The usefulness of quantitative orbital magnetic resonance imaging in Graves' ophthalmopathy

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.

The efficacy and safety of selenium supplementation versus placebo in the treatment of Graves' orbitopathy: A systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Selenium is a trace element crucial for thyroid function, and has potential therapeutic benefits in Graves' orbitopathy (GO). Therefore, we aim to evaluate its efficacy and safety in GO patients to provide valuable insights into its role as a therapeutic option for this condition.

DESIGN

Systematic review and meta-analysis.

PATIENTS

GO Patients treated with selenium compared to placebo.

MEASUREMENTS

Clinical activity score (CAS), Graves' orbitopathy quality of life (GO-QOL), eye symptoms and signs, and adverse events.

RESULTS

Out of 1684 records screened, four randomised controlled trials were included. Selenium was superior at 6 months in lowering the CAS (MD = -1.27, 95% confidence interval [CI] [-1.68, -0.85], p < .0001]), improving total GO-QOL (RR = 2.54, 95% CI [1.69-3.81], p < .00001), and improving the visual and the psychological functioning scores (MD = 10.84, 95% CI [4.94-16.73], p = .003), (MD = 12.76, 95% CI [8.51-17.00], p < .00001) respectively. Similarly, it significantly improved these outcomes at 12 months. It also showed a significant decrease in the palpebral aperture at 6 months (MD = -1.49, 95% CI [-2.90, -0.08], p = .04). However, no significant differences were observed in proptosis, soft tissue involvement, ocular motility, and adverse effects.

CONCLUSIONS

Selenium is effective in reducing CAS and improving the palpebral aperture and GO-QOL in patients with GO. Additionally, it is safe and has promising therapeutic implications. However, further research is needed to validate its long-term efficacy and safety.

The evaluation of retrobulbar fat tissue in Graves' orbitopathy with shear-wave ultrasound elastography

PURPOSE

To evaluate retrobulbar adipose tissue of patients with active and inactive Graves' orbitopathy (GO) by shear-wave ultrasound elastography (SWE).

METHODS

Followed-up in our ophthalmology clinic due to GO, 72 eyes of 36 patients and 38 eyes of 19 healthy controls were included in this cross-sectional case-control study. Graves' patients were divided into two subgroups under clinical activity score (CAS): active Graves' orbitopathy (AGO) (CAS ≥ 3) and inactive Graves' orbitopathy (IGO) (CAS < 3). SWE measurement values of retrobulbar adipose tissue of all participants were recorded in meters/second, and the intergroup comparisons were performed.

RESULTS

Thirty-four eyes of 17 patients in AGO, 38 eyes of 19 patients in IGO, and 38 eyes of 19 participants in the control group were included in the study. Mean values measured from retrobulbar adipose tissue through SWE were 1.00 ± 0.01 m/sec in AGO, 1.16 ± 0.01 m/sec in IGO, and 0.94 ± 0.01 m/sec in the control groups. Even so, the mean SWE value was significantly higher in the IGO group than in the other groups (p < 0.001). Mean SWE values were significantly higher in the AGO group than in the controls (p = 0.008). In the correlation analysis performed, a significant positive correlation was found between SWE and Hertel exophthalmometer measurement values (p = 0.026, r = 0.212), and thyroid-stimulating hormone receptor antibody (TSHR-Ab) levels (p = 0.018, r = 0.224).

CONCLUSION

We detected SWE values of retrobulbar adipose tissue high in GO, especially in the IGO group. Such a situation, which we associated with the development of fibrosis, may be an indicator of unresponsiveness to immunomodulatory treatments.

Predictive markers for anti-inflammatory treatment response in thyroid eye disease

Anti-inflammatory treatment is the primary and vital therapeutic approach for active, moderate-to-severe thyroid eye disease (TED). Accurate pretreatment prediction of treatment response is of paramount importance for the prognosis of patients. However, relying solely on the clinical activity score asa determinant of activity has led to unsatisfactory treatment outcomes. In recent years, significant advancements have been made in identifying predictive markers for anti-inflammatory treatment response in TED, clinical markers, body fluid biomarkers and imaging biomarkers. Several clinical studies have developed prediction models based on these markers. However, there is still a lack of comprehensive elucidation or comparison between the different markers. Therefore, this review aims to provide a detailed analysis of the definition, characteristics, and application of predictive markers for anti-inflammatory treatment response in TED. Through detailed literature search, 26 articles applying anti-inflammatory treatment effect prediction with a total of 1948 TED patients were used for analysis and discussion. By gaining a better understanding of the current research on predictive markers, we can accelerate and guide the exploration of treatment prediction strategies, leading us towards an era of precise therapy for TED.

Magnetic Resonance Imaging in the Management of Thyroid Eye Disease: A Systematic Review

PURPOSE

MRI may potentially detect active thyroid eye disease prior to elevation of clinical activity score. We aimed to systematically review the existing literature pertaining to MRI thyroid eye disease and to assess the role of MRI in the diagnosis of thyroid eye disease.

METHODS

A Population, Intervention, Comparison, Outcome/Preferred Reporting Items for Systematic Reviews and Meta-Analyses selection criteria was applied to identify studies for inclusion published between the years 2000 and 2023.

RESULTS

Twenty-four articles were identified for inclusion in the systematic review. All included studies utilized MRI as the imaging modality. MRI sequences used included T2-weighted imaging in 87.5%, T1-weighted imaging in 54.2%, diffusion-weighted imaging in 20.8%, and short tau inversion recovery in 16.7%. The most common parameters quantified were signal intensity ratio in 10 studies (41.7%) and T2-relaxation time in 8 studies (33.3%). Signal intensity ratio and T2-relaxation time were shown to correlate with clinical activity score and identify the phase of the disease.

CONCLUSIONS

MRI has untapped potential for further elucidating the highly complex biological processes in thyroid eye disease. As we move away from clinical activity score as a predictor of response to biologic therapy, MRI may prove more important than ever in the risk-benefit analysis around the use of immunomodulators.

Computed tomography and magnetic resonance imaging of the orbit in the diagnosis and treatment of thyroid-associated orbitopathy - experience from practice. A Review

The purpose is to acquaint readers with the contribution of imaging methods (IMs) of the orbit, specifically computed tomography (CT) and magnetic resonance imaging (MRI), in the diagnosis of thyroid-associated orbitopathy (TAO). Methods: IMs of the orbit are an indispensable accessory in the clinical and laboratory examination of TAO patients. The most frequently used and probably most accessible method is an ultrasound examination of the orbit (US), which, however, has a number of limitations. Other methods are CT and MRI. Based on the published knowledge implemented in our practice and several years of experience with the diagnosis and treatment of TAO patients, we would like to point out the benefits of CT and MRI in the given indications: visualisation of the extraocular muscles, assessment of disease activity, diagnosis of dysthyroid optic neuropathy and differential diagnosis of other pathologies in the orbit. Our recommendation for an ideal MRI protocol for disease activity evaluation is also included.  Conclusion: IMs play an irreplaceable role not only in the early diagnosis of TAO, but also in the monitoring of the disease and the response to the applied treatment. When choosing a suitable IM for this diagnosis, a number of factors must always be taken into account; not only availability, cost and burden for the patient, but especially the sensitivity and specificity of the given method for the diagnosis of TAO.

