Department of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, 28 Yeongon-dong, Jongno-gu, Seoul 110-744, Korea.
AJR Am J Roentgenol. 2011 Jan;196(1):102-8. doi: 10.2214/AJR.09.3971.
The purpose of this study was to compare the arterial enhancement fraction (AEF) calculated at multiphasic liver CT with the hepatic perfusion index (HPI) measured with cine mode perfusion CT.
Cine mode perfusion CT was performed after VX2 tumor implantation in the livers of 10 rabbits. HPI and its color map were obtained with a computer application. With raw data from cine mode perfusion CT, images were extracted in the unenhanced, arterial, and portal venous phases to simulate multiphasic liver CT. On the basis of simulated multiphasic CT images, the AEF color map was obtained with prototype software. HPI and AEF were compared for the same regions of interest in the liver parenchyma, whole liver tumor, and viable tumor portion.
In the liver parenchyma, the mean HPI was 23.3% ± 2.6% (SD) and the AEF 24.4% ± 2.8%; in whole liver tumor, 73.4% ± 9.5% and 78.4% ± 10.5%; and in the viable tumor portion, 78.0% ± 7.7% and 78.3% ± 7.5%. The differences were not statistically significant (p > 0.05, Wilcoxon's signed rank test). Measurement agreement between the two parameters was moderate (Bland-Altman 95% limits of agreement, -14.9% and 19.2%), but there was a strong positive correlation between AEF and HPI (within-subject r = 0.91, p < 0.001). Functional maps of HPI and AEF correlated with the histologic findings.
AEF calculated from simulated multiphasic liver CT images correlates strongly with HPI obtained at cine mode perfusion CT. Further study of the AEF is warranted to explore its value in providing hepatic perfusion information without additional radiation exposure.
本研究旨在比较多期肝脏 CT 计算的动脉增强分数（AEF）与电影模式灌注 CT 测量的肝灌注指数（HPI）。
在 10 只兔子的肝脏中植入 VX2 肿瘤后，进行电影模式灌注 CT。使用计算机应用程序获得 HPI 及其彩色图。利用电影模式灌注 CT 的原始数据，在未增强、动脉和门静脉期提取图像，以模拟多期肝脏 CT。基于模拟的多期 CT 图像，使用原型软件获得 AEF 彩色图。在肝实质、整个肝肿瘤和存活肿瘤部分的相同感兴趣区比较 HPI 和 AEF。
在肝实质中，平均 HPI 为 23.3%±2.6%（标准差），AEF 为 24.4%±2.8%；在整个肝肿瘤中，HPI 为 73.4%±9.5%，AEF 为 78.4%±10.5%；在存活肿瘤部分，HPI 为 78.0%±7.7%，AEF 为 78.3%±7.5%。差异无统计学意义（p>0.05，Wilcoxon 符号秩检验）。两种参数的测量一致性中等（Bland-Altman 95%一致性界限，-14.9%和 19.2%），但 AEF 与 HPI 呈强正相关（受试者内 r=0.91，p<0.001）。HPI 和 AEF 的功能图与组织学发现相关。
从模拟的多期肝脏 CT 图像计算的 AEF 与电影模式灌注 CT 获得的 HPI 密切相关。进一步研究 AEF 有望在不增加额外辐射暴露的情况下探索其提供肝灌注信息的价值。
