Prevalence of Radiological Signs of Dysthyroid Optic Neuropathy in Magnetic Resonance Imaging in Patients with Active, Moderate-to-Severe, and Very Severe Graves Orbitopathy

Diagnosis of dysthyroid optic neuropathy: combined value of orbital MRI and intracranial visual pathway diffusion kurtosis imaging

OBJECTIVES

To evaluate the combined performance of orbital MRI and intracranial visual pathway diffusion kurtosis imaging (DKI) in diagnosing dysthyroid optic neuropathy (DON).

METHODS

We retrospectively enrolled 61 thyroid-associated ophthalmopathy (TAO) patients, including 25 with DON (40 eyes) and 36 without DON (72 eyes). Orbital MRI-based apical muscle index (MI), diameter index (DI) of the optic nerve (ON), area index (AI) of the ON, apparent diffusion coefficient (ADC) and signal intensity ratio (SIR) of the ON, DKI-based kurtosis fractional anisotropy (KFA) and mean kurtosis (MK) of the optic tract (OT), optic radiation (OR), and Brodmann areas (BAs) 17, 18, and 19 were measured and compared between groups. The diagnostic performances of models were evaluated using receiver operating characteristic curve analyses and compared using the DeLong test.

RESULTS

TAO patients with DON had significantly higher apical MI, apical AI, and SIR of the ON, but significantly lower ADC of the ON than those without DON (p < 0.05). Meanwhile, the DON group exhibited significantly lower KFA across the OT, OR, BA17, BA18, and BA19 and lower MK at the OT and OR than the non-DON group (p < 0.05). The model integrating orbital MRI and intracranial visual pathway DKI parameters performed the best in diagnosing DON (AUC = 0.926), with optimal diagnostic sensitivity (80%) and specificity (94.4%), followed by orbital MRI combination (AUC = 0.890), and then intracranial visual pathway DKI combination (AUC = 0.832).

CONCLUSION

Orbital MRI and intracranial visual pathway DKI can both assist in diagnosing DON. Combining orbital and intracranial imaging parameters could further optimize diagnostic efficiency.

CLINICAL RELEVANCE STATEMENT

The novel finding could bring novel insights into the precise diagnosis and treatment of dysthyroid optic neuropathy, accordingly, contributing to the improvement of the patients' prognosis and quality of life in the future.

KEY POINTS

• Orbital MRI and intracranial visual pathway diffusion kurtosis imaging can both assist in diagnosing dysthyroid optic neuropathy. • Combining orbital MRI and intracranial visual pathway diffusion kurtosis imaging optimized the diagnostic efficiency of dysthyroid optic neuropathy.

Real-World Experience With Teprotumumab in Patients With Dysthyroid Optic Neuropathy

BACKGROUND

Teprotumumab, an insulin-like growth factor I receptor inhibitory antibody, improved proptosis, diplopia, inflammatory signs/symptoms, and quality of life in patients with active thyroid eye disease (TED) in clinical trials. The trials excluded patients with dysthyroid optic neuropathy (DON). Recently, many case reports and case series have reported the successful use of teprotumumab to treat DON. Here, we review the data from published cases and our clinical experience in treating patients having DON with teprotumumab.

METHODS

A literature search was conducted of patients with DON treated with teprotumumab from January 2020 through September 2022. Data from DON patients from the authors' (M.A.T. and C.A.B.) clinical practice were included. Primary outcome measure was mean (SD) improvements for visual acuity, color vision, and visual fields. Improvements in proptosis and clinical activity score (CAS) and diplopia were compared before and after teprotumumab administration.

RESULTS

Ten observational studies/case reports were identified along with 2 patients in our practice. In all, there were 24 active TED patients with DON (37 eyes) who were treated with teprotumumab. Mean (SD) age was 66.5 (13.6) years and 13 (54%) were females, disease duration ranged from 2 months to >15 years. 22/24 patients had none, minimal improvement or progression of visual loss with intravenous/oral corticosteroids, orbital decompression (n = 9), and orbital radiation (n = 2). There were 2 patients who received teprotumumab as the only therapy. Overall, 88% (21/24) reported improvement in visual acuity after teprotumumab and in 75% (18/24), improvement in vision was observed after just 2 infusions of teprotumumab. Three eyes had decompression surgery in close proximity to teprotumumab infusions and were excluded from analyses. Mean (SD) improvement in visual acuity was 3.73 lines (SD 3.74), range 2-15 lines in 33 eyes. The mean (SD) improvement in the mean deviation on visual field testing in 15 eyes was 5.6 db (3.0 db). Mean (SD) improvement in proptosis was 4.37 mm (SD: 2.11) (20 patients, 32 eyes); and clinical activity score: mean reduction of 5.1 (1.3) for 18 patients. Teprotumumab was well tolerated in all but one patient. Adverse events reported included fatigue, dysgeusia, hearing loss, nausea, hyperglycemia, and muscle spasms.