MRI in the assessment of thyroid-associated orbitopathy activity

Management of patients with thyroid-associated orbitopathy (also called Graves' disease) is dependent on the assessment of the disease activity. Evaluation of disease activity is based on ophthalmological examination. Magnetic resonance imaging (MRI) is an auxiliary method that may help quantify the activity and is also helpful in obtaining anatomical information concerning muscle thickness, exophthalmos, or optic neuropathy. We present a review of MRI techniques of the orbits with emphasis on the evaluation of disease activity. The most convincing seems to be the group of T2-weighted techniques such as conventional T2 weighting, T2 relaxometry, and T2 mapping. Dynamic contrast-enhanced MRI is another promising method.

Evaluation of extraocular muscles in patients with thyroid associated ophthalmopathy using apparent diffusion coefficient measured by magnetic resonance imaging before and after radiation therapy

BACKGROUND

Thyroid-associated ophthalmopathy (TAO) is an autoimmune orbital disease characterized by edema of extraocular muscles (EOMs).

PURPOSE

To characterize the inflammation of EOMs in patients with TAO before and after radiation therapy using apparent diffusion coefficient (ADC) and to analyze the correlation between ADC and clinical activity of TAO.

MATERIAL AND METHODS

The ADCs of superior rectus (SR), inferior rectus (IR), medial rectus (MR), and lateral rectus (LR) muscles were measured in 52 eyes of 26 patients with TAO before and three months after orbital radiation therapy. In addition, 38 eyes of 20 healthy volunteers were included. The clinical activity score (CAS) was evaluated. The ADC maps were reconstructed and measured on the coronal diffusion-weighted imaging (DWI) sequence and calculated in mm²/s.

RESULTS

The mean ADCs of EOMs before treatment were 1.42 ± 0.23 in SR, 1.37 ± 0.23 in IR, 1.41 ± 0.21 in MR, and 1.28 ± 0.25 in LR. The mean ADCs after treatment were 1.27 ± 0.18, 1.22 ± 0.26, 1.30 ± 0.22, and 1.15 ± 0.21, respectively. The ADCs were significantly decreased after treatment (all P < 0.001). The ADCs of patients with TAO were significantly higher than those of controls. There was a statistically significant correlation between the mean ADCs and the CAS in each patient with TAO both before and after treatment (before: r = 0.520; P < 0.001; after: r = 0.625; P < 0.001).

CONCLUSION

The ADC values of EOMs can be exploited as a quantitative indicator to evaluate the clinical activity and monitor the therapeutic responses of patients with TAO.

Advances in magnetic resonance imaging of orbital disease

Magnetic resonance imaging (MRI) is increasingly used by the orbital surgeon to aid in the diagnosis, surgical planning, and monitoring of orbital disease. MRI provides superior soft tissue detail compared with computed tomography or ultrasound, and advancing techniques enhance its ability to highlight abnormal orbital pathology. Diffusion-weighted imaging is a specialized technique that uses water molecule diffusion patterns in tissue to generate contrast signals and can help distinguish malignant from benign lesions. Steady-state free precession sequences such as Constructive Interference in Steady-State (CISS) and Fast Imaging Employing Steady-state Acquisition (FIESTA) generate highly detailed, 3-dimensional reconstructed images and are particularly useful in distinguishing structures adjacent to cerebral spinal fluid. Magnetic resonance angiography can be used to characterize vascular lesions within the orbit. New developments in magnetic field strength as well as the use of orbital surface coils achieve increasingly improved imaging resolution.

Non-EPI-DWI for Detection, Disease Monitoring, and Clinical Decision-Making in Thyroid Eye Disease

BACKGROUND AND PURPOSE

The Clinical Activity Score is widely used to grade activity of thyroid eye disease and guide treatment decisions, but as a subjective measurement and being confined to the anterior orbit, it has limitations. Non-EPI-DWI of the extraocular muscles may offer advantages as a functional imaging technique with reduced skull base artifacts, but the correlation with the Clinical Activity Score and patient outcome is unknown. Our aim was to establish the correlation between the Clinical Activity Score and non-EPI-DWI and to describe the additional value provided by adjunctive non-EPI-DWI in making clinical decisions.

MATERIALS AND METHODS

This was a retrospective longitudinal study of 31 patients seen in a multidisciplinary thyroid eye disease clinic during 5 years who had at least 1 ophthalmic and endocrine assessment including the Clinical Activity Score and a non-EPI-DWI ADC calculation. The Spearman rank correlation coefficient was used to determine the relationship between the Clinical Activity Score and non-EPI-DWI. A patient flow chart was constructed to evaluate clinical decision-making, and receiver operating characteristics were generated.

RESULTS

From 60 non-EPI-DWI scans, 368 extraocular muscles were selected for analysis. There was a significant positive correlation between the Clinical Activity Score and ADC (r _s = 0.403; 95% CI, 0.312-0.489; P < .001). ADC values were significantly higher in the Clinical Activity Score ≥ 3 group compared with the Clinical Activity Score < 3 group (P < .001). Our patient flow chart identified a third intermediate-severity cohort in which the non-EPI-DWI was particularly useful in guiding clinical decisions.

CONCLUSIONS

The non-EPI-DWI correlated well with the Clinical Activity Score in our patients and was a useful adjunct to the Clinical Activity Score in making clinical decisions, especially in patients with intermediate activity and severity of thyroid eye disease.

Radiological Staging of Thyroid-Associated Ophthalmopathy: Comparison of T1 Mapping with Conventional MRI

BACKGROUND

Accurate staging of patients with thyroid-associated ophthalmopathy (TAO) is crucial for clinical decision. Full cognition of pathologic changes and staging TAO using conventional T2-weighted imaging is still limited.

PURPOSE

To investigate the feasibility of using T1 mapping to evaluate changes of extraocular muscles (EOMs) in TAO patients, as well as to compare T1 mapping and conventional T2-weighted imaging in staging TAO.

MATERIALS AND METHODS

Forty TAO patients were retrospectively enrolled. "Hot spot" and "cold spot" T1 relaxation times (T1RT_HS and T1RT_CS) of EOMs, as well as conventionally applied highest signal intensity ratio (SIR) of EOMs, were measured and compared between active and inactive groups.

