Role of octreoscan and correlation with MR imaging in Graves' ophthalmopathy

Octreotide inhibits secretion of IGF-1 from orbital fibroblasts in patients with thyroid-associated ophthalmopathy via inhibition of the NF-κB pathway

PURPOSE

We investigated the effect of octreotide, a long-acting somatostatin (SST) analogue, on IGF-1 secretion and its possible mechanism of action in orbital fibroblasts (OFs) from patients with thyroid-associated ophthalmopathy (TAO).

MATERIALS AND METHODS

OFs were isolated from the orbital fat of patients with TAO or healthy individuals. The expression level of insulin-like growth factor (IGF)-1, at the protein and mRNA level, was determined with ELISA and quantitative RT-PCR, respectively. The expression pattern of somatostatin receptor (SSTR) 2, which has the highest affinity for octreotide, was examined by flow cytometry. The activity of NF-κB pathway was determined by examining the levels of phosphorylation of IKKα/β and p65, and degradation of IκB via western blot analysis, and by measuring the activity of NF-kB-dependent luciferase via transfection with plasmids containing luciferase and NF-κB binding site.

RESULTS

OFs from patients with TAO showed significantly higher levels of IGF-1 secretion and NF-κB activity even in the absence of stimulation, compared to those from controls. Treatment with octreotide reduced the level of IGF-1 secretion in OFs from patients with TAO, but not in OFs from controls. OFs from patients with TAO expressed higher levels of SSTR2 on the cell surface, compared to controls. In addition, the expression of IGF-1 at the protein and mRNA level was dependent on the activity of NF-κB pathway in OFs from patients with TAO. Furthermore, treatment with octreotide reduced on the activity of NF-κB pathway in OFs from patients with TAO.

CONCLUSION

OFs from patients with TAO showed significantly higher levels of IGF-1 secretion via up-regulation of NF-κB activity. Treatment with octreotide inhibited the secretion of IGF-1 by reducing the NF-κB pathway in OFs, which expressed higher levels of SSRT2 on the cell surface, from patients with TAO.

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.

Update on advanced imaging options for thyroid-associated orbitopathy

Thyroid-associated orbitopathy (TAO) is a diverse spectrum of signs and symptoms that appears to have immunologic and pathologic causative factors as diverse as its clinical presentations. Lymphocytes, hormones, and cytokines affect orbital fibroblasts and other similar cells, which exert their effects on orbital tissues, including the extraocular muscles, orbital fat, and optic nerve. This complicated inflammatory cascade and the myriad of clinical findings that result contributes to the active phase of TAO. The distinction between the active and inactive phases of TAO is an important one, as the proper treatment will depend on the disease phase and degree thereof. Several clinical grading scales and scores have been established to help qualify and quantify the disease severity. Aiding clinical exam and acumen, proper and reproducible imaging of the orbit and ocular adnexa is incredibly important to the management of TAO. Orbital ultrasound, computed tomography, magnetic resonance imaging, and scintigraphy each have unique abilities, including quantifying orbital changes, assessing disease activity, correlating orbital findings with clinical changes, guiding appropriate treatment, and monitoring therapeutic responses. Further, study ease, accessibility, cost, sensitivity, specificity, reproducibility, and risks are all important considerations in picking the right test with which to diagnose and follow TAO. This analysis will provide a review of orbital imaging for TAO, including the mechanism of each imaging technique as well as their rationales, advantages, disadvantages, and utilities.

Neuroimaging of Graves' orbitopathy

Neuroimaging of Graves' orbitopathy (GO) plays an important role in the differential diagnosis and interdisciplinary management of patients with GO. Orbital imaging is required in unclear or asymmetric proptosis, in suspected optic neuropathy and prior to decompression surgery. Especially computed tomography and magnetic resonance (MR) imaging show the actual objective morphological findings, quantitative MR imaging giving additional information concerning the acuteness or chronicity of the disease. Major morphological diagnostic criteria include a spindle like spreading of the rectus muscles without involvement of the tendon, a compression of the optic nerve in the orbital apex (crowded orbital apex syndrome) and the absence of any space occupying intraorbital process. A longer lasting course of the disease may lead to a corresponding impression of the lamina papyracae, the normally parallel configured medial wall of the orbit, similar to a spontaneous decompression.

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.

