MRI鉴别诊断肝硬化退变结节与小肝癌

MR imaging in differential diagnosis of dysplastic nodules in cirrhosis and small hepatocellular carcinoma

目的 探讨高场强MRI对肝硬化退变结节和小肝癌诊断与鉴别诊断价值。方法 对经临床和病理证实18 例24个肝硬化退变结节(DN)和15例26个小肝细胞癌(sHCC)的磁共振影像资料作回顾性对比分析。结果 18例24个DN中,同、反相位T1WI上呈等信号者4个,呈稍高信号者20个,占DN的83%(20/24); 26个HCC结节中,同相位T1WI上呈稍高信号者6个,其中3个在反相位T1WI上呈低信号;同、反相位T1WI上均呈等低信号者19 个结节,占76%(19/25)。抑脂T2WI上DN组24个结节均为低信号;而小HCC组26 个结节中,呈稍高或不均匀等高信号者24 个,占92%(24/26), 2个在T2WI上为低信号。Gd DTPA动态增强扫描,14 例中15 个DN呈缓升速降型14 个,占93%;14 例中24个HCC呈速升速降型19个,占79%(19/24); HCC包膜强化率占增强病灶中的70%(17/24),而13个DN见不规则纤细网状纤维隔强化,占86%(13/15),仅1个DN呈假包膜样强化。结论 综合分析高场强MR不同序列及动态增强像特点,能够区别绝大多数大DN和HCC。

Objective To investigate the clinical value of high-field MR imaging in the differential diagnosis of dysplastic nodules (DN) with cirrhosis and small hepatocellular carcinoma (sHCC). Methods MR imaging of 18 patients with 24 DN and 15 patients with 26 HCC proved by clinic and pathology were reviewed retrospectively. All the examinations were performed using a 1.5 Tesla MR unit with SE and GE sequences, in/out-phase T1 weighed and fat saturated T2 weighed images, and gadolinium as a contrast agent, T1 weighted GE imaging was carried out in 14 patients with 15 DN and 14 patients with 24 sHCC, according to the signal change of different phase, there are four types of dynamic gadolinium-enhanced scans. Results Out of 18 patients with 24 DN, 20 were slightly hyperintense and 4 were isointense on in /out phase T1WI. Of 15 patients with 26 HCC, 6 were slightly hyperintense on in-phase T1WI, within 3 were hypointense on out-phase T1WI, 19 were iso-hypointense on in/out phase T1WI. On fat saturated T2WI, all DN were hypointense, 24 sHCC were slightly hyperintense or heterogeneous intense, 2 sHCC were hypointense. Fourteen patients with 14 DN showed synchronous enhancement with normal hepatic parenchyma (Ⅱ type) on gadolinium-enhanced scans, i.e. 93% (14/15, while 14 patients with 19 sHCC showed obvious enhancement during arterial phase, decreased during the portal phase (Ⅰtype) on gadolinium-enhanced scans, i.e. 79% (19/24). Pseudo-capsule in 17 sHCC showed slight enhancement during portal and delayed phase, i.e. 70% (17/24), while irregular reticular fibrous septum in 13 DN showed slightly enhancement during delayed phase, i.e. 86% (13/15), only one case of DN showed like-capsule enhancement. Conclusion Most of the DN and sHCC can be distinguished by comprehensive analysis of the different sequence and dynamic Gd-DTPA enhanced imaging. Biopsy is necessary when MRI shows characteristic of HCC within DN.