Chambon C, Clement O, Le Blanche A, Schouman-Claeys E, Frija G
Laboratoire Guerbet, Aulnay-Sous-Bois, France.
Magn Reson Imaging. 1993;11(4):509-19. doi: 10.1016/0730-725x(93)90470-x.
The ability of superparamagnetic iron oxides (SPIO) and ultrasmall superparamagnetic iron oxides (USPIO) to act as positive contrast enhancers due to a marked T1 relaxivity was investigated. At low concentrations, an important signal enhancement was observed in vitro, reaching 120% for SPIO and 140% for USPIO in a spin echo 500/22 sequence. The more heavily the sequence was T1-weighted the greater the enhancement. As the concentration increased, the signal dropped. The in vivo study of USPIO in the rat showed that at low doses (14 mumol Fe/kg), the myocardial signal was enhanced by 30%, whereas at high doses (77 mumol Fe/kg), it fell by -50%. These results indicate that in T1-weighted spin echo sequences, the MR signal can be enhanced by low concentrations of superparamagnetic compounds. This effect could be useful in perfusion imaging, and is also important for a better understanding of any possible paradoxical positive enhancement which could occur in perfused organs.
研究了超顺磁性氧化铁（SPIO）和超小超顺磁性氧化铁（USPIO）由于显著的T1弛豫率而作为阳性对比增强剂的能力。在低浓度下，体外观察到重要的信号增强，在自旋回波500/22序列中，SPIO达到120%，USPIO达到140%。序列的T1加权越重，增强越大。随着浓度增加，信号下降。对大鼠体内USPIO的研究表明，在低剂量（14 μmol Fe/kg）时，心肌信号增强30%，而在高剂量（77 μmol Fe/kg）时，心肌信号下降50%。这些结果表明，在T1加权自旋回波序列中，低浓度的超顺磁性化合物可增强MR信号。这种效应在灌注成像中可能有用，对于更好地理解灌注器官中可能出现的任何矛盾性阳性增强也很重要。
