MR扩散加权成像中ADC值对肝脏肿瘤性病变的定性评估

目的评估MR扩散加权成像(DWI)对肝脏肿瘤性病变、特别是影像学表现不典型肿瘤性病变的诊断价值及其良恶性鉴别诊断价值。资料与方法对2010年8月至2011年5月的55例患者(34例为肿瘤患者怀疑有肝脏转移,21例CT、B超等影像学检查拟诊肝脏占位性病变无法进行定性诊断)行MR常规序列及DWI,共发现92个病灶(25个原发性肝癌,27个肝转移瘤,3个肝胆管细胞癌,2个肝硬化结节,2个肝脏局灶性结节增生,7个肝血管瘤,26个肝囊肿)。通过分析肝脏病灶信号强度随b值不同的变化及病灶表观扩散系数(ADC)值的大小(平均数±标准差)等对肝脏肿瘤性病变、特别是不典型肿瘤性病变的良恶性进行诊断及鉴别诊断,以病理结果或随访结果为标准计算其敏感性及特异性。结果 MR DWI上,b=50 s/mm2、500s/mm2及b=50 s/mm2、1000 s/mm2时,良性病变的信号衰减程度高于恶性病变,即b为50 s/mm2、1000 s/mm2时,恶性病变为高信号,而良性病变呈相对等信号或低信号,良恶性病灶信号强度差异明显。恶性病变的ADC值(b值为50 s/mm2、1000 s/mm2时计算)(0.845±0.0110)×10-3mm2/s,n=55]明显低于良性病变的ADC值(b值为50 s/mm2、1000 s/mm2时计算)(2.230±0.0497)×10-3mm2/s,n=37],经秩和检验差异具有统计学意义(Z=-7.905,P<0.01),敏感性及特异性分别为96.36%和83.78%。结论 DWI对肝脏肿瘤性病变、特别是影像学表现不典型肿瘤性病变具有较大诊断价值,对肝脏肿瘤性病变的良恶性鉴别诊断是一种简单、实用的影像学检查方法。

Value of ADC in Diffusion-Weighted Magnetic Resonance Imaging in the Diagnosis of Hepatic Neoplasm

Objective To evaluate the feasibility of diffusion-weighted imaging(DWI) in screening and differential diagnosis of benign and malignant hepatic neoplasm.Materials and Methods Fifty five patients underwent liver MRI conventional sequences and DWI examinations using the 1.5T Siemens Magnetom Symphony(Erlangen,German).Among them,97 lesions were detected,including 25 hepatocellular carcinomas(HCC),3 cholangiocarcinomas,27 metastatic liver cancers,2 cirrhosis nodule,2 liver focal nodules hyperplasia,7 hemangiomas,and 26 cysts.Signal intensity and apparent diffusion coefficient(ADC) were compared between benign and malignant lesions.The sensitivity and specificity were calculated.Results ADCs(mean ± SD,× 10-3mm2/s) were significantly lower(P < 0.05) in malignant lesions(0.845±0.0110×10)-3mm2/s,n=55]than that in benign lesions(2.230±0.0497)×10-3mm2/s,n=37].The sensitivity and specificity were 96.36%,83.78%,respectively.Conclusion DWI is a simple and sensitive method for screening hepatic neoplasm and is useful for differential diagnosis.