早期肝脓肿CT动态增强与MR影像分析

The Correlation of the Early Stage of Pyogenic Liver Abscess Between Dynamic Contrast Enhanced CT Scan and MR Plain Scan

目的通过螺旋CT动态增强扫描与MR平扫影像分析,探讨早期肝脓肿的特征性影像表现,为该病的早期诊断与及时治疗提供根据。方法回顾经多种方法证实的早期肝脓肿患者19例,对其进行CT、MR同层对照,研究病变的分期、病因、范围、形态、强化方式。结果早期肝脓肿多发14例,单发5例。病因不同,影像表现既相似也有差异。(1)平扫表现为水肿区与小囊腔共存的"大水肿,小脓腔"征象(t=6.25,P<0.01),增强为"簇状逐渐强化、衰减延迟"。(2)一过性肝段性强化:门静脉炎、血栓等所致的狭窄区与未狭窄区比较、炎性水肿区与正常肝实质比较,狭窄区、炎性水肿区发生该征象的几率明显高于后两者(χ2=11.73,P=0.001;χ2=9.14,P=0.002)。(3)炎性水肿区与正常肝实质增强扫描后密度比较:前者可表现为动脉期强化明显,门静脉期两者密度相近,延迟期前者密度衰减速率低于后者;延迟期密度差异有统计学意义(t=3.92,P<0.011)。结论采用螺旋CT动态增强扫描与MR平扫相对照,发挥各自特长,从影像学的角度揭示肝脓肿早期病变的特征,为其早期诊断与及时治疗提供依据。

Objective The characteristic findings of pyogenic liver abscess（PLA） were studied through the con＇elation between dynamic enhanced CT scan and MRI plain scan in order to offer the imaging basement for early diagnosis and treatment. Methods The study were retrospectively reviewed nineteen patients with PLA belonged to the early stage of abscess which were confirmed by various ways. All patients were underwent CT and MRI plain scan and dynamic enhanced CT scan. Lesions of all patients of them were compared in the same situation on CT and MRI to analysis the stage of lesions, sizes, morphology, the pattern of enhancement, the amount of cholangitis, portal vein thrombosis or stenosis, and pylephlebits. Results Fourteen patients of PLA in the early stage of abscess were multiple. Five patients were single. PLA originating from biliary tract, portal circulation, arterial hematogenous spread, and directed extension. （1）The perilesion edema and pus cavity （〈2cm） were coexisting in the enhanced CT scan. It was so called i°large edema area, small pus cavityi± （t=6.25, P〈0.01 ）.After enhanced, it showed ＂cluster sign in gradual enhancement and reduced attenuation in a less speed than normal liver parenchyma＂. （2） Transient hepatic attenuation difference （THAD）：The ratio showing the sign in the obstruction area due to the result of pylephlebits or stenosis and thrombosis had a significant difference （Χ^2 = 11.73, P=0.001 ） than the area of no obstruction. The ratio showing the sign in perilesion edema area had a more signifcant difference （Χ^2 =9.14, P=0.002）than normal liver parenchyma. （3）The comparison of density between the perilesion edema area and normal liver parenchyma of enhancement： The time-density curve showed that the former had a significant enhancement than the later during PAH and then the density was similar during PVE Moreover, the foriner which the speed of density reduced in a lower speed had difference （t = 3.93, P〈0.011 ）than the later during PLH. Conclusion Making use full of their advantages of three phase enhanced CT scan and MR plain scan, the process evolution of early stage of pyogenic liver abscess could be disclosed in order to offer a new view for the early diagnosis and treatment of this disease.