细菌性肝脓肿56例影像学征象特点分析

Imaging Findings of Bacterial Liver Abscess:Report of 56 Cases

目的分析细菌性肝脓肿影像学诊断的征象特点。方法回顾性分析56例经手术、随访或穿刺检查证实的细菌性肝脓肿患者的临床资料,内容包括临床表现、超声、CT及MRI影像表现。结果 56例细菌性肝脓肿患者各项症状体征的发生率比较,差异有统计学意义(χ2=135.49,P<0.01)。其中发热与肝区疼痛及叩击痛的发生率比较,差异无统计学意义(P>0.05);发热与寒战的发生率比较,差异有统计学意义(P<0.05)。病灶脓肿包括单个病灶42例、2个病灶5例,≥3个病灶9例。B超检查42例患者,诊断肝脓肿38例(90.5%),典型表现为为肝实质内低回声或无回声区,脓肿后方回声轻度增强,其中液性暗区内出现飘浮移动现象8例,呈蜂窝状结构15例。CT检查56例患者,诊断肝脓肿53例,诊断率为94.6%,平扫表现为肝内单个或多个低密度灶,边缘模糊或清晰,密度不均匀,可见环形带及分房样改变;病灶内伴气体6例,平扫表现为软组织密度3例;增强扫描表现:(a)动脉期表现:肝内低密度灶周围肝组织强化明显,而病灶本身或边缘无明显强化或轻度强化,伴肝段一过性强化4例;(b)门静脉期表现:不同形态强化5例;"环征"(单、二、三环征)34例;病灶呈分隔状或花瓣样强化6例;(c)延迟期表现:水肿带消失或模糊,腔壁或房隔结构强化加浓呈持续性强化36例。MRI检查12例患者,9例诊断为肝脓肿,3例不除外肝脓肿;肝脓肿MRI典型表现为T1WI呈不均匀性低信号,T2W I上脓肿坏死区呈圆形或类圆形大片状高信号区,其周围由中等高信号包绕;其中6例行MRI增强扫描后脓肿坏死区无强化,脓肿壁在各期均强化明显;增强呈多房性分隔强化2例;肝内多发病灶呈环状强化1例。结论影像学是诊断及鉴别诊断细菌性肝脓肿的方法,结合临床发热病史及白细胞增高具有重要的诊断价值。

Objective To analyze the features of diagnostic imaging findings of bacterial liver abscess（BLA）.Methods A retrospective analysis was performed on clinical data（including clinical manifestations,imaging presentations of ultrasound,CT and MRI）of 56 patients diagnosed as BLA by surgery,puncture,follow-ups.Results There was significant difference in symptom and sign incidence between 56 BLA patients（χ2=135.49,P0.01）.Thereinto incidence of fever was significantly different from that of ague（P0.05）,but not from that of liver pain and percussion pain（P0.05）.Lesion abscess included single lesion（42 cases）,2 lesions（5 cases）,over 3 lesions（9 cases）.Forty-two patients had ultrasound,38 of whom were diagnosed as BLA typically showing hypoechoic or anechoic area in liver parenchyma and mild abscess posterior echo enhancement.Floating mobile phenomenon appeared in liquid anechoic area in 8 patients,honeycomb structure in 15.Fifty-six patients had CT,53 diagnosed as BLA（94.6%）,plain scan showing one or more low-density liver lesions,with unsharp or sharp edge,uneven density,ring-and loculation-like changes being seen.Lesions associated with gas in 6,scan soft tissue density in 3.Enhanced scanning performances were：（a） in arterial phase,marked enhancement of liver tissues around low-density lesions,but the lesions themselves with mild or no marked enhancement,transient enhancement of companion liver segment in 4 cases.（b） in portal venous phase,different forms of enhancement in 5 cases,＂ring sign＂（single,second,third ring sign） in 34,separation-or petal-like enhancement in 6.（c） in lag period,edema disappeared or blurred,parietal or atrial septum enriched continuous enhancement in 36 cases.Twelve patients received MRI,9 diagnosed as BLA,3 not excluded.BLA typical manifestations by MRI were T1WI being heterogeneous low signal,T2WI abscess necrotic area being round or oval lamellar high signal area,around which were moderate high signal.After enhanced MRI scan,no enhancement was noted in abscess necrosis area but abscess wall enhanced markedly in 6 patients;2 patients showed multilocular separated enhancement;1 showed ring-like enhancement of liver multiple lesions.Conclusion Radiology imaging,a method of diagnosis and differential diagnosis of BLA,is of very important value when applied in combination with clinical fever history and elevated white blood cells.