Thyroid-associated ophthalmopathy in juvenile Graves' disease--clinical, endocrine and therapeutic aspects

Children have about the same risk (or slightly increased) as adults to develop Graves' ophthalmopathy (GO) once they have contracted Graves' hyperthyroidism. The severity of childhood GO appears to be less than that of adult GO. The female preponderance is similar between children and adults with Graves' hyperthyroidism (87% and 83%, respectively), but the prevalence of smoking is much lower in children than in adults (4% and 47%, respecttively). Smoking is a risk factor for GO, and the odds increase significantly with increasing severity of GO. It has also been shown that the manifestation of GO begins to resemble the adult findings more closely when adolescence approaches. This could be explained by increasing smoking prevalence with age. A recent study supports the above data and provides a very interesting clue: the difference might be caused by exposure to tobacco smoke. Regarding treatment of thyroid eye disease (TED) in childhood, most physicians who are dealing with such cases prefer a 'wait-and-see' policy. Pharmacological intervention, predominantly with steroids, is considered appropriate in case of worsening of eye changes or no improvement of eye changes when the patient has become euthyroid. Doses between 5 and 20 g prednisone daily are used depending on the severity of the case. It has to be kept in mind that prolonged prednisone administration, which should be used in some severe cases of TED, is associated with weight gain, immune suppression and growth failure in children. Recently, it has been shown that somatostatin analogs (SM-as) might be of therapeutic value in the treatment of active TED in adults. However, initial studies were uncontrolled, non-randomized, and included only small numbers of patients. In the past 2 years, three double-blind, placebo-controlled clinical studies have been published, which have demonstrated only a modest improvement in proptosis. The current range of SM-a drugs target two of five somatostatin receptors present in the orbital tissues of TED patients. Therefore, there is a reason to believe that newer generations of SM-as that target a wider range of somatostatin receptors may show markedly superior results in the treatment of TED. Retrobulbar irradiation, which has proved beneficial in adults with TED, has no place in the treatment of juvenile GO, in view of the theoretical risk of tumor induction. The same applies to orbital decompression.

Viral conjunctivitis interfering with the clinical activity score and management of thyroid ophthalmopathy

INTRODUCTION

The management of Graves' ophthalmopathy is shared between endocrinologists and ophthalmologists. Assessment and treatment of the active inflammatory stage is based on the clinical activity and disease severity scores, often without detailed eye examination by the treating endocrinologist.

MATERIALS AND METHODS

We report a case of acute viral keratoconjunctivitis occurring during immunosuppressive treatment for Graves' ophthalmopathy which masked the signs, symptoms and response to treatment of the orbitopathy, posing a differential diagnostic challenge.

RESULTS

The apparent worsening of the ophthalmopathy and the increased clinical activity score led the treating endocrinologist to alter the management decisions. Ophthalmic examination confirmed the diagnosis of viral keratoconjunctivitis and immunosuppressive treatment was continued with significant final improvement of Graves' ophthalmopathy.

DISCUSSION

Ocular surface conditions, unrecognised by the treating physician, may complicate the assessment of thyroid ophthalmopathy when detailed eye examination is not performed. The diagnostic challenge of Graves' ophthalmopathy requires a combined approach by an endocrinologist and an ophthalmologist working as a team.

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.

Investigation of the use of positron emission tomography for neuroreceptor imaging in rabbit eyes

To determine whether positron emission tomography (PET) can be used for imaging of neuroreceptors in eyes of rabbits. PET imaging of dopamine D(2) receptor, dopamine transporter, serotonin(1A) receptor and sigma(1) receptor in the eyes and brain was performed using corresponding positron-emitting ligands in baseline, pretreatment and displacement conditions. The 4 radioligands outlined the eyes and brain in the baseline. Pretreatment resulted in a slight reduction (26-28%) in the uptake in the anterior segments of eyes. The binding of each radioligand in the iris-ciliary body and retina was confirmed by ex vivo autoradiography. However, the PET signal in the eyes was unexpectedly higher than the autoradiography signal. The identification of radioligand-neuroreceptor binding by PET in the rabbit eyes is not specific enough.

Thyroid-associated orbitopathy: a clinicopathologic and therapeutic review

PURPOSE OF REVIEW

To review the literature related to thyroid-associated orbitopathy and to emphasize recent developments in its pathophysiology, diagnosis, and therapy. Current therapeutic trends and controversies are discussed.

RECENT FINDINGS

Expression of thyroid stimulating hormone receptor is highest in the fat and connective tissue of patients with thyroid-associated orbitopathy, where fibroblasts have the potential for adipogenesis. Electrophysiology can now detect subclinical optic neuropathy, and somatostatin-receptor scintigraphy can help justify immunomodulation. Other than steroids, radiotherapy can control inflammation, but its use is controversial. Current trends in orbital decompression are to camouflage incisions and to limit strabismus with balanced decompression, deep lateral wall techniques, fat removal, and onlay implants. Proptosis reductions of 0.9 to 12.5mm are possible by the use of various algorithms. Before or after decompression, botulinum toxin can correct strabismus, intraocular pressure elevation, and retraction. The latter is now also treated with full-thickness blepharotomy.

SUMMARY

As knowledge of the pathophysiology of thyroid-associated orbitopathy grows, there is a slow movement from nonspecific and invasive measures to more directed treatments causing less morbidity.