CONCLUSIONS

Teprotumumab is an effective treatment for DON in our experience and in published cases in whom treatment with steroids, surgery, or orbital radiation was unsuccessful.

3.0 T multi-parametric MRI reveals metabolic and microstructural abnormalities in the posterior visual pathways in patients with thyroid eye disease

Introduction

We aim to explore the microstructural and metabolic changes in visual pathways in patients with thyroid eye disease (TED) using 3T multi-parametric MRI.

Methods

Thirty-four TED patients (inactive group = 20; active group = 14; acute group = 18; chronic group = 16) and 12 healthy controls (HC) were recruited from November 2020 to July 2021. Proton magnetic resonance spectroscopy (1H-MRS), glutamate chemical exchange saturation transfer (GluCEST) and diffusion kurtosis imaging (DKI) were performed on 3.0T MR scanner. Data analysis and group comparisons were performed after MR data processing.

Results

As compare to HC group, the levels of total choline (tCh) in optic radiation (OR) in active group ([1.404 ± 0.560] vs. [1.022 ± 0.260]; p < 0.05), together with tCh ([1.415 ± 0.507] vs. [1.022 ± 0.260]; p < 0.05) in OR in acute group were significantly increased. Glutamine (Gln) levels were higher in OR in the chronic group than those in HCs and were positively correlated with the levels of thyroglobulin antibody (TgAb), thyroid peroxidase antibody (TPOAb), free triiodothyronine (FT3) and FT4 in chronic group. Glutamate (Glu) levels by 1H-MRS did not show significant differences between any two groups. Interestingly, MTRasym (3.0 ppm) was higher in OL in inactive group, active group, acute group and chronic group than those in HCs, and was positively correlated with Glu levels in OL in 1H-MRS. Fractional anisotropy (FA) values from DKI in OR in acute group were significantly lower than those in HCs.

Discussion

Our initial study demonstrate that GluCEST performs better than 1H-MRS to monitor Glu alterations in visual pathway in TED patients. Changes of brain glutamine levels in TED patients are closely related to their associated hormones alterations, indicating that disease injury status could be reflected through non-invasive metabolites detection by brain 1H-MRS. FA is the most sensitive DKI index to reveal the visual pathway impairment in TED patients. Altogether, our study revealed that 3T multiparametric MR techniques are useful to demonstrate metabolic and microstructural alterations in visual pathways in TED patients. We found that damage to visual pathways occurs in mild TED cases, which not only offers a new approach to the diagnosis of dysthyroid optic neuropathy, but also demonstrates neuropathy in TED is a gradual and continuous spatio-emporal progression.

Computed tomography and magnetic resonance imaging approaches to Graves' ophthalmopathy: a narrative review

Graves' ophthalmopathy (GO) affects up to 50% of patients with Graves' disease (GD) ranging from mild ocular irritation to vision loss. The initial diagnosis is based on clinical findings and laboratory tests. Orbital imaging, such as magnetic resonance imaging (MRI) and computed tomography (CT), is an important tool to assess orbital changes, being also useful for understanding disease progression and surgical planning. In this narrative review, we included 92 studies published from 1979 to 2020 that used either MRI and/or CT to diagnose and investigate GO, proposing new methods and techniques. Most of the methods used still need to be corroborated and validated, and, despite the different methods and approaches for thyroid eye disease (TED) evaluation, there is still a lack of standardization of measurements and outcome reports; therefore, additional studies should be performed to include these methods in clinical practice, facilitating the diagnosis and approach for the treatment of TED.

Dysthyroid Optic Neuropathy

PURPOSE

Dysthyroid optic neuropathy (DON) is a sight-threatening complication of thyroid eye disease (TED). This review provides an overview of the epidemiology, pathogenesis, diagnosis, and current therapeutic options for DON.

METHODS

A literature review.

RESULTS

DON occurs in about 5% to 8% of TED patients. Compression of the optic nerve at the apex is the most widely accepted pathogenic mechanism. Excessive stretching of the nerve might play a role in a minority of cases. Increasing age, male gender, smoking, and diabetes mellitus have been identified as risk factors. Diagnosis of DON is based on a combination of ≥2 clinical findings, including decreased visual acuity, decreased color vision, relative afferent pupillary defect, visual field defects, or optic disc edema. Orbital imaging supports the diagnosis by confirming apical crowding or optic nerve stretching. DON should be promptly treated with high-dose intravenous glucocorticoids. Decompression surgery should be performed, but the response is incomplete. Radiotherapy might play a role in the prevention of DON development and may delay or avoid the need for surgery. The advent of new biologic-targeted agents provides an exciting new array of therapeutic options, though more research is needed to clarify the role of these medications in the management of DON.

