likert）评分的情况下，随着辐条数量的增加，运动状态的增加数量没有变化。随着运动状态数量的减少，归一化的最大强度时间比，峰值增强比和肿瘤动脉分数增加（p <0.05），而从门静脉血浆到周围组织的转移常数显着降低（p <0.05）。在肿瘤移位超过1 cm的情况下，这些相同的灌注参数显示出显着差异（p <0。05），而在相反的情况下则没有显着差异。虽然较高数量的运动状态和较高数量的轮辐可以改善SNR，但所得的较低时间分辨率会影响捕获快速信号变化的定量参数。最后，由于较高的时间分辨率，较少的位移补偿对于较少数量的运动状态是有利的。XD-GRASP可用于在肝脏中执行定量灌注测量，但是运动状态的数量可能会显着改变某些定量参数。由于较高的时间分辨率，较少的位移补偿对于较少的运动状态是有利的。XD-GRASP可用于在肝脏中执行定量灌注测量，但是运动状态的数量可能会显着改变某些定量参数。由于较高的时间分辨率，较少的位移补偿对于较少的运动状态是有利的。XD-GRASP可用于在肝脏中执行定量灌注测量，但是运动状态的数量可能会显着改变某些定量参数。