Recent developments in Graves' ophthalmopathy imaging

Orbital ultrasound, computed tomography, and magnetic resonance are commonly used as imaging techniques to demonstrate pathological changes in ocular adnexa of patients with Graves' ophthalmopathy. Low cost, short time of investigation, and lack of radiation characterize ultrasound. Nevertheless, a clear differentiation regarding disease activity is not possible, nor is the evaluation of orbital tissue precise enough. Short investigation time, precise imaging of the orbital apex and moderate costs are advantages of tomography. This method delivers a significant radiation dose to the lens, which if repeated constitutes a risk for cataract development. For this reason, magnetic resonance imaging is preferable, particularly if repeated scans are required to assess response to treatment. Precise tissue differentiation and lack of ionizing radiation uniquely suit magnetic resonance for eye studies. Although sensitive in demonstrating interstitial edema within the rectos muscles in active disease, as well as providing a good predictive value with respect to immunosuppressive therapy, quantitative magnetic resonance imaging is an expensive method and is non-specific for the orbital changes in ophthalmopathy. Because of a favorable target to background ratio, octreoscan carries a high sensitivity and may be regarded as a semi-objective tool in the evaluation of patients with Graves' ophthalmopathy, both at initial stages as well as during treatment. A positive orbital octreoscan indicates a clinically active disease in which immunosuppressive treatment might be of therapeutic benefit. However, it is an expensive method with a non-negligible radiation burden. Also, it is neither specific nor does it offer detailed orbital imaging. In summary, in unclear cases of proptosis or recently developed diplopia, prior to orbital decompression surgery, or if imaging is needed in subjects with ophthalmopathy, magnetic resonance actually is the imaging method of choice.

Novel aspects of immunosuppressive and radiotherapy management of Graves' ophthalmopathy

Treatment of severe Graves' ophthalmopathy (GO) is a complex therapeutic challenge and, in spite of any efforts, about one third of patients are disappointed with the outcome of treatment. Glucocorticoids (GC), orbital radiotherapy (RT), or a combination of both, are most frequently used for their immunosuppressive effects. Novel immunosuppressive treatment procedures (or novel modalities of established treatments) are reviewed in the present article. GC has recently been used by the i.v. route and this treatment modality has been shown to be more effective and better tolerated than the oral route. Promising preliminary results have been reported by some authors with somatostatin analogs, octreotide and lanreotide. The number of patients treated so far is limited, most of the results have been obtained in nonrandomized or uncontrolled studies, and comparison with other validated methods of treatment is also needed. Because of the pathogenic role of cytokines, cytokine antagonists, currently evaluated in other autoimmune diseases, have been tested with positive results also in a small series of GO patients. The use of antioxidants might also be envisioned in the future, since in vitro studies have shown that oxygen free radicals might be involved in GO. Based on the shared antigen(s) theory, total thyroid ablation, by removing the bulk of shared antigens(s), might be beneficial for the course of GO. New data on recently performed placebo-controlled studies on orbital radiotherapy are discussed, together with studies on long-term safety of orbital radiotherapy.

Peptide Targeted Imaging of Cancer

After the discovery of several specific peptide receptors in a variety of cancer types more than 10 years ago, radiolabeled peptide analogs with adequate stability, receptor binding properties, and biokinetic behavior were introduced for imaging of neuroendocrine tumors, several adenocarcinomas, lymphoma, and melanoma. Although initially 123I or 111In were used for labeling, recent efforts have also concentrated on 99mTc or PET-radionuclides (18F,68Ga), as they result in better image resolution with lower radiation dose to patients. Scintigraphy with labeled somatostatin analogs (99mTc, 111In,18F,68Ga), with 123I-labeled vasoactive intestinal peptide, and recently 99mTc-bombesin/GRP-or-111In gastrin analogs, have shown a mean sensitivity of greater than 85% to localize deposits of tumors, with appropriate receptor expression frequently scarcely visible with other imaging procedures. Moreover, these observations introduced peptide-targeted metabolic radiotherapy for metastatic cancers. This development has produced a considerable amount of preclinical studies to broaden the impact of labeled peptide ligands on the management of cancer.

The role of Tc-99m polyclonal human immunoglobulin G scintigraphy in Graves' ophthalmopathy

OBJECTIVE

The aim of this study was to clarify whether Tc-99m HIG (Polyclonal Human Immunoglobulin G) can image and determine the severity of orbital involvement in patients with Graves' ophthalmopathy.

MATERIALS AND METHODS

Twenty-six patients between 19 and 56 years old with Graves' ophthalmopathy were examined. All patients received approximately 370 MBq Tc-99m HIG by i.v. injection. Planar and SPECT examination were performed 4 hours after the injection. Visual and semiquantitative evaluations were performed for both orbits by two independent observers,

RESULTS

Clinically active ophthalmopathy patients had noticeably increased orbital accumulation of Tc-99m HIG. In patients with inactive disease, and 14 of 19 had no uptake, whereas 5 patients had orbital radioactivity accumulation. The duration of Graves' ophthalmopathy did not correlate with the presence of active ophthalmopathy and Tc-99m HIG grade. There was no correlation between clinical classification and clinical activity (r = 278). There was a good correlation between clinical activity and the radioactivity grade with r = 0.666 (p = 0.01). The clinical classification closely correlated with Tc-99m HIG grade (r = 0.423, p = 0.05).

