磁共振弥散加权成像对肝局灶性病变良恶性的鉴别诊断

MR Diffusion-weighted Magnetic Resonance Images in the Differential Diagnosis between Benign and Malignant Focal Liver Lesions

目的探讨磁共振弥散加权成像(DWI)在肝局灶性病变的良恶性鉴别诊断中的应用价值。方法收集肝脏局灶性病变患者106例,其中原发性肝癌34例,肝脏转移瘤16例,海绵状血管瘤33例,肝囊肿15例,局灶性结节性增生8例。所有病例均行常规磁共振(MRI)扫描和单次激发的自旋回波平面回波成像(SE-EPI)序列的DWI,DWI采用b值为0s/mm2和500s/mm2。各组局灶性病灶平均表观弥散系数(ADC)值的比较采用t检验。结果原发性肝癌、肝脏转移瘤、海绵状血管瘤、肝囊肿和局灶性结节性增生的平均ADC值分别为(1.77±0.60)×10-3mm2/s、(1.74±0.42)×10-3mm2/s、(2.52±0.75)×10-3mm2/s、(3.60±0.69)×10-3mm2/s和(2.09±0.52)×10-3mm2/s,肝囊肿和血管瘤与恶性病变比较,ADC值高且有统计学意义(P<0.01),而恶性肿瘤(原发性肝癌、肝转移瘤)与局灶性结节性增生比较,ADC值的差别不具有统计学意义(P>0.05)。结论DWI和ADC值能够鉴别常见肝局灶性病变的良恶性,但肝实质性局灶性良恶性病灶之间的ADC值无明显差别,与普通MRI相比,DWI对肝脏实质性病灶性质的鉴别意义有限。

Objective To assess whether diffusion-weighted imaging（DWI）and apparent diffusion coefficient（ADC）values may be used in the differential diagnosis of malignant and benign focal hepatic lesions.Methords One hundred and six patients with focal disease in liver,including hepatocellular carcinoma（n =34）,hepatic metastatic tumor（n =16）,hepatic cavernous hemangioma（n =33）,hepatic cysts（n =15）,and focal nodular hypertension（n =8）,and six normal volunteers underwent magnetic resonance imaging（MRI）of the liver including DWI.A single-shot echo planar imaging sequence was applied in axial orientation with two b-values（0,500 s/mm2）.The ADC values of these lesions were calculated respectively.The statistical significance of differences between benign and malignant lesions was determined by use of t test.Results The mean ADC values（mm2/s）were（1.77±0.60）×10^-3 in hepatocellular carcinomas,（1.74±0.42）×10^-3 in hepatic metastatic tumors,（2.52±0.75）×10^-3 in hepatic cavernous hemangiomas,（3.60±0.69）×10^-3 in hepatic cysts,and（2.09±0.52）× 10^-3 in focal nodular hypertensions.The mean ADC values in hepatic cavernous hemangiomas and hepatic cysts were more than those in the malignant lesions（P〈0.01）,and there was no significant difference of the mean ADC values between focal nodular hypertension and the malignant lesions（P〉0.05）.Conclusion DWI and ADC measurements can be useful in differentiating most commonly encountered malignant from benign focal liver lesions,however,It may be limit value in characterizing and differentiating local hepatic parenchyma lesions compared to common MRI.