Computed tomographic features of nonthyroid extraocular muscle enlargement

Magnetic Resonance Imaging of Idiopathic Orbital Myositis

PURPOSE

To characterize the qualitative and quantitative features of idiopathic orbital myositis (IOM) on MRI.

METHODS

This was a multicenter retrospective study of patients with active IOM with MRI. Patients with incomplete clinical records, poor-quality or interval scans without active myositis, and specific orbital myositis (i.e., orbital myositis secondary to an identified condition) were excluded. An enlargement ratio was calculated by dividing the diameters of the affected extraocular muscle (EOM) by the contralateral unaffected EOM.

RESULTS

Twenty-four patients (mean age: 44.4 ± 17.8 years-old, male: 11) between 2011 and 2022 were included. One case (4.2%) was pediatric (17 years old), and 6 cases presented with recurrence. Active IOM was characterized by fusiform EOM enlargement, high T2 signal, and contrast enhancement. Average maximal EOM diameters ranged from 4.6 to 7.7 mm (enlargement ratio: 1.4-2.2). Eighteen (75%) patients had single EOM involvement, most commonly the medial rectus. Other ipsilateral structures affected included focal orbital fat (16/24, 66.7%) and lacrimal gland (8/24, 33.3%). Contralateral changes in the EOM and/or lacrimal gland were observed in 7 patients (29.2%). Patients presenting with recurrence were likely to develop ongoing recurrent episodes ( p = 0.003).

CONCLUSIONS

Various radiological patterns of involvement described including EOM enlargement, contrast enhancement, abnormal signal, and involvement of other orbital structures are indicative of active IOM. IOM remains a heterogeneous spectrum of acute and chronic clinico-radiological presentations. Inflammation may involve other ipsilateral or contralateral orbital structures or may be bilateral despite presenting clinically as unilateral disease. Quantitative measurements may have utility in differentiating IOM from other causes of orbital myositis.

A Case of Congenital Idiopathic Enlargement of Extraocular Muscles

The purpose of this case report is to report a case of congenital idiopathic enlargement of extraocular muscles. A four-month-old girl showed limitation of adduction and supraduction in the right eye. A computerized axial tomography (CAT) scan revealed hypertrophy of the lateral rectus muscle and inferior rectus muscle of the right eye. Thyroid hormone and antibody levels were normal. No inflammatory findings on magnetic resonance imaging (MRI). A traction test under general anesthesia revealed a strong limitation of supraduction and a mild limitation of adduction. Therefore, the inferior rectus muscle was recessed 4.5 mm at the age of six months. A partial biopsy of the inferior rectus showed no inflammatory cell infiltration. After the first surgery, the patient's limitation of supraduction improved, but the limitation of adduction persisted. So, a 5 mm recession of the right lateral rectus muscle was added at one year and one month. However, the hypertropia of the sound eye became stronger after treatment of amblyopia. Because of the strong limitation of supraduction, tenotomy of the inferior rectus was performed at the age of six years. Postoperatively, no impairment of infraduction occurred, and the limitation of supraduction was mildly improved. Since the findings on MRI were not changed through our observation period, we concluded that the patient had idiopathic external ophthalmoplegia.

Extraocular muscle enlargement and proptosis in carotid cavernous fistulas

PURPOSE

To evaluate the prevalence and pattern of extraocular muscle enlargement and proptosis in patients with carotid cavernous fistulas (CCF).

METHODS

We conducted a retrospective study on patients with digital subtraction angiography (DSA) confirmed CCFs with neuroimaging (computed tomography or magnetic resonance imaging) performed prior to the DSA. The maximum extraocular muscle diameters were recorded. Extraocular muscles were considered enlarged if they were greater than two standard deviations above the normal muscle diameters. Proptosis was defined as the distance between the interzygomatic line to the anterior globe of ≥2 mm compared to the contralateral orbit or ≥21 mm.

RESULTS

Forty orbits from 20 patients were included. The mean age of participants was 65 ± 15 years and 13 (65%) were female. Thirteen (65%) fistulas were indirect and seven (35%) were direct. There was enlargement of at least one muscle in 11 (27.5%) orbits, and this was not correlated with the type of fistula (direct/indirect). The inferior rectus was most commonly enlarged in seven orbits (17.5%), followed by the medial rectus in five orbits (12.5%). Proptosis was found in 17 (43%) orbits and was more common ipsilateral to the fistula (58% ipsilateral group vs 19% contralateral group, p < .01).

CONCLUSION

Extraocular muscle enlargement was observed in over one-fourth of CCFs. When enlarged, the inferior and medial rectus muscles are most commonly involved. These findings may help clinicians and radiologists when evaluating the CT or MRI scans of patients with suspected CCFs.

Extraocular Muscle Enlargement in Acromegaly

BACKGROUND

To determine whether acromegaly is associated with increased extraocular muscle (EOM) size at time of presentation.

METHODS

Patients with a new diagnosis of acromegaly in a single tertiary care clinic with a CT scan that adequately delineated the EOMs were included. Control subjects were age- and sex-matched patients with a new diagnosis of nonfunctioning pituitary adenoma. Retrospective chart review was performed to extract baseline clinical and laboratory parameters including growth hormone, insulin-like growth factor 1, thyroid stimulating hormone, free T3, and free T4. A single neuroradiologist analyzed all CT scans and measured the maximum diameter and cross-sectional area of the superior rectus, inferior rectus, medial rectus, and lateral rectus in both eyes of all patients.

