MR动态增强扫描对小肝癌的诊断价值探讨

目的 探讨MR动态增强扫描的扫描技术及对小肝癌的诊断价值。方法 搜集25例本室经动态增强扫描诊为“小肝癌”，且随访资料完整的病例进行分析，其中22例经病理、1例经DSA证实。增强前后T1W1常规采用FL2D屏气扫描序列或采用反相位的T1W1-FL2D屏气扫描序列，也可采用T1-TFL序列行增强前后扫描。结果 26个已确诊为小肝癌的病灶行增强扫描，动脉晚期24个与平扫相比均不同程度强化，门静脉期大多数病灶与动脉期相比信号衰减，有5个病灶周围可见线状包膜强化；延时至平衡期扫描所有病灶信号较动脉期均衰减，病灶边缘强化的假包膜更为明显。结论 (1)用MR动态增强扫描能动态观察小结节肝动脉和门静脉的供血情况，对小肝癌的定性起关键作用。(2)从退交结节(DN)到小肝癌(SHCC)是一个渐变的过程，有时退交结节与小肝癌的MR影像表现重叠，难以鉴别。(3)动态增强扫描小肝癌的包膜显示较有特征性。(4)动态增强扫描较平扫能提高病灶的检出率及定性准确率。(5)我们选用的序列各有优缺点。

The value of MR dynamic enhancement in the diagnosis of small hepatocellular carcinoma

Objective To study the techniques of MR dynamic enhancement and to evaluate its value in the diagnosis of small hepatocellular carcinoma(SHCC).Materials and Methods 25 cases diagnosed as SHCC by dynamic enhancement were reviewed.Among them,22 cases were confirmed by pathology and one by DSA.Scanning techniques:FL2D breath-hold sequence or opposed-phase FL2D was routinely adopted at T1WI scanning before and after GD-DTPA injection,and T1-TFL was adopted in some cases.Results Out of 26 lesions performed dynamic enhancements,24 showed various enhancement on arterial phase.On portal phase,decreased signal intensity was seen in most of the lesions and enhanced linear edge(pseudocapsule) in 5 lesions.On balanced and delayed phase signal intensity further decreased in all the lesions,while the enhanced pseudocapsules became more obvious.Conclusions 1.The blood supply of small hepatic nodules from hepatic artery and portal vein can be observed by MR dynamic enhancement,which is important to SHCC diagnosis.2.It's a gradual process from dysplastic nodule(DN) to SHCC,sometimes MR manifestations of DN and SHCC are partly overlapped,making it difficult to differentiate them.3.It's characteristic in the findings of SHCC's pseudocapsule on dynamic enhancement.4.Compared with plain scan,dynamic enhancement can promote the diagnostic accuracy of SHCC.5.The sequences we chose have both advantages and disadvantages.