CONCLUSIONS

Even with appropriate management, DON can result in irreversible loss of visual function. Prompt diagnosis and management are pivotal and require a multidisciplinary approach. Methylprednisolone infusions still represent first-line therapy, and surgical decompression is performed in cases of treatment failure. Biologics may play a role in the future.

Application of Quantitative MRI in Thyroid Eye Disease: Imaging Techniques and Clinical Practices

Thyroid eye disease (TED) is a complex autoimmune disorder that impairs various orbital structures, leading to cosmetic damage and vision loss. Magnetic resonance imaging (MRI) is a fundamental diagnostic tool utilized in clinical settings of TED, for its accurate demonstration of orbital lesions and indication of disease conditions. The application of quantitative MRI has brought a new prospect to the management and research of TED, offering more detailed information on morphological and functional changes in the orbit. Therefore, many researchers concentrated on the implementation of different quantitative MRI techniques on TED for the exploration of clinical practices. Despite the abundance of studies utilizing quantitative MRI in TED, there remain considerable barriers and disputes on the best exploitation of this tool. This could possibly be attributed to the complexity of TED and the fast development of MRI techniques. It is necessary that clinical and radiological aspects of quantitative MRI in TED be better integrated into comprehensive insights. Hence, this review traces back 30 years of publications regarding quantitative MRI utilized in TED and elucidates this promising application in the facets of imaging techniques and clinical practices. We believe that a deeper understanding of the application of quantitative MRI in TED will enhance the efficacy of the multidisciplinary management of TED. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 3.

Thyroid-associated ophthalmopathy: Using diffusion tensor imaging to evaluate visual pathway microstructural changes

Objective

The aim of this study was to determine whether the visual pathway is affected by thyroid-associated ophthalmopathy (TAO) before the development of dysthyroid optic neuropathy (DON) with diffusion tensor imaging (DTI).

Materials and methods

Fifty-seven TAO patients (22 mild, 35 moderate-severe TAO) and 30 healthy controls (HCs) were included. The DTI parameters of the lateral geniculate (LG) and optic radiation (OR) were measured. A full ophthalmic examination such as intraocular pressure, exophthalmos, and visual acuity was performed. Clinical activity scores (CAS) were also calculated. One-way ANOVA and Pearson's correlation were carried out. A binary logistic regression was used to identify variables that can diagnose TAO.

Results

Moderate-severe TAO patients showed significantly lower fractional anisotropy (FA) and higher mean diffusivity (MD) than HCs for both LG and OR (p &lt; 0.05). FA of OR was negatively correlated with CAS and intraocular pressure (p &lt; 0.05). Multivariate analysis showed that FA of LG and FA of OR were a significant predictor for the diagnosis TAO.

Conclusion

Diffusion tensor imaging parameters of the visual pathway were significantly altered in moderate-severe TAO patients. The FA of LG, in particular, can be used as a sensitive imaging biomarker for assessing subclinical visual pathway damage in TAO.

Radiomics analysis of the optic nerve for detecting dysthyroid optic neuropathy, based on water-fat imaging

Objective

Detecting dysthyroid optic neuropathy (DON) in the early stages is vital for clinical decision-making. The aim of this study was to determine the feasibility of using an optic-nerve-based radiomics nomogram on water-fat imaging for detecting DON.

Methods

This study included 104 orbits (83 in the training cohort) from 59 DON patients and 131 orbits (80 in the training cohort) from 69 thyroid-associated ophthalmopathy (TAO) without DON patients. Radiomic features were extracted from the optic-nerve T2-weighted water-fat images for each patient. Selected radiomics features were retrained to construct the radiomic signature model and calculate the radiomic score (Rad-score). The conventional MRI evaluation model was constructed based on apical crowding sign, optic-nerve stretching sign and muscle index. The radiomics nomogram model combining the Rad-score and conventional MRI evaluation factors was then developed. Predictive performance of the three models was assessed using ROC curves.

Results

Eight radiomics features from water-fat imaging were selected to build the radiomics signature. The radiomics nomogram (based on Rad-score, apical crowding sign and optic-nerve stretching sign) had superior diagnostic performance than did the conventional MRI evaluation model (AUC in the training set: 0.92 vs 0.80, the validation set:0.88 vs 0.75). Decision curve analysis confirmed the clinical usefulness of the radiomics nomogram.

Conclusions

This optic-nerve-based radiomics nomogram showed better diagnostic performance than conventional MRI evaluation for differentiating DON from TAO without DON. The changes of the optic-nerve itself may deserve more consideration in the clinical decision-making process.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13244-022-01292-7.

