The Clinical Application Of Dynamic-contrast Enhanced MR Imaging And Immunological Study On Eye Muscle Autoantigens In Patients With Thyroid Associated Ophthalmopathy

Part Ⅰ Evaluation of rectus extraocular muscles using dynamic contrast enhanced MR imaging to assess the activity of thyroid associated ophthalmopathyObjective:To analyze the changes of rectus extraocular muscles (EOMs) in patients with TAO using dynamic contrast enhanced MR imaging (DCE-MRI) and to explore the feasibility in the assessment of disease activity.Methods:There were34cases of TAO and10volunteers without eye disease or thyoid disease (control group, CG). Based on the clinical activity score (CAS), all TAO patients were divided into2groups, activity group (AG) and inactivity group (IAG). MRI and DCE-MRI orbit scan were performed in each subject. Drew time-intensity curves (TICs) by Siemens3.0(syngo) post-processing workstation. The semi-quantitative paramters of DCE-MRI were calculated. The semi-quantitative paramters based on TICs include early enhancement ratio (EER), maximum enhancement ratio (Emax) and wash-out ratio (WR5min).Results:(1)There were significant difference in signal intensity (SI) of rectus EOMs on T2W images among CG, AG and IAG.(2)EER, Emax and WR5min values of rectus EOMs of TAO group were significantly lower than those of CG. EER, Emax and WR5min values of medial rectus and inferior rectus EOMs of IAG were significantly lower than those of AG. WR5min values of superior rectus EOMs of IAG were significantly lower than those of AG. There were no differences in EER and Emax values of lateral rectus and superior rectus EOMs between IAG and AG. There were no differences in WR5min values of lateral rectus EOMs between IAG and AG (3)A statistically correlation was found between CAS and mean WR5min.(4)The cut-off values for mean EER, mean Emax, and mean WR5min were53.85%,118.4%and12.09%. The area under the curve (AUC) were0.771,0.879and0.898, respectively.Conclusions:The semi-quantitative paramters of DCE-MRI are useful to show the clinical activity of TAO and can be considered as the quantitative index to assess the disease activity.Part Ⅱ Application of DCE-MRI quantitative analysis to assess function of rectus EOMs and clinical efficacy of thyroid associated ophthalmopathyObjective:To explore the feasibility of the quantitative paramters of DCE-MRI in the assessment of function of rectus EOMs and clinical efficacy of thyroid associated ophthalmopathy.Methods:There were30cases of TAO and10volunteers without eye disease or thyoid disease (CG). Based on CAS, all TAO patients were divided into2groups, AG and IAG. MRI and DCE-MRI orbit scan were performed in each subject. The SI of rectus EOMs on T2WI was evaluated. Drew contrast-times curves (CTCs) by Sienenas3.0MR (syngo) post-processing workstation. The quantitative paramters based on CTCs include transfer constant (Ktrans) and rate constant (Kep).Results:(1)There were significant differences in SI of rectus EOMs on T2WI among CG, AG and IAG.(2)There were significant differences in Ktrans and Kep values of medial rectus among the hyperintensity group, isointensity group and hypointensity group, the same as inferior rectus. Ktrans and Kep values of medial rectus and inferior rectus in hyperintensity group were significant higher than those of isointensity group. The cut-off values for Ktrans and Kep of medial rectus between the hyperintensity group and isointensity group were0.148and0.274, The AUC were0.847and0.857. The cut-off values for inferior rectus were0.151and0.284. The AUC were0.870and0.775.(3)There was significant correlation between CAS and maxKtrans, maxKep values.(4)MaxKtrans and maxKep values decreased in AG after treatment, in line with CAS scores.Conclusions:(1)The quantitative paramters of DCE-MRI is a method for judging inflammatory changes of rectus EOMs in TAO.