RESULTS

We evaluated 17 patients with acromegaly and 18 control subjects. Mean maximum diameter of the superior, inferior, medial, and lateral recti were 4.80 mm (SD = 0.81), 4.67 mm (SD = 0.54), 4.86 mm (SD = 0.77), and 4.53 mm (SD = 0.70) respectively, in the acromegaly group. In the control group, they were 3.62 mm (SD = 0.58),3.71 mm (SD = 0.46), 3.66 mm (SD = 0.32), and 3.21 mm (SD = 0.44), respectively. The maximum diameter and cross-sectional area of all 4 EOMs measured in the acromegaly group were significantly larger ( P < 0.001) compared with the control group.

CONCLUSIONS

Patients with acromegaly present with significantly enlarged EOMs compared with control subjects with nonfunctioning pituitary adenomas.

Diagnostic performance of MRI for the assessment of extraocular muscle invasion in malignant sinonasal tumors

PURPOSE

Preoperative assessment of extraocular muscle invasion is essential for therapeutic strategies and prognostic evaluation. The aim of this study was to assess the diagnostic accuracy of MRI for evaluation of extraocular muscle (EM) invasion by malignant sinonasal tumors.

MATERIALS AND METHODS

Consecutively, 76 patients of sinonasal malignant tumors with orbital invasion were included in the present study. Preoperative MRI imaging features were analyzed by two radiologists independently. The diagnostic performances of MR imaging features for detecting EM involvement were evaluated by comparing imaging findings to histopathology data.

RESULTS

A total of 31 extraocular muscles were involved by sinonasal malignant tumors in 22 patients, including 10 medial rectus muscles (32.2%), 10 inferior rectus muscles (32.2%), 9 superior oblique muscles (29.1%), and 2 external rectus muscles (6.5%). The EM involved by sinonasal malignant tumors usually showed relatively high signal intensity on T2-weighted images, indistinguishable from the tumor, nodular enlargement and abnormal enhancement (p = 0.001, < 0.001, < 0.001 and < 0.001, respectively). Using a combination of EM abnormal enhancement and indistinguishable from the tumor in multivariate logistic regression analysis, sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy for detecting orbital EM invasion by sinonasal tumors were 93.5, 85.2, 76.3, 96.3 and 88%, respectively.

CONCLUSION

MRI imaging features show high diagnostic performance for the diagnosis of extraocular muscle invasion by malignant sinonasal tumors.

Normative orbital measurements in an Australian cohort on computed tomography

PURPOSE

To determine the normal diameters of the extraocular muscles (EOMs) and optic nerve sheath complex (ONSD) and correlate with patient demographics in an Australian cohort.

METHODS

Consecutive patients who underwent contrast enhanced computed tomography (CT) orbits between December 2017 and March 2021 were included. Patients with bilateral disease, previous orbital surgery, or poor scan quality were excluded. Normal orbit was used in patients with unilateral orbital disease.

RESULTS

Two hundred one orbits from 201 patients were included. Normal measurements (mean ± SD) were as follows: medial rectus (MR) 4.22 ± 0.56 mm; inferior rectus (IR) 4.20 ± 0.70 mm; lateral rectus (LR) 3.40 ± 0.56 mm; superior muscle group (SMG) 4.13 ± 0.72 mm; superior oblique (SO) 2.60 ± 0.43 mm; inferior oblique (IO) on quasi-sagittal plane 2.19 ± 0.42 mm, and the ONSD 5.62 ± 0.82 mm. The mean diameters of the LR, SMG, IR, SO, and ONSD were significantly larger in male than female patients (p < .05). Statistically significant correlation was found between age and the diameters of the LR (r = 0.29, p < .01), SMG (r = 0.22, p < .01), IO on a coronal plane (r = -0.18, p < .01), and ONSD (r = 0.16, p = .02).

CONCLUSION

This normative data may be used to diagnose pathological enlargement of the optic nerve and extraocular muscles, including involvement of the oblique muscles.

Turbo Gradient and Spin-Echo BLADE-DWI for Extraocular Muscles in Thyroid-Associated Ophthalmopathy

Purpose: To investigate feasibility and diagnostic performance of turbo gradient and spin-echo BLADE (proprietary name for Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction [PROPELLER] in Siemens MR systems)-diffusion weighted imaging (TGSE-BLADE-DWI) for depicting extraocular muscle (EOM) involvement and activity in thyroid-associated ophthalmopathy (TAO), and to compare TGSE-BLADE-DWI with readout-segmented echo-planar imaging (RESOLVE). Materials and methods: Thirty-five patients with identified TAO underwent the two DWI scans. Two radiologists visually scored the image quality of the two DWIs with respect to the susceptibility artifacts and geometric distortions on a three-point scale. The maximum size (Size_max) of EOMs and corresponding ADCs (cADCs) of each patient were compared between the active and inactive phases. The clinical activity score (CAS) was used as a reference to assess the diagnostic performance of EOM ADCs for grading TAO activity. ROC analysis, Pearson correlation, and Wilcoxon signed-rank test were used for statistical analyses. Results: For scores of EOMs, the image quality of TGSE-BLADE-DWI was significantly higher than that of RESOLVE. There were no statistically significant differences between the AUCs of the two DWIs, Size_max, or cADCs between the active and inactive phases. TGSE-BLADE-DWI ADCs were significantly higher than the RESOLVE ADCs in the right superior rectus, right lateral rectus, left superior rectus, and left inferior rectus. There were no statistically significant correlations between the cADC or Size_max, and CAS. The highest AUC was 0.697 for RESOLVE and 0.657 for TGSE-BLADE-DWI. The best performing ADC threshold was 1.85 × 10^-3 mm²/s with 85.7% sensitivity, 58.8% specificity and 66.67% accuracy for RESOLVE and 1.99 × 10^-3 mm²/s with 79.0% sensitivity, and 55.6% specificity and 65.27% accuracy for TGSE-BLADE-DWI. Conclusion: Compared to RESOLVE, TGSE-BLADE-DWI provided improved image quality with fewer susceptibility artifacts and geometric distortions for EOM visualization and showed an equivalent performance in detecting active TAO.

