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Objective: This study aimed to develop and test a model for predicting dysthyroid optic neuropathy (DON) based on clinical factors and imaging markers of the optic nerve and cerebrospinal fluid (CSF) in the optic nerve sheath., Methods: This retrospective study included patients with thyroid-associated ophthalmopathy (TAO) without DON and patients with TAO accompanied by DON at our hospital. The imaging markers of the optic nerve and CSF in the optic nerve sheath were measured on the water-fat images of each patient and, together with clinical factors, were screened by Least absolute shrinkage and selection operator. Subsequently, we constructed a prediction model using multivariate logistic regression. The accuracy of the model was verified using receiver operating characteristic curve analysis., Results: In total, 80 orbits from 44 DON patients and 90 orbits from 45 TAO patients were included in our study. Two variables (optic nerve subarachnoid space and the volume of the CSF in the optic nerve sheath) were found to be independent predictive factors and were included in the prediction model. In the development cohort, the mean area under the curve (AUC) was 0.994, with a sensitivity of 0.944, specificity of 0.967, and accuracy of 0.901. Moreover, in the validation cohort, the AUC was 0.960, the sensitivity was 0.889, the specificity was 0.893, and the accuracy was 0.890., Conclusions: A combined model was developed using imaging data of the optic nerve and CSF in the optic nerve sheath, serving as a noninvasive potential tool to predict DON., (© 2024. Huazhong University of Science and Technology.)

Objectives: To investigate the brain functional alterations in dysthyroid optic neuropathy (DON) by evaluating spontaneous neural activity, using functional magnetic resonance imaging (fMRI) with regional homogeneity (ReHo), and its relationship with ophthalmologic performance., Methods: Forty-seven patients with thyroid-associated ophthalmopathy (TAO; 20 with DON, 27 with non-DON) and 33 age-, sex-, and education-matched healthy controls (HCs) underwent fMRI. ReHo values were compared using one-way analysis of variance (ANOVA) with post hoc pairwise comparisons (voxel-level p < 0.01, Gaussian random field correction, cluster-level p < 0.05). Correlations between ReHo values and ophthalmological metrics were assessed for DONs, with Bonferroni correction for multiple comparisons (p < 0.004). ROC curves were applied to evaluate the diagnostic performance of ReHo metrics., Results: ReHo values were significantly lower in the left insula and right superior temporal gyrus, and higher in the left posterior cingulate cortex (LPCC), of DON than of non-DON patients. ReHo values were also significantly lower in the right middle temporal, left insula, and left precentral gyrus in DON than in HCs. Meanwhile, ReHo values were higher in LPCC in non-DON than in HCs. ReHo values correlated with ophthalmic examinations to varying degrees in DON. For distinguishing DON, the ReHo values in LPCC showed optimal individually (AUC = 0.843), the combination of the ReHo in both the left insula and LPCC performed better (AUC = 0.915)., Conclusion: Spontaneous brain activity differed between TAO with and without DON, which may reflect the underlying pathological mechanism of DON. The ReHo index can be considered a diagnostic biomarker., Clinical Relevance Statement: Spontaneous brain activity in DON differed from that in TAO without DON, which may reflect the underlying pathological mechanism of DON. The ReHo index can be considered a diagnostic biomarker for early detection of DON., Key Points: • Dysthyroid optic neuropathy (DON) affects brain activity, which contributes in the understanding of its visual dysfunction. • Regional homogeneity values differ between thyroid-associated ophthalmopathy with and without DON in various brain regions. • Regional homogeneity values can be used as a biomarker in the differential diagnosis of DON., (© 2023. The Author(s), under exclusive licence to European Society of Radiology.)

Background: Increasing evidence has indicated that the entire visual pathway from retina to visual cortex may be involved in dysthyroid optic neuropathy (DON) pathological mechanisms., Purpose: To explore the functional and morphological brain characteristics in DON and their relationship with ophthalmologic performance., Study Type: Retrospective., Population: A total of 30 DON patients, 40 thyroid-associated ophthalmopathy (TAO) without DON patients and 21 healthy-controls (HCs)., Field Strength/sequence: A 3.0 T, 3D T1-weighted spoiled gradient-recalled echo and gradient-recalled echo-planar imaging., Assessment: Functional and structural alterations in brain regions were evaluated with fractional amplitude of low-frequency fluctuations, degree centrality (DC), and gray matter volume (GMV). Clinical activity score (CAS) is assessed across patients., Statistical Test: One-way analysis of variance with post hoc two sample t-tests (GRF-corrected, voxel level: P < 0.005, cluster level: P < 0.05) and correlation analysis (significance level: P < 0.05)., Results: Compared to HCs, DON patients had significantly decreased DC values in the bilateral BA17 and BA18 regions. Compared to the TAO group, DON patients had decreased GMV in the left anterior cingulate cortex, left middle frontal gyrus, left lingual gyrus, left parietal gyrus, right Rolandic operculum, left supplementary motor area, and right middle temporal gyrus. In addition, GMV in the right Rolandic operculum was significantly positively correlated with CAS (correlation coefficient: r = 0.448)., Data Conclusion: This study showed significant morphological and functional alterations in visual cortex and morphological alterations in partial default mode network regions of DON patients, which may provide insights into the mechanism of vision loss and may facilitate the diagnosis and treatment of DON., Evidence Level: 3., Technical Efficacy: Stage 3., (© 2022 International Society for Magnetic Resonance in Medicine.)

