Hayashi Shigeki, Fujioka Mikihiro, Ikoma Kazuya, Saito Masazumi, Ueshima Keiichiro, Ishida Masashi, Kuribayashi Masaaki, Ikegami Akira, Mazda Osam, Kubo Toshikazu
Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
J Magn Reson Imaging. 2015 Apr;41(4):935-40. doi: 10.1002/jmri.24632. Epub 2014 Apr 10.
To evaluate perfusion during the early phase after steroid administration in vivo using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with a high magnetic field MRI system. The main pathogenesis of steroid-induced osteonecrosis is considered to be ischemia.
A single dose of methylprednisolone (MPSL) was injected into nine rabbits. DCE-MRI was performed for these rabbits before MPSL administration and 1, 5, 10, and 14 days after administration. Time-signal intensity curves were created for each femur based on the signal intensity to evaluate perfusion. Enhancement ratio (ER), initial slope (IS), and area under the curve (AUC) were calculated and the value before MPSL administration and the minimal value after administration were compared statistically.
ER, IS, and AUC values after MPSL administration significantly decreased (P < 0.05, P < 0.01, and P < 0.01, respectively). All of them decreased by the 5th day in 56% of the femora and by the 14th day in 83%, and some femora even showed a decrease from the 1st day.
In this study, decreased perfusion in the femora after steroid administration was proven. Additionally, we could show that it occurred from the early days after steroid administration.
使用高磁场磁共振成像系统的动态对比增强磁共振成像（DCE-MRI）评估体内给予类固醇后早期阶段的灌注情况。类固醇诱导的骨坏死的主要发病机制被认为是缺血。
向9只兔子注射单剂量的甲泼尼龙（MPSL）。在给予MPSL之前以及给药后1、5、10和14天对这些兔子进行DCE-MRI检查。基于信号强度为每只股骨创建时间-信号强度曲线以评估灌注情况。计算增强率（ER）、初始斜率（IS）和曲线下面积（AUC），并对MPSL给药前的值和给药后的最小值进行统计学比较。
给予MPSL后，ER、IS和AUC值显著降低（分别为P < 0.05、P < 0.01和P < 0.01）。在56%的股骨中，所有这些值在第5天下降，在83%的股骨中在第14天下降，并且一些股骨甚至从第1天就开始下降。
在本研究中，证实了给予类固醇后股骨灌注减少。此外，我们能够表明这种情况在给予类固醇后的早期就发生了。