Extraocular muscle enlargement

Extraocular muscle enlargement can occur secondary to a range of orbital and systemic diseases. Although the most common cause of extraocular muscle enlargement is thyroid eye disease, a range of other inflammatory, infective, neoplastic, and vascular conditions can alter the size and shape of the extraocular muscles. Imaging with computed tomography and magnetic resonance imaging plays an essential role in the workup of these conditions. This article provides an image-rich review of the wide range of pathology that can cause enlargement of the extraocular muscles.

Extraocular Muscle Enlargement in Growth Hormone-Secreting Pituitary Adenomas

BACKGROUND AND PURPOSE

While Graves disease is the most common cause of extraocular muscle enlargement, case reports have also associated growth hormone-secretory pituitary adenomas with this same phenomenon. We investigated the prevalence and response to treatment of extraocular muscle enlargement in patients with growth hormone-secretory pituitary adenomas.

MATERIALS AND METHODS

We retrospectively reviewed extraocular muscle sizes using MR imaging in patients with growth hormone-secretory pituitary adenomas who underwent a transsphenoidal surgical resection compared with a matched control group with nonsecretory pituitary adenomas. Descriptive and comparative statistics were used to evaluate patient characteristics and extraocular muscle sizes between the 2 groups.

RESULTS

We identified 16 patients who presented with growth hormone-secreting pituitary adenomas and underwent transsphenoidal surgical resection from 2010 to 2019. The average diameter of the extraocular muscle at the time of diagnosis for the group with growth hormone-secretory pituitary adenomas was larger than that in the control group (4.7 versus 3.8 mm, P < .001). Nine patients achieved insulin-like growth factor 1 level normalization at a median of 11.5 months before their most recent MR imaging evaluation. The average size of the extraocular muscles of patients who achieved a normalized insulin-like growth factor 1 was smaller compared with those that did not (difference, 0.7 mm; 95% CI, 0.3-1.2 mm; P < .001), approaching the size of extraocular muscle in the control group.

CONCLUSIONS

We describe a high prevalence of extraocular muscle enlargement in patients with growth hormone-secreting pituitary adenomas. Additionally, we note that the size of extraocular muscles decreased with associated improvement in the biochemical control of acromegaly.

Idiopathic Orbital Myositis Revisited

PURPOSE OF REVIEW

To review current knowledge regarding idiopathic orbital myositis.

RECENT FINDINGS

Recent publications have focused on possible causes of orbital myositis and the process to reach a diagnosis of idiopathic orbital myositis. With inflamed and enlarged extraocular muscles, features to distinguish between competing diagnostic possibilities are based on imaging in the context of history and clinical signs. Idiopathic orbital myositis is characterized by the clinical triad of acute onset of orbital pain exacerbated on eye movement, double vision, and redness or swelling of the eyelids or conjunctiva, along with the radiological finding of homogeneous, fusiform enlargement of one or more extraocular muscles. In atypical or inconclusive clinico-radiological findings for a diagnosis of idiopathic orbital myositis, or where the clinical behavior changes or fails to respond to corticosteroid treatment, a systemic and oncologic work-up and muscle biopsy are warranted to exclude specific local or systemic disease as cause of the inflamed and enlarged muscle. As our understanding of idiopathic orbital myositis evolves, the diagnostic focus is shifting toward earlier identification of underlying local or systemic disease through systemic work-up and muscle biopsy.

Normative magnetic resonance imaging measurements of orbital structures in pediatric population of North-Eastern India: A retrospective cross-sectional study

Purpose:

The people of Northeast India comprise mostly of Mongoloid descent with characteristic craniofacial features. The purpose of this study was to evaluate the normal orbital structures with MRI and determine normative data in the Northeast Indian pediatric population.

Methods:

MRI images of the 302 orbits of 151 pediatric patients below 16 years of age were retrospectively evaluated to measure the various orbital structures. Both axial and coronal MRI images were utilized for various orbital measurements. An independent sample t-test was done to compare various orbital data according to the sex and side. Linear regression was also done.

Results:

The mean age of the pediatric population was 9.64 ± 1.47 years with a male: Female ratio of 1.13:1. The mean interzygomatic line was 88.4 ± 9.09 mm and the interorbital line was 22.18 ± 3.62 mm. The mean thicknesses of medial, lateral, superior, and inferior recti muscles were 2.58 ± 0.46, 2.34 ± 0.42, 2.16 ± 0.40, and 2.53 ± 0.49 mm in males and 2.41 ± 0.41, 2.08 ± 0.34, 2.08 ± 0.46, and 2.46 ± 0.49 mm in females. The mean horizontal orbital, vertical orbital diameters, orbital index, mean volume of eyeball, and orbital cavity were 30.27 ± 2.97,3 7.06 ± 3.57, 122.58 ± 7.39, 4.63 ± 0.84, and 15.29 ± 3.52 in males, while 29.16 ± 3.23, 34.96 ± 3.99,119.96 ± 7.31, 4.49 ± 0.87, and 14.65 ± 3.47 in females, respectively. With an increase in age, the interzygomatic line (r = 0.883, r² = 0.780; P < 0.0005), anterior medial interorbital line (r = 0.808, r² = 0.652; P < 0.0005), mean volume of eyeball (r = 0.915, r² = 0.838; P < 0.0005), orbital cavity (r = 0.924, r² = 0.854; P < 0.0005), and distance between the optic nerve entry site (r = 0.829, r² = 0.687; P < 0.0005) were increased.

