Application Of Quantitative Evaluation Of Ocular Muscle Structure In The Diagnosis,staging And Efficacy Evaluation Of Thyroid Associated Ophthalmopathy

Objective: To evaluate the diagnostic and clinical staging value in patients with Thyroid-associated ophthalmopathy(TAO)based on the quantitative ocular muscle structure measurement of MRI.Methods: The MRI scan was used to compare parameters in 23 patients with TAO and 18 healthy controls;and different CAS groups in TAO respectively.Quantitative measurement of orbital structures including exophthalmos values,fatty tissue thickness of the inner side of eye balls,cross-sectional areas of extraocular muscles and signal intensity ratios of extraocular muscles to the ipsilateral temporal muscles(SIR values)were compared between these groups.We also analysised that the relationship between the quantitative values and clinical active score(CAS).Receiver operating characteristic(ROC)curve analysis was then performed to evaluate the diagnostic value of using the most correlated quantitative value to discriminate active TAO patients from the inactive ones.Results: Exophthalmos values,fatty tissue thickness of the inner side of eye balls,cross-sectional areas of extraocular muscles and signal intensity ratios of extraocular muscles to the ipsilateral temporal muscles(SIR values)were increased in TAO groups than in control.SIR values were higher in active phase group(CAS≥3 score)than inactive phase group in TAO(CAS<3 score).No significant difference of exophthalmos values,fatty tissue thickness of the inner side of eye balls,cross-sectional areas of extraocular muscles was found between patients with active phase and those with inactive phase in TAO.Strong positive correlation was found between SIR values and CAS(r=0.730,P<0.001),and a cut off value of 3.25 might be the critical threshold value to differentiate activity of TAO.Conclusion: MRI quantitative measurement of ocular muscle structures could assist in diagnosing and staging TAO.Objective: To investigate the ability of readout-segmented echo-planar imaging(rs-EPI)-based diffusion tensor imaging(DTI)in assessing the microstructural change of extraocular muscles(EOM)and optic nerve in TAO patients.Methods: A retrospective study including thirty-five TAO patients and 22 healthy controls(HCs)was carried out.Area-weighted mean,axial and radial diffusivity(MD,AD,and RD)and fraction anisotropy(FA)of EOM and optic nerve were calculated with 3.0 T MRI and rs-EPI-based DTI analysis.Difference of DTI parameters between TAO and HC groups,or active and inactive phase groups were compared using independent-samples t test.Correlation between significant DTI parameters and muscle thickness or signal intensity ratio(SIR)of EOM were analyzed by Pearson correlation.Results: TAO patients showed significantly lower FA and higher MD,AD and RD than HCs for both medial and lateral EOMs(P<0.001),except the AD value of lateral EOM(P=0.619).Active patients had significantly higher FA,MD and AD than inactive patients for medial EOM(P<0.005),whereas only FA differed significantly in the lateral EOM(P=0.018).Positive correlation was found between SIR and FA of the medial EOM(r=0.237,P=0.048).For optic nerve,MD,AD and RD were significantly lower in TAOs than HCs(P<0.05),while FA showed no significance(P=0.129).Negative correlation was found between muscle thickness of the medial EOM and RD of the optic nerve(r=-0.342,P=0.004).Conclusion: rs-EPI-based DTI is promising in assessing the microstructural change of EOM and optic nerve,and can help to make a diagnosis of TAO.FA and diffusivity of EOMs,especially the medial EOM,can even serve as an indicator of disease activity.Objective : To assess the changes of ocular parameters after pulse treatment of glucocorticoid and to evaluate the therapeutic effect of quantitative measurement of orbital structures in patients with Thyroid-associated ophthalmopathy(TAO)after glucocorticoid treatment based on quantitative ocular muscle structure measurement of MRI.Methods: Eighteen TAO patients were enrolled for 3.0T MRI orbit scan before and after methylprednisolone treatment.Quantitative measurement of orbital structures including exophthalmos values,fatty tissue thickness of the inner side of eye balls,thickness of extraocular muscles with maximum signal intensity and signal intensity ratios of extraocular muscles to the ipsilateral temporal muscles(SIR values)were compared before and after treatment.Paired t test was used to compare the changes of parameters before and after methylprednisolone treatment.Results: After the treatment of classical methylprednisolone,the exophthalmos values,and fatty tissue thickness of the inner side of eye balls were not obvious changed in the orbit while signal intensity ratios of extraocular muscles to the ipsilateral temporal muscles(SIR values),thickness of extraocular muscles with maximum signal intensity and CAS score decreased significantly,especially in the patients without smoking.The pretherapeutic CAS score was positively correlated with baseline SIR.The exophthalmos values and the cause of disease were also positively correlated with fatty tissue thickness of the inner side of eye balls before treatment,respectively.The pretherapeutic CAS score was positively correlated with the SIR D-value after treatment.Conclusion: Glucocorticoid therapy can reduce signal intensity ratios of extraocular muscles to the ipsilateral temporal muscles(SIR values),thickness of extraocular muscles with maximum signal intensity in TAO patients,especially in patients without smoking.The decrease in SIR was more obvious in the patient with high baseline CAS scores.MRI quantitative ocular muscle measurement can assist the evaluation of the glucocorticoid treatment efficacy of TAO.Objective: To evaluate the efficacy of rituximab in the treatment of TAO with the changes of CAS scores and immune index.We also evaluate the therapeutic effect of quantitative measurement of orbital structures in patients with TAO based on MRI after rituximab treatment.Methods: Patients with active TAO were treated with low dose and long course rituximab.The clinical activity score,thyroid related antibody,thyroid function and immune index were collected with 52 weeks follow-up to evaluate the inhibitory effect on immunization and the protection of visual acuity.MRI orbital scan was performed before and 28 w,52w after the treatment of rituximab,respectively.The measurement of the exophthalmos values,fatty tissue thickness of the inner side of eye balls,signal intensity ratios of extraocular muscles to the ipsilateral temporal muscles(SIR values)and thickness of extraocular muscles with maximum signal intensity were measured.Paired t test and ANOVA were used to analyze the changes of parameters before and after rituximab treatment.Results: The activity of CAS in TAO patients decreased significantly and maintained with no obvious rebound after rituximab treatment in 52 weeks follow-up.CD19,CD20 decreased significantly at 5 weeks,then gradually increased in 28 weeks and further increased in the 52 week.However,they are still lower after trestment than in the baseline.The quantitative measurement of 3T-MRI showed that signal intensity ratios of extraocular muscles to the ipsilateral temporal muscles(SIR values)and thickness of extraocular muscles with maximum signal intensity decreased significantly;but the exophthalmos and fatty tissue thickness of the inner side of eye balls were not obvious change in the orbit.Conclusion: MRI quantitative measurement showed that signal intensity ratios of extraocular muscles to the ipsilateral temporal muscles(SIR values)and thickness of extraocular muscles with maximum signal intensity decreased significantly after low dose and long course rituximab treatment,and has no obvious inhibitory effect on the patient’s immunity index.Rituximab treatment can significantly improve the activity of TAO and decease the thickness of extraocular muscles,which indicates its good effects.