Xu Jack Junchi, Boesen Mikkel Ranum, Hansen Sofie Lindskov, Ulriksen Peter Sommer, Holm Søren, Lönn Lars, Hansen Kristoffer Lindskov
Department of Diagnostic Radiology, Copenhagen University Hospital, Rigshospitalet, 2100 Copenhagen, Denmark.
Department of Clinical Medicine, University of Copenhagen, 2100 Copenhagen, Denmark.
Diagnostics (Basel). 2022 Mar 14;12(3):708. doi: 10.3390/diagnostics12030708.
We assessed the correlation between liver fat percentage using dual-energy CT (DECT) and Hounsfield unit (HU) measurements in contrast and non-contrast CT. This study included 177 patients in two patient groups: Group A ( = 125) underwent whole body non-contrast DECT and group B ( = 52) had a multiphasic DECT including a conventional non-contrast CT. Three regions of interest were placed on each image series, one in the left liver lobe and two in the right to measure Hounsfield Units (HU) as well as liver fat percentage. Linear regression analysis was performed for each group as well as combined. Receiver operating characteristic (ROC) curve was generated to establish the optimal fat percentage threshold value in DECT for predicting a non-contrast threshold of 40 HU correlating to moderate-severe liver steatosis. We found a strong correlation between fat percentage found with DECT and HU measured in non-contrast CT in group A and B individually (R = 0.81 and 0.86, respectively) as well as combined (R = 0.85). No significant difference was found when comparing venous and arterial phase DECT fat percentage measurements in group B ( = 0.67). A threshold of 10% liver fat found with DECT had 95% sensitivity and 95% specificity for the prediction of a 40 HU threshold using non-contrast CT. In conclusion, liver fat quantification using DECT shows high correlation with HU measurements independent of scan phase.
我们评估了在增强CT和非增强CT中，使用双能CT（DECT）测量的肝脏脂肪百分比与亨氏单位（HU）之间的相关性。本研究纳入了177例患者，分为两个患者组：A组（n = 125）接受了全身非增强DECT检查，B组（n = 52）接受了多期DECT检查，包括常规非增强CT。在每个图像序列上放置三个感兴趣区，一个位于左肝叶，两个位于右肝叶，以测量亨氏单位（HU）以及肝脏脂肪百分比。对每个组以及合并后的组进行线性回归分析。生成受试者操作特征（ROC）曲线，以确定DECT中预测与中度至重度肝脂肪变性相关的40 HU非增强阈值的最佳脂肪百分比阈值。我们发现，A组和B组单独以及合并后，DECT测得的脂肪百分比与非增强CT测得的HU之间均存在强相关性（分别为R = 0.81和0.86，合并后R = 0.85）。比较B组静脉期和动脉期DECT脂肪百分比测量值时，未发现显著差异（P = 0.67）。DECT测得的肝脏脂肪百分比阈值为10%时，对于使用非增强CT预测40 HU阈值具有95%的敏感性和95%的特异性。总之，使用DECT进行肝脏脂肪定量显示，与HU测量值具有高度相关性，且与扫描期相无关。