Conclusion:

This study provides normative data of various orbital structures in a pediatric population and these data likely to be useful for diagnosing various pediatric orbital disorders and helps in the planning of various surgical procedures of orbits.

A rare case of intramuscular angioma involving the medial rectus muscle

Benign benign vascular tumors (e.g., hemangiomas) and malformations are commonly encountered lesions in all ages of life, especially in infancy and childhood. Hemangiomas are considered to be proliferative vascular lesions while malformations are defects of embryonal vascular morphogenesis. Less than 1% of hemangiomas within the body occur in skeletal muscle and of these approximately 15% have been reported to occur in the head and neck musculature (e.g. masseter, trapezius, sternocleidomastoid, mylohyoid, temporalis muscles) Intramuscular angioma (the preferred term for lesions formerly known as intramuscular hemangiomas by WHO Tumors of Soft Tissue and Bone Classification, 5th edition 2020) (IA) occurring in the extraocular muscles or palpebral muscles (orbicularis oculi) are extremely rare with only a few case reports in the English literature. To date, all the extraocular muscles have reportedly been involved. With the case reported herein, the medial rectus muscle appears to be the most common extraocular muscle involved.

A Case of Compressive Optic Neuropathy Secondary to Lymphoma of the Extraocular Muscles

Compressive optic neuropathy is an urgent condition that may lead to blindness. We report a rare case of compressive optic neuropathy secondary to lymphoma of the extraocular muscles in which the vision was successfully rescued. A 67-year-old man presented with visual acuity of hand motion in the right eye for 1 month. Magnetic resonance imaging demonstrated enlargement of the medial and inferior rectus muscles with their tendons. Tendon enlargement, which is uncommon as Graves' orbitopathy, motivated us to perform a biopsy. Intravenous steroids following biopsy and chemotherapy after definitive diagnosis allowed for recovery of vision. Clinicians should be aware that enlarged extraocular muscles due to lymphoma can cause compressive optic neuropathy.

Computed tomography imaging-based normative orbital measurement in Indian population

Purpose:

This study aims to evaluate normal orbital structures with nonenhanced computed tomography (NCCT) and determine normative data for the Indian population.

Methods:

CT images of the orbits of 100 patients were retrospectively reviewed on a work station to record the normative data of the orbits. Clinical details of all patients were reviewed to ensure that they did not have ocular/orbital diseases. Both axial and coronal images were utilized to record the data.

Results:

The mean age of the population evaluated was 34.07 years, with male to female ratio of 1.77. The average orbital index for the left orbit was 97 and for the right side was 103. The mean thickness of left inferior rectus, lateral rectus, medial rectus, and the superior rectus was 3.36 mm, 3.14 mm, 3.80 mm, and 3.75 mm, respectively. The right inferior rectus, lateral rectus, medial rectus, and the superior rectus measured 3.46 mm, 3.14 mm, 3.83 mm, and 3.78 mm, respectively. The optic nerve sheath complex diameter varied between 3.05 mm and 7.17 mm for the left eye and 3.05 mm and 7.0 mm for the right eye.

Conclusion:

The study provides normative data on various orbital structures in an Indian population. This data is likely to be useful for diagnosing various orbital pathologies and in planning surgical orbital procedures.

Paraneoplastic syndrome - a rare but treatable cause of non-thyroid-related extraocular muscle enlargement

Paraneoplastic syndrome is a rare but reversible cause of non-thyroid-related extraocular muscle enlargement. We present a 71-year-old lady with diplopia, restricted eye movements, suppressed thyroid-stimulating hormone and enlargement of all extraocular muscles while on thyroxine replacement for hypothyroidism. She had distant history of metastatic breast cancer treated with chemotherapy, surgical resection and tamoxifen. She had negative anti-thyroid autoantibodies and thyroid ultrasound was not consistent with autoimmune thyroid disease. Carcinoembryonic antigen and cancer antigens 15-3, 125 and 72-4 were elevated, and whole-body positron emission tomography-computed tomography showed avid liver, left adrenal and skeletal lesions, with liver biopsy confirming breast cancer recurrence. She received prednisone and chemotherapy (letrozole, palbociclib) and achieved normalisation of eye movements and reduction in her EOME at 9-month follow-up. Our case highlights the importance of exploring paraneoplastic syndrome as a treatable cause of EOME in a patient lacking features of thyroid orbitopathy and autoimmune thyroid disease.

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.

Metastasis to the extraocular muscles: a case report, literature review and pooled data analysis

Metastasis to the extraocular muscles (EOM) is rare. The existing literature comprises only of isolated case reports therefore a summative description of these lesions is lacking. This study presents a case of bilateral rectus muscle metastasis from malignant melanoma. Furthermore a literature review and pooled data analysis is undertaken with 43 articles encompassing 77 patients and 101 eyes. Mean age was 53 years, 54% were male, 66% had unilateral involvement and 34% had bilateral involvement. The primary malignancies were melanoma (n = 17, 22%), breast (n = 15, 15%) and carcinoid (n = 11, 14%). A single muscle was involved in 56 eyes (67%) and multiple muscles in 27 eyes (33%). Lateral rectus was most commonly affected (n = 44, 53%). Presenting symptoms included restricted eye movements (n = 48, 62%), proptosis (n = 45, 58%), diplopia (n = 27, 35%) and pain (n = 18, 23%). Scattered case reports have previously made it difficult to characterise this phenomenon thus a pooled data analysis is presented.