RESULTS

T1RT_CS and SIR were significantly higher in active TAOs than in the inactive ones (P < 0.001), while T1RT_HS was not (P=0.093). Meanwhile, T1RT_CS and SIR were positively correlated with clinical activity score (r = 0.489, 0.540; P < 0.001). TIRT_CS and SIR showed no significant area under curve for staging TAO (0.830 vs. 0.852; P=0.748). T1RT_CS ≥ 1000 alone showed optimal staging specificity (90.0%), while integration of T1RT_CS ≥ 1000 and SIR ≥ 2.9 demonstrated optimal staging efficiency and sensitivity (area under curve, 0.900; sensitivity, 86.0%).

CONCLUSIONS

Our findings suggest that the T1-mapping technique holds the potency to be utilized in TAO. The derived T1RT_CS of EOMs, which may be associated with fat infiltration, could be a useful biomarker to stage the disease, serving added efficiency, sensitivity, and specificity to single usage of conventional SIR.

ROLE OF MAGNETIC RESONANCE IMAGING IN THE ASSESSMENT OF ACTIVE THYROID-ASSOCIATED OPHTHALMOPATHY PATIENTS WITH LONG DISEASE DURATION

Objective: In thyroid-associated ophthalmopathy (TAO), long disease duration is negatively correlated with the response to immunosuppression treatment. The current treatment decision-making process does not involve magnetic resonance imaging (MRI); thus, we investigated the predictive value of MRI parameters for the immunosuppressive response in active moderate to severe TAO patients with different disease durations. Methods: We retrospectively analyzed the baseline MRI parameters of active TAO patients treated with guideline-recommended weekly glucocorticoid therapy in our center. Data were stratified by the quartile of disease duration. The signal intensity ratio (SIR) of T2-weighted images was used to describe the activity of extraocular muscles (EOMs). Results: Compared to the lowest quartile of disease duration, SIR values of EOMs were significantly lower in quartile 3 (Q3) and quartile 4 (Q4). Meanwhile, the clinical activity score (CAS) curve did not change in parallel and was not correlated with the SIR curve. In the highest quartile of disease duration, nonresponders had significantly lower SIR values of the most inflamed muscle (P = .03) and the medial rectus (P = .004) than did the responders, while no such significance was observed in patients within the lower 3 quartiles. A multivariable predictive model (including CAS, TAO duration, and SIR value) was established in each quartile. The fit of the model was better than CAS with regard to prognostic prediction and showed a high positive predictive value (Model 1: 86.67%; Model 2: 92.86%) and negative predictive value (Model 1: 88.89%; Model 2: 90%) in the top quartile. Conclusion: The anterior manifestation assessed by CAS is not always consistent with retro-orbital activity in long-term TAO patients. CAS is sufficient to reflect disease activity in short-term TAO patients. The supplementation of CAS with orbital MRI would be valuable in selecting appropriate active patients with a long disease duration. Abbreviations: AUC = area under the curve; CAS = clinical activity score; EOM = extraocular muscle; FT3 = free triiodothyronine; FT4 = free thyroxine; GC = glucocorticoid; ivGC = intravenous glucocorticoids; MRI = magnetic resonance imaging; NPV = negative predictive value; PPV = positive predictive value; SIR = signal intensity ratio; TAO = thyroid-associated ophthalmopathy; TRAb = thyroid-stimulating hormone receptor antibody; TSH = thyroid-stimulating hormone.

Thyroid-associated Orbitopathy: Quantitative Evaluation of the Orbital Fat Volume and Edema Using IDEAL-FSE

Background and Purpose

To compare orbital quantitative data obtained by fast spin-echo iterative decomposition of water and fat with echo asymmetry and least-squares estimation (FSE-IDEAL) in patients with thyroid-associated orbitopathy (TAO) and healthy controls and to investigate the characteristics of these data in TAO patients.

Materials and Methods

Twenty-two TAO patients (4 males and 18 females; median age 51.0 years) and 22 healthy subjects (5 males and 17 females; median age 50.5 years) underwent orbital T2-weighted FSE-IDEAL. The water fraction in orbital fat was defined as the signal intensity (SI) water / (SI water + SI fat). The orbital fat volume was measured on fat images. The degree of proptosis was evaluated using in-phase imaging. Mann–Whitney U test was used to compare these quantitative data in the two groups. In TAO patients we ascertained the correlation among these values with the Spearman's rank correlation coefficient.

Results

In TAO patients, the water fraction (right and left, p = 0.04), fat volume (right and left, p = 0.03) and degree of proptosis (right and left, p < 0.01) were higher than in the controls. In TAO patients, only the water fraction and the fat volume of left orbit showed negative correlation (p = 0.01).

Conclusion

The water fraction of orbital fat, the orbital fat volume and the degree of proptosis obtained with FSE-IDEAL were higher in TAO patients than in the controls. The water fraction was a new parameter for differentiating between TAO patients and healthy subjects.

Novel use of non-echo-planar diffusion weighted MRI in monitoring disease activity and treatment response in active Grave's orbitopathy: An initial observational cohort study

AIM

To examine the novel use of non-echo-planar diffusion weighted MRI (DWI) in depicting activity and treatment response in active Grave's orbitopathy (GO) by assessing, with inter-observer agreement, for a correlation between its apparent diffusion coefficients (ADCs) and conventional Short tau Inversion Recovery (STIR) MRI signal-intensity ratios (SIRs).

METHOD AND MATERIALS

A total of 23 actively inflamed muscles and 30 muscle response episodes were analysed in patients with active GO who underwent medical treatment. The MRI orbit scans included STIR sequences and non-echo-planar DWI were evaluated. Two observers independently assessed the images qualitatively for the presence of activity in the extraocular muscles (EOMs) and recorded the STIR signal-intensity (SI), SIR (SI ratio of EOM/temporalis muscle), and ADC values of any actively inflamed muscle on the pre-treatment scans and their corresponding values on the subsequent post-treatment scans. Inter-observer agreement was examined.

RESULTS

There was a significant positive correlation (0.57, p < 0.001) between ADC and both SIR and STIR SI of the actively inflamed EOM. There was also a significant positive correlation (0.75, p < 0.001) between SIR and ADC values depicting change in muscle activity associated with treatment response. There was good inter-observer agreement.

CONCLUSION

Our preliminary results indicate that quantitative evaluation with non-echo-planar DWI ADC values correlates well with conventional STIR SIR in detecting active GO and monitoring its treatment response, with good inter-observer agreement.

[A novel method for quantitative measurement of orbital fat volume based on magnetic resonance images]

OBJECTIVE

To establish a new method for rapid and quantitative measurement of orbital fat volume based on magnetic resonance imaging (MRI) data.

