| Objective : To explore the advantages of MRI in diagnostic PM/DM and richer medical information for diagnostic PM/DM.Methods: From January 2014 to February 2020,55 patients with suspected first-onset PM /DM were treated in Affiliated Hospital of Inner Mongolia Medical University.All patients underwent muscle enzymes(creatine kinase,aspartate aminotransferase,alanine aminotransferase,lactate dehydrogenase),myositis antibody profile,electromyography(EMG),MRI,muscle biopsy(pathological analysis),and observation of skin damage,of which magnetic resonance imaging uses GE 3.0T superconductor Magnetic resonance machine(GE MEDICAL SYSTEM Signa-HDx3.0T),the coronal,sagittal,and axial positions were selected for scanning using orthogonal body coils,the sequences used were T1 weighted imaging(T1WI),short-term flip recovery sequence or fat suppression sequence(STIR)and enhanced scanning.Specimens taken from muscle biopsies were immediately fixed with 10% neutral buffered formalin fixator,routinely paraffin-embedded sections,hematoxylin eosin(HE)stained,observed under light microscope by experienced pathologists,and all patients undergoing muscle biopsies signed informed consent.The IIM classification standard recommended by the International Collaborative Group on Myopathy in 2004 are the "gold standard" for diagnostic PM/DM.This experiment is counting data,using SPSS22.0 and Medcalc software analysis: Comparing the positive rate of MRI and muscle biopsy diagnosis of PM and DM;by respectively calculating and comparing the sensitivity,specificity,coincidence or actual agreement rate(kappa value),area under the ROC curve(AUC)of MRI and muscle biopsy diagnosis of PM and DM,the authenticity and reliability of the two diagnosis of PM and DM are evaluated,all P <0.05 had statistical significance.Results : There were23 patients with PM,14 patients with DM,13 patients with clinically amyoppathic dermatomyositis,and 5 patients with immune-mediated necrotizing myopathy.The average age of onset of PM and DM patients was(43.9 ± 14.8)years,and the ratio of men to women was 1: 3.6,with an average duration of(5.30 ± 4.91)months.Myositis antibody positive rate was 43.6%(24/55),including 16 cases of anti-RO-52 antibody positive patients(16/55),and 4cases of anti-JO-1 antibody positive(2 of which were combined with anti-RO-52 antibody positive,4 /55),3 cases were positive for anti-SRP antibody(1 case was combined with anti-RO-52 antibody and anti-TIF1 ? antibody positive,3/55),2 cases were anti-Ku antibody positive(1 case was combined with anti-RO-52 positive,2/55),2 cases were positive for anti-MDA5 antibody(1case was combined with anti-RO-52 positive,2/55),1 case was positive for anti-Mi-2? antibody(1/55),1 case was positive for anti-TIF1 ? antibody(combined with anti-RO-52 ?anti-SRP antibody positive,1/55),anti-PM-SCL100 antibody positive in 1 case(1/55).We researched:(1)When diagnosing PM and DM,the positive rate of muscle MRI was 72.7%(40/55),the positive rate of muscle biopsy was 56.4%(31/55),and the positive rate of MRI in diagnostic PM and DM was high and statistically significant(P<0.05).(2).The sensitivity of MRI in diagnostic PM and DM was 86.5%(32/37),the specificity was 55.6%(10/18),kappa value was 0.439,AUC was 0.710,the sensitivity of muscle biopsy diagnosis was 64.9%(24/37),the specificity was 61.1%(11/18),kappa value was 0.327,AUC was 0.630.Through statistical analysis,the sensitivity of MRI diagnosis PM and DM is higher than that of muscle biopsy in the range of idiopathic inflammatory myositis,and the MRI is in good agreement with clinical comprehensive diagnosis results(that is,diagnosis results according to the gold standard),at the same time,we compared the AUC of the two to find that the accuracy of muscle MRI and muscle biopsy in diagnosis of PM and DM was not statistically significant.(z=1.277,P=0.2016).(3)MRI in the diagnosis of PM/DM manifested as multiple muscle involvement,flaky or strip inflammatory edema,muscle atrophy,with or without fasciitis,patients with dermatomyositis can also show subcutaneous panniculitis.At the same time,MRI can also early detect the muscle involvement of patients with clinically amyoppathic dermatomyositis.(4)Findings of muscle biopsy(HE staining)in patients with PM and DM:muscle fibrosis,necrosis,atrophy,inflammatory cell infiltration were observed in PM patients with high magnification;DM patients not only had typical skin pathological findings,butmuscle histopathology(×100)showed focal cell infiltration of the muscle bundles,and some patients failed to obtain samples.Conclusions:The positive rate and sensitivity of diagnostic PM and DM of MRI are higher than those muscle biopsy in the range of idiopathic inflammatory myositis,and the accuracy is comparable to that of muscle biopsy;at the same time,MRI can evaluate the affected muscle and guide the muscle biopsy site,thereby reducing the false negative rate of muscle biopsy and avoiding the pain of repeated invasive examination,even the muscle involvement of CADM patients can be identified at an early stage,so that the patients can be treated in time. |
PDF Full Text Request