Extraocular muscle sampled volume in Graves' orbitopathy using 3-T fast spin-echo MRI with iterative decomposition of water and fat sequences

Background

Current magnetic resonance imaging (MRI) techniques for measuring extraocular muscle (EOM) volume enlargement are not ideally suited for routine follow-up of Graves’ ophthalmopathy (GO) because the difficulty of segmenting the muscles at the tendon insertion complicates and lengthens the study protocol.

Purpose

To measure the EOM sampled volume (SV) and assess its correlation with proptosis.

Material and Methods

A total of 37 patients with newly diagnosed GO underwent 3-T MRI scanning with iterative decomposition of water and fat (IDEAL) sequences with and without contrast enhancement. In each patient, the three largest contiguous coronal cross-sectional areas (CSA) on the EOM slices were segmented using a polygon selection tool and then summed to compute the EOM-SV. Proptosis was evaluated with the Hertel index (HI). The relationships between the HI value and EOM-SV and between HI and EOM-CSA were compared and assessed with Pearson’s correlation coefficient and the univariate regression coefficient. Inter-observer and intra-observer variability were calculated.

Results

HI showed a stronger correlation with EOM-SV (P < 0.001; r = 0.712, r²= 0.507) than with EOM-CSA (P < 0.001; r = 0.645 and r²= 0.329). The intraclass correlation coefficient indicated that the inter-observer agreement was high (0.998). The standard deviation between repeated measurements was 1.9–5.3%.

Conclusion

IDEAL sequences allow for the measurement EOM-SV both on non-contrast and contrast-enhanced scans. EOM-SV predicts proptosis more accurately than does EOM-CSA. The measurement of EOM-SV is practical and reproducible. EOM-SV changes of 3.5–8.3% can be assumed to reflect true volume changes.

Review of extraocular muscle biopsies and utility of biopsy in extraocular muscle enlargement

Aims

To review the distribution of pathology in extraocular muscle (EOM) biopsies performed at a tertiary orbital centre, identify clinical and imaging features which are associated with benign or malignant diseases and indicate when biopsy is necessary for EOM enlargement.

Methods

Retrospective case series including 93 patients with EOM enlargement who underwent an EOM biopsy. Clinical, radiological and histopathological information was recorded from the medical records. Statistical analysis was used to compare variables between patients with malignant and benign biopsies.

Results

The median age of subjects was 61.1 years. Forty-eight cases (52%) were benign and 45 (48%) were malignant. Those with malignant pathology were significantly older (P<0.0001). Males were more likely affected by a benign disease and females by a malignancy (P=0.029). A history of malignancy (P<0.0001) and diplopia (P=0.029) were significant factors in predicting a malignancy. Pain (P=0.005) and eyelid erythema (P=0.001) were more likely in benign conditions. Idiopathic orbital inflammation was the most common benign diagnosis and lymphoma the most common malignancy.

Conclusions

Biopsy is warranted in those with an atypical presentation of EOM enlargement or suspected of having a malignancy. Some features such as age, gender, pain, diplopia, history of malignancy and eyelid erythema may help indicate a particular diagnosis; however, clinical features and imaging findings are often not pathognomonic of each disease.

Systemic Amyloidosis and Extraocular Muscle Deposition

Isolated amyloid deposition in an extraocular muscle is a rare event but can be a presenting feature of systemic amyloidosis. A 67-year-old woman with an acquired exotropia and hypertropia was found to have unilateral diffuse extraocular muscle enlargement on magnetic resonance imaging. Owing to the progressive nature of her strabismus and the negative laboratory testing for thyroid disease, she underwent an extraocular muscle biopsy that revealed amyloid deposition. Further workup demonstrated a monoclonal gammopathy consistent with systemic amyloidosis. This case demonstrates the need to consider amyloidosis in the differential diagnosis of patients presenting with an atypical acquired strabismus. We review other reports of isolated amyloid deposition in extraocular muscles and its association with systemic amyloidosis, emphasizing the importance of the ophthalmologist in the early recognition of this disease to prevent irreversible, life-threatening end organ damage.

Evaluating the Microcirculation of Normal Extraocular Muscles Using Quantitative Dynamic Contrast-Enhanced Magnetic Resonance Imaging

PURPOSE

The purpose of this work was to evaluate the microcirculation of normal extraocular muscles using quantitative dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) (DCE-MRI).

MATERIALS AND METHODS

The institutional review board approved the study. Forty-eight eyes were examined using quantitative DCE-MRI on a 3-T MRI system. Quantitative parameters, including the volume transfer constant (Ktrans), the fractional volume of extravascular extracellular space (Ve), and the rate constant (Kep) of each extraocular muscles, were analyzed. The type of DEC time-intensity curve (TIC) was evaluated. The parameters of bilateral extraocular muscles were compared using the Wilcoxon test. The difference in quantitative values of different extraocular muscles was compared using independent-samples Kruskal-Wallis test.

RESULTS

No statistical differences of parameters were found between the left and right extraocular muscles (P > 0.05). Volume transfer constant values in medial rectus (MR) muscles and inferior rectus (IR) muscles were significantly higher than those in the lateral rectus (LR) muscles and superior rectus (SR) muscles (P < 0.05). The median Ktrans value of the MR (0.170) was higher than that of the IR (0.151); however, the difference was not significant (P > 0.05). In the 4 extraocular muscles, the Ve values of MR are the largest, followed by the IR, LR, and SR values. The DCE time-intensity curves of extraocular muscles are type II or type III. Medial rectus and IR are mainly type III, and LR and SR are mainly type II.