CONCLUSION

Tc-99m HIG scan can clearly identified clinically active patients, and subclinicial inflammation can be shown by this scintigraphic evaluation. The current preliminary results suggested that Tc-99m HIG SPECT might be useful for the assessment of disease activity in Graves' ophthalmopathy.

Diagnosis and management of thyroid eye disease

Recent advances are helping elucidate the pathogenesis and improve the management of thyroid eye disease. While biochemical investigations and imaging may be supportive, ophthalmological and medical clinical assessments remain the key to the diagnosis and management of this sight-threatening disorder.

Octreoscan in thyroid-associated ophthalmopathy

Until recently, there was no imaging technique available that could be considered as a reliable measure of inflammation in thyroid-associated opthalmopathy (TAO). Pentetreotide (a synthetic derivative of somatostatin) labeled with 111In has been used to visualize somatostatin receptors in endocrine-related tumours in vivo. It has also been used to measure the orbital uptake in patients with TAO. An increased uptake in the orbit was found in patients with active disease. It was suggested that it is caused by the expression of somatostatin receptors on activated T-lymphocytes. Thus, a positive orbital octreoscan indicates clinically active eye disease in which immunosuppressive treatment might be of therapeutic benefit, in contrast to the fibrotic end stage. Indeed, successful immunosuppression with prednisone, orbital irradiation, or very recently with somatostatin analogues, has been demonstrated in patients with TAO and positive octreoscan. It is inferred that an orbital octreoscan is mainly indicated to select patients with TAO who will benefit from immunosuppression. However, limitations such as cost, nonnegligible radiation burden, nonspecific examination for TAO, and finally, lack of evaluation of eye muscle swelling restrict the widespread use of this technique. It remains to be seen if orbital octreoscan will become a widely available tool in the management of patients with TAO.

Role of magnetic resonance imaging in the assessment of disease activity in thyroid-associated ophthalmopathy

Two different phases in disease activity are observed during the clinical course of thyroid-associated ophthalmopathy (TAO). The assessment of disease activity is important for predicting the outcome of medical management because medical treatment can be effective in the active stage. The aim of this study was to investigate whether magnetic resonance imaging (MRI) could assess the disease activity in TAO. To investigate the relation between MRI-T2 signal intensity (SI) and extraocular muscle (EOM) size, 11 patients with TAO were evaluated. EOM sizes (enlargement, volume) were measured by MRI-T1 image. T2-SI of EOM was expressed as a percentage of temporal muscle. The reduction in T2-SI was significantly positively correlated with that of EOM enlargement after treatment. Additionally, T2-SI in pretreatment showed a significant correlation with reduction in EOM volume for therapeutic effect, which indicates T2-SI in pretreatment can be one of the reliable parameters for predicting the therapeutic outcome of treatment. To investigate whether MRI-T2 pattern could predict the reversibility of diplopia, 28 patients with Graves' disease with or without ophthalmopathy were evaluated. Patients with TAO with reversible diplopia showed an uniform T2 pattern in enlarged EOM. However, in patients with irreversible diplopia caused by the mechanical limitation of EOM, MRI-T2 image showed no uniformity with a partial appearance of low T2-SI. The partial low T2-SI may indicate the progress of inactive (fibrotic) change in EOM after active (inflammatory) change. In conclusion, MRI is a useful tool for detection not only of EOM enlargement, but also disease activity in TAO. MRI-T2 SI and pattern can predict the outcome of medical management in TAO.

Controversies in the clinical evaluation of active thyroid-associated orbitopathy: use of a detailed protocol with comparative photographs for objective assessment

Despite many learned publications over recent decades, the assessment of active thyroid-associated orbitopathy (TAO) remains difficult and controversial. There are no biochemical, immunological or imaging investigations which can identify active disease reliably, and clinical assessment is still of paramount importance. We therefore review the strengths and weaknesses of all methods of clinical assessment. A new atlas for clinical assessment of soft tissue signs has been developed, and its reproducibility assessed. It details a suggested protocol that could help standardize descriptions of TAO and allow more objective assessment of its activity and severity. This is relevant to general endocrinologists, who have a crucial role in the identification of patients who require ophthalmological assessment. Certain aspects are more relevant to ophthalmologists and endocrinologists who have a special clinical and research interest in TAO. Unless a reproducible system of assessment is devised and widely adopted, it will remain difficult to interpret research meaningfully, particularly if results appear to contradict.

