Quantitative MRI Study Of Gluteal Muscle And Muitifidus Muscle In Patients With Lumbosacral Nerve Root Compression

Objective1.To qualitatively evaluate the atrophy and fatty infiltration of gluteus maximus,gluteus medius,gluteus minimus and multifidus muscle in patients with lumbosacral nerve root compression,and to evaluate its diagnostic efficacy.2.To quantitatively evaluate the characteristics of atrophy and fatty infiltration of gluteus maximus,gluteus medius,gluteus minimus and multifidus muscle in patients with lumbosacral nerve root compression at different levels and their correlation with clinical activity.Materials and methods1.The images of thirty patients with unilateral lumbosacral nerve root compression in our hospital from June 2018 to January 2019 were retrospectively analyzed.Twenty healthy volunteers without nerve root compression were enrolled as controls.Three dimensional fast imaging empolying steady-state acquisition with phase cycling(3D-FIESTA-C)sequence and Iterative decomposition of water and fat with echo asymmetry and least squares estimation quantitation(IDEAL-IQ)sequence were selected to measure the cross-sectional area(CSA)and fat fraction(Ff)of gluteus maximus,gluteus medius,gluteus minimus and multifidus muscle respectively.Paired sample t test was performed between sides in both case and control group.On this basis,a ROC curve was drawn to evaluate the accuracy of diagnosis assisted by each measurement value.2.A total of eighty-eight patients with unilateral lumbosacral nerve root compression and seventy healthy volunteers were enrolled in our study from June2019 to June 2020.The CSA and Ff of bilateral gluteus maximus,gluteus medius,gluteus minimus and multifidus muscle were measured on 3D-FIESTA-C sequence and the fat fraction images of IDEAL-IQ sequence.Independent sample t test was performed to compare bilateral ratio of CSA(CSAr)and Ff(Ffr)between case and control group.In different groups of nerve root compression and symptom duration,paired t tests were used to compare the CSA and Ff between the affected and unaffected side.Muscle content(CSAm)was defined as CSA*(1-Ff)and its correlation with JOA scores was analyzed using Pearson correlation analysis.Results1.In case group,the affected side had smaller CSA and greater Ff of gluteus maximus,gluteus medius,gluteus minimus than unaffected side(P<0.001,P<0.001,P<0.05;P<0.001,P<0.001,P<0.01).There was no significant difference between CSA and Ff of bilateral multifidus muscle(P>0.05).The area under the receiver operating characteristic(ROC)curve(AUC)of gluteus maximus Ff、gluteus minimus CSA and gluteus medius Ff were greater than 0.7(P<0.05).Both the CSA and Ff of gluteal muscles were included in the logistic regression model,and the ROC curve was then obtained,with an AUC of0.847,sensitivity of 90.0% and specificity of 69.7%.2.CSAr of gluteus maximus,gluteus medius,gluteus minimus,and multifidus muscle in the case group was smaller than in the control group(P<0.001),and Ffr was greater(P<0.001,P<0.001,P<0.001,P<0.01).There was no difference in CSA of bilateral multifidus muscle in L5 short course and long course groups,however,the difference in Ff of multifidus muscle in both groups was statistically significant(P < 0.01,P < 0.01).S1 nerve root compression group had 20 patients with short course of disease and 15 patients with long course.The side-to-side difference of multifidus Ff in short and long course of S1 patients did not reach statistical significance.No bilateral difference of multifidus CSA was showed in short course of S1 patients,but there was a significant difference in the long course group(P < 0.05).The CSAmr of gluteus maximus,gluteus medius,gluteus minimus and multifidus were correlated with JOA scores to different degrees(r=0.274,P<0.001;r=0.516,P<0.001;r=0.473,P<0.001;r=0.790,P<0.001).Conclusion1.The gluteus maximus,gluteus medius,gluteus minimus and multifidus muscle on the affected side show different degrees of atrophy and fatty infiltration in patients with lumbosacral nerve root compression.The fat fraction of gluteus maximus is helpful for the diagnosis of nerve root compression.With the cross sectional area and fat fraction of gluteus maximus,gluteus medius,gluteus minimus in consideration,the diagnosis can be more accurate.2.The change of multifidus muscle is related to the level of compressed nerve root.By using MRI fat quantification analysis,the muscle changes can not only be applied to the diagnosis of lumbosacral nerve root compression disease,but also can quantitatively reflect the changes of neuromuscular-related clinical functions in patients with this disease.