Background: The mechanism driving dysthyroid optic neuropathy (DON) is unclear. Diffusion-tensor imaging (DTI) allows for noninvasively assessing the microstructure of the entire visual pathway and may facilitate a better understanding of the mechanism of DON., Purpose: To assess microstructural changes of the whole visual pathway and to investigate the potential mechanism of trans-synaptic damage（TSD） pathogenesis in DON with DTI., Study Type: Cross-sectional., Population: Sixty-four patients with bilateral thyroid-associated ophthalmopathy (TAO), 30 with and 34 without DON, and 30 age- and sex-matched healthy controls (HCs)., Field Strength/sequence: 3 T/DTI (A single-shot diffusion-weighted echo-planar imaging sequence)., Assessment: Differences in DTI parameters including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) in each segment (optic nerve, tract, and radiation) of the entire visual pathway among the groups were compared. The parameters of visual evoked potentials (VEPs), visual field tests, and mean retinal nerve fiber layer (mRNFL) thickness on optical coherence tomography were also compared across patients., Statistical Tests: Student's t-test, chi-square test; ANOVA with post-hoc testing, interclass correlation coefficient, and correlation analysis. Significance level: P < 0.05., Results: TAO patients with DON showed significantly reduced mRNFL thickness and abnormal VEPs. There was a tendency for gradually reduced FA and AD, and increased RD and MD from HCs, with non-DON to with DON in optic nerve and tract, statistically. For radiation, the RD and MD showed statistical increase, the AD and FA just showed numerical decrease (P = 0.119 and 0.059, respectively). For DON, the FA and MD of visual pathway segments showed correlations with abnormal VEPs., Data Conclusion: DTI may be a useful tool for detecting microstructural changes in the entire visual pathway in DON. The changes in RNFL thickness and DTI parameters suggested TSD as a potential pathogenic mechanism of DON., Evidence Level: 4 Technical Efficacy: Stage 5., (© 2022 International Society for Magnetic Resonance in Medicine.)

Objective: To evaluate the microstructural changes of the orbital optic nerve in thyroid-associated ophthalmopathy (TAO) patients with or without dysthyroid optic neuropathy (DON) using diffusion tensor imaging (DTI) and investigate whether DTI can be used to detect DON., Materials and Methods: 59 bilateral TAO patients with (n= 23) and without DON (non-DON, n= 36) who underwent pretreatment DTI were included and 118 orbits were analyzed. The clinical features of all patients were collected. DTI parameters, including mean, axial, and radial diffusivity (MD, AD, and RD, respectively) and fractional anisotropy (FA) of the intra-orbital optic nerve for each orbit were calculated and compared between the DON and non-DON groups. ROC curves were generated to evaluate the diagnostic performance of single or combined DTI parameters. Correlations between DTI parameters and ophthalmological characteristics were analyzed using correlation analysis., Results: Compared with non-DON, the DON group showed decreased FA and increased MD, RD, and AD (P < 0.01). In the differentiation of DON from non-DON, the MD was optimal individually, and the combination of the four parameters had the best diagnostic performance. There were significant correlations between the optic nerve's four DTI metrics and the visual acuity and clinical active score (P < 0.05). In addition, optic nerve FA was significantly associated with the amplitude of visual evoked potentials (P = 0.022)., Conclusions: DTI is a promising technique in assessing microstructural changes of optic nerve in patients with DON, and it facilitates differentiation of DON from non-DON eyes in patients with TAO., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Liu, Luo, Zhai, Wu, Wang, Yuan, Jiang, Chen and Zhang.)