METHODS

We collected MRI data from normalized mold and patients with the diagnosis of thyroid-associated ophthalmopathy (TAO). The cross-sectional areas of the orbital fat on each MR image slice were measured to calculate the fat volume on each slice and then the total orbital fat volume. We recorded the time for completing the measurement and assessed the precision, reliability, repeatability and interoperator variations of the results.

RESULTS

This MRI data-based method allowed precise measurement of the orbital fat volumes with an absolute value of the mean percentage difference <1%. This method was fast and the results showed a good repeatability (with CVs <1%), a high reliability (ICC=0.996, 95%CI: 0.985-0.999) and a high interoperator concordance (95%CI of the Bland-Altman: -0.54-0.90).

CONCLUSION

The novel method we established for orbital fat volume measurement is rapid, accurate, reliable and reproducible with a low learning cost for clinical use.

Quantitative MR imaging of intra-orbital structures: Tissue-specific measurements and age dependency compared to extra-orbital structures using multispectral quantitative MR imaging

The orbit can be affected by unique pathologic conditions and often requires MRI evaluation. The purpose of this study was to investigate the age-related changes in multiple intra-orbital structures using quantitative MRI (qMRI). Thirty-eight subjects (20 males, 18 females; ages 0.5-87 years) underwent MRI with a mixed turbo spin echo sequence. T1 and T2 measurements were obtained within ROI in 6 intra-orbital structures (medial and lateral rectus muscles, medial and lateral retrobulbar fat, lacrimal gland, and optic nerve), and compared with those of corresponding extra-orbital structures (masseter muscle, subcutaneous cheek fat, buccal fat, parotid gland, and frontal white matter). Statistical analyses were performed using Pearson's correlation coefficients. T1 and T2 values of the extra-ocular muscles increased with age, with higher T1 and T2 values compared to the masseter muscles. Retrobulbar fat showed significant age-associated increases in T1 values in the lateral side and in T2 values in both sides. T1 and T2 values in the lacrimal gland increased with age, while the parotid gland showed an age-associated increase in T2 values and decrease in T1 values. Optic nerves demonstrated age-related changes, similar to that of frontal white matter; rapid decreases with age in T1 and T2 times in early stages of life, and slight increases in T1 and T2 times later in life. Intra-orbital structures demonstrated specific qMRI measurements and aging patterns, which were different from extra-orbital structures. Location-specific age-related changes of intra-orbital structures should be considered in the qMRI assessment of the orbital pathology.

Orbital Fat Volumetry and Water Fraction Measurements Using T2-Weighted FSE-IDEAL Imaging in Patients with Thyroid-Associated Orbitopathy

BACKGROUND AND PURPOSE

The quantitative evaluation of orbital fat proliferation and edema and the assessment of extraocular muscles are useful for diagnosing and monitoring thyroid-associated orbitopathy. To evaluate therapy-induced quantitative changes in the orbital fat of patients with thyroid-associated orbitopathy, we performed volumetric and water fraction measurements by using T2-weighted FSE iterative decomposition of water and fat with echo asymmetry and least-squares estimation (FSE-IDEAL) imaging.

MATERIALS AND METHODS

Orbital FSE-IDEAL images of 30 volunteers were acquired twice within 1 week. Nine patients with thyroid-associated orbitopathy underwent FSE-IDEAL imaging before and after methylprednisolone pulse therapy, and the treatment results were assessed by using their pre- and post-methylprednisolone pulse therapy clinical activity scores. We performed volumetric and water fraction measurements of orbital fat by using FSE-IDEAL imaging and evaluated interscan differences in the volunteers. In patients with thyroid-associated orbitopathy, we compared pre- and posttherapy orbital fat measurements and assessed the correlation between the pretherapy values and clinical activity score improvement.

RESULTS

The reproducibility of results obtained by the quantitative evaluation of orbital fat in volunteers was acceptable. After methylprednisolone pulse therapy, the water fraction in the orbital fat of patients with thyroid-associated orbitopathy was significantly decreased (P < .001). There was a significant positive correlation between the pretherapy water fraction and clinical activity score improvement (right, r = 0.82; left, r = 0.79) and a significant negative correlation between the pretherapy volume and clinical activity score improvement (bilateral, r = -0.84).

CONCLUSIONS

Volumetric and water fraction measurements of orbital fat by using FSE-IDEAL imaging are feasible and useful for monitoring the effects of therapy and for predicting the response of patients with thyroid-associated orbitopathy to methylprednisolone pulse therapy.

Imaging Evaluation of the Orbit in Graves Ophthalmopathy

ABSTRACT: Diagnosis of Graves ophthalmopathy is based on the typical eye signs and symptoms, the exclusion of other orbital pathologies and evidence of thyroid autoimmunity. We report the case of a non-smoker 61 years old woman, known with Graves disease, which performed a 3T MRI examination in order to evaluate the orbits. The MRI exam revealed eye protrusion, increased orbital fat with compression on the optic nerve and increased volume of the extraocular muscles. We concluded that MRI, using high-field 3T imaging techniques, is very important for diagnosis of these anomalies, making the differential diagnosis with other pathology and also providing additional information in the decision for therapy.

Diagnostic accuracy of short-time inversion recovery sequence in Graves' Ophthalmopathy before and after prednisone treatment

INTRODUCTION

In Graves' Ophthalmopathy, it is important to distinguish active inflammatory phase, responsive to immunosuppressive treatment, from fibrotic unresponsive inactive one. The purpose of this study is, first, to identify the relevant orbital magnetic resonance imaging signal intensities before treatment, so to classify patients according to their clinical activity score (CAS), discriminating inactive (CAS < 3) from active Graves' Ophthalmopathy (GO) (CAS > 3) subjects and, second, to follow post-steroid treatment disease.

METHODS

An observational study was executed on 32 GO consecutive patients in different phases of disease, based on clinical and orbital Magnetic Resonance Imaging parameters, compared to 32 healthy volunteers. Orbital Magnetic Resonance Imaging was performed on a 1.5 tesla Magnetic Resonance Unit by an experienced neuroradiologist blinded to the clinical examinations.

RESULTS

In pre-therapy patients, compared to controls, a medial rectus muscle statistically significant signal intensity ratio (SIR) in short-time inversion recovery (STIR) (long TR/TE) sequence was found, as well as when comparing patients before and after treatment, both medial and inferior rectus muscle SIR resulted significantly statistically different in STIR. These increased outcomes explain the inflammation oedematous phase of disease, moreover after steroid administration, compared to controls; patients presented lack of that statistically significant difference, thus suggesting treatment effectiveness.

CONCLUSION

In our study, we proved STIR signal intensities increase in inflammation oedematous phase, confirming STIR sequence to define active phase of disease with more sensibility and reproducibility than CAS alone and to evaluate post-therapy involvement.

