肝局灶性结节增生的影像诊断及误诊分析

Imaging differential diagnosis and misdiagnosis analysis of liver focal nodular hyperplasia

目的探讨肝局灶性结节增生(FNH)的影像学鉴别诊断,分析其误诊原因。方法回顾性分析17例经手术病理证实的肝脏FNH的CT和MR资料,三期法(动肪、门脉、延迟)扫描肝脏,分析其影像学表现,讨论其鉴别诊断和误诊原因。结果17例FNH中有12例表现较为典型,CT平扫呈低或等密度,T1WI为等信号,T2WI为等信号或稍高信号;部分病灶可见中央区低密度瘢痕,增强动脉期除中央瘢痕外均明显强化,门静脉期常见明显强化,延时期多为等密度,瘢痕可稍有强化;均作出了正确诊断。5例FNH表现不典型,CT低密度灶,T1WI为低信号,T2WI为高信号,无瘢痕或瘢痕不明显,轻度强化;5例中有3例误诊为肝癌,2例诊为血管瘤。结论不典型FNH容易误诊,应注意与肝癌及肝血管瘤鉴别,误诊另一原因是三期扫描技术不规范造成病灶表现不典型而引起。

Objective To analyze the differential diagnosis and misdiagnosis of imaging findings of liver focal nodular hyperplasia （FNH） and study the courses of misdiagnosis so as to improve their diagnostic accuracy. Methods To study the CT and MRI films of 17 FNH patients which were surgically and pathologically confirmed retrospectively.Pre- and post-contrast tri-phase （arterial, portal venous and delayed） scans were performed to analyse the findings of CT and MRI on FNH and discuss its differential diagnosis and misdiagnosis causes. Results 12 of 17 patients imagings demonstrated typical findings. Pre-contrast scans showed hypodensity and isodensity on CT, and isointensity on MRI T1WI,isointensity or hyperintensity on T2WI; part of these patients can find hypodensity scar in the central of FNH nodulars on CT. Except central scar, all lesions were markedly and homogeneously enhanced in the arterial phase and portal venous phase. Isodensity appeared at delayed phase. The scar showed a little enhanced at the delayed phase.All above cases were made the correct diagnosis.5 of the 17 patients showed atypical imaging fmdings：CT features showed hypodensity and MRI features were hypointensity on T1WI and hyperintensity on T2WI. Central scar is not so marked or none of scar found wihin the lesion.The lesions enhanced slightly after contrast scan at tri-phase on CT.3 of 5 were misdiagnosis to hepatocellular carcinoma and 2 of 5 patients to hepatic cavernous haemangioma. Conclusion The atypical FNH were easier to be misdiagnosed ,and these cases should be differential with hepatocellular carcinoma and hepatic cavernous haemangioma. The causes of misdiagnosis were that none regulation skills were performed during the tri- phase scan on Imaging process.