Orbital Morphology for Decompression Surgery in Thyroid Eye Disease Using 2-D Orbital CT and 4 Parameters

PURPOSE: To present easily measurable 2D orbit computed tomography (CT) reference data that can be used in a preoperative study for orbital decompression and classification of individual orbital morphologies. METHODS: The study sample was composed of 77 patients with orbital contusion (42 Asian males + 35 Asian females = 154 orbits) who visited the emergency room of the Korea University Guro Hospital from September 2012 to June 2013. Patients with orbital wall fracture, retrobulbar hemorrhage, or eyeball rupture were excluded. Medical records including 2D orbit or facial bone CT were retrospectively reviewed and 4 orbital parameters (orbital length, OL; globe length, GL; GL/OL ratio and 2D cone angle) were measured. RESULTS: The average OL was 42.53 +/- 2.46 mm (35.63-49.09 mm) and average GL was 24.83 +/- 1.09 mm (22.75-28.13 mm). The average GL/OL ratio using these 2 parameters was 0.59 +/- 0.04 (0.50-0.68). The posterior cone angle was on average, 45.96 +/- 5.91degrees (29.35-60.04degrees). CONCLUSIONS: Simple measurement of 4 parameters using 2D orbit CT and classification of Asian individual orbital morphology may help in the choice of the most effective surgical technique for decompression surgery in thyroid eye disease patients.

Nontraumatic Subperiosteal Orbital Hematoma Associated with Ethmoid Sinusitis: A Case Report

Subperiosteal hematoma of the orbit is a rare disease and most of the cases occur in young adult males as a result of direct facial or orbital trauma. In the absence of direct facial or orbital trauma, nontranmatic subperiosteal orbital hematoma has rarely been reported in association with a sudden elevation of cranial venous pressure or venous congestion, systemic diseases associated with a bleeding diathesis and paranasal sinusitis. We report here on a rare case of subperiosteal orbital hematoma associated with ethmoid sinusitis, as was seen on CT imaging.

Choroidal Osteoma: US and CT Ffindings

PURPOSE: The purpose of this study was to evaluate US and CT features of choroidal osteoma. MATERIALS AND METHDOS: US and CT scans of seven cases of choroidal osteoma occurring in six patients were retrospectively analyzed. We analysed US and CT findings with particular attention to the location, size, and shape of calcification associated with choroidal osteoma, and sought the possible cause of the tumor, if any. RESULTS: None of six patients had any possible