(2)The quantitative paramters of DCE-MRI contribute to evaluate the clinical results PartⅢ A study on histopathology of the orbital tissue and ultrastructure of in thyroid associated ophthalmopathyObjective:To investigate histopathology the orbital tissue and ultrastructure of rectus extraocular muscles in thyroid associated ophthalmopathy in order to collect some evidences of pathogenesis and informations for the semi-quantitative paramters and quantitative paramters of DCE-MRI.Methods:Ten thyroid associated ophthalmopathy cases with typical clinical symptoms and signs who were treated in our hospital from January2010to October2013were collected. Every case was confirmed by thyroid functions and image examination and underwent orbital decompression or correction of diplopia. Each of EOMs was cut into two pieces. One of them and the specimens of orbital fat were stained with HE, Masson and immunohistochemistry. Each of them was observed by light microscope. The other was sectioned with ultrathin method and observed by transmission electron microscope. All of the cases were underwent dynamic contrast enhanced and MRI of the orbit before the surgery.Results:(1)Under the light microscope, the biopsy of EOMs of hyperintensity group showed non-uniform muscle fiber size, increase and irregular-shaped muscle cells and some of the perimeter of muscles fiber unclear. Inter-adipocytic and inter-muscle bundle spaces enlarging, GAGs aggregation, lymphocytes infiltration and angiogenesis were found. Muscle fiber rupture, dissolving, vacuolization, fibrogenesis and adipose interstitial fibrogenesis compose of histopathologic characteristics of EOMs in hypointensity group.(2)Under the electron microscope, there were disappearance and disturbance of the Z line in par of muscular fibers, myofilament destruction with formation of vacuoles in EOMs of hyperintensity group. At the same time, vascular endothelial cell vacuolization and intercellular junction enlarging were found. In EOMs of hypointensity group, the muscular cells could be destroyed. There were fibrosis occurred and myofibroblasts.Conclusions:(1)The extraocular muscles in TAO are destroyed at various degrees and the muscular cells may be the target cells in TAO.(2)There were GAGs aggregation and lymphocytes infiltration in EOMs of hyperintensity group, and fibrogenesis in hypointensity group.(3)The characteristic of DCE-MRI is closely related to histopathology changes of the orbital tissue and ultrastructure of rectus extraocular muscles.PartlV Immunological studied of four eye muscle antigens and the corresponding serum autoantibodies in patients with thyroid associated ophthalmopathyObjective:To explore the role and characteristics of four eye muscle antigens and the corresponding serum autoantibodies in the pathogenesis of thyroid associated ophthalmopathyMethods:A total of98subjects were recruited in this study, including56patients with thyroid associated ophthalmopathy,22Graves’hyperthyroidism (GH) without ophthalmopathy and20age and sex matched normal subjects. All TAO patients were divided into2groups, activity group (AG) and inactivity group (IAG). The proliferative response of T cells to calsequestrin, Fp, G2s and UACA was examined via MTT assay. The enzyme linked immunosorbent assay (ELISA) was used to measure the corresponding serum autoantibodies.Results:(l)Signigicantly stronger proliferative response of T cells to calsequestrin, UACA and Fp, but not G2s, were noted in AG than CG, GH and IAG. T cell proliferative response to calsequestrin and Fp in IAG were no significant differences comparer to CG and GH. There was no obvious difference in proliferative response of T cells to G2s amongCG, GH, IAG and AG.(2)Significantly greater serum levels of antibodies against calsequestrin, UACA and Fp, but not G2s, were found in AG compared to control group, GH and IAG. There was no obvious difference in serum levels of antibodies against G2s among CG, GH, IAG and AG. The serum antibodies levels against calsequestrin, UACA and Fp were no obvious differences between CG, GH and IAG. Conclusions:(1)Humoral and cellular immunity are involved in the initiation and progression of TAO.(2)The extraocular muscles may be the main and primary target. The eye muscle antigens play a pivotal role in the pathogenesis of TAO.(3)Calsequestrin, UACA and Fp are sensitive markers for eye muscle antoimmunity in patients with TAO.(4)The different responses of peripheral blood of patients with TAO in active stage and inactive to Calsequestrin, UACA, and Fp can help assess the disease severity grading.