The Clinical Application of MRI Quantitative Analysis of Orbital Structures in Graves Ophthalmopathy

Objective To quantitatively measure the values of exophthalmoses,short and long diameters of extraocular muscles,the thickness of fatty tissue at the inner side of eye ball,and the T_2 values of extraocular muscles and fat tissue both in normal groups and Graves Ophthalmopathy(GO)patients,in order to evaluate the MRI values in the diagnosis,clinic stages,and curative effect of Graves Ophthalmopathy.Materials and Methods 25 normal cases(50 eyes)and 30 cases of Graves Ophthalmopathy(double sides,totally 60 eyes)were included in this study.All the cases were performed MRI orbital scan.The short and long diameters of extraocular muscles were measured on T_1WI axial or coronal images.The ratios of short diameter to long diameter(R values)of extraocular muscles were calculated.The thickness of fatty tissue at the inner side of eyeballs and the values of exophthalmos were also measured.At the same time,the T_2 values of extraocular muscles and the orbital fatty tissue were measured in the SE dual echo images.Results(1)The exophthalmos value of GO group was larger than that of normal group.There was significant difference between these two groups in exophthalmos value(P0.01).(2)The short diameter of extraocular muscles in GO group was larger than that in control group.There was significant difference between these two groups in the short diameter of extraocular muscles(P0.01).There was no significant difference between this two groups in the long diameter of extraocular muscles(P0.05).The R-value of extraocular muscles in GO group was larger than that in control group.There was statistical difference between the GO group and control group in the R-values of extracular muscles.(3)The thickness of fatty tissue at the inner side of eye balls in GO group was larger than that in control group.There was significant difference(P0.01).(4)There were statistically differences between GO group and control group in the T_2 values of extraocular muscles(P0.01),but there was no statistically difference in fat tissue between these two groups(P0.05).Conclusion MRI quantitative analysis of orbital structures is helpful in the diagnosis,clinic stages,and curative effect of Graves Ophthalmopathy.