不同MR扫描序列在SPIO增强大鼠肝癌模型的对比研究

目的：比较多种扫描序列超顺磁氧化铁（SPIO）增强扫描对显示大鼠肝癌病灶的能力，找出最佳扫描方案。TSE T2WI、SE双回波的T2WI＋PDWI、GRE T1WI、T2^＊WI，分析增强前后大鼠肝癌病灶的强化特征，并进行病理学检查对照分析。结果：注射SPIO对比剂后，所有扫描序列均显示肝脏的信号强度较增强前有不同程度的下降，肝癌病灶CNR均分别高于平扫。增强后GRE T2^＊WI中病灶的CNR明显高于其它序列，但增强后TSE T2WI和常规SE T2WI在显示病变的SNR、CNR方面没有显著性差异。结论：SPIO增强后检测肝癌病灶的各种序列中，以GRE T2^*WI最为敏感，其次是双回波的T2WI＋PDWI序列。

The comparison of different MR sequences in rat HCC model after superparamagnetic iron oxide enhancement

Objective:To evaluate the different MR sequences in visualization of hepatocellular carcinoma (HCC) rat model after administration of superparamagnetic iron oxide(SPIO),and to seek the optimal scanning parameter.Methods:Experimental model of hepatocellular carcinoma was induced in 20 rats by feeding DEA.MR imaging was performed before and after SPIO injection using SE T 1W,TSE T 2W,T 2W+PDW of SE dual echo,GRE T 1W and T 2 *W sequences.Their characteristics of MR enhancement were evaluated by calculating SNR and CNR of tumors and correlated to the pathological findings.Results:After SPIO enhancement, signal intensity of liver decreased in varying degree in all sequences;the contrast to noise ratio of HCC was greater than that before enhancement in all sequences;and the CNR in GRE T 2 *WI was significantly greater than that in the other sequences,but there was no difference between Turbo SE and conventional SE sequence in the CNR and SNR.Conclusion:With SPIO enhancement,GRE T 2 *W and T 2W+PDW of SE dual echo sequences are the most sensitive sequences.