多模态MRI技术在激素性股骨头坏死微循环及脂肪含量病理机制研究中的应用

Application of multimodal magnetic resonance imaging in the study of pathological mechanism of microcirculation and fat content in steroid-induced osteonecrosis of the femoral head

目的利用多模态MRI技术检测塌陷前期激素性股骨头坏死(SIONFH)患者的股骨头骨组织微循环障碍及脂肪化的情况,并探讨二者与SIONFH疾病发展的相关性。方法纳入在广州中医药大学第一附属医院骨科确诊的SIONFH塌陷前期患者(即ARCO I期~Ⅲ期早期),运用多模态MRI技术[包括功能性磁共振非对称回波的最小二乘估算法迭代水脂分离序列(IDEAL-IQ)、体素内不相干运动磁共振扩散加权成像(IVIM-DWI)、T1WI和T2WI/fs]进行诊断研究。具体流程包括在采用T1WI和T2WI/fs实现原发灶结构定位的基础上,运用IVIM-DWI和IDEAL-IQ分别测量不同区域(坏死区、硬化区、正常区)的局部微循环(f)和脂肪含量(FF)。重点分析股骨头骨组织微循环障碍及组织脂肪化情况与ARCO分期的相关性,同时对2种病理机制之间相关性进行探讨研究。数据比较采用单因素方差分析、LSD-t检验、Pearson相关性分析。结果SIONFH不同区域的局部微循环和脂肪含量比较,差异均有统计学意义(P值均小于0.05)。其中,在IDEAL-IQ序列中,坏死区FF值最高,硬化区FF值最低。在IVIM-DWI中,坏死区f值最低,硬化区其次,正常区最高。部微循环和脂肪含量呈负相关(r=-0.37,P值均小于0.05)。ARCOⅢ期早期的f值最小,而FF值最小(P值均小于0.05),并且FF值与ARCO分期呈正相关(r=0.72,P值均小于0.01),但f值与ARCO分期之间无明显相关性。结论多模态MRI技术(IDEAL-IQ、IVIM-DWI、T1WI和T2WI/fs)定量测量得出,SIONFH在塌陷前期中局部微循环进行性障碍和组织脂肪化增加会关联性出现,并随ARCO分期的进展而逐步加重。

Objectives To investigate the fat content and microcirculation in the steroid-induced osteonecrosis of the femoral head(SIONFH)and their relationship with the development of SIONFH by multimodal magnetic resonance imaging.Methods SIONFH patients in pre-collapse stage(ARCO I to early ARCOⅢstage)diagnosed in the First Affiliated Hospital of Guangzhou University of Chinese Medicine were involved in our research.Multimodal magnetic resonance imaging[including sequences as iterative decomposition of water andfat with echo asymmetry and least squares estimation(IDEAL-IQ)、intravoxel incoherent motion diffusion-weightedimaging(IVIM-DWI),T1WI and T2WI/fs]were taken to measure the values in the research.The specific procedure was as follow:sequence of IVIM-DWI and IDEAL-IQ were utilized in the evaluation of fat fraction(FF)and microcirculation(f)in necrosis area,penumbra area and normal area,according to location of primary lesion assessed by sequence of T1WI and T2WI/fs.The correlations among the fat content,microcirculation and ARCO stage were explored in order to investigate the relationship between these two pathological mechanisms.The data were processed with one-way analysis of variance,least significant difference t test,and Pearson correlation analysis.Results There were significant differences in fat content and microcirculation in different regions of SIONFH(P<0.05).In IDEAL-IQ,the FF value was highest in necrosis area and lowest in penumbra area.In IVIM-DWI,the f value was lowest in necrosis area,and then penumbra area,and highest in normal area.The FF value was negatively correlated with the F value(r=-0.37,P<0.05).In the early stage of ARCOⅢ,the FF value was highest while the f value was lowest(P<0.05),and the FF value was positively correlated with the ARCO staging(r=0.72,P<0.01),but not in that of f value.Conclusion Quantitative analysis of multimodal magnetic resonance imaging(IDEAL-IQ,IVIM-DWI,T1WI and T2WI/fs)showed that there was a correlation between the fat content and microcirculation in the pre-collapse stage of SIONFH and both the pathological mechanism developed with the progress of SIONFH.