Xu Peng-Ju, Yan Fu-Hua, Wang Jian-Hua, Shan Yan, Ji Yuan, Chen Cai-Zhong
Department of Radiology, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China.
J Comput Assist Tomogr. 2010 Jul;34(4):506-12. doi: 10.1097/RCT.0b013e3181da3671.
To evaluate the diagnostic value of diffusion-weighted magnetic resonance imaging (DWI) for the characterization of hepatocellular carcinoma (HCC) and dysplastic nodule (DN) in cirrhotic liver, compared with contrast material-enhanced magnetic resonance imaging (CE-MRI).
A total of 54 patients with 40 HCC and 19 DN lesions were included in our study, and all lesions were histopathologically confirmed. All lesions were evaluated with CE-MRI, and breath-hold DWI was performed with b = 500 s/mm. The signal intensity (SI) of the lesions were classified as low, iso-, slightly high, and strongly high SI compared with that of the surrounding liver parenchyma on DWI for qualitative assessment. Apparent diffusion coefficients (ADCs) and lesion-to-liver ADC ratio of HCCs and DNs were measured and compared by using the Mann-Whitney U test. The lesions were characterized with the use of CE-MRI criteria and DWI, respectively. Receiver operating characteristic analysis was performed to assess the diagnostic value of DWI, CE-MRI, and these techniques combined in the differentiation of HCCs from DNs.
In the qualitative analysis, among 40 HCCs, 39 (97.5%) had slightly high or strongly high SI on DWI, and 1 (2.5%) had low SI; only 4 (21.5%) of 19 DNs had slightly high SI, and 15 (78.95%) had iso-SI or low SI. The mean (SD) ADC and ADC ratio for HCCs (1.28 x 10 [0.25] mm/s and 0.88 [0.15], respectively) were significantly lower (P < 0.01 and P < 0.001, respectively) than those for DNs (1.53 x 10 [0.33] mm/s and 1.00 [0.08], respectively). The area, Az, under the receiver operating characteristic curve for the SI feature, the ADC ratio, and the ADCs based on the diagnosis of HCC versus DN were 0.88, 0.81, and 0.68, respectively. When the slightly high SI of lesion with a cutoff ADC ratio less than 0.92 was applied as a criterion, the Az, the sensitivity, the specificity, and the accuracy of DWI for the diagnosis of HCC versus DN were 0.81, 67.50%, 94.74%, and 76.27%, respectively. The corresponding Az, sensitivity, specificity, and accuracy of CE-MRI were 0.70, 82.50%, 57.89%, and 74.58%, respectively. Combined DWI plus CE-MRI had 0.91 Az, 97.50% sensitivity, and 93.22% accuracy, which increased significantly compared with those of CE-MRI alone.
Diffusion-weighted MRI can provide additional information to differentiate HCC from DN. Combined with CE-MRI, DWI allows improved characterization of HCC versus DN in cirrhotic liver.
与对比剂增强磁共振成像（CE-MRI）相比，评估扩散加权磁共振成像（DWI）对肝硬化肝脏中肝细胞癌（HCC）和发育异常结节（DN）特征的诊断价值。
本研究共纳入54例患者，其中有40个HCC病变和19个DN病变，所有病变均经组织病理学证实。所有病变均接受CE-MRI评估，并在屏气状态下进行b值为500 s/mm²的DWI检查。在DWI上，根据病变与周围肝实质信号强度（SI）的比较，将病变的SI分为低、等、略高和高SI进行定性评估。采用Mann-Whitney U检验测量并比较HCC和DN的表观扩散系数（ADC）及病变与肝脏的ADC比值。分别使用CE-MRI标准和DWI对病变进行特征描述。进行受试者操作特征分析，以评估DWI、CE-MRI以及这两种技术联合应用在鉴别HCC与DN中的诊断价值。
在定性分析中，40个HCC中，39个（97.5%）在DWI上表现为略高或高SI，1个（2.5%）为低SI；19个DN中，仅4个（21.5%）表现为略高SI，15个（78.95%）为等SI或低SI。HCC的平均（标准差）ADC及ADC比值（分别为1.28×10⁻³[0.25]mm²/s和0.88[0.15]）显著低于DN（分别为1.53×10⁻³[0.33]mm²/s和1.00[0.08]）（P均<0.01）。基于HCC与DN诊断的受试者操作特征曲线下面积（Az），SI特征为0.88，ADC比值为0.81，ADC为0.68。当以ADC比值小于0.92为界值，将病变略高SI作为标准时，DWI诊断HCC与DN的Az、敏感性、特异性和准确性分别为0.81、67.50%、94.74%和76.27%。CE-MRI相应的Az、敏感性、特异性和准确性分别为0.70、82.50%、57.89%和74.58%。DWI联合CE-MRI的Az为0.91，敏感性为97.50%，准确性为93.22%，与单独使用CE-MRI相比有显著提高。
扩散加权MRI可为鉴别HCC与DN提供额外信息。DWI与CE-MRI联合应用可更好地对肝硬化肝脏中的HCC与DN进行特征描述。
