Experimental And Clinical Study Of Diffusion Kurtosis Imaging(DKI)in Dermatomyositis/polymyositis

Objective:To explore the imaging diagnosis and characteristic parametersdiffuse of the diffusion kurtosis imaging?DKI?in early dermatomyositis/polymyositis?DM/PM?in rats.And to explore the application value of DKI and clinical patients.In order to instruct the clinical diagnosis?evaluate the curative effect and even establish a non-invasive diagnostic method for early DM/PM in theory.Methods:1.Rat models of early DM/PM were established by alloimmunization with rabbit skeletal muscle.And healthy rats?control group?was enrolled in this study.The MR sequence?TIWI/T2WI?and DKI sequence of 7.0 T MRI,blood biochemical test and hematoxylin-eosin staining were performed.2.We reviewed the images of 12 patients with the diagnostic criteria of DM/PM proposed by Bohan and Peter in 1975,who were treated in our hospital and rheumatism hospital of matang xianning between 2016 and 2017.And 12 healthy volunteers?control group?was enrolled in this study.Axial views with T1WI/T2WI and DKI sequences were performed on bilateral thighs of all subjects.The DKI parameters included MK?mean kurtosis??MD?mean diffusivity?were measured after post-processing workstation of GE 3.0 T.One-way analysis of variance was used for statistical analyses.Results:1.The success rate of early DM/PM rat model was not high,about 60%,the success rate of in high dose group C?immune protein concentration12 mg/kg?was slightly higher than that in other groups.Serum creatine kinase in DM/PM group was significantly different from that in normal control group,and CK value was positively correlated with immune concentration.Results in early DM/PM rat model,there were limited?slice and high signal on T2WI,DKI showed corresponding high signal.Diffusion limitation of water molecules in early DM/PM rats be proved.2.Results in DM/PM patients,there were high signal in different range and degree on T2WI,DKI showed corresponding high signal.The MD of diseased muscles in the DM/PM group and normal muscle in control group was?2.102±0.3570?×10^-3mm²/s??2.221±0.538?×10^-3mm²/s respectively,with statistic difference?P<0.05?.The MK value of the two groups mentioned above was?0.507±0.100???0.411±0.052?respectively,with statistic difference?P<0.05?.The MD value of diseased muscles in DM/PM group was lower than that of normal group with statistic difference?P<0.05?.The MK value of diseased muscles in DM/PM group was higher than that of normal group with statistic difference?P<0.05?.Conclusion:DKI technique could be used to diagnosis myopathy,particularly,it is more sensitive to edematous muscle,quantitatively evaluate the H₂0 diffusion of muscles,DKI provided important diagnostic information for DM/PM,had evident advantage in active DM/PM.MD?MK could have characteristic and sensltive diagnostic value for patients with DM/PM in early diagnosis.