CONCLUSION

The quantitative DCE-MRI can be used as an important and noninvasive technique to evaluate the microcirculation of extraocular muscles. Further investigations for other extraocular muscles diseases by using quantitative DCE-MRI are warranted.

Not All Orbitopathy Is Graves': Discussion of Cases and Review of Literature

INTRODUCTION

Graves' orbitopathy is the extra thyroidal manifestation of Graves' disease and the most common cause of exophthalmos. It is also known as thyroid-associated orbitopathy (TAO) as it occasionally occurs in euthyroid or hypothyroid patients with chronic thyroiditis. 5% of patients with Graves' orbitopathy can be euthyroid or hypothyroid as they have low titers of anti-thyrotropin-receptor antibodies, which are difficult to detect in some assays. Orbitopathy has also been seen in a small percentage of patients with Hashimotos thyroiditis. The eye involvement in Graves' is frequently bilateral and symmetric. These patients pose few diagnostic difficulties when the ocular findings occur concomitantly with the thyroid disease. However, when unilateral and asymmetric ocular findings occur with normal or mildly abnormal thyroid function tests, alternate etiologies should also be pursued. We aim to discuss some conditions like sarcoidosis, lymphoma, orbital pseudotumor, and orbital malignancy that mimic TAO.

CASES

Three patients were referred to us with concern for Graves' orbitopathy. After further work-up, we diagnosed the first patient with specific orbital myositis from sarcoidosis. Our second patient had CD10-positive B-cell lymphoma. Our third patient had orbitopathy likely secondary to Hashimotos or orbital pseudotumor.

CONCLUSION

Our cases and discussion describe some other conditions that clinically mimic TAO and the importance of pursuing further work-up for accurate diagnosis when presentation of orbitopathy is atypical.

The enlarged extraocular muscle: to relax, reflect or refer?

PurposeExtraocular muscle enlargement (EOME) is most commonly associated with thyroid eye disease, but there are other causes. We report our outcomes of investigating and managing non-thyroid-related EOME (NTR-EOME).MethodsRetrospective consecutive case series. Sixteen patients identified by clinical features and orbital imaging. Patient demographics, radiological features, and adjuvant tests including biopsy and final diagnosis were recorded.ResultsMean age at presentation 59.3 years (range 24-89 years). Mean follow-up 3.2 years (range 3 months to 5.5 years). Superior rectus (SR) was most commonly involved muscle (8/16 cases) followed by lateral rectus (4/16). Of the 16 cases, 14 were associated with underlying systemic neoplasia (5 lymphoma, 5 metastatic carcinoma, and 4 presumed paraneoplastic syndrome). All SR enlargement was associated with underlying neoplasia. All patients underwent orbital imaging followed by systemic imaging based on clinical index of suspicion (14/16 patients (13 full body CT (FBCT), 1 mammography)). Positive systemic radiological findings were detected in 12/14 cases. Of the remaining 2 patients, 1 underwent full body positron emission tomography-computed tomography (FBPET-CT), which detected thyroid carcinoma, and the second patient underwent FBCT for staging following orbital biopsy showing lymphoma. Four patients (25%) died within 3 years of follow-up due to disseminated systemic malignancy.ConclusionsAll cases of NTR-EOME should be viewed with a high level of clinical suspicion for systemic neoplasia, especially when the SR is involved. FBCT can help to identify a primary systemic cause. FBPET-CT is best reserved for cases negative on FBCT or for staging and monitoring systemic disease. NTR-EOME can be associated with significant mortality (25%), hence warrants prompt and thorough systemic investigation.

Graves' ophthalmopathy: the role of diffusion-weighted imaging in detecting involvement of extraocular muscles in early period of disease

OBJECTIVE

To evaluate involvement of the extraocular muscle (EOM) using diffusion-weighted imaging (DWI), to determine whether there is correlation with conventional orbital MRI and apparent diffusion coefficient (ADC) values in patients with Graves' ophthalmopathy (GO).

METHODS

35 patients known clinically with GO and 21 healthy controls were studied. Patients were assessed with clinical activity scores. All subjects underwent conventional MRI and DWI study. Involvement of the EOM was evaluated. The patients were classified as involved or uninvolved on orbital MRI and their ADC values in DWI compared.

RESULTS

There was significant difference in the mean ADC value of all the EOMs in patients vs controls. The ADC values of all the EOMs were higher in patients. There were significant differences in ADC values between uninvolved muscles on conventional MRI and controls for the MR, SR and LR. There was no significant difference in ADC value between the two groups when considering the IR. ADC values of medial, lateral and superior rectus muscles were increased.

CONCLUSION

Increased ADC values of the EOM in patients with GO suggest that EOM damage begins at a very early stage before being detected on routine orbital MRI. The routine MRI with DWI sequence will be a useful adjunct in the selection of a group of patients most likely to benefit from early treatment.

ADVANCES IN KNOWLEDGE

This study can help to evaluate the involvement of GO in early period with MRI added DWI.

Epiphora and proptosis as a presenting complaint in acromegaly: Report of two cases with review of literature

Acromegaly is an endocrine disorder characterized by the excess of growth hormone leading to bony and soft-tissue enlargement. Eye involvement due to extraocular muscle enlargement has been described rarely in these patients. Epiphora has been described only once earlier in a patient with acromegaly. Here, we describe two females with acromegaly who presented with the complaints of watering from the eye and proptosis.