Magnetic resonance imaging with diffusion-weighted imaging in the evaluation of thyroid-associated orbitopathy: getting below the tip of the iceberg

OBJECTIVES

To compare extraocular muscles (EOMs) T2, post-contrast T1 (T1Gad) signal intensity ratios (SIRs) and normalized-apparent diffusion coefficient (n-ADC) values in patients with thyroid-associated orbitopathy (TAO) at different phases of activity and severity and correlate MRI modifications to clinical evolution during follow-up.

METHODS

A total of 74 TAO patients were classified as active or inactive on the basis of the clinical activity score (CAS). Severity of EOM impairment was evaluated by assigning a functional score to each rectus. T2, T1Gad SIRs and n-ADC of EOMs were compared in patients with active inflammation, those with inactive disease and 26 healthy controls, and correlated with clinical scores. MRI parameter variation was correlated with clinical modifications during follow-up.

RESULTS

All MRI parameters in TAO EOMs were significantly higher than in healthy subjects and correlated with muscle dysfunction and CAS. EOMs of active patients showed higher T2 and T1Gad SIRs than those with inactive disease. The T2 SIR and n-ADC of normally functioning TAO EOMs were higher than those of healthy controls. SIRs decreased in clinically improved and clinically stable EOMs after therapy.

CONCLUSIONS

T2 SIR, T1Gad SIR and n-ADC are objective measures of activity and severity of EOMs in TAO patients. MRI shows clinically silent muscle involvement and modifications.

KEY POINTS

• MRI and DWI measures are objective, quantitative parameters of TAO activity and severity • MRI and DWI measures significantly correlate with clinical scores in TAO patients • MRI and DWI can identify clinically silent inflammation of deep orbital structures • MRI and DWI can depict subclinical modifications during follow-up • MRI and DWI may aid clinicians in choosing the most appropriate treatment.

Disease activity in Graves' ophthalmopathy: diagnosis with orbital MR imaging and correlation with clinical score

In Graves' ophthalmopathy (GO) it is important to distinguish acute inflammation at an early stage, responsive to immunosuppressive treatment, from inactive fibrotic end stage disease, unresponsive to the same treatment. The purpose of this study was to identify the most relevant signal intensities on orbital MR imaging with contrast administration both to classify patients according to their clinical activity score (defined by a cut-off value of 3) and to make a prediction of patient's CAS. Such threshold was considered as widely used in literature. Sixteen consecutive patients with a diagnosis of GO in different phases of thyroid disease based on clinical and orbital MR imaging signs, and six normal volunteers were examined. Orbital MR imaging was performed on a 1.5 Tesla MR Unit. MR scans were assessed by an experienced neuroradiologist, blinded to the clinical examinations. We found a statistical correlation between CAS and both STIR and contrast enhanced T1-weighted sequences. There was also a statistically significant correlation between STIR and contrast-enhanced T1 images disclosing the possibility of avoiding the injection of contrast medium. Our study proved that signal intensity values on STIR sequence increase in the inflammatory oedematous phase of disease. We confirmed the correlation between signal intensities on this sequence and CAS, showing an increase in signal intensity proportional to the CAS value. So we validated MRI use to establish the activity phase of disease more sensitively than CAS alone.

Semiautomatic regional segmentation to measure orbital fat volumes in thyroid-associated ophthalmopathy. A validation study

This study was designed to validate a novel semi-automated segmentation method to measure regional intra-orbital fat tissue volume in Graves' ophthalmopathy. Twenty-four orbits from 12 patients with Graves' ophthalmopathy, 24 orbits from 12 controls, ten orbits from five MRI study simulations and two orbits from a digital model were used. Following manual region of interest definition of the orbital volumes performed by two operators with different levels of expertise, an automated procedure calculated intra-orbital fat tissue volumes (global and regional, with automated definition of four quadrants). In patients with Graves' disease, clinical activity score and degree of exophthalmos were measured and correlated with intra-orbital fat volumes. Operator performance was evaluated and statistical analysis of the measurements was performed. Accurate intra-orbital fat volume measurements were obtained with coefficients of variation below 5%. The mean operator difference in total fat volume measurements was 0.56%. Patients had significantly higher intra-orbital fat volumes than controls (p<0.001 using Student's t test). Fat volumes and clinical score were significantly correlated (p<0.001). The semi-automated method described here can provide accurate, reproducible intra-orbital fat measurements with low inter-operator variation and good correlation with clinical data.

Signal intensity and T2 time of extraocular muscles in assessment of their physiological status in MR imaging in healthy subjects

Background:

Lack of standardised orbital MR protocols leads to a situation, when each institution/centre may arbitrarily choose sequence parameters. Therefore, the results obtained and published by the authors may not be compared freely, and what is most important may not be considered fully reliable. Signal intensity (IS) and T2 time (T2) are important parameters in estimation of inflammatory processes of extraocular muscles in the clinical practice.

The aim of this study was to determine the reference values (i.e. cut-off values) for absolute signal intensity and T2 relaxation time in healthy subjects, their relativised values to white matter (WM) and temporal muscles (TM) and to evaluate the correlation between those parameters.

Material/Methods:

The orbital examination was performed in healthy volunteers according to the protocol prepared in the Radiology-Imaging Diagnostic Department of the Medical University of Lodz for patients with suspected/diagnosed thyroid orbitopathy. Using two of the standard sequences IS and T2 time were calculated for the muscles and two relativisation tissues in realtion to WM and TM. Subsequently cut-off values for healthy volunteers were calculated.

Results:

The differences between muscles for IS, IS MAX, IS/TM, IS/WM, IS MAX/TM, IS MAX/WM and T2 MAX/WM were not statistically significant. Therefore one cut-off value of these parameters for all the rectus muscles was calculated. T2-relaxation time and T2 relativised to white matter had to be calculated separately for each muscle.

Conclusions:

No statistical correlation was found between IS and T2-time for extraocular muscles in healthy volunteers. We calculated the reference ranges (cut-off values) for absolute IS and T2-time values and relativised parameters. In the clinical practice the objectification of IS and T2-time values should be done to WM, than to IS or T2 of the temporal muscle. The T2 MAX/WM seems to have the highest clinical utility for the assessment of the pathophysiological status of extraocular muscles.

The impact of 99mTc-DTPA orbital SPECT in patient selection for external radiation therapy in Graves' ophthalmopathy

OBJECTIVE

In Graves' ophthalmopathy (GO), there is a demand to differentiate the immunologically active disease state, when immunosuppressive therapy is necessary, from the inactive state, when the patient would not benefit from it. We measured the inflammatory activity in the retrobulbar region using Tc-diethylene triamine pentaacetic acid (DTPA) SPECT before and after external radiation to determine whether this method is suitable for predicting the effectiveness of this therapy.

