Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA.
J Magn Reson Imaging. 2012 Aug;36(2):411-21. doi: 10.1002/jmri.23636. Epub 2012 Mar 5.
To develop a postprocessing method to correct saturation of arterial input function (AIF) in T1-weighted dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for quantification of hepatic perfusion.
The saturated AIF is corrected by parameterizing the first pass of the AIF as a smooth function with a single peak and minimizing a least-squares error in fitting the liver DCE-MRI data to a dual-input single-compartment model. Sensitivities of the method to the degree of saturation in the AIF first-pass peak and the image contrast-to-noise ratio were assessed. The method was also evaluated by correlating portal venous perfusion with an independent overall liver function measurement.
The proposed method corrects the distorted AIF with a saturation ratio up to 0.45. The corrected AIF improved hepatic arterial perfusion by -23.4% and portal venous perfusion by 26.9% in a study of 12 patients with liver cancers. The correlation between the mean voxelwise portal venous perfusion and overall liver function measurement was improved by using the corrected AIFs (R(2) = 0.67) compared with the saturated AIFs (R(2) = 0.39).
The method is robust for correcting AIF distortion and has the potential to improve quantification of hepatic perfusion for assessment of liver tissue response to treatment in patients with hepatic cancers.
开发一种后处理方法，以纠正 T1 加权动态对比增强磁共振成像（DCE-MRI）中动脉输入函数（AIF）的饱和度，从而对肝灌注进行定量分析。
通过将 AIF 的初次通过参数化为具有单个峰值的平滑函数，并最小化拟合肝脏 DCE-MRI 数据到双输入单室模型的最小二乘误差，来校正饱和的 AIF。评估了该方法对 AIF 初次通过峰值的饱和度和图像对比噪声比的灵敏度。还通过将门静脉灌注与独立的整体肝功能测量相关联来评估该方法。
该方法可校正饱和度高达 0.45 的失真 AIF。在对 12 例肝癌患者的研究中，校正后的 AIF 使肝动脉灌注降低了-23.4%，门静脉灌注增加了 26.9%。与使用饱和 AIF（R(2) = 0.39）相比，使用校正后的 AIF 可改善平均体素门静脉灌注与整体肝功能测量之间的相关性（R(2) = 0.67）。
该方法对于校正 AIF 失真非常有效，有望提高肝癌患者治疗后肝组织反应评估中的肝灌注定量分析的准确性。