Imaging studies for diagnosing Graves' orbitopathy and dysthyroid optic neuropathy

Although the diagnosis of Graves' orbitopathy is primarily made clinically based on laboratory tests indicative of thyroid dysfunction and autoimmunity, imaging studies, such as computed tomography, magnetic resonance imaging, ultrasound and color Doppler imaging, play an important role both in the diagnosis and follow-up after clinical or surgical treatment of the disease. Imaging studies can be used to evaluate morphological abnormalities of the orbital structures during the diagnostic workup when a differential diagnosis versus other orbital diseases is needed. Imaging may also be useful to distinguish the inflammatory early stage from the inactive stage of the disease. Finally, imaging studies can be of great help in identifying patients prone to develop dysthyroid optic neuropathy and therefore enabling the timely diagnosis and treatment of the condition, avoiding permanent visual loss. In this paper, we review the imaging modalities that aid in the diagnosis and management of Graves' orbitopathy, with special emphasis on the diagnosis of optic nerve dysfunction in this condition.

Metastatic tumor to the extraocular muscles: report of 5 cases

We report the findings in 5 patients with metastases to the extraocular muscles. Familiarity with this condition will aid ophthalmologists in differentiating it from thyroid ophthalmopathy, the most common form of muscle enlargement. Palliative treatment is effective in ameliorating visual symptoms.

Restrictive extraocular myopathy: a presenting feature of acromegaly

A 45-year-old man presented with binocular diplopia in primary gaze for 1 year. Orthoptic evaluation showed 10-prism diopter right eye hypotropia and 6-prism diopter right eye esotropia. The elevation and abduction of the right eye were mechanically restricted. This was associated with systemic features suggestive of acromegaly. Magnetic resonance imaging (MRI) of the brain demonstrated a pituitary macroadenoma. An elevated serum insulin-like growth factor I level and the failure of growth hormone suppression after an oral glucose load biochemically confirmed the diagnosis of acromegaly. Computed tomography (CT) of the orbit demonstrated bilateral symmetrical enlargement of the medial rectus and inferior rectus muscle bellies. All tests regarding Graves-Basedow disease were negative. Although rare, diplopia due to a restrictive extraocular myopathy could be the presenting symptom of acromegaly.

Bilateral multiple extraocular muscle metastasis from hepatocellular carcinoma

Hepatocellular carcinoma (HCC) rarely metastasizes to the extra ocular muscles (EOMs). We present a case of bilateral metastasis of HCC to the EOMs and focus on the magnetic resonance imaging (MRI) features. Orbital MRI revealed nodular enlargement of bilateral multiple EOMs, with isointensity on T1-weighted images and heterogeneous, intermediate-to-high signal intensity on T2-weighted images, and showed mild-to-significant heterogeneous contrast enhancement with gadolinium. Physicians should be aware of this rare cause of EOM enlargement, understand the radiologic characteristics of EOM metastasis, and thus make appropriate treatment strategy.

Update in pathological diagnosis of orbital infections and inflammations

Orbital infections and inflammations include a broad spectrum of orbital diseases that can be idiopathic, infectious, from primary or secondary inflammatory processes. Being able to properly diagnose and manage these orbital diseases in a timely manner can avoid permanent vision loss and possibly save a patient's life. When clinicians are faced with such patients, quite often the exact diagnosis cannot be made just based on clinical examination, various laboratory tests and imaging are needed. Moreover, orbital biopsies with histopathological analyses are often required, especially for the atypical cases. Thus, it is important for the clinicians to be familiar with the pathological features and characteristics of these orbital diseases. This review provides a comprehensive update on the clinical and pathological diagnosis of these orbital infections and inflammations.

Thyroid orbitopathy obscuring the diagnosis of a rare neuromuscular hamartoma of the superior rectus muscle in an adult

A neuromuscular hamartoma is a rare benign tumour that is most frequently associated with peripheral nerves. The authors present a case of a 61 year-old man with bilateral exophthalmos and lid retraction who developed further proptosis and chemosis in the left eye over a five month period. An initial diagnosis of thyroid orbitopathy was made and he had a limited response to two courses of oral steroid administered in another centre. He was subsequently referred to our institution for further management when his condition worsened following withdrawal of treatment. Orbital CT scan showed a thickening of the recti muscles and particularly the left superior rectus and overlying soft tissue. Given this unusual pattern of muscle involvement in thyroid orbitopathy, a muscle biopsy was performed. This showed the presence of a neuromuscular hamartoma without malignant features. The orbital fat biopsy showed no pathological findings. A neuromuscular hamartoma not associated with a peripheral nerve is a rare entity, especially when coupled with an extraocular muscle. We wish to highlight the importance of a muscle biopsy when faced with a clinical picture and radiological pattern of extraocular muscle enlargement not typical of what we know to occur traditionally in thyroid eye disease.

[Orbital metastasis]

Orbital metastases are uncommon, accounting for 4% of all adult orbital tumors. The mean age at time of presentation is 60 years. The primary tumor is most often a carcinoma involving the breast (40%), lung (11%), or prostate (8%). Proptosis is the main clinical sign at diagnosis and is often associated with visual impairment, pain or ptosis. Imaging features are not specific; nevertheless, an enhanced extraconal tumor with osteolysis suggests the diagnosis. From a pathological point of view, there are no differences between the metastasis and the primary tumor. Regarding the average survival, the gold standard treatment remains radiotherapy.