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

BACKGROUND

Two-thirds of patients with Graves' ophthalmopathy (GO) respond to immunosuppressive treatment (prednisone or orbital irradiation), but one-third do not respond. Responders are likely to be in the active, oedematous stage of the eye disease, nonresponders in the inactive fibrotic stage. Clinical distinction between the two stages can be difficult. Quantitative magnetic resonance imaging (MRI) might be helpful in this respect, as T2 relaxation times are longer in oedematous than in fibrotic tissues.

STUDY DESIGN

Prospective study on quantitative orbital MRI in healthy subjects and patients with moderately severe GO, evaluating T2 relaxation time of extraocular muscles (EOM): (a) in patients vs. controls, and (b) in patients, as a predictor of outcome to orbital irradiation.

SUBJECTS AND MEASUREMENTS

Nine healthy volunteers and 64 consecutive patients with moderately severe untreated GO, who were euthyroid for > or = 2 months and qualified for orbital irradiation. T2 relaxation times were measured at the site of the largest diameter in all eight EOM of each subject. Baseline T2 values in patients were related to outcome of radiotherapy, as assessed by an independent observer 6 months later according to predefined criteria.

RESULTS

T2 relaxation times of the eight EOM were longer in GO patients than in controls: median [range] 126 [52--250] vs. 88 [50--126] msec; P = 0.003. Per subject the single eye muscle with the longest T2 time was selected to represent active inflammation (excluding the lateral muscles for technical reasons). Again patients were different from controls: 160 [68--250] vs. 103 [86--115] msec, P < 0.001. In the group of 34 responders to subsequent radiotherapy, these T2 times tended to be longer than in the 30 nonresponding patients: 168 [108--250] vs. 138 [68--216] msec, P = 0.07. Using a cut-off value of 130 msec (derived from a receiver-operator-characteristics curve) a positive predictive value of 64% and a negative predictive value of 92% for the outcome of radiotherapy was calculated.

CONCLUSION

Quantitative orbital magnetic resonance imaging was found to be less accurate in predicting successful outcome of radiotherapy than expected. It seems more useful in detecting the fibrotic end-stage than the active stage of Graves' ophthalmopathy. It is therefore of limited use in the decision whether or not to apply immunosuppression in patients with moderately severe Graves' ophthalmopathy.

Somatostatin-receptor scintigraphy in Graves' disease: reproducibility and variance of orbital activity

Somatostatin-receptor (SSTR) scintigraphy using the single photon emission computed tomography (SPECT) technique allows the assessment of orbital inflammation in patients with Graves' disease. Previous studies showed differences in orbital octreotide uptake already 4 hr after injection. In this study, analysis of inter-/intra-observer variance and reproducibility in the evaluation of orbital SPECT images was performed. First, SPECT data of one representative female patient with clinically active Graves' ophthalmopathy (GO), obtained 4 hr after intravenous injection of 110 MBq 111In-pentetreotide and processed by filtered backprojection, were analyzed. Transverse SPECT images were reconstructed, an optimal orbital image was selected and predetermined regions of interests (ROIs) for both orbits were positioned by three independent observers 15 to 19 times each. In a second step, SPECT data of 8 different patients with GO were evaluated in the same manner by four independent observers 3 to 4 times each. Variance component partitioning was used to compare the order of intra- and inter-observer variation. For the right and the left orbit, the inter-observer variance proportion was 90% and 79%, whereas intra-observer variance partition was 10% and 21%, respectively. The corresponding ratios 0.11 and 0.27 summarize the comparison of sources of variance. The overall reliability was 84%, representing the patients influence on the total variance. Intra-observer reliability for both orbits was 88%, 89%, 97% and 98% (mean over orbits), respectively for observers I to IV. Using the Spearman Brown prophecy formula it follows that two replications per patient are sufficient to ensure a minimum reproducibility of 90%, which is also confirmed by the low intra-observer variation. Furthermore, intra-class correlation as a measure of (multiple) observer reproducibility was 94%. In conclusion, due to the increased inter-observer variance proportion and the high variation in intra-observer reliability, evaluations of orbital SSTR scintigraphy have to be done by the same and experienced observer leading to comparable data. But an automatic and quantitative computerized technique for evaluation of these SPECT data should be exactly reproducible and probably lead to more accurate and representative results.

Octreotide-scintigraphy is a disease-activity parameter in Graves' ophthalmopathy

OBJECTIVE

It is thought that immunosuppressive treatment of Graves' ophthalmopathy should be restricted to patients with active eye disease, but assessing disease activity is difficult. Octreotide scintigraphy has been claimed to differentiate active from inactive disease. Here we study the intraobserver variability and diagnostic accuracy of the quantitative measurement of orbital octreotide uptake.

PATIENTS AND DESIGN

Twenty-two consecutive patients with moderately severe ophthalmopathy were treated with retrobulbar radiotherapy. Pretreatment octreotide scintigraphic data were related to the response at six months after radiotherapy, using Receiving-Operator-Characteristic curves.

