分次锰增强磁共振成像
Fractionated manganese-enhanced MRI.
作者信息
Bock Nicholas A, Paiva Fernando F, Silva Afonso C
机构信息
Cerebral Microcirculation Unit/Laboratory of Functional and Molecular Imaging/National Institute of Neurological Disorders and Stroke/National Institutes of Health, Bethesda, MD 20892-1065, USA.
出版信息
NMR Biomed. 2008 Jun;21(5):473-8. doi: 10.1002/nbm.1211.
We investigated the use of manganese-enhanced MRI (MEMRI) with fractionated doses as a way to retain the unique properties of manganese as a neuronal contrast agent while lessening its toxic effects in animals. First, we followed the signal enhancement on T1-weighted images of the brains of rats receiving 30 mg/kg fractions of MnCl2 . 4H2O every 48 h and found that the signal increased in regions with consecutive fractionated doses and ultimately saturated. Second, we used T1 mapping to test whether the amount of MRI-visible manganese that accumulated depended on the concentration of manganese in the fractions. For a fixed cumulative dose of 180 mg/kg MnCl2 . 4H2O, increasing fraction doses of 6 x 30 mg/kg, 3 x 60 mg/kg, 2 x 90 mg/kg and 1 x 180 mg/kg produced progressively shorter T1 values. The adverse systemic health effects, including complications at the injection site and poor animal well-being, also rose with the fraction dose. Thus, fractionated MEMRI can be used to balance the properties of manganese as a contrast agent in animals against its toxic effects.
我们研究了采用分次给药的锰增强磁共振成像（MEMRI）方法，旨在在减轻锰对动物毒性作用的同时，保留其作为神经元造影剂的独特性质。首先，我们对每48小时接受30mg/kg MnCl₂·4H₂O分次给药的大鼠大脑进行T1加权成像，观察信号增强情况，发现连续分次给药区域的信号增强，并最终达到饱和。其次，我们采用T1图谱来测试累积的MRI可见锰量是否取决于分次给药中的锰浓度。对于180mg/kg MnCl₂·4H₂O的固定累积剂量，6×30mg/kg、3×60mg/kg、2×90mg/kg和1×180mg/kg的分次给药剂量逐渐增加，T1值逐渐缩短。包括注射部位并发症和动物健康状况不佳在内的不良全身健康影响也随分次给药剂量增加而上升。因此，分次给药的MEMRI可用于在动物体内平衡锰作为造影剂的特性及其毒性作用。
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