磁共振扩散加权成像在肝脓肿诊断中的价值

摘要

目的:探讨肝脓肿的磁共振扩散加权成像(DWI)影像特征,提高其影像诊断水平.方法:回顾性分析20例患者中30个肝脓肿的常规磁共振扫描加动态增强扫描及DWI图像,表观扩散系数(ADC)值定量分析肝脓肿的脓腔、脓肿壁及周围正常肝组织.结果:ADC图上,30个肝脓肿的脓腔中24个呈明显低信号,2个等信号,4个明显高信号,ADC值为(0.69～2.62)×10-3 mm2/s.30个肝脓肿中,8个未见明显脓肿壁形成; 22个脓肿壁在DWI图像上呈多样信号,在ADC图上均呈稍高信号,平均ADC值为(1.70 ± 0.23)×10-3 mm2/s.结论:肝脓肿的脓腔在DWI上常表现为明显高信号,ADC值较低;但部分脓腔ADC值较高,与肿瘤囊变坏死区难以鉴别;脓肿壁在ADC图上呈稍高信号的影像学特征有助于其诊断和鉴别诊断.%Objective: To investigate the imaging fcatures of hepatic abscess on DWI and improve its diagnosis.Methods:Twenty patients with 30 hepatic abscesses underwent conventional, dynamic enhanced MRI and diffusion-weighted imaging were studicd retrospectively.The cavities, abscess wall of hepatic abscesses and surrounding normal liver tissues were analyzed quantitatively with ADC valucs rcspectively.Results: On ADC map of 30 hepatic absccsscs cavities, there were obvious hypointense signal on 24, isointense on 2, and obvious hyperintense signal on another 4.The ADC value ranged from 0.69 × 10-3mm2 /s to 2.62 × 10-3mm2 /s, 22 abscess walls of 30 hepatic abscesses on DWI images were isointense or slightly hypointense signal or slightly hyperintense signal, however, all 22 absccss walls of the hepatic abscesses showcd slightly higher signal on the ADC map with the average ADC value of 1.70 ± 0.23 ×10-3mm2 /s.Conclusion: Cavities of hepatic abscess are usually in obvious hyperintense signal on DWI with lower ADC values.But some cases may present with high ADC value in the cavity of hepatic abscess, which are difficult to diffcrcntiate hepatic abscess from cystic or necrotic tumor.The imaging feature of abscess wall, which is slightly hypcrintense signal on the ADC map, can help to diagnose hepatic abscess.