Diagnostic Ability of Barrett’s Index and Presence of Intracranial Fat Prolapse in Dysthyroid Optic Neuropathy

Background

Dysthyroid optic neuropathy (DON) is one of the most serious visual loss threats for patients with Graves’ ophthalmopathy (GO). Barrett’s index (BI) and intracranial-fat prolapse have been used in diagnosing DON. However, these parameters are rarely used in Southeast Asian populations with a variety of cut-off values.

Objective

To evaluate the performance of BI and fat prolapse in diagnosing of DON, and to study the correlation between their parametric values with visual acuity (VA) and visual field defect (VF).

Methods

Between January 2011 and December 2020, orbits affected by GO were retrospectively reviewed and classified into 2 groups based on the presence or absence of DON. All orbital-computed-tomography (CT) scans were measured for BI and fat prolapse. Diagnostic performance of BI and fat prolapse was analyzed and evaluated in relation to visual outcome.

Results

We included orbits with DON (23 orbits) and the absence of DON (61 orbits). BI was significantly higher in patients in the DON group (47.68 ± 12.52%) compared to the absence of DON (37.55 ± 10.88%), p < 0.001. The presence of fat prolapse was significantly higher in the DON group (p = 0.003). BI at 40% provided best diagnostic performance with sensitivity of 78.3%/specificity of 63.9%. The presence of fat prolapse 4.5 mm via the superior-ophthalmic-fissure (SOF) had a lower sensitivity compared with fat prolapse 2.5 mm. Comparison between area under the curve (AUC) of BI and fat prolapse revealed no statistically significant difference (AUC 0.742 and 0.705 in BI and fat prolapse, respectively, p = 0.607). A negative correlation between the BI and fat prolapse with VA and VF was observed (p < 0.001).

Conclusion

Measurement of BI is a simple diagnostic method for detecting DON in Thai populations. The presence of fat prolapse (2.5 mm) provides a lower sensitivity compared with a BI at 40%. A slightly larger BI or fat prolapse should be suspected of DON for early treatment.

Management of patients with dysthyroid optic neuropathy treated with intravenous corticosteroids and/or orbital decompression surgery

Purpose

To assess the characteristics and long-term outcomes of adult patients with dysthyroid optic neuropathy (DON) who underwent orbital decompression surgery and/or received intravenous (IV) methylprednisolone.

Methods

Retrospective chart review of 98 eyes of 49 patients who were diagnosed and treated with bilateral DON between 2007 and 2018 at the Department of Ophthalmology and Optometry and Oral and Maxillofacial Surgery of the Medical University of Vienna.

Results

The mean follow-up period was 4.1 ± 2.7 years. The most common presenting symptoms were eyelid and periorbital swelling (45%) representing active inflammation. Upgaze restriction was the most common clinical finding (73%). At time of diagnosis, the mean clinical activity score was 4 ± 1/4 ± 1 (right/left eye, respectively). Sixty-three percent (31/49) of the patients were treated both with IV methylprednisolone and underwent orbital decompression surgery, 22% (11/49) were treated with IV methylprednisolone alone and 14% (7/49) underwent surgical decompression only. Seventy-one percent (30/42) of the patients underwent 3-wall decompression. The mean reduction of proptosis in patients treated with both IV methylprednisolone and orbital decompression surgery was 4/5 mm. Mean of reduction in proptosis in patients receiving IV methylprednisolone only was 1/0 mm and in patients with surgical decompression only was 5/5 mm. Mean VA was 0.1 ± 0.5/0.1 ± 0.5 logMAR at baseline and 0.05 ± 0.7/0.05 ± 0.7 at final follow-up. In 92% (45/49), VA was preserved or improved at final follow-up.

Conclusions

The majority of patients with DON were treated both with IV corticosteroids and 3-wall decompression surgery. Vision could be successfully preserved in most cases and reduction of proptosis was achieved, especially after orbital decompression surgery.

Multi-Parametric Diffusion Tensor Imaging of The Optic Nerve for Detection of Dysthyroid Optic Neuropathy in Patients With Thyroid-Associated Ophthalmopathy

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.

Current insights of applying MRI in Graves' ophthalmopathy

Graves' ophthalmopathy (GO) is an autoimmune disease related to Grave's disease (GD). The therapeutic strategies for GO patients are based on precise assessment of the activity and severity of the disease. However, the current assessment systems require development to accommodate updates in treatment protocols. As an important adjunct examination, magnetic resonance imaging (MRI) can help physicians evaluate GO more accurately. With the continuous updating of MRI technology and the deepening understanding of GO, the assessment of this disease by MRI has gone through a stage from qualitative to precise quantification, making it possible for clinicians to monitor the microstructural changes behind the eyeball and better integrate clinical manifestations with pathology. In this review, we use orbital structures as a classification to combine pathological changes with MRI features. We also review some MRI techniques applied to GO clinical practice, such as disease classification and regions of interest selection.

