Wang Shiyang, Fan Xiaobing, Medved Milica, Pineda Federico D, Yousuf Ambereen, Oto Aytekin, Karczmar Gregory S
Department of Radiology, University of Chicago, Chicago, IL 60637.
Department of Radiology, University of Chicago, Chicago, IL 60637.
Magn Reson Imaging. 2016 Feb;34(2):197-203. doi: 10.1016/j.mri.2015.10.025. Epub 2015 Oct 30.
Measurements of arterial input function (AIF) can have large systematic errors at standard contrast agent doses in dynamic contrast enhanced MRI (DCE-MRI). We compared measured AIFs from low dose (AIFLD) and standard dose (AIFSD) contrast agent injections, as well as the AIF derived from a muscle reference tissue and artery (AIFref). Twenty-two prostate cancer patients underwent DCE-MRI. Data were acquired on a 3T scanner using an mDixon sequence. Gadobenate dimeglumine was injected twice, at doses of 0.015 and 0.085 mmol/kg. Directly measured AIFs were fitted with empirical mathematical models (EMMs) and compared to the AIF derived from a muscle reference tissue (AIFref). EMMs accurately fitted the AIFs. The 1st and 2nd pass peaks were visualized in AIFLD, but not in AIFSD, thus the peak and shape of AIFSD could not be accurately measured directly. The average scaling factor between AIFSD and AIFLD in the washout phase was only 56% of the contrast dose ratio (~6:1). The shape and magnitude of AIFref closely approximated that of AIFLD after empirically determined dose-dependent normalization. This suggests that AIFref may be a good approximation of the local AIF.
在动态对比增强磁共振成像（DCE-MRI）中，在标准造影剂剂量下测量动脉输入函数（AIF）可能会有较大的系统误差。我们比较了低剂量（AIFLD）和标准剂量（AIFSD）造影剂注射所测量的AIF，以及源自肌肉参考组织和动脉的AIF（AIFref）。22名前列腺癌患者接受了DCE-MRI检查。使用mDixon序列在3T扫描仪上采集数据。钆贝葡胺分两次注射，剂量分别为0.015和0.085 mmol/kg。将直接测量的AIF与经验数学模型（EMM）拟合，并与源自肌肉参考组织的AIF（AIFref）进行比较。EMM准确地拟合了AIF。在AIFLD中可以看到首次通过和第二次通过峰值，但在AIFSD中则看不到，因此无法直接准确测量AIFSD的峰值和形状。在洗脱期，AIFSD与AIFLD之间的平均缩放因子仅为造影剂剂量比（约6:1）的56%。在根据经验确定剂量依赖性归一化后，AIFref的形状和大小与AIFLD非常接近。这表明AIFref可能是局部AIF的良好近似。