MATERIALS AND METHODS

Thirty-two patients with suspected active GO were involved in this retrospective study. The initial image, DTPA uptake value (UV) and its change after therapy were assessed to monitor the effect of the therapy and investigate whether a pretreatment scan is capable of predicting the outcome.

RESULTS

Depending on the change in DTPA UV after radiotherapy, three patient groups were formed: decreased, increased or minimally changed (less than 1×10 injected dose (ID)/ml). The initial DTPA UVs of these groups were significantly different (P<0.001). Improvement was observed mainly in patients with higher initial values. When comparing the groups with low (<12×10 ID/ml) versus high (≥12×10 ID/ml) initial uptake, an unexpected increase was observed in the first group after therapy (mean: +2.89±2.66×10 ID/ml), whereas the average change in the DTPA UV was negative in the latter group as anticipated (-2.24±4.47×10 ID/ml, P<0.00001).

CONCLUSION

We found that in GO patients a high DTPA UV may predict the response to orbital radiation therapy. DTPA orbital SPECT may be a suitable technique for the selection of GO patients for radiation therapy.

Evaluation of rectus extraocular muscles using dynamic contrast-enhanced MR imaging in patients with Graves' ophthalmopathy for assessment of disease activity

BACKGROUND

It is important to assess the activity of Graves' ophthalmopathy (GO) for planning optimal treatment strategy. Dynamic contrast-enhanced MR imaging (DCE-MRI) is a technique for assessment of microcirculation status. The correlation between disease activity and the microcirculation characteristics of extraocular muscles (EOMs) has been demonstrated in GO.

PURPOSE

To investigate the changes of rectus EOMs in patients with active vs. inactive GO using DCE-MRI, and to evaluate the value of DCE-MRI in assessing the activity of GO.

MATERIAL AND METHODS

Rectus EOMs of 20 healthy controls, 18 patients with active GO, and 16 patients with inactive GO were studied. The signal intensity (SI) of rectus EOMs on T(2)W images was evaluated. Regions of interest were placed on each rectus on DCE-MRI images. The DCE-MRI parameters including time to peak enhancement (Tpeak), enhancement ratio (ER), and wash-out ratio (WR) were calculated.

RESULTS

There were significant differences in SI and T(peak), ER and WR values among the three groups (P = 0.000). However, there was no significant difference in SI between the active and inactive groups (P = 0.07). T(peak) values of each rectus were significantly increased in inactive group compared with the active group (P < 0.05). ER and WR values of the inferior rectus and WR values of the superior rectus in inactive group were significantly lower than those in active group (P < 0.05). There was significant correlation between clinical activity score (CAS) and minimum T(peak) (minT(peak)), maximum ER (maxER) and maximum WR (maxWR) (P < 0.001). The cut-off values of minT(peak), maxER and maxWR were 156.98s, 1.31 and 13.50% respectively, giving positive predictive values of 68.00%, 88.90%, and 94.44% for the assessment of disease activity.

CONCLUSION

DCE-MRI could demonstrate the microcirculatory changes of rectus EOMs in both active and inactive GO, and this MRI method is a useful tool in differentiating active from inactive GO.

Thyroid eye disease

Thyroid eye disease (TED) is the most common cause of proptosis in adults, and should always be a consideration in patients with unexplained diplopia, pain, or optic nerve dysfunction. At least 80% of TED is associated with Graves disease (GD), and at least 50% of patients with GD develop clinically evident symptomatic TED. The most confusing patients for doctors of all subspecialties are the patients with eye symptoms and signs that precede serum evidence of a thyroid imbalance. Management of TED may include immunosuppressive medications, radiation, or surgery. Although the prognosis for optic nerve function is excellent, the restrictive dysmotility can result in permanent disability. Orbit and eyelid reconstruction are reserved for stable, inactive patients and are the final steps in minimizing facial alterations and enhancing the patient's daily functioning.

Oftalmopatia tireoidea revisitada

A oftalmopatia tireoidea é doença orbitária autoimune intimamente associada com o hipertireoidismo, porém podendo existir separadamente. Pode preceder, coincidir ou suceder o início da disfunção tireoidea, raramente ocorrendo em eutireoideos ou hipotireoideos. Os músculos extraoculares são os principais alvos acometidos e tornam-se aumentados de volume, determinando oftalmoplegia e proptose. Outros sinais importantes incluem retração palpebral, hiperemia conjuntival e edema periorbitário. Perda visual pode ocorrer se há compressão do nervo óptico no ápice orbitário. A oftalmopatia tireoidea é caracterizada por inflamação, congestão, hipertrofia e fibrose da gordura e músculos orbitários. A atividade da doença é dividida em fase aguda ou inflamatória, seguida pela fase inativa associada com alterações fibróticas e infiltração gordurosa. O diagnóstico é clínico, e quando este é difícil ou se suspeita de neuropatia óptica os métodos de imagem são indicados. A tomografia computadorizada e a ressonância magnética podem confirmar o diagnóstico e avaliar a área crítica do ápice orbitário. A ressonância magnética é superior, em virtude da resolução tecidual e da sua capacidade de avaliar a atividade da doença (mediante sequências com TR longo) e detectar alterações inflamatórias, auxiliando o planejamento terapêutico no momento certo, melhorando o prognóstico.

T(1) and T(2) measurements of the fine structures of the in vivo and enucleated human eye

PURPOSE

To measure T(1) and T(2) of the fine structures of the in vivo eye.

MATERIALS AND METHODS

Involuntary saccades make it difficult to obtain artifact-free images. Using a method recently reported (Bert et al, Acad Radiol 2006;12:368-378), near artifact-free spin-echo images were obtained. Both an isolated enucleated eye and eight human subjects were studied at 1.5 T. Spin-echo variable TR/TE data was acquired for T(1)/T(2) determination. Average relaxation times were calculated two ways. First, an arithmetic average over different subjects was computed. Second, all data was normalized using the fitted amplitudes of each data set and pooled to obtain a single least squares fit.

RESULTS

In vivo T(1)/T(2) (msec) are: arithmetic average T(1), T(2), normalized data T(1), T(2). Anterior chamber: 6233 +/- 979, 468 +/- 149, 5053 +/- 1052, 450 +/- 49. Ciliary body: 1916 +/- 184, 80 +/- 7, 2038 +/- 114, 76 +/- 3. Chorioretina: 1717 +/- 500, 72 +/- 25, 1511 +/- 230, 78 +/- 3. Extraocular muscle: 1581 +/- 646, 41 +/- 7, 1470 +/- 231, 41 +/- 1. Iris: 3334 +/- 989, 163 +/- 63, 3376 +/- 338, 153 +/- 10. Lens cortex: 1712 +/- 466, 93 +/- 36, 1413 +/- 177, 100 +/- 5. Lens nucleus: 1133 +/- 40, 26 +/- 3, 1138 +/- 47, 25 +/- 0.4. Optic nerve: 1906 +/- 301, 68 +/- 16, 1805 +/- 244, 71 +/- 2. Posterior chamber: 7915 +/- 4897, 241 +/- 14, 3323 +/- 2154, 251 +/- 38. Vitreous humor: 5768 +/- 1190, 756 +/- 804, 4855 +/- 1846, 390 +/- 8.

