Clinical usefulness of a MRI contrast medium (Gd-DTPA) and its effect on SCE frequency in lymphocytic chromosomes.

二聚戊二胺（Magnevist [] SY.encircledR.[）)是目前在日本商业化的MRI造影剂，其渗透压相对较高，临床上使用的溶液渗透压为1940 mOsm/kg水。该试剂含有在4f轨道上有7个不成对电子的钆。4f中大量的未配对电子是钆具有强磁矩和顺磁性的原因，这使水的氢的质子Tl明显缩短。Tl的缩短是导致Tl加权MR成像对比度增强的原因。中性钆配合物如gadodiamide和gadoteridol在日本已被引入临床试验。这些造影剂的临床有效性和安全性已被各种研究者证实，包括本研究中的研究者。除了Gd-DTPA外，我们还研究了强磁场和/或射频暴露对外周血淋巴细胞姐妹染色单体交换（SCE）频率的影响，以检测MRI造影剂使用时的细微副作用。在临床使用的Gd-DTPA浓度水平上，造影剂对SCE频率没有影响。随着Gd-DTPA浓度上升到临床使用水平的约100倍，SCE的发生频率增加。强磁力和射频暴露也显著增加了SCE频率。

Dimeglumine gadopentetate (Magnevist (〕SY.encircledR.〔)) is only a contrast agent in MRI, commercialized so far in Japan, and has a relatively high osmolality, that is, 1940 mOsm/kg water in clinically used solution. The agent contains of gadolinium having seven unpaired electrons in 4f orbital. The large number of unpaired electrons in 4f is responsible for a strong magnetic moment and paramagnetism of gadolinium which produces a marked shortening of Tl of protons of hydrogens of water. The shortening of Tl is causative of contrast enhancement in Tl-weighted MR imaging. Neutral gadolinium complexes such as gadodiamide and gadoteridol have been introduced into the clinical trial in Japan. The clinical usefulness and saftey of those contrast agents have been proven by various investigators, including ones in the present study.Effects of a strong magnetic field and/or radiofrequency exposure, in addition to Gd-DTPA, on sister chromatid exchange (SCE) frequency in peripheral lymphocytes were investigated in order to detect subtle side-effect in the use of MRI contrast media. At the level of concentration of Gd-DTPA in the clinical use, the contrast medium did not affect SCE frequency. As the concentration of Gd-DTPA rose up to the level of approximately 100 times over the clinical use, the frequency of SCE increased. A strong magnetic force and RF exposure also induced a increase of SCE frequency significantly.