Kodama Yoshihisa, Ng Chaan S, Wu Tsung T, Ayers Gregory D, Curley Steven A, Abdalla Eddie K, Vauthey Jean Nicolas, Charnsangavej Chusilp
Department of Diagnostic Radiology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Box 368, Houston TX 77030, USA.
AJR Am J Roentgenol. 2007 May;188(5):1307-12. doi: 10.2214/AJR.06.0992.
The purpose of this study was to assess which of a number of methods of measuring attenuation on CT scans is best for prediction of hepatic fat content.
This retrospective study was approved by our institutional review board. Consecutively registered patients who underwent liver resection for metastatic disease formed the study group. Attenuation measurements were obtained from 12 regions of interest in the liver and three in the spleen on both unenhanced and portal phase contrast-enhanced preoperative hepatic CT images. Hepatic attenuation measurements were analyzed both with and without normalization with the spleen. Normalization included both differences and ratios between hepatic and splenic attenuation values. Pathologic fat content was graded semiquantitatively as a percentage of the nonneoplastic liver parenchyma of the resected specimen. Average attenuation values of the liver were compared with pathologic fat content, as were the differences and ratios between hepatic and splenic attenuation values. Linear regression analysis was conducted on a log-log scale.
Data on 88 patients were analyzed. On unenhanced and contrast-enhanced CT images, all associations between pathologic fat content and attenuation measurements were significant (p < 0.0001). All series of R2 values for unenhanced CT scans were much higher than those for contrast-enhanced CT scans. The R2 values of liver-only measurement were higher than those of hepatic values normalized with splenic values on both unenhanced (0.646-0.649 > 0.523, 0.565) and contrast-enhanced (0.516 > 0.242, 0.344) CT.
Measurement of attenuation of liver only on unenhanced CT scans is best for prediction of pathologic fat content.
本研究旨在评估多种CT扫描衰减测量方法中哪种最适合预测肝脏脂肪含量。
本回顾性研究经机构审查委员会批准。因转移性疾病接受肝切除术的连续登记患者组成研究组。在术前肝脏CT平扫及门静脉期增强图像上，从肝脏的12个感兴趣区和脾脏的3个感兴趣区获取衰减测量值。对肝脏衰减测量值进行分析，分析时既考虑了不与脾脏进行归一化处理的情况，也考虑了与脾脏进行归一化处理的情况。归一化处理包括肝脏与脾脏衰减值之间的差值和比值。病理脂肪含量通过半定量分级，以切除标本中非肿瘤性肝实质的百分比表示。将肝脏的平均衰减值与病理脂肪含量进行比较，同时也比较了肝脏与脾脏衰减值之间的差值和比值。在对数-对数尺度上进行线性回归分析。
分析了88例患者的数据。在CT平扫及增强图像上，病理脂肪含量与衰减测量值之间的所有相关性均具有统计学意义（p < 0.0001）。所有CT平扫系列的R2值均远高于增强CT扫描系列。仅测量肝脏的R2值在CT平扫（0.646 - 0.649 > 0.523, 0.565）和增强CT（0.516 > 0.242, 0.344）上均高于用脾脏值进行归一化处理后的肝脏值。
仅在CT平扫上测量肝脏衰减最适合预测病理脂肪含量。