RAPD as a clinical alert for early evidence of dysthyroid optic neuropathy

Dysthyroid optic neuropathy (DON) is a serious manifestation of thyroid eye disease (TED) resulting in permanent visual loss. There is controversy regarding the diagnostic features of DON. Relative afferent pupil defect (RAPD) in TED is highly specific for DON. Our first patient, a 42-year-old male presented with proptosis and intermittent blurring of vision with best corrected visual acuity of 6/6 in both eyes and right RAPD as an early sign of DON. Our second patient, a 54-year-old female presented with proptosis and clinical activity score <3 at the time of presentation. She developed intermittent blurring of vision with left RAPD on her second presentation as clue of bilateral asymmetric DON in her eyes, though BCVA was 6/6 both eyes. Both cases of bilateral asymmetric DON had RAPD as early specific sign of DON, which prompted us to do detailed radio-imaging to confirm DON, hence highlighting the importance of RAPD.

Risk Factors for New Onset Diplopia After Graduated Orbital Decompression

PURPOSE

The aim of the study was to identify possible risk factors for new onset diplopia in 20° of primary position (NOD PP) after orbital decompression. A predisposition for NOD has been established for patients with pre-existing diplopia in secondary gaze; therefore, the authors focused on patients without preoperative diplopia.

METHODS

Retrospective chart review of patients who underwent balanced orbital decompression between 2012 and 2019 due to Graves orbitopathy at the authors' institution. Exclusion criteria were incomplete clinical data set, revision surgery, and medial or lateral decompression only. The following clinical parameters were evaluated preoperatively and postoperatively: Hertel exophthalmometry, objective measurement of misalignment using the prism-cover-test, assessment of the field of binocular single vision, and measurement of monocular excursions. In addition, the diameter of the extraocular eye muscles was measured in all preoperative CT scans.

RESULTS

We included 327 patients (612 orbits), 126 patients (242 orbits) had no preoperative diplopia. In patients with NOD PP (34%, n = 43/126), enlargement of the medial rectus muscle and restriction of abduction and elevation were significantly more frequent than in patients with no NOD PP. The degree of exophthalmos decrease positively correlated with postoperative squint angle.

CONCLUSION

We were able to identify the diameter of the medial rectus muscle, restriction of abduction, and elevation as well as an extensive reduction of exophthalmos as risk factors for NOD PP in patients with no preoperative diplopia.

Altered peripapillary vessel density and nerve fiber layer thickness in thyroid-associated ophthalmopathy using optical coherence tomography angiography

Objective

To measure the peripapillary vessel density (VD) and retinal nerve fiber layer thickness (RNFLT) in thyroid-associated ophthalmopathy (TAO) and dysthyroid optic neuropathy (DON) patients using optical coherence tomography angiography (OCTA), and determine their prognostic relevance.

Methods

Forty-three TAO patients with or without DON (82 eyes in total) and 26 healthy subjects (52 eyes) were enrolled. All participants underwent ophthalmology and endocrinology tests. The peripapillary VD in retinal peripapillary capillary layer and RNFLT were analyzed using OCTA images. Multiple linear regression analysis was used to assess the relationship between peripapillary VD /RNFLT and the relevant factors.

Results

The total peripapillary VD and RNFLT were significantly lower in the DON patients compared to the other groups (P < 0.001, 95% confidence intervals), and each quadrant of VD and RNFLT showed similar results except temporal RNFLT. No significant difference was seen between the RNFLT and VD of active non-DON (ANDON), inactive non-DON (NDON) patients and normal control (NC) group. Multivariable linear regression model showed that high IOP is an independent risk factor for lower peripapillary VD and RNFLT (β = −0.465, P < 0.001 and β = −0.343, P = 0.002 respectively).

Conclusion

OCTA parameters are suitable indicators for diagnosing DON. TAO patients with high IOP should be considered at high risk of retinal vessel and nerve fiber layer deterioration. In addition, patients with TAO should be advised to quit smoking since it could affect peripapillary VD and RNFLT.

Multiparametric quantitative MRI for the evaluation of dysthyroid optic neuropathy

OBJECTIVE

To evaluate the ability of quantitative MRI parameters for predicting dysthyroid optic neuropathy (DON).

METHODS

We retrospectively collected and analyzed the clinical features and 3.0 T MRI data of 59 patients with Graves orbitopathy (GO), with (n = 26) and without DON (n = 33). We compared MRI quantitative parameters, including the modified muscle index (mMI), proptosis, volume of intra-orbital fat, mean apparent diffusion coefficient value, and T2 value of the optic nerve among patients with and without DON. A logistic regression analysis was performed to identify the risk factors associated with DON. Moreover, we performed a receiver operating characteristic curve analysis and decision curve analysis to evaluate the diagnostic performance of the identified parameters for DON.