Adenocarcinoma metastasis causing discrete extraocular muscle enlargement

BACKGROUND

Discrete extraocular muscle (EOM) metastasis is rarely reported. Clinical signs and symptoms of EOM metastasis can often be indistinguishable from primary idiopathic orbital myositis, posing a significant clinical challenge.

CASE REPORT

A case of a 61-year-old man with acute-onset unilateral periorbital pain and diplopia is presented. Magnetic resonance imaging showed an isolated edematous superior rectus/levator muscle complex with an isointense T2-weighted signal, supporting a diagnosis of orbital myositis. He was started on corticosteroids, with resolution of pain and improved motilities. Subsequently, his condition worsened. Repeat imaging results suggested the possibility of neoplastic infiltration of the muscle because of the newly demonstrated hyperintensity of the T2-weighted signal and perineural extension along the trigeminal nerve. Fine-needle aspiration biopsy showed adenocarcinoma cytology in the muscle.

CONCLUSIONS

This case illustrates discrete adenocarcinoma metastasis of an EOM, initially displaying characteristics predominantly consistent with orbital myositis. There is a paucity of epidemiologic data on EOM cancer, and clinical characteristics are derived only from a selection of case reports in the literature. Thus, the predominant features of global orbital metastatic cancer versus primary inflammation are highlighted in this presentation. This case shows that the variable characteristics of each process prohibit identification of any clinical feature that would prove pathognomonic for either disorder. The varied practice philosophies and standard of care regarding the proper time to biopsy are reviewed. This case shows the importance of early referral for orbital biopsy, even in the presentation of isolated, discretely edematous, and painful EOM enlargement.

Diverse clinical presentations of orbital sarcoid

PURPOSE

To review the clinical presentation, location, systemic features, management, and natural history of orbital sarcoid.

DESIGN

Retrospective, noncomparative, interventional case series.

METHODS

Twenty patients with sarcoid and sarcoidal reactions of the orbit underwent biopsy, excision of localized mass, and systemic and local treatment at a tertiary referral center. Age, gender, onset, symptoms and signs, characterization of disease process, location, systemic disease, associated systemic features, management, and recurrence of the disease were identified.

RESULTS

Of the 20 patients studied, five were male and 15 were female. The mean age was 50.55 +/- 16.43 years (range, 18 to 77 years). The most common symptom was the presence of a palpable mass, followed by eyelid swelling. Review of the computed tomographic scans revealed four main categories of presentation: lacrimal gland infiltration (n = 11; 55%), orbital mass (n = 4; 20%), optic nerve sheath and dural involvement (n = 4; 20%), and extraocular muscle involvement (n = 1; 5%). Concurrent systemic sarcoidosis discovered after the diagnosis of orbital sarcoid was present in 10 cases (50%). The remaining showed no evidence of systemic disease at follow-up. Angiotensin converting enzyme analysis was performed in 10 cases; in only two (20%) was elevated, and in the remaining eight, it was within normal levels.

CONCLUSIONS

Orbital sarcoid has a diverse clinical presentation varying from lacrimal gland infiltration, soft tissue orbital mass, intraorbital and extraorbital optic nerve sheath and dural involvement, to extraocular muscle involvement. The orbital site most commonly involved was the lacrimal gland.

Normal measurement of orbital structures: implications for the assessment of Graves' ophthalmopathy

Compute tomography anatomy of the orbits is well described, but only a few reports are available on normal measurements of the extraocular muscles (EOM) and globe position (GP). We obtained CT images from patients who were referred to our department for CT of the paranasal sinuses using a standard protocol for evaluation of normal orbital measurements. Our study suggests that optimum results are attained with the use of a coronal scan at a window level and width setting that results in an optimum image at the maximum muscle width for assessment of EOM and an axial scan at the mid-GP for GP and interzygomatic line. Based on our normal values, a right-to-left ratio of more than 1.4 for EOM diameter or 1.2 for GP is indicative of asymmetry. An absolute diameter of EOM > 8 mm and GP < 2 mm are abnormal.

Extraocular muscle quantification using mathematical morphology: A semi-automatic method for analyzing muscle enlargement in orbital diseases

Mathematical morphology was used to quantify the dimensions of the human extraocular muscles in computed tomography orbital scans. Coronal images of 28 patients with Graves orbitopathy and 5 controls (218 orbital scans) were analyzed with an algorithm for extraocular muscle segmentation. The results showed that measurements of extraocular muscle area obtained with semi-automatic segmentation are highly correlated with manual tracing and provides a simple method to quantify orbital structures including the extraocular muscles.

[Bilateral idiopathic orbital myositis]

INTRODUCTION

Orbital myositis is an idiopathic inflammation of the extraoccular muscles. It is often included under the broad description of orbital pseudotumor. It is commonly a unilateral affection.

CASE REPORT

We report one case of bilateral orbital myositis in a 45-year-old woman. The first symptoms were diplopia and acute bilateral orbital pain exacerbated by eye movements. Physical examination especially neurological was normal. Serum creatine kinase and biological thyroid function were normal. CT scan found a bilateral enlargement of rectus oculi medialis and lateralis. Clinical improvement was obtained a few days after oral corticosteroid treatment with remission of all signs.

CONCLUSION

Orbital myositis is a rare entity. 90-95p.cent of cases are unilateral. Bilateral forms are exceptional and in this case require search for specific etiologies particularly thyroid ophthalmopathy. There is controversy concerning treatment options but corticosteroids are still the most common first choice therapy with good outcome.

The Ticking Time Bomb

A man with orbital myositis and optic neuritis tested positive serologically for multiple tick-borne diseases. Erlichiosis, babesiosis, and Lyme disease may occur together and affect the eye or orbit.