MEASUREMENTS

Octreotide uptake was measured at 4 and 24 h after i.v. injection of approximately 3 mCi (= 111 MBq; range 75-150 MBq) 111Indium-DTPA-Octreotide with a neuro-SPECT camera. Counts were measured in fixed regions-of-interest in 4 transversal slices of the orbit, the temporal and the occipital area. Measurements were done twice and intraobserver variability was analysed by coefficients of variations (CV). Uptake is expressed as orbital/background ratio. The nature of the temporal uptake was studied by matching an octreoscan with a technetium scan and MRI.

RESULTS

Intra-observer variability of measuring octreotide uptake was acceptable, and the coefficient of variation slightly better using the orbital/occipital ratio (11%), than the orbital/temporal ratio (16%). From matching studies it appears that the temporal uptake takes place, in part, in the parotid gland. The orbital/occipital ratio was used to predict the outcome of radiotherapy. Mean (+/- SD) uptake on the 4 h scan was higher in responders (2.2 +/- 0.66) than in nonresponders (1.7 +/- 0.39; P = 0.04). From the Receiving-Operator-Characteristic curve we determined a cut-off value of 1.85, which yielded a positive predictive value of 92% and a negative predictive value of 70%. The 24 h scan could not predict a response.

CONCLUSION

Quantitative measurement of orbital octreotide uptake is possible. Using the orbital/occipital ratio on the 4 h scan, the octreoscan seems useful in predicting response to subsequent radiotherapy. The 24 h scan seems not to be useful in predicting therapeutic outcome.

[Endocrine orbitopathy 1998]

BACKGROUND

Ophthalmopathy is the most common extrathyroidal manifestation of Graves' disease, also called thyroid-associated ophthalmopathy.

CLINICS

This autoimmune disorder is characterized by a lymphocyte infiltration of the retrobulbar space. Activated T cells react with the target organ and secrete cytokines, leading to accumulation of glycosaminoglycans, interstitial edema of the peri- and retrobulbar tissue and enlargement of the extraocular muscles. During the inflammatory stage, the increased orbital pressure results in the clinical manifestation of the eye disease.

DIAGNOSIS AND TREATMENT

Thus, therapeutic immunosuppression is often used initially, and by suppressing inflammatory changes, it can result in subjective and objective improvement of the thyroid eye disease. In recent years, new pathogenetic aspects and clinical randomized trials led to modified therapy concepts.

CONCLUSION

Interdisciplinary management is recommended for rapid diagnosis and effective therapy of patients with thyroid-associated ophthalmopathy.

The measurement of change in Graves' ophthalmopathy

Precise measurements of treatment response are a prerequisite for correct interpretation of therapeutic benefit. In the field of Graves' ophthalmopathy we have relied for too long on methods of measurement that are poorly reproducible, subjective, and that often rely on indices derived from aggregated measurements and subjective impressions. In consequence, our conclusions about the benefits of particular therapies are frequently controversial. Until the pathogenic agent of Graves' ophthalmopathy has been identified and is measurable, we are forced to limit our observations to the consequences of the action of that agent. Two critically important consequences are swelling of the retrobulbar muscles and connective tissue and shortening of the extraocular muscle range of contraction. From these primary events all the clinical features of Graves' ophthalmopathy are derived. Effective treatment of Graves' eye disease will affect at least one of five relevant measurements. These are: lid fissure width, range of extraocular motion, diplopia fields, and volume of retrobulbar muscle and connective tissue. These measurements, selected to correspond to the claims of the particular therapy under study, are recommended as the indicators of choice in clinical trials.

Somatostatin receptor scintigraphy in thyroid eye disease

Orbital lymphocytic infiltration in thyroid eye disease (TED), as well as identification of somatostatin (SMS) receptors on activated lymphocytes, has provided a rationale for receptor imaging with the radiolabeled SMS analog Pentetreotide. In 80 patients with TED, single-photon emission computed tomography (SPECT) images of the orbit were performed 4 and 24 hours after injection of Pentetreotide. Semiquantitative evaluation was performed using the SPECT slices with irregular regions of interests placed over the orbits and both hemispheres. In contrast to controls (median 5 counts per voxel per millibecquerel (cts/vox/MBq) injected activity), TED patients showed threefold increased orbital accumulation of Pentetreotide (15 cts/vox/MBq, p = 0.003). When considering patients with active TED only, even higher uptake was registered (23 cts/vox/MBq, p = 0.0006 vs. controls, sensitivity for active TED 61/68, 90%; specificity 12/12, 100%). In 40 patients with active TED, the radionuclide accumulation decreased sharply after completion of immunosuppressive therapy. A high pretreatment Pentetreotide orbit-to-brain ratio correlated with a response to therapy (positive and negative predictive values 28/32, 88%, and 8/8, 100%, respectively). In conclusion, SMS receptor scintigraphy may be regarded as a semiobjective tool in the evaluation of TED, both at initial stages as well as during treatment.

