Clinical Study On The Application Of Magnetic Resonance Imaging In Evaluating Activity Of Graves' Ophthalmopathy

Objective1.To investigate the difference of quantitative parameters using orbital magnetic resonance imaging(MRI)between Graves' ophthalmopathy(GO)and healthy control group,including exophthalmos degree,intracranial fatty thicknesses,short diameters,long diameters,the ratios of short diameter to long diameter(R values)and the signal intensity ratios of the extraocular muscle to the white matter(SIR values)in the group of Han population in Linyi,Shandong Province,China.2.To investigate the correlation between clinical activity score(CAS)and MRI quantitative parameters of GO,including exophthalmos degree,intracranial fatty thicknesses,short diameters,long diameters,R values and SIR values in the group of Han population in Linyi,Shandong Province,China.Methods22 patients with GO were treated in endocrinology of Linyi,Shandong Province from November 2015 to January 2017.There are 13 males and 9 females aged(47.6±12.8)years.All of binocular lesions were diagnosed according to the medical history,symptoms,laboratory examination and image scan.We excluded orbital tumors,white matter lesions and other causes of eye diseases,intracranial lesions.17 healthy subjects of the same period were recruited as control,including 8 males and 9 females aged(41.3±11.5)years.Who were measured peripheral blood thyroid hormone and antibody levels to exclude thyroid disease,orbital disease and intracranial lesions.22 patients with GO and 17 healthy subjects underwent 1.5T-MRI scanning.We measured the quantitative parameters,including the exophthalmos degree,intracranial fatty thicknesses,short diameters,long diameters,R values and SIR values.And the differences between the quantitative parameters of orbital tissue were compared.We analysed the Spearman's correlation between MRI quantitative parameters and CAS in GO groups,and selected the highest correlation of quantitative parameters.To determine the diagnostic value on GO activity,we selected CAS33 as the critical point to calculate the threshold by receiver operating characteristic(ROC)curve method.And we should calculate the sensitivity and specificity.Results1.There were differences between GO groups and healthy control groups of orbital Quantitative parameters using MRI.There were 22 with GO(all binocular exophthalmos and 44 eyes)and 17 healthy subjects(34 eyes).MRI scan showed that exophthalmos degree,intracranial fatty thicknesses,short diametere,R value and SIR value of GO groups thicked significantly for the healthy control group(P<0.01).Excepting for the long diameter of lateral rectus,there was no significant difference between GO group and the healthy control group(P(29)0.05).The other long diametes were significant difference between GO group and the healthy control group(P<0.01).2.There was correlation between CAS and most of MRI quantitative parameters.Spearman's related analysis showed that all of exophthalmos degree were moderately correlated with the CAS in GO group(r=0.626,P(27)0.01).There was no correlation between the intracranial fatty thicknesses and the CAS(r=0.278,P(29)0.05).The short diameters of the medial rectus muscle and inferior rectus muscle were moderately correlated with the CAS(r=0.586,0.550,P(27)0.01),The short diameters of lateral rectus muscle,upper muscle group,average(AV)-short diameter,maximum(MAX)-short diameter of the extraocular muscles were slightly correlated with the CAS(r=0.369,0.330,0.460,0.469,P(27)0.01).The long diameters of inferior rectus muscle were moderately correlated with the CAS(r=0.472,P(27)0.01).AV-long diameters,MAX-long diameters were slightly correlated with CAS(r=0.329,0.319,P(27)0.01).There were no significant correlations between the long diameters of medial rectus muscle,lateral rectus muscle,upper muscle group and CAS(r=0.269,0.062,0.272,P(29)0.05).The R values of medial rectus muscle,inferior rectus muscle,AV-R values,and MAX-R values were moderately correlated with the CAS(r=0.472,0.419,0.582,0.582,P(27)0.01).There were no significant correlations between the R values of lateral rectus muscle,upper muscle group and the CAS(r=0.248,0.267,P(29)0.05).The SIR values of medial rectus muscle,lateral rectus muscle,upper muscle group and inferior rectus muscle were moderately correlated with the CAS(r=0.666,0.523,0.491,0.690,P(27)0.01).AV-SIR value and MAX-SIR value were significantly correlated with CAS(r=0.724,0.777,P(27)0.01).In especially,The MAX-SIR values and CAS were the strongest correlation(r=0.777,P(27)0.01).3.MAX-SIR31.59 have the best evaluation effect on GO activity.GO groups(44 eyes)were divided into active and inactive using CAS33,with 34 eyes of an active phase and 10 eyes of an inactive phase.The study found that there was a significant difference between active and inactive(P(27)0.01).Using the ROC curve method showed that the threshold of SIR were 1.59 for distinguishing active from inactive phase.And the area under the curve(AUC)was 0.851,the sensitivity was 82.4% and the specificity was70%.So we hold that MAX-SIR31.59 have the best evaluation effect for GO activity.Conclusion1.Excepting for the long diameter of lateral rectus,the other long diameters were significant difference between GO group and the healthy control group.2.The exophthalmos degree,the short diameter(medial rectus muscle and inferior rectus muscle),the long diameter(inferior rectus muscle),the R values(medial rectus muscle,inferior rectus muscle,AV-R value,MAX-R value),the SIR values(medial rectus value,lateral rectus muscle,superior muscle group,inferior rectus muscle)and CAS were stronger correlation.The remaining quantitative parameters were lower correlation.Especially,The MAX-SIR value and CAS were the strongest correlation.3.MAX-SIR value can be used as objective index to evaluate the activity of GO,MAX-SIR value31.59 can divide into the threshold of active and inactive.