MR弥散加权成像对泡型肝包虫病的评估价值研究

Evalulation Value of Diffusion Weighted Magnetic Resonance in Hepatic Alveolar Echinococcosis

目的分析泡型肝包虫病的磁共振(MR)弥散加权成像(DWI)的特征,评估表观弥散系数(ADC)在泡型肝包虫病中的潜在应用价值。方法回顾性分析2013年11月至2015年1月期间青海大学附属医院根据流行病学、实验室检验和影像学检查及外科手术确诊为泡型肝包虫病的26例患者的临床资料,行3.0 T MR肝脏平扫,DWI序列的b值分别为0、600、1 000、1 200 s/mm^2。所有数据储存至PACS系统,经两名副主任医师参与评定病灶的分型、大小、分布、位置、钙化(CT检查)特征,测量不同b值下包虫中心区、边缘区、周边区肝实质的ADC值并进行比较。结果 1 26例患者共有29个病灶,多累及多个肝段,21个(72%)病灶分布于右半肝,同时累及左、右叶者有4个。24个病灶侵犯肝静脉或门静脉,20个病灶侵犯肝内胆管,10个病灶侵犯右侧肾上腺。7例患者出现肝门区、腹膜后多发增大淋巴结,5例患者出现肺转移,3例患者出现脑转移,同时有肺转移及脑转移患者3例。2液化坏死性病灶20个,其中5个病灶的T2WI边缘有多发小囊,15个病灶的T2WI边缘均为实性成分并未见小囊;12个病灶的中心区DWI呈明显高信号,8个病灶的中心区DWI呈低信号。实性病灶9个,其中有2个病灶的边缘T2WI有小囊,有7个病灶的T2WI为实性成分;实性病灶的DWI为均匀一致的低信号,边缘有均匀少量较连续或不连续环形高信号。3在同一b值下,液化坏死性病灶中心区的ADC值均明显高于实性病灶(P<0.01)。在液化坏死性病灶内不同b值下,周边区的ADC值均明显低于边缘区(P<0.01)和中心区(P<0.05);在实性病灶内不同b值下,周边区和边缘区的ADC值均明显低于中心区(P<0.05)。结论 MR的DWI能清晰分辨泡型肝包虫的结构及成分,对区别肝脏其他疾病有较高的价值。液化坏死性病灶中心区的平均ADC值明显高于实性病灶中心区的ADC值。

Objective To analyze findings of 3.0 T diffusion weighted magnetic resonance（MR） in hepatic alveolar echinococcosis and evaluate potential role of apparent diffusion coefficients（ADC） in hepatic alveolar echinococcosis. Methods The clinical data of 26 patients with hepatic alveolar echinococcosis from November 2013 to January 2015 in this hospital were analyzed retrospectively. Hepatic MR scannings with diffusion weighted imaging（DWI） sequences（b-value=0, 600, 1 000, and 1 200 s/mm^2） were performed in 26 patients with hepatic alveolar echinococcosis. The data of all the patients were stored to the PACS. The lesion features including type, size, distribution, location, and calcification（on the CT） were assessed by two deputy radiologists. The ADC values of marginal area, centre area, surrounding area of liver parenchyma tissue were measured at different b values（0, 600, 1 000, and 1 200 s/mm^2） and compared. Results（1） There were 26 patients with a total of 29 lesions, of which involved multiple liver segments, 21（72%） lesions located in the right lobe, 4 lesions involved simultaneously the left and right lobes. Twenty-four lesions invaded the hepatic vein or portal vein, 20 lesions invaded the intrahepatic bile duct, 10 lesions invaded the right adrenal gland. Seven patients occurred hilar and retroperitoneal lymph nodes metastases, 5 patients occurred pulmonary metastasis, 3 patients occurred brainmetastasis, while 3 patients occurred lung and brain metastases simultaneously.（2） There were 20 liquefied necrotic lesions,of which 5 lesions marginal area had multiple small round cysts in T2WI, 15 were only solid and without small cyst; The DWI of the centre area in 12 lesions showed a high signal, 8 lesions showed a low signal. There were 9 solid lesions, of which 2 lesions marginal area had multiple small round cysts in T2WI, 7 lesions marginal area were only solid and without cyst in T2 WI. The DWI of the solid lesions showed a low signal, there was a ＂ring＂ high signal in the edge of lesions.（3） At the same b value, the ADC value of the centre area in the liquefied necrosis lesions were significantly higher than that in the solid lesions（P〈0.01）. At different b values, the ADC value of the surrounding liver parenchyma tissue was significantly lower than that of the marginal area（P〈0.01） and the centre area（P〈0.01） in the liquefied necrosis lesions; the ADC value of the centre area was significantly higher than that of the marginal area or surrounding liver parenchyma tissue（P〈0.05, P〈0.01） in the solid lesions. Conclusions DWI could clearly distinguish structure and composition of hepatic alveolar echinococcosis and has a higher value in distinguishing from other liver dieases. The average ADC value of centre area in liquefied necrotic lesions is higher than that in solid lesions.