Somatostatin analogues in the treatment of thyroid eye disease

Recent studies have shown successful therapy with the long-acting somatostatin (SM) analogues octreotide and lanreotide in patients with thyroid eye disease (TED). In one such study it was also found that response to low-dose octreotide treatment (300 microg) in these patients was correctly predicted by [111In-DTPA-D-Phe1]-octreotide scintigraphy and concluded that this parameter should be used as a predictive test of the effectiveness of treatment with nonradioactive octreotide. It has also been suggested that octreoscan-111 may be seen as a parameter of disease activity in TED. However, it remains to be clarified whether octreoscan-111 predicts the therapeutic outcome better than the clinical activity score, or magnetic resonance imaging (MRI) or finally measurement of glucosaminoglycan (GAG) in the plasma and/or urine. The exact mechanism of action of SM analogues has not yet been fully clarified. Three explanations may be offered. First, SM suppresses insulin-like growth factor 1 (IGF-1) activity and inhibits IGF-1-mediated effects. A second possible mechanism could be the direct inhibition of the release of cytokines from T-lymphocytes, and finally, SM analogues may act on target cells through specific cell surface receptors. In view of the encouraging therapeutic results reported thus far in several studies, SM analogues may provide a valuable therapeutic alternative to corticosteroids, especially in patients who cannot tolerate the latter. However, further prospective, placebo-controlled studies with a large number of patients are needed before we can reach final conclusions.

Treating severe Graves' ophthalmopathy

Most patients with Graves' disease have some evidence of ocular involvement, but this is commonly mild, requiring only local measures. A minority of patients (3-5%) have severe Graves' ophthalmopathy, for which the three main treatment procedures are represented by high-dose glucocorticoids, orbital radiotherapy and orbital decompression. Favourable results with medical treatment have been reported in approximately 60% of patients, with particular regard to inflammatory changes, newly developed eye muscle dysfunction and optic neuropathy. Orbital decompression is indicated in severe eye disease not responsive to glucocorticoids and/or irradiation, particularly in the presence of marked proptosis and optic neuropathy. Not conclusive or unsatisfactory results have been obtained with other medical treatment procedures, including immunosuppressive drugs, intravenous immunoglobulins and plasmapheresis. Recently favourable responses have been reported with somatostatin analogues. Rehabilitative surgery involving either the eye muscles or the eyelids is not infrequently required after medical treatment or decompression. Permanent control of thyroid hyperfunction by radioiodine or thyroidectomy is advisable when severe ophthalmopathy is present. Exacerbation of ophthalmopathy following radioiodine may occur but can be prevented by concomitant administration of glucocorticoids. Smoking deleteriously influences the course of ophthalmopathy and its response to treatment.

Hodgkin's disease treated with neck radiation is associated with increased antibody-dependent cellular cytotoxicity against human extraocular muscle cells

Patients with Hodgkin's disease have higher a prevalence of thyroid function abnormalities and, perhaps, orbitopathy than the general population, but the pathophysiology of this association and its relationship to Hodgkin's disease treatment remain unclear. We analyzed the frequency of thyroid function abnormalities, autoantibodies against thyroid antigens, and autoimmunity against extraocular muscle cell antigens by Western blot analyses and antibody-dependent cellular cytotoxicity (ADCC) assays in patients with Hodgkin's disease (n = 20) and controls (n = 10). Hodgkin's disease patients were subdivided into those treated with thyroidal external beam radiation therapy (XRT, n = 15) or chemotherapy (MOPP/ABVD, n = 5). The ADCC assay against extraocular muscle cells was increased in patients with Hodgkin's disease (5.5% vs. <1.0%, p = .026) when compared with controls. In addition, Hodgkin's disease patients treated with XRT (with or without chemotherapy) had significantly higher ADCC tests than controls (9.7% vs. <1.0%, p = .010), In contrast, ADCC assays were not different between Hodgkin's disease patients treated with chemotherapy alone and controls (<1.0% vs. <1.0%, p = .53). Hodgkin's patients treated with XRT had higher ADCC assays than those treated with chemotherapy alone (p = .087), although this difference did not achieve statistical significance. Serum measurements of antithyroid peroxidase (TPO) antibodies, antithyroglobulin (Tg) antibodies, thyroid binding inhibitory immunoglobulins (TBII), and thyroid stimulating immunoglobulin (TSI) were similar in all groups. Antibodies against the 64 kDa orbital antigen were detected in 1 patient and 1 control subject. Excluding patients already treated with L-thyroxine for hypothyroidism (n = 5), free T3, but not free T4, was lower in the Hodgkin's disease group than in controls (2.2 pg/mL vs. 2.7 pg/mL, p = .008). Thyrotropin (TSH) concentrations were not statistically different between these groups. In summary, these data show: (1) ADCC against human orbital muscle cells is increased in patients with Hodgkin's disease compared with controls: (2) these differences were noted among Hodgkin's disease patients treated with thyroidal XRT, with or without chemotherapy, and not among those patients treated with chemotherapy alone; and (3) no statistically significant differences in the frequency of thyroid autoantibodies were found. These data suggest that patients with Hodgkin's disease display altered antibody-dependent immune function toward extraocular muscle cells that may possibly be related to by XRT. Larger, prospective studies assessing thyroid and orbital-related immunologic abnormalities in Hodgkin's disease are warranted.

