Hahn P F, Stark D D, Saini S, Lewis J M, Wittenberg J, Ferrucci J T
Radiology. 1987 Jul;164(1):37-41. doi: 10.1148/radiology.164.1.3588924.
Diverse materials with varying physical and magnetic properties have been evaluated as gastrointestinal contrast agents for magnetic resonance (MR) imaging. Uniform marking of the small bowel remains the greatest challenge. Ferrites are magnetically active iron oxide particles that are miscible with water and cause loss of signal on MR images. The decrease in MR signal intensity produced by ferrites occurs with a wide range of iron concentrations (0.1-10 mM) and with both T1- and T2-weighted pulse sequences. These effects of ferrites are explained by predominant T2 shortening with negligible T1 effects. The ferrite preparation used in this study was stable in vitro, with little iron solubilized by acid. Intragastric administration of ferrite (5 mg of iron per kg in 6 ml) routinely marked the small bowel of rats. The authors conclude that ferrites represent a promising new class of contrast agents for gastrointestinal MR imaging.
多种具有不同物理和磁特性的材料已被评估用作磁共振（MR）成像的胃肠道造影剂。小肠的均匀标记仍然是最大的挑战。铁氧体是与水可混溶的具有磁活性的氧化铁颗粒，会导致MR图像上信号丢失。铁氧体产生的MR信号强度降低在很宽的铁浓度范围（0.1 - 10 mM）以及T1加权和T2加权脉冲序列下都会出现。铁氧体的这些效应主要是由T2缩短导致的，T1效应可忽略不计。本研究中使用的铁氧体制剂在体外是稳定的，几乎没有铁被酸溶解。胃内给予铁氧体（每千克5毫克铁，溶于6毫升溶液中）常规标记大鼠的小肠。作者得出结论，铁氧体代表了一类有前景的用于胃肠道MR成像的新型造影剂。
