肝囊肿和血管瘤的磁共振扩散加权成像诊断及鉴别诊断价值

摘要

Objective To investigate the diagnostic value of diffusion-weighted images and ADC map between liver cysts and hemangiomas. Methods Magnetic resonance diffusion-weighted imaging (DWI) was obtained in a total of 80 cases with hepatic lesions including 140 lesions (80 were of liver cysts, 60 were of hemangiomas). All patients were synthetically judged by clinical diagnosis and/or comprehensive imaging examinations. The characteristics of the DWI and apparent diffusion coefficient (ADC) values were analyzed, liver parenchyma signal to noise ratio (SNR), le-sions-liver contrast to noise ratio (CNR) and the relations between them, respectively. Results The lesions with liver cysts (98.5%)presented as hypo intensity or slight hyper intensity and that of hepatic hemangiomas (96.7%)as homo-geneous high signal on diffusion-weighted imaging. There were negative correlation between b value and the SNR of the liver parenchyma, between b value and the both lesions-liver CNR, between b value and the ADC value of focal hepatic lesions. There was significant difference between liver parenchyma and liver cysts and hemangiomas ( P<0.05), and there was significantly difference of the ADC value between liver cysts and liver hemangiomas ( P<0.05).As the b values increased, the ADC values of liver cysts and liver hemangiomas, both lesions-liver CNR were both decreased, liver cysts particularly, when b was more than 500 s/mm2, the signals between liver cysts were almost identical with liver. when b was 500 s/mm2, the ADC values of hemangioma, liver cysts were (3.24 ±1.27) ×10-3 mm2/s and (2.53 ± 0.53)×10-3 mm2/s, respectively. Conclusion Magnetic resonance diffusion-weighted imaging can do help for diagno-sis and differential diagnosis of liver hemangiomas and liver cysts.%目的：研究磁共振扩散加权成像（DWI）对肝囊肿和肝血管瘤的诊断和鉴别诊断价值。方法收集80例患者共140个病变（囊肿80个，血管瘤60个），所有患者均经临床和/或综合影像学检查证实综合判断已确诊的病例，对80例患者均进行常规磁共振扫描和磁共振DWI扫描，分析肝囊肿和肝血管瘤DWI的特点并测量不同b值下肝脏实质和病变的表观弥散系数（ADC）值、肝实质信噪比（SNR）、病灶-肝脏对比噪声比（CNR）及其相关关系。结果 DWI图像显示肝囊肿病灶（98．5％）呈低信号或略高信号，肝血管瘤病灶（96．7％）呈均匀高信号，b值与肝脏SNR、肝囊肿和血管瘤病灶与肝实质CNR、肝囊肿和血管瘤ADC值均存在负相关。肝囊肿和血管瘤与肝脏的ADC值差异有统计学意义（P＜0．05），随着b值的增大，肝囊肿和血管瘤ADC值、二者与肝实质的CNR均降低，尤以囊肿明显，当b＞500 s/mm2时囊肿的信号与肝脏几乎一致。当b值选用500 s/mm2时，肝囊肿和血管瘤的ADC值不同，分别为（3．24±1．27）×10-3 mm2/s和（2．53±0．53）×10-3 mm2/s。结论磁共振DWI有助于对肝血管瘤和肝囊肿两种疾病的诊断及鉴别诊断。