ENHANCEMENT OF MR-ANGIOGRAPHY WITH IRON-OXIDE - PRELIMINARY STUDIES IN WHOLE-BLOOD PHANTOM AND IN ANIMALS
ENHANCEMENT OF MR-ANGIOGRAPHY WITH IRON-OXIDE - PRELIMINARY STUDIES IN WHOLE-BLOOD PHANTOM AND IN ANIMALS
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DOI：
10.2214/ajr.162.1.8273667
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发表时间：
1994-01-01
影响因子：
5
通讯作者：
BRADY, TJ
中科院分区：
文献类型：
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作者：
FRANK, H;WEISSLEDER, R;BRADY, TJ
OBJECTIVE.我们假设，以前观察到的小单晶氧化铁制剂的T1效应可以用来减少血液的T1弛豫时间。这种降低，特别是如果存在很长一段时间，可以用来提高MR血管造影片的质量。为了验证这一假设，我们进行了体模研究和体内动物实验。首先在体模（单晶氧化铁制剂的剂量范围，0-3 μ mol Fe/ml）中测试单晶氧化铁制剂对人全血的MR信号强度（在稳态脉冲序列中的受扰梯度回忆采集，各种定时参数）的影响。随后在大鼠（n=7）和兔（n=6）中进行实验，以确定是否可以在体内观察到预测的信号强度变化。大鼠剂量优化研究表明，注射剂量为15-50 μ mol Fe/kg（0.8-2.8 mg Fe/kg）的单晶氧化铁制剂导致主动脉信噪比增加三倍至四倍。由于其较长的血浆半衰期（大鼠中为180 min），氧化铁制剂显著改善了肺、腹部和四肢血管系统的图像质量。我们的实验结果表明，这种氧化铁制剂和其他可能的氧化铁制剂是含有大分子钆的化合物的替代品，可用于临床MR血管造影。
OBJECTIVE. We hypothesized that the previously observed T1 effect of a small monocrystalline iron oxide preparation can be exploited to decrease T1 relaxation time of blood. Such a decrease, particularly if present for a long time, could be used to improve the quality of MR angiograms. To test the hypothesis, we performed phantom studies and in vivo animal experiments.MATERIALS AND METHODS. The effect of the monocrystalline iron oxide preparation on the MR signal intensity (spoiled gradient-recalled acquisition in the steady state pulse sequences, various timing parameters) of human whole blood was first tested in a phantom (dose range of monocrystalline iron oxide preparation, 0-3 mu mol Fe/ml). Subsequent experiments were performed in rats (n=7) and in rabbits (n=6) to determine whether predicted changes in signal intensity could be observed in vivo.RESULTS. Dose optimization studies in rats indicate that injected doses of 15-50 mu mol Fe/kg (0.8-2.8 mg Fe/kg) of monocrystalline iron oxide preparation resulted in threefold to fourfold increases of aortic signal-to-noise ratio. Because of its long plasma half-life (180 min in rats), the iron oxide preparation markedly improved the quality of images of the vasculature of the lungs, abdomen, and extremities.CONCLUSION. Our experimental results suggest that this and possibly other iron oxide preparations are alternatives to compounds containing macromolecular gadolinium and could be useful for clinical MR angiography.