CONCLUSION

In vivo T(1) and T(2) for many of the fine structures of the human eye have been measured.

Eyeball muscles' diameters versus volume estimated by numerical image segmentation

PURPOSE

To determine the clinical usefulness of the numerical segmentation image technique (NSI) in estimating the volume of extraocular muscles and to compare this value to widely used measurements of single diameters of the muscles.

METHODS

Forty-five patients underwent magnetic resonance examinations in 1.5-T scanner. SE T1 sequences in transversal and coronal planes were provided and data were sent to a personal computer, where the degree of exophthalmos, horizontal diameter of medial rectus muscles, and vertical diameter of inferior rectus muscles were determined on the basis of two-dimensional images. The quantity estimation of all eye muscles volumes using NSI application in three-dimensional space was carried out with use of level set segmentation algorithm.

RESULTS

A strong correlation between the total eye muscle volume and degree of exophthalmos was determined. The usefulness of measuring single diameters for estimating the muscles' enlargement was confirmed. The difference between a single muscle's volume and its width also was confirmed. Estimates of muscle volume correlate with the degree of exophthalmos more accurately than measurements of single diameters.

CONCLUSIONS

The NSI technique is a clinically useful application, providing objective data calculated individually for each orbit. It allows an objective estimation of the pathologic processes leading to exophthalmos and may be especially helpful in monitoring discrete changes in the muscles volume during treatment.

Magnetic resonance imaging and ultrasound measurements of extraocular muscles in thyroid-associated ophthalmopathy at different stages of the disease

PURPOSE

To assess extraocular muscle (EOM) involvement in thyroid-associated orbitopathy (TAO) of different stages with magnetic resonance imaging (MRI) and ultrasound techniques.

METHODS

A total of 32 patients with TAO were divided into three groups according to whether they had mild active, pronounced active or longstanding inactive disease. Six patients with Graves' disease but no clinical signs of TAO and 10 healthy control subjects were also studied. Muscle volume and cross-sectional area were measured with MRI. A-scan ultrasound was used to measure muscle thickness.

RESULTS

The average MRI volume and maximal cross-sectional area of the EOM were significantly larger in patients with pronounced active and longstanding inactive TAO than in control subjects. Increased average muscle thickness measured by ultrasound was found mainly in patients with longstanding disease. Muscle enlargement was seen with MRI and ultrasound in individual patients in all patient groups, including those with Graves' disease but no TAO. Bilateral muscle enlargement was revealed by MRI in about two-thirds of patients with mild active TAO and in all patients with pronounced active and longstanding inactive TAO. Bilateral involvement estimated with ultrasound was less common in all patient groups. The MRI and ultrasound findings were not well correlated in any patient group.

CONCLUSIONS

Extraocular muscle enlargement was seen in all patient groups with TAO of differing levels of severity. Measurements with MRI of muscle volume or maximal cross-sectional area are considered good indicators of muscle enlargement in TAO.

Slow-release lanreotide in Graves' ophthalmopathy: A double-blind randomized, placebo-controlled clinical trial

SS analogs are an attractive alternative in treating Graves' ophthalmopathy (GO). Most of the previous studies were uncontrolled and enrolled few patients. The present study was conducted as a larger scale, prospective, randomized controlled study to determine the effectiveness of a slow-release formulation of lanreotide in GO. Sixty patients with active GO received an im injection every two weeks of either lanreotide 30 mg or placebo for 12 weeks. They were then followed and further treated in the traditional way if necessary. The Clinical Activity Score (CAS) was the primary efficacy criterion. Proptosis, diplopia, corneal erosion or ulcer, visual acuity, extraocular muscle movement and intraocular pressure were also evaluated. At the end of the 12 weeks, the mean CAS was not significantly decreased in the lanreotide group compared to the placebo group. The overall mean difference of proptosis between these two groups also did not reach significance at 12 weeks. Only diplopia at downward gaze had significant improvement for the lanreotide- treated group vs placebo group (p = 0.03). No differences were observed between the two groups compared to other outcome measures. During the 24-month follow-up after the clinical trial, 14 patients received eye surgery in the placebo group compared with 10 patients in the lanreotide group (p = 0.29). Six patients received methylprednisolone pulse therapy in the placebo group and two patients in the lanreotide group (p = 0.25). In conclusion, lanreotide treatment had no significant effects on GO compared with placebo.

Measuring disease activity to predict therapeutic outcome in Graves' ophthalmopathy

OBJECTIVE

The concept of disease activity in Graves' ophthalmopathy (GO) might explain why as many as one-third of patients do not respond to immunosuppressive treatment, because only patients in the active stage of disease are expected to respond. The hypothesis was adopted that a parameter used to measure disease activity should be able to predict a response to immunosuppressive treatment. The aim of this study was to develop a multivariate prediction model in which all previous tested activity parameters are integrated.

DESIGN AND PATIENTS

We included 66 consecutive patients with untreated moderately severe GO who had been euthyroid for at least 2 months. All patients were treated with radiotherapy. Measurements Treatment efficacy after 6 months follow-up was used as the primary outcome measure. Disease severity and 15 different disease activity parameters were assessed before treatment. Univariate and multivariate logistic regression models were used to predict response (model 1) or no change (model 2).

RESULTS

In multivariate analyses, we found that duration of GO, soft tissue involvement, elevation, soluble interleukin-2 receptor (sIL-2R), soluble CD30 (sCD30), eye muscle reflectivity and octreotide uptake ratio were significant predictors of a response to radiotherapy. Gender, duration of GO, soft tissue involvement, eye muscle reflectivity, IL-6 and urinary glycosaminoglycan (GAG) excretion were significant predictors of no change upon radiotherapy. Prognostic score charts were developed for use in clinical practice to calculate the probability of response (model 1) and the probability of no change (model 2) for each new patient. Finally we used a combination of both models to define a recommended treatment modality for each individual patient, based on both the predicted probabilities of response and no change. We were able to identify the correct treatment (based on a comparison with the observed response) in 89% of the patients.

CONCLUSIONS

Although we strongly recommend that our results should be confirmed in other studies, our findings are the first evidence for the idea that disease (in)activity should determine which kind of treatment should be used.