RESULTS

We studied 118 orbits (43 and 75 with and without DON, respectively). The mMI and mean T2 value of the optic nerve were significantly greater in orbits with DON (p < 0.001). A greater mMI at 21 mm (odds ratio (OR), 1.039; 95% confidence interval (CI): 1.019, 1.058) and higher mean T2 value of the optic nerve (OR, 1.035; 95% CI: 1.017, 1.054) were associated with a higher risk of DON. A model combining the mMI at 21 mm and mean T2 values for the optic nerve effectively predicted DON in patients with GO, with a sensitivity and specificity of 95.3% and 76%, respectively.

CONCLUSION

A quantitative MRI parameter combining the mMI at 21 mm and mean T2 value of the optic nerve can be an effective imaging marker for identifying DON.

KEY POINTS

• Patients with GO and DON had greater mMI than those without DON. • Optic nerves in patients with DON demonstrated an increased T2 value. • The quantitative MRI parameter combining the mMI at 21 mm and mean T2 value of the optic nerve is the most effective method for diagnosing DON.

Combination Model of Thyrotrophin Receptor Antibody and Volumetric Orbital Apex Crowding Index as an Indicator of Dysthyroid Optic Neuropathy

Background

Dysthyroid optic neuropathy (DON) is one of the most serious vision-threatening complications of thyroid eye disease (TED); however, accurate and established diagnostic tools for DON are yet lacking. The present study was aimed at identifying new diagnostic factors for the accurate diagnosis of DON.

Methods

This retrospective cross-sectional study included 25 TED patients (50 eyes) with enlarged extraocular muscles, no previous anti-inflammatory therapy, and the absence of other vision-affecting diseases between May 2017 and August 2019. Baseline data, such as gender, age, ophthalmological history, thyroid disease and management, TED history including clinical features, management, and long-term results, ophthalmological examinations, serology examinations, and single-photon emission computed tomography/computed tomography (SPECT/CT) results, were extracted. The diagnostic criteria were as follows: (1) best-corrected visual acuity (BCVA) loss coexisting with either of the following—increased latency or reduction of amplitude on visual evoked potential (VEP), impaired color vision, visual field defects, contrast sensitivity impairment, and optic disk swelling—and (2) Barrett′s index ≥ 60% in CT. Univariate and multivariate logistic regression analyses assessed the differences in age, gender, eyes, medical history, clinical activity, thyroid hormone and antibodies, uptake ratio (UR) of extraocular muscles in SPECT/CT, and volumetric orbital apex crowding index (VACI) using the generalized estimation equation. Consequently, the receiver operating characteristic curve (ROC) of the significant factors was constructed.

Results

Univariate analysis revealed significant differences in the clinical activity, free triiodothyronine (FT3), free thyroxine (FT4), thyrotrophin receptor antibody (TRAb) levels, the UR of superior and medial rectus, and VACI between DON and TED (without DON) groups. Multivariate regression analysis revealed that TRAb and VACI were significantly different. ROC analysis showed that the univariate models of TRAb or VACI and the multivariate model were effective indicators of DON, while the multivariate model had the highest area under the ROC curve.

Conclusion

A combination of TRAb and VACI is an effective indicator for DON.

The diagnostic value of the IDEAL-T2WI sequence in dysthyroid optic neuropathy: a quantitative analysis of the optic nerve and cerebrospinal fluid in the optic nerve sheath

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.

Severity of thyroid eye disease and type-2 diabetes mellitus: Is there a correlation?

Purpose

To study the correlation between thyroid eye disease (TED) with type-2 diabetes mellitus.

Methods

A cross-sectional cohort study was conducted from Jan 2018 to Dec 2018, in patients presenting with thyroid eye disease to orbit and oculoplasty clinic of a tertiary eye care hospital. A total of 105 patients were included in the study. All patients underwent detailed ophthalmic evaluation and thyroid eye disease workup. Patients were categorized into mild, moderate, and severe/sight-threatening TED based on EUGOGO classification. Systemic history of diabetes was noted. RBS was done in all patients.

Results

Mild disease was noted 61 patients of which 11 were diabetics, moderate in 26 patients (8 diabetics), and severe disease in 18 patients (14 diabetics). All patients were treated accordingly. Among the TED patients, the percentage of diabetic patients was noted to be in increasing order toward the severity spectrum of TED. The prevalence of severe TED was found to be much higher in diabetic patients accounting upto 77.77% of 18 patients. A statistically significant correlation was noted (P = 0.014) between severe TED and type-2 diabetes mellitus. In addition, early onset of thyroid eye disease was noted in type-2 diabetes patients. Even though female preponderance was noted, severe TED was more in men (66.6%).

