目的 探讨肝胆特异性对比剂钆塞酸二钠(Gd-EOB-DTPA)对正常肝实质及肿瘤组织的表观扩散系数(apparent diffusion coefficient，ADC)值的影响。方法 20例患者共检出肝脏肿瘤性病变灶21个，在静脉注射Gd-EOB-DTPA前、后20 min分别行肝脏容积加速快速成像(liver acquisition with volume acceleration， LAVA))和扩散加权成像(diffusion weighted imaging，DWI)扫描(b值=0及800 s/mm²)，分别测量增强前后T₁WI图像的信噪比(signal-to-noise ratio，SNR)、肝脏及肿瘤的对比噪声比(contrast-to-noise ratio，CNR)、正常肝实质及肿瘤组织的ADC值，应用配对t检验比较增强前、后SNR、CNR、ADC值的变化。结果 静脉注射Gd-EOB-DTPA 20 min后T₁WI图像的SNR(186.67±59.64)显著高于增强前(102.79±26.95)，差异有统计学意义(t=6.841， P<0.01);增强后CNR(84.86±46.2)显著高于增强前(33.09±21.79)，差异有统计学意义(t=5.758， P<0.01);增强前、后肿瘤的ADC值分别为(1.45±0.57)×10^-3mm/s和(1.37±0.48) ×10^-3mm/s，差异无统计学意义(t=1.320， P=0.202);增强后正常肝实质的ADC值(1.27±0.23)×10^-3mm/s较增强前(1.34±0.25)×10^-3mm/s降低，差异有统计学意义(t=2.189， P=0.033)。结论 静脉注射Gd-EOB-DTPA 20 min后肝脏T₁WI的SNR和CNR均显著高于增强前，故有利于病变的显示及检出;增强前、后肝脏肿瘤的ADC值未见显著差异，而正常肝实质的ADC值较增强前降低，静脉注射Gd-EOB-DTPA20 min后会影响正常肝实质的ADC值的测量。

Objective To evaluate the effect of intravenous administration of Gd-EOB-DTPA on SNR and CNR in T1WI and ADC values of normal liver parenchyma and neoplasm. Methods T1WI using LAVA protocol (Liver Acquisition with Volume Acceleration, LAVA) and DWI was performed before and 20 min after Gd-EOB-DTPA injection in 20 patients with liver neoplasm detected by MR imaging.The signal-to-noise ratio(SNR),contrast-to-noise ratio(CNR) on T1WI and ADC values were measured on ADC maps when b=0 and 800 s/mm² were selected.A paired t-test was used to compare the differences between SNR,CNR and ADC values before and 20 min after enhancement in liver parenchyma and neoplasm.Results There were significant differences between the SNR(102.79?26.95 and 186.67?59.64) and CNR (33.09?21.79 and 84.86?46.2) and ADC values of normal liver parenchyma [(1.34?0.25)?10^-3 mm/s and (1.27?0.23)?10^-3 mm/s] before and 20 min after administration of Gd-EOB-DTPA in liver,and no significant differences between the ADC values of neoplasm before and 20 mins after administration of Gd-EOB-DTPA in liver (1.45?0.57)?10^-3 mm/s vs (1.37?0.48) ?10^-3 mm/s. Conclusions Gd-EOB-DTPA-enhanced MR imaging contributes to lesion detection for improved SNR and CNR in T1WI. ADC values of normal liver parenchyma decrease in liver DWI 20 min after IV Gd-EOB-DTPA.