静脉注射Gd-DTPA肝脏局灶性病变弥散加权成像的定量对照研究

Comparison of diffusion-weighted Imaging before and after intravenous administration of Gd-DTPA in focal liver lesions by quantitative analysis

目的:探讨静脉注射Gd-DTPA前后肝脏局灶性病变(FLLs)弥散加权成像(DWI)的信噪比(SNR)、对比噪声比(CNR)及表观弥散系数(ADC)值的变化。方法:26例26个病灶中,肝脏海绵状血管瘤6个,肝细胞癌20个。所有病灶静脉注射Gd-DTPA前后分别进行DWI检查,b值600s/mm2。病灶的SNR、CNR在DWI测量及计算得出,ADC值的测量在ADC图完成。结果:静脉注射Gd-DTPA后病灶的SNR、CNR均增大,前后差异均有统计学意义(P=0.036,P=0.008)。病灶的ADC值减小,前后差异有统计学意义(P=0.019)。结论:尽管静脉注射Gd-DTPA后FLLs的DWI图像质量有所提高,但是FLLs的ADC值显著减小,从ADC值定量研究考虑,DWI应在注射Gd-DTPA前进行。

Objective： To evaluate whether intravenous administration of Gd-DTPA signifi- cantly affects diffusion-weighted imaging （DWl） and apparent diffusion coefficient（ADC） values at the focal liver lesions（FLLs）. Methods： A total of twenty-six patients with 26 FLLs, including 6 he-mangioma and 20 hepatocellular carcinoma,underwent DWI with b value of 600 s/mm2 before and after intravenous administration of Gd-DTPA. The signal-to-noise ratio （SNR）and contrast-to-noise ratio （CNR）of the lesions were calculated on DWl. ADC values of the lesions were measured on ADC maps. The statistical significance of differences between precontrast and postcontrast data was determined by use of a paired t test. Results： On the DWl, the SNR of lesions and CNR were significantly increased after Gd-DTPA injection （P=0.036, P=0.008）. ADC values of the focal liver lesions significantly decreased after Gd-DTPA injection （P=0.019）. Conclusion： The SNR and CNR of the lesions on DWl were significantly increased after Gd-DTPA injection. However, ADC values of the lesions significantly decreased after Gd-DTPA injection. If ADC measurement are planned, DWl should be performed before Gd-DTPA injection.