Objectives: To evaluate the optic nerve and CSF in the optic nerve sheath as imaging markers of dysthyroid optic neuropathy (DON)., Methods: In this single-centre retrospective study, orbital images of 30 consecutive participants (54 orbits) with DON, 30 patients (60 orbits) with thyroid-associated ophthalmopathy (TAO) without DON, and 19 healthy controls (HCs; 38 orbits) were analysed. The diameter and cross-sectional area of the optic nerve and its sheath, water fraction of the optic nerve, and volume of the fluid in the optic nerve sheath were measured and compared. The associations between MR parameters and clinical measures were assessed using correlation analysis., Results: The diameter and water fraction of the optic nerve (3 mm and 6 mm behind the eyeball), optic nerve subarachnoid space (ONSS) (3 mm and 6 mm behind the eyeball), and subarachnoid fluid volume in the optic nerve sheath were significantly greater in the DON group than in the TAO group (p < 0.01) or HC group (p < 0.01). ROC analysis showed that ONSS 3 mm behind the eyeball (ONSS3) was a robust predictor of DON (AUC = 0.957, sensitivity = 0.907, specificity = 0.9). Water fraction of the optic nerve 3 mm behind the eyeball (water fraction3) had the best specificity (0.967). Water fraction3, fluid volume in the optic nerve sheath, and optic nerve diameter (3 mm behind the eyeball) were correlated with clinical measures (i.e. clinical activity score, mean defect, and pattern standard deviation)., Conclusions: Increased water fraction of the optic nerve and ONSS3 are promising and easily accessible radiological markers for diagnosing DON., Key Points: • The water fraction of the optic nerve and optic nerve subarachnoid space (ONSS) are greater in patients with dysthyroid optic neuropathy (DON) than in patients with thyroid-associated ophthalmopathy (TAO) without DON. • The optic nerve and the cerebrospinal fluid in the optic nerve sheath measures are associated with visual dysfunction. • The water fraction of the optic nerve and ONSS may be promising imaging markers for diagnosing DON., (© 2021. European Society of Radiology.)

Objective: To determine the diagnostic ability of isolated-check visual evoked potential (icVEP), pattern visual evoked potential (pVEP), and standard automated perimetry (SAP) between dysthyroid optic neuropathy (DON) and thyroid-associated ophthalmopathy (TAO) without DON (non-DON)., Methods: This is a case-control study, 49 bilateral patients (26 DON and 23 non-DON) were included. icVEP, pVEP, and SAP were conducted in all the subjects, icVEP parameters compared were signal-to-noise ratios (SNRs) under 8, 16, and 32% depth of modulation (DOM). pVEP parameters compared were amplitude and latency. SAP parameters were mean deviation (MD) and pattern standard deviation (PSD). The area under the receiver operating characteristic (ROC) curve (AUC), net reclassification index (NRI), integrated discrimination index (IDI), and decision curve analysis (DCA) were applied for analysis., Results: In icVEP, values of SNR in DON were significantly smaller than non-DON (p < 0.05). In pVEP, P100 latent time in DON was significantly larger than non-DON (p = 0.0026). In SAP, value of PSD in DON was larger than non-DON (p = 0.0006), and value of MD in DON was smaller (p = 0.0007). AUC, NRI, and IDI among the three tests were not significantly different. DCA showed that SNR of icVEP under 8% DOM was the farthest from the two extreme curves., Conclusions: icVEP, pVEP, and SAP have equal diagnostic capabilities to discern between DON and non-DON. In addition, icVEP may represent a significant ancillary diagnostic approach to DON detection, with more clinical benefit., (© 2020. The Author(s), under exclusive licence to The Royal College of Ophthalmologists.)

Background: With the extensive development of endoscopic sinus surgery, iatrogenic medial rectus muscle injury should be treated with caution. Traditional methods to repair a ruptured medial rectus need an anterior orbitotomy approach, with more injury and difficulty in finding the posterior end of the ruptured medial rectus. Objective: To explore a new method to repair a ruptured medial rectus. Methods: Eight cases of iatrogenic medial rectus rupture after endoscopic sinus surgery were reviewed from July 2015 to January 2019. Assisted by image-guided navigation, the ruptured medial rectus was sutured under an endoscopic endonasal orbital approach. Two methods were designed to suture the ruptured medial rectus. Optic nerve and orbital decompression were performed in 5 cases with visual impairment. The extent of exotropia and diplopia were followed up for 5 to 33 months after surgery. Results: With the help of image guidance, the posterior and anterior ends of the ruptured medial rectus of all patients were pinpointed, and operations using medial rectus anastomosis were successfully completed in 7 patients. The exotropia of these patients was corrected, and they have recovered. The vision of 2 patients recovered. There were no minor or major complications intraoperatively or postoperatively. Conclusion: Assisted by image-guided navigation, medial rectus anastomosis under an endoscopic endonasal orbital approach is a feasible method. The key to preventing orbital complications is strict professional training, including identification of the Onodi air cell and correct application of powered instrumentation. [ABSTRACT FROM AUTHOR]