摘要目的 探讨胰腺组织3T磁共振(MR)扩散加权成像(DWI)的可行性及其在胰腺肿瘤定性诊断中的价值。方法 应用3T MR成像仪对20名健康志愿者和47名胰腺肿块患者(胰腺癌21例，肿块型胰腺炎7例，胰腺囊性肿瘤19例)行胰腺常规MRI及两组不同扩散梯度因子(b值，500和1000 mm2/s)DWI检查，测量病灶、病灶旁胰腺DWI信号强度(signal intensity，SI)及病灶表观扩散系数(apparent diffusion coefficient,ADC)值。结果 在b=500和1000 mm2/s DWI图像上，正常胰腺实质信号均匀，胰头、体、尾各部分的ADC值差异均无统计学意义；而胰腺癌、肿块型胰腺炎均显示为高信号，且在b=1000mm2/s的DWI上胰腺癌的相对SI1000值显著高于肿块型胰腺炎(1.238 +0.448比0.371±0.293，P＜0.01)。胰腺癌与肿块型胰腺炎ADC500和ADC1000均显著低于正常胰腺(P＜0.01)，且胰腺癌ADC1000显著低于肿块型胰腺炎[(1.087±0.175) mm2/s比(1.279 +0.213) mm2/s,P＜0.01]。胰腺囊性病变在b= 500 mm2/s时显示为高信号，在b=1000mm2/s的DWI上表现为低或等低信号，其ADC500和ADC1000均显著高于正常胰腺(P值均＜0.01)。结论 3T磁共振胰腺DWI有助于胰腺肿块型病变的鉴别诊断，高b值DWI对胰腺病变定性诊断更有价值。

abstractsObjective To investigate the feasibility of pancreatic DWI at a 3T MR imager and its value for the qualitative diagnosis of pancreatic tumors. Methods For 20 normal healthy volunteers and 47 patients with pancreatic tumors [21 pancreatic carcinoma (PC), 7 mass-forming chronic pancreatitis (MFCP)and 19 cystic lesions), routine pancreatic MRI and pancreatic DWI using b values (500 and 1000 mm2/s)were obtained, the DWI signal intensity (SI) and apparent diffusion coefficient (ADC) value of pancreatic lesions and adjacent tissue was measured. Results In the b = 500 and 1000 mm2/s DWI images, there was no significant difference in ADC value between different parts of normal pancreas. But PC and MFCP were shown as hyperintensity mass, in addition, the related SI1000 of PC at b = 1000 mm2/s DWI was significantly higher than that of MFCP (1.238 +0.448 vs. 0.371 +0.293, P＜0. 01). Compared with normal pancreas,beth PC and MFCP presented as decreased ADC500 and ADC1000 value. The ADC1000 of PC was significantly lower than that of MFCP [ ( 1. 087 + 0. 175 ) mm2/s vs. ( 1. 279 ± 0.213 ) mm2/s]. Pancreatic cystic lesions were shown as hyperintensity in DWI at b = 500 mm2/s, but were depicted as iso-intense signal or low-signal lesions in DWI using b = 1000 mm2/s. Both ADC500 and ADC1000 of pancreatic cystic lesions were higher than that of normal pancreas. Conclusions 3T-MR DWI is helpful to differentiate pancreatic lesions. High b value DWI is more valuable for the qualitative diagnosis of pancreatic mass.