中文摘要：

目的探讨钆对比剂对腹部实性脏器体素内不相干运动（IVIM）MRI图像质量及其参数值的影响,寻找腹部IVIM序列扫描的合适时机。资料与方法 20例患者分别于对比剂注射前后行相同腹部IVIM扫描,测量并计算b=50、300、800 s/mm2扩散加权成像（DWI）图像上肝脏、脾脏、胰腺、肾脏的信噪比（SNR）以及肝细胞癌（HCC）的SNR以及对比噪声比（CNR）,并测量肝脏、脾脏、肾脏及HCC的表观扩散系数（ADC）值及IVIM参数（D值、D＊值、f值）,对各测量值增强扫描前后的差异进行比较。结果增强扫描后b=50 s/mm2肝脏的SNR较增强前明显下降（t=2.397,P〈0.05）。b=300 s/mm2 HCC的CNR显著增高（t=-3.380,P〈0.01）。肾脏各b值的SNR均较增强扫描前显著下降（Z=-2.675~-2.201,P〈0.05）;而脾脏、胰腺及HCC各b值的SNR与增强扫描前的差异均无统计学意义（t或Z=-1.324~1.104,P〉0.05）。增强扫描后仅肾脏的ADC值、D值下降,差异有统计学意义（tADC=3.569,P〈0.01;ZD=-3.053,P〈0.01）,而肝脏、脾脏及HCC的各参数值增强扫描前后差异均无统计学意义（t=-1.102~1.689,P〉0.05）。结论注射钆对比剂可降低肝脏低b值和肾脏各b值DWI的SNR,使中等b值肝脏病变的CNR增高,而不影响脾脏、胰腺和肝脏病变的SNR。钆对比剂亦可降低肾脏的ADC值、D值,而对肝脏及其病变、脾脏的DWI及IVIM参数无影响。

英文摘要：

PurposeTo prospectively investigate the effect of gadolinium contrast media on the quality of intravoxel incoherent motion （IVIM） MRI images and the quantification of corresponding parameters for abdominal solid organs, and to explore the appropriate time for abdominal IVIM scan.Materials and MethodsTwenty patients underwent the same abdominal IVIM scan before and after gadolinium contrast administration. The signal-to-noise ratio （SNR） of liver, spleen, pancreas and kidneys were measured on diffusion-weighted imaging （DWI） images at b=50 s/mm2, 300 s/mm2 and 800 s/mm2. SNR and contrast-to-noise ratio （CNR） of hepatocellular carcinoma （HCC） （n=16） were also calculated. Apparent diffusion coefficient （ADC） value and IVIM parameters including pure diffusion coefficient （D）, pseudo-diffusion coefficient （D＊） and perfusion fraction （f） of liver, spleen, kidneys parenchyma and HCC were measured and compared. ResultsSNR of liver on post-contrast DWI at b=50 s/mm2 were significantly lower than that of pre-contrast （t=2.397,P〈0.05）. CNR of HCC increased significantly on b=300 s/mm2 DWI images after contrast （t=-3.380,P〈0.01）. SNR of kidneys on DWI of any b value decreased after contrast administration （Z=-2.675--2.201,P〈0.05）. SNR of spleen, pancreas and HCC were not statistically different between pre-contrast and post-contrast images （t orZ=-1.324-1.104,P〉0.05）. As for IVIM parameters, only ADC and D values of kidneys demonstrated a significant reduction after contrast （ADC：t=3.569,P〈0.01; D：Z=-3.053,P〈0.01）. No significant differences were detected for all parameters of liver, spleen and HCC between pre-contrast and post-contrast images （t=-1.102-1.689,P〉0.05）. ConclusionAdministration of gadolinium contrast media may result in decrease of SNR of liver on low b value DWI and SNR of kidneys at any b value, but it increases CNR of hepatic lesions on medium b value DWI. Administration of gadolinium contrast media does not make a significa