3．0T磁共振三维容积内插屏气检查在小肝癌诊断中的应用

Application of 3.0T MRI 3D-VIBE dynamic contrast-enhanced in the diagnosis of small hepatoceHular carcinomas

目的探讨3．0T磁共振（MRI）三维容积内插屏气检查（3D—VIBE）序列动态增强扫描对小肝癌的检出率，并评价其在小肝癌定性诊断中的价值。方法回顾性分析经临床手术及病理学检查证实的61例小肝癌患者的影像学资料，用3．0T磁共振扫描仪进行平扫及3D—VIBE序列动态增强扫描。分析病灶在3D—VIBE序列动态增强扫描各个时相的信号特点及强化特征，评价各平扫及增强序列对病灶的检出率及定性诊断价值。结果61例患者手术共发现66个病灶，49个病灶见假包膜形成。T1加权成像（T1WI）发现病灶43个（65．15％），19个（38．78％）见假包膜。T2加权成像（T2WI）发现病灶53个（80．30％）。3DVIBE序列动态增强扫描共发现65个病灶（98．48％），35个（71．43％）见假包膜。3种不同序列对病灶检出率的差异具有统计学意义（Χ^2=24．197，P〈0．05）。平扫（T1WI＋T2WI）与3D—VIBE序列动态增强扫描对病灶的定性准确率的差异也具有统计学意义（Χ^2=66，P〈0．05）。结论3．0TMRI3D—VIBE序列动态增强扫描的扫描速度快，可清楚显示动脉期、门静脉期及实质期等各个时相的特点，这不仅有利于发现平扫所不能发现的小病灶，而且可以通过绘制时间-信号强度曲线协助诊断。对肝癌癌灶的检出及鉴别诊断具有重要价值。

Objectives To investigate the detection rate of small hepatocellular carcinomas using 3.0T MRI 3D-volumetric interpolated breath-hold examination （VIBE） sequence dynamic contrast-enhanced scan, and to evaluate its application in the diagnosis of small hepatocellular carcinomas. Methods Imaging data of 61 cases of small hepatocellular carcinomas obtained using a 3.0 T Siemens Magnetom Trio Tim magnetic resonance scanner for plain scan and multi-phase dynamic contrast-enhanced scans of three-dimensional volumetric interpolated breath-hold examination （3D-VIBE） were retrospectively analyzed with reference to their pathological diagnoses. The signal and enhanced features and the detection rates of the tumors in different phases of examination were analyzed. Results Sixty-six lesions were detected in the livers of the 61 patients by pathological examinations, of which 49 had pseudocapsule formation. In their T1WI plain scanning, 43 （65.15%） lesions were found, of which pseudocapsules were found in 19 （38.78%）. In their T2WI imaging, 53 （80.30%） lesions were found. In dynamic enhanced 3D-VIBE sequence, 65 （98.48%） lesions were found, of which 35 （71.43%） were found with pseudocapsules. The sizes of the carcinomas ranged from 0.8 to 3.0cm, 2. 1 cm on the average. The results of statistical analysis for the detection rates of the cancers of the three different sequences were significantly different （ Χ^2 = 24.197, P 〈 0.05）. The differences of qualitative accuracy obtained by plain scan （TIWI ＋ T2WI） and 3D-VIBE sequence were significantly different （ Χ^2 = 66, P 〈 0.05）. Conclusion 3.0 T MRI 3D-VIBE sequence dynamic contrast-enhanced scan is high-speed and can clearly demonstrate the arterial phase, the portal venous phase and the parenchymal phase images. It not only can find small lesions which can not bc found with a plain scan, but also can assist diagnosis through a time- intensity curve. It is of great value for detection and differential diagnosis of small hcpatocellular carcinomas.