不同b值扩散加权MRI诊断肝脏局灶性病变的初步研究

Study of Focal Hepatic Lesions by Diffusion-weighted MRI with Different b Values

目的:探讨不同b值磁共振扩散加权成像(DWI)系列分析及表观扩散系数(ADC)值对肝脏常见局灶性病变定性诊断的价值。方法:对45例肝脏常见局灶性病变(15例肝癌,18例肝血管瘤,12例肝囊肿)行不同b值DWI(b=600 s/mm2,1000 s/mm2,2000 s/mm2),观察病灶DWI信号强度连续变化并计测表观扩散系数(ADC)值。结果:肝癌不同b值DWI均表现为高信号,随b值增加,病灶信号强度无显著性改变(P﹥0.05);肝血管瘤DWI(b=600 s/mm2)表现为高信号,DWI(b=1000 s/mm2,2000 s/mm2)表现为高或等信号,随b值增加,病灶信号强度降低(P﹤0.05);肝囊肿DWI(b=600)表现为高、等或低信号,DWI(b=1000 s/mm2,2000 s/mm2)表现为低信号,随b值增加,囊肿信号强度降低(P﹤0.05)。随b值增加,肝癌、肝血管瘤、肝囊肿的ADC值均逐渐降低(P﹤0.05)。结论:不同b值DWI系列分析可能鉴别诊断肝脏常见局灶性病变。

Purpose： To evaluate the efficacy of diffusion-weighted imaging （DWI） with different b values and apparent diffusion coefficient （ADC） in diagnosis of focal hepatic lesions. Methods： DWI with different b values （b=600 s/mm^2, b=1000 s/mm^2, b=2000 s/mm^2） was performed in 45 patients with focal hepatic lesions. The signal intensity character of the lesions and that of the surrounding liver parenchyma were compared and classified on DWI. Apparent diffusion coefficient （ADC） values of the lesions were measured. Results： ttepatocellular carcinomas were hyper-intense on DWI with different b values （b=600, 1000, 2000 s/mm^2） . Haemangiomas were hyper-intense on DWI with b=600 s/mm^2, and were hyper-intense or iso-intense on DWI with b=1000 or 2000 s/mm^2. With the increased of b value, the signal intensity of haemangiomas decreased （P〈0.05） . Cysts were hyper-intense, iso-intense or hypo-intense on DWI with b=600 s/ram2, and were hypo-intense on DWI with b=1000 and 2000 s/mm^2. With the increased of b value, the signal intensity of cysts decreased （P〈 0.05）. With the increased of b value, ADC value of hepatocellular carcinomas, haemangiomas and cysts decreased （P〈 0.05）. Conclusion： DWI with different b values could be used to differentiate focal hepatic lesions.