Evaluation of immunological mechanisms mediating thyroid-associated ophthalmopathy by radionuclide imaging using the somatostatin analog 111In-octreotide

Thyroid associated ophthalmopathy (TAO) is a disorder involving the soft tissues and extraocular muscles of the orbit seen mainly in cases of Graves' disease. Although an immunogenic pathogenesis has been proposed, the actual mechanisms of the in vivo retrobulbar involvement are not well defined. The recent introduction of the 111In-labeled somatostatin analog, octreotide, which can bind in vivo to the cell membrane of activated lymphocytes expressing somatostatin receptors, has provided a new investigational tool for diseases with a presumed immunological background. Based on this property, octreotide scans can be expected to be positive in cases of immunological disease showing tracer accumulation within affected sites. The aim of this study was to evaluate the utility of scintigraphic imaging with octreotide of the retrobulbar space in cases of TAO, including sequential studies of patients undergoing immunosuppressive therapy. We studied a series of 51 patients who had Graves' disease with varying degrees of TAO. Nine patients had received immunosuppressive therapy. The degree of orbital inflammation was classified according to the clinical activity score of Mourits. Both planar and tomographic imaging of the orbit were carried out using 111 MBq of the 111In-labeled octreotide (OctreoScan) 2 h after tracer injection. A significant tracer accumulation in the retrobulbar space was seen in all 20 patients with a high activity score, in 8 of 16 cases with a negative score, and in 11 of 20 cases with an intermediate Mourits' score. In cases of persistent eye disease in spite of immunosuppressive therapy, the octreotide scan remained positive. Successful therapy either with prednisolone, external radiation, or i.v. immunoglobulins showed a significant diminution of tracer uptake after finishing the therapeutic regime. Three-dimensional reconstruction of the images also revealed a significant tracer accumulation in the areas of the lacrimal gland, the nasal region, and the pituitary. Controls cases (n = 30) showed no uptake in the orbital region. We conclude that 111In octreotide scintigraphy is an objective method that identifies patients with active inflammatory eye disease, i.e., having significant tracer uptake in the retrobulbar space. This uptake appears to reflect an immunological process, since immunosuppressive therapy will significantly decrease tracer accumulation.

The effect of somatostatin versus corticosteroid in the treatment of Graves' ophthalmopathy

Uncontrolled study has demonstrated the usefulness of somatostatin in the treatment of mild Graves' ophthalmopathy (GO). We performed a prospective study to evaluate the usefulness of somatostatin as compared to corticosteroid in the treatment of moderately severe GO. All patients were rendered euthyroid and observed for 3 months to exclude spontaneous improvement without active treatment. They were randomized to receive either somatostatin (SS, octreotide 200 micrograms q8h subcutaneously, n = 8) or corticosteroid (CS, prednisone 1 mg/kg/day in decreasing doses, n = 10). Assessments of soft tissue inflammation, exophthalmos, palpebral aperture, intraocular pressure, diplopia, cornea, and visual acuity were made every 4 weeks for 3 months. MRI of the orbit was performed before and after treatment. Both SS and CS therapy decreased the palpebral aperture and activity score after 3 months (p < 0.05), but those treated with CS had a lower activity score after treatment when compared to SS [2.5 (1-7) v.s. 3.5 (0-4), median (range), p < 0.05]. Only CS, but not SS, was able to reduce intraocular pressure and muscle size as documented by MRI, but no significant reduction in proptosis was observed in either group. Also, patients' self-assessments of the eye changes after treatment were similar between the two groups. Both groups showed significant elevation of urinary glycosaminoglycan (GAG) excretion before therapy (SS 24.6 +/- 10.8; CS 27.8 +/- 11.4 mg/24 h), which was reduced after treatment (SS 12.5 +/- 7.3; CS 10.8 +/- 6.3 mg/24 h, p < 0.05). However, no significant correlation could be observed between the degree of GAG reduction and the clinical outcome of the patients. In conclusion, the long acting SS octreotide was effective in reducing soft tissue inflammation and providing symptomatic relief in GO but not as effective as corticosteroid in reducing muscle size. In view of the minimal side-effects and similar efficacy as compared to corticosteroid in patients with minimal extraocular muscle enlargement, it is suggested that a trial of SS may be considered in selected patients with GO.