Serum antibodies to collagen XIII: a further good marker of active Graves' ophthalmopathy

OBJECTIVE

In Graves' ophthalmopathy (GO) intercellular adhesion molecule-1 (ICAM-1) is thought to play a key role in lymphocyte infiltration into the orbit, and serum levels of its soluble form are positively correlated to clinical activity score (CAS). Serum antibodies against collagen XIII (CollXIIIAb), a plasma membrane protein expressed at a low level in almost all connective tissue-producing cells, have been detected in GO, but their significance is unclear. The aim of this study was to search for CollXIIIAb in Graves' patients with and without ophthalmopathy and to correlate their levels with CAS and with serum soluble ICAM-1 (sICAM-1) values.

PATIENTS

We studied 66 patients with Graves' disease whose sera had been previously tested for sICAM-1 levels, grouped as follows: 28 with moderate and active ophthalmopathy (group 1), 12 of them hyperthyroid (group 1a) and 16 euthyroid (group 1b); 13 with mild and inactive ophthalmopathy and normal thyroid function (group 2); 25 without ophthalmopathy (group 3), 11 of them hyperthyroid (group 3a) and 14 euthyroid (group 3b). Finally, 26 sera of normal controls were studied.

MEASUREMENTS

CollXIIIAb were evaluated by an enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

In group 1 patients, CollXIIIAb were detected at high levels in 8/12 (66.6%) in group 1a [optical density (OD) ranging from 0.529 to 0.894] and in 10/16 (62.5%) in group 1b (OD 0.560-0.855). In group 2 patients, CollXIIIAb were detected but at low levels (OD 0.205-0.260) in 4/13 patients (30.7%). In group 3 patients, CollXIIIAb were present at low levels in 6/11 (54.5%) of group 3a and in 5/14 (35.7%) of group 3b (OD 0.215-0.290 and 0.144-0.245, respectively). CollXIIIAb were detected in only 4/26 normal controls (15%) but at low levels (OD 0.150-0.185). CollXIIIAb values in both groups 1a and 1b were significantly higher than those of the remaining groups. A positive correlation between CollXIIIAb levels and CAS but not thyroid hormone levels was found in groups 1a, 1b and 2. Moreover, a positive correlation between CollXIIIAb levels and sICAM-1-values was also evidenced in all three groups.

CONCLUSIONS

Our results suggest that CollXIIIAb could be considered as a further good marker of active inflammatory processes involving the adipose connective tissue in GO. In particular, the high levels of CollXIIIAb in sera of Graves' patients with active ophthalmopathy could reflect an increased expression of type XIII collagen on the membrane of activated fibroblasts in these patients. Thus, the evaluation of these antibodies could be added to other known markers as a useful and inexpensive tool in monitoring Graves' patients and in modulating the treatment of GO.

Comparison of practical methods for urinary glycosaminoglycans and serum hyaluronan with clinical activity scores in patients with Graves' ophthalmopathy

OBJECTIVE

Immunosuppressive treatment of Graves' opthalmopathy (GO) should be restricted to patients with active eye disease, but assessing disease activity is difficult. Several methods to evaluate GO activity have been introduced, but none of them is satisfactory. Glycosaminoglycans (GAGs) are complex polysaccharides that participate on the pathogenesis of GO and attempts to correlate its local increase to urinary GAGs (uGAGs) or serum hyaluronan (sHA) have been made, but the available techniques are labourious, time-consuming and difficult for routine use. The aim of the present study is to develop practical and simple methods for uGAGs and sHA and compare them to the activity and severity of thyroid-associated ophthalmopathy.

DESIGN, PATIENTS AND MEASUREMENTS

We developed a microelectrophoresis technique for uGAGs and a fluoroassay for sHA and assessed each in 152 patients with Graves' disease, 25 without GO and 127 with GO, classified according to the Clinical Activity Score (CAS). All patients had been euthyroid for > 2 months.

RESULTS

Patients with inactive disease (CAS = 2, n = 100) had uGAGs (4.2 +/- 1.3 micro g/mg/creatinine) and sHA (11.1 +/- 7.2 micro g/l) that did not differ from normal subjects (3.1 +/- 1.1 micro g/mg/creatinine, n = 138 and 13.9 +/- 9.6 micro g/l, n = 395). In contrast, patients with active eye disease (CAS = 3, n = 27) had uGAGs (8.4 +/- 2.7 micro g/mg/creatinine) and sHA (32.3 +/- 17.8 micro g/l) 2-3 times higher than those patients with inactive eye disease. Using a cut-off of 6.1 micro g/mg creatinine for uGAGs and 20.7 micro g/l for sHA we found, respectively, 85% and 81% sensitivity and 93% and 91% specificity for each test. The positive and negative predictive values were 77% and 96% for uGAGs and 71% and 95% for sHA.

CONCLUSION

Employing these two new methods we have established a significant relationship between the levels of uGAGs and/or sHA and the clinical activity of GO. Therefore, together with CAS, uGAGs determination, and, to a lesser degree, sHA, would be very useful in the discrimination from active and inactive ocular disease and aid in deciding on the best therapy for GO patients.

Evaluation of extraocular muscles in the edematous phase of Graves ophthalmopathy on contrast-enhanced fat-suppressed magnetic resonance imaging

OBJECTIVE

Extraocular muscles (EOMs) reveal characteristic contrast-enhancement patterns on magnetic resonance (MR) imaging due to their rich vascular supply. The objective of this study was to evaluate contrast-enhancement patterns of EOMs in patients with edematous phase of Graves ophthalmopathy (GO) using contrast-enhanced fat-suppressed MR imaging in comparison with normal volunteers.

METHODS

EOMs of 15 patients with edematous phase of GO and those of 15 normal volunteers were evaluated using coronal T1-weighted MR images with fat suppression before and after intravenous administration of gadolinium. The image sequence was a fast spin-echo with chemical shift selective fat saturation. The degree of contrast enhancement for EOMs and temporal muscles (TMs) was assessed via a 4-step grading system and by 2 reviewers.

RESULTS

There were statistically significant differences for the degrees of contrast enhancement in all EOMs between the patients with GO and normal volunteers. The degrees of contrast enhancement for all EOMs were significantly decreased in patients with edematous phase of GO.

CONCLUSIONS

The microcirculation within the EOMs tends to be impaired during the progress of disease, and the MR imaging pattern gives a semiquantitative measurement of the microcirculatory impairment of the EOMs during the edematous phase of the disease.

Graves ophthalmopathy

Graves ophthalmopathy (GO) is an autoimmune disease that typically affects the thyroid gland and the orbit. The roles of the thyroid stimulating hormone receptor and cellular and humoral immunity in the pathogenesis of GO are being investigated. Investigators are gaining insights into the epidemiology of GO as it relates to other ocular and autoimmune diseases. Several possible tools for assessing GO disease activity are being studied. Medical and radiation therapy for GO recently have been evaluated prospectively. Orbital surgeons continue to refine orbital decompression techniques to improve patient outcomes and minimize surgical complications.