磁化传递对比成像在大鼠肝硬化的初步应用

Primary Application of Magnetization Transfer Contrast Imaging for Cirrhosis in Rats

目的探讨磁化传递对比(MTC)成像在大鼠肝硬化的初步应用价值。材料与方法二乙基亚硝胺诱导的单纯性肝硬化Wistar大鼠6只,5只正常大鼠作为对照组;全部大鼠均行附加磁化传递(MT)脉冲前后SE序列T1WI及FSE序列T2WI扫描。测量感兴趣区平均信号强度、背景噪声,计算信噪比及磁化传递率(MTR)。结果6只大鼠病理证实均为单纯性肝硬化。电镜下见肝硬化细胞间隔增宽,胶原纤维明显增多。T1WI上正常肝实质附加MT脉冲后信噪比(SNR)低于无MT脉冲图像(P=0.002);肝硬化附加MT后SNR明显低于无MT时(P=0.000);肝硬化的MTR显著高于正常肝实质(P=0.000)。T2WI上正常肝实质附加MT后SNR低于无MT时(P=0.021);肝硬化附加MT后SNR显著低于无MT时(P=0.000);肝硬化的MTR较正常肝实质明显增高(P=0.002)。结论MTC成像能间接反映肝硬化组织中胶原成分变化,为肝硬化的诊断和分期提供依据,可作为评价肝硬化的有效手段。

Objective To discuss the application value of magnetization transfer contrast （MTC） magnetic resonance imaging （MRI） for cirrhotic liver of rat. Materials and Methods 6 wistar rats with pure cirrhosis induced by diethylnitrosamine solution, 5 normal wistar rats were served as the controls. All rats were performed with T1 weighted spin echo （SE） imaging and fast SET2 weighted imaging with or without MT presaturation pulse. Average signal intensity （SI）, region of interest （ROI）, signal to noise ratio （SNR） and MT ratio background signal noise （SN） were measured on MR images. Results 6 rats were confirmed as pure cirrhosis by pathology. SNR of MTC images were lower than that of non MTC in normal liver （ P = 0.002） and SNR of MTC images was significant lower than that of non MTC images （ P = 0.000） in cirrhosis on T1WI. On T2WI, SNR of normal liver with MTC was significant lower than that of non MTC （ P = 0.021 ）. In cirrhosis liver, SNR of T2WI with MTC images was remarkably lower than that of non MTC （ P = 0. 000）. MT ratio （MTR） of cirrhosis was significant higher than that of the normal liver on T1WI. On T2WI, MTR of cirrhosis was remarkably higher than that of the normal （ P = 0.002）. In cirrhotic tissues, intercellular space was broadened and collagenous fibers remarkably increased. Conclusion Cirrhotic liver has a strong MT effect due to the abundance of collagen. MT contrast imaging can indirectly reflect the changes of collagen content and provide some indirect evidence about diagnosis and stages of cirrhosis. MTC can be regarded as effective method to evaluate cirrhosis.