Conclusion

An autoimmune etiology for the association of thyroid and type-1diabetes has been well established. This study shows that type-2 diabetic patients can have more severity in the clinical presentation of TED. Therefore, the presence of type-2 DM in patients with TED can be a predictive factor for onset, progression, and severity of disease. Hence, a high concern of interest among treating ophthalmologists and endocrinologists regarding this entity would help in early prediction and decreased morbidity among such patients.

Early efficacy of teprotumumab for the treatment of dysthyroid optic neuropathy: A multicenter study

Purpose

To study post-interventional findings in patients with dysthyroid optic neuropathy (DON) treated with teprotumumab.

Observations

In this multicenter observational Case series, patients with DON were treated with teprotumumab, an insulin-like growth factor I receptor inhibitor (10 mg/kg for the first infusion then 20 mg/kg for subsequent infusions, every three weeks for a total 8 infusions). This study included patients with acute and chronic thyroid eye disease (TED) with DON who had failed conventional therapies and were not candidates for surgical decompression. Data collected included best corrected visual acuity (BCVA), color vision, RAPD when present, and orbital CT or MRI. Proptosis, clinical activity score (CAS), Gorman diplopia score (GDS), and Humphrey visual fields (HVF) were also evaluated.

Ten patients (6 women, 4 men) with an average age 64 years old were included in this study. Mean follow up after completion of infusions was 15 weeks. Baseline visual acuity (VA) impairment ranged from hand motion (HM) to 20/25 in affected eyes. All patients had pre-treatment orbital CT or MRI that confirmed orbital apex compression. Seventy percent of patients had objective improvement in DON after 2 infusions of teprotumumab measured as significant improvement in visual acuity, resolution of RAPD, or both. After completion of treatment, affected eyes had a mean BCVA improvement of 0.87 logMAR (p=0.0207), proptosis reduction of 4.7 mm (p<0.00001), CAS improvement of 5.25 points (p<0.00001), and GDS improvement of 0.75 points (p=0.160). All 6 patients who presented with an RAPD had resolution or improvement of RAPD. All 7 patients who presented with color vision deficits had normalization or improvement of color vision.

Conclusions and Importance

Teprotumumab infusions resulted in medical decompression and objective resolution or improvement of dysthyroid optic neuropathy. Most patients had rapid improvement of visual acuity and reversal of RAPD. Post-infusion imaging demonstrated reduction in extraocular muscle size that correlated with improvement in visual dysfunction. However, patients who presented with longstanding severe visual loss had limited improvement. There was no recurrence of DON after completion of teprotumumab in our cohort.

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Teprotumumab is effective for the treatment of dysthyroid optic neuropathy.

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Most patients demonstrated rapid objective improvement after 2 infusions.

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Visual acuity improved and relative afferent pupillary defect resolved after treatment.

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Orbital imaging showed improvement of orbital apex crowding after treatment.

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Patients with longstanding severe vision loss had limited improvement in visual acuity.

Dixon-T2WI magnetic resonance imaging at 3 tesla outperforms conventional imaging for thyroid eye disease

OBJECTIVES

To determine the diagnostic performances of a single Dixon-T2-weighted imaging (WI) sequence compared to a conventional protocol including T1-, T2-, and fat-suppressed T2-weighted MRI at 3 T when assessing thyroid eye disease (TED).

MATERIALS AND METHODS

This IRB-approved prospective single-center study enrolled participants presenting with confirmed TED from April 2015 to October 2019. They underwent an MRI, including a conventional protocol and a Dixon-T2WI sequence. Two neuroradiologists, blinded to all data, read both datasets independently and randomly. They assessed the presence of extraocular muscle (EOM) inflammation, enlargement, fatty degeneration, or fibrosis as well as the presence of artifacts. The Wilcoxon signed-rank test was used.

RESULTS

Two hundred six participants were enrolled (135/206 [66%] women, 71/206 [34%] men, age 52.3 ± 13.2 years). Dixon-T2WI was significantly more likely to detect at least one inflamed EOM as compared to the conventional set (248/412 [60%] versus 228/412 [55%] eyes; (p = 0.02). Dixon-T2WI was more sensitive and specific than the conventional set for assessing muscular inflammation (100% versus 94.7% and 71.2% versus 68.5%, respectively). Dixon-T2WI was significantly less likely to show major or minor artifacts as compared to fat-suppressed T2WI (20/412 [5%] versus 109/412 [27%] eyes, p < 0.001, and 175/412 [42%] versus 257/412 [62%] eyes, p < 0.001). Confidence was significantly higher with Dixon-T2WI than with the conventional set (2.35 versus 2.24, p = 0.003).

CONCLUSION

Dixon-T2WI showed higher sensitivity and specificity and showed fewer artifacts than a conventional protocol when assessing thyroid eye disease, in addition to higher self-reported confidence.

KEY POINTS

• Dixon-T2WI has better sensitivity and specificity than a conventional protocol for assessing inflamed extraocular muscles in patients with thyroid eye disease. • Dixon-T2WI shows significantly fewer artifacts than fat-suppressed T2WI. • Dixon-T2WI is faster and is associated with significantly higher self-reported reader confidence as compared to a conventional protocol when assessing inflammatory extraocular muscles.

Utility of Optical Coherence Tomography in the Diagnosis and Management of Optic Neuropathy in Patients with Fibrous Dysplasia

Optic neuropathy (ON) is a highly disabling complication of fibrous dysplasia (FD). The optimal test for identifying and monitoring ON in FD is unknown. Optical coherence tomography (OCT) is an imaging modality that detects retinal nerve fiber layer (RNFL) thinning, a sign of optic nerve atrophy. The purpose of this study was to (i) assess the ability of OCT RNFL thickness measurements to identify ON in FD; (ii) compare the performance of RNFL thickness to computed tomography measurements; and (iii) examine changes in RNFL thickness over time to assess disease progression. A retrospective cohort study was performed to assess subjects (n = 70) who underwent neuro-ophthalmologic examination, including OCT. The diagnostic utility of RNFL thickness was determined using receiver operator characteristic (ROC) curve analysis, and the accuracy was compared with computed tomography measurements. The relationship between RNFL thickness and age was assessed cross-sectionally, using generalized estimating equation methodology, and longitudinally, using a generalized mixed model. Eleven subjects were identified with ON. RNFL thickness identified ON (area under curve = 0.997, p < 0.0001) with sensitivity and specificity of 100% and 95%, respectively, when using the diagnostic criterion of ≤71 μm. RNFL thickness outperformed computed tomography measurements of optic canal narrowing and optic nerve stretch. Subjects with ON exhibited a greater decrease in RNFL thickness with each year of age (-0.70 μm/year, p < 0.001) than subjects with normal vision (-0.16 μm/year, p < 0.05). When assessed longitudinally, subjects with normal vision demonstrated an increase in RNFL thickness until approximately age 20 years that decreased thereafter. In contrast, subjects with ON exhibited an earlier decrease in RNFL thickness during adolescence. In conclusion, RNFL thickness of ≤71 μm accurately identified ON in this population. By establishing the difference in rate of RNFL thinning in patients with and without ON, clinicians may distinguish between patients at risk for ON and intervene before irreversible damage. © 2020 American Society for Bone and Mineral Research.

Predictive parameters on CT scan for dysthyroid optic neuropathy

AIM

To evaluate the value of parameters on CT scan in predicting dysthyroid optic neuropathy (DON) and to provide guidance for early diagnosis of DON accordingly.

METHODS

A total of 67 eyes of 35 patients with thyroid-associated ophthalmopathy (TAO) were included in this study. Patients were divided into 2 groups (DON group and non-DON group). Parameters were measured on high resolution CT, including muscle index (MI), superior ophthalmic vein (SOV) dilatation, extraocular muscle volume/orbit volume (MV/OV), and intracranial fat prolapsed, and be compared between these 2 groups. The relation between those parameters and visual function [visual acuity (VA) and visual field defect (VF defect)] were also evaluated.

RESULTS

MI and MV/OV were significantly higher in DON group (P=0.00035 and P=0.00026). No significant difference was detected regarding intracranial fat prolapse existence and SOV dilatation (P=0.37 and P=0.15). MV/OV was found to have significant negative correlation with both VF defect (R=-0.332, P=0.0273) and VA (R=-0.635, P=0.00) while MI was found to have negative linear correlation with VA only (R=-0.456, P=0.00017). The area under receiver operating characteristic curves was 0.82 for MV/OV and 0.75 for MI. The best performance in detecting DON was achieved when MV/OV is set at 0.20 with 72% sensitivity and 87% specificity and MI is set at 0.52 with 64% sensitivity and 80% specificity.

CONCLUSION

MI and MV/OV are predictive parameters for DON. Together with clinical manifestations, MV/OV≥0.2 can be used as a good indicator for DON in TAO patients.

Management of graves myopathy: Orbital imaging in thyroid-related orbitopathy

A broad understanding of the different imaging modalities used to assess the physiologic changes seen in Graves' orbitopathy complement clinical examination. Subtle applications of radiographic imaging techniques allow for a better understanding of the overall physiology of the orbit, quantify progression of disease, and differentiate it from orbital diseases with overlapping features. A nuanced approach to interpreting imaging features may allow us to delineate inactive from active thyroid eye disease, and advances within this field may arm clinicians with the ability to better predict and prevent dysthyroid optic neuropathy.