螯合α-甲基色氨酸的超顺磁性氧化铁纳米粒子用于颞叶癫痫MRI的最佳扫描时间探讨

Optimal scan time of MRI with alpha-methyl-L-tryptophan superparamagnetic iron oxide nanoparti-cles for temporal lobe epilepsy

目的探讨螯合α－甲基色氨酸的超顺磁性氧化铁纳米粒子探针（α－MTrp－SPIONs） MRI特异定位颞叶癫致灶的最佳扫描时间。 方法将α－MTrp－SPIONs分别于颞叶癫急性期（癫大发作后72 h）、慢性期（癫大发作后8周）经尾静脉注入模型大鼠体内，于注射前及注射后1、2、4、8、24 h同步行T2序列同参数MRI，测量T2值。数据间的比较行单因素重复测量方差分析。 结果急、慢性期癫大鼠在注射α－MTrp－SPIONs后各时间点的MRI示病灶局部组织T2信号发生负增强，急性期注射前，注射后1、2、4、8、24 h T2值分别为112.08±5.85、107.83±6.59、105.08±6.79、95.58±5.14、100.92±5.81、105.17±6.31，慢性期各时间点T2值分别为112.08±7.53、107.75±7.10、102.75±5.50、96.17±5.01、97.75±4.37、102.92±4.74，给药前后差异均有统计学意义（均P〈0.01）；注射后4 h T2值下降最明显。 结论α－MTrp－SPIONs MRI能在分子水平上精确定位致灶，MRI最佳扫描时间是注射后4 h。

Objective To investigate tie optimal scan time of MRI using the imaging probe alpha- methyl-L-tryptophan （a-MTrp） -superparamagnetic iron oxide nanoparticles （SPIONs） for localizing temporal lobe epilepsy （TLE） foci. Methods a-MTrp-SPIONs were injected into rat models of TLE through the tail vein during the acute and chronic stages （72 h and 8 weeks after status epilepticus, respectively）. MRI was performed before and 1, 2, 4, 8, 24 h after the injection in all animals, and the T2 values of the epilepto- genic regions were measured. One-way repeated measures analysis of variance was used for data analysis. Results Compared with the T2 values before the injection of a-MTrp-SPIONs, the T2 signal of epileptogen- ic regions after the injection had a negative increased change. The T2 values before and 1, 2, 4, 8, 24 h af- ter the injection in acute stage were 112.08±5.85、107.83±6.59、105.08±6.79、95.58±5.14、100.92±5.81、105.17±6.31 respectively, and those in chronic stage were112.08±7.53、107.75±7.10、102.75±5.50、96.17±5.01、97.75±4.37、102.92±4.74. The T2 values after the injection were significantly different from those before the injection （both P〈0.01 ）. The T2 value at 4 h after the injection decreased mostly. Conclusions a-MTrp-SPIONs can precisely localize epileptogenic regions of TLE on MRI. The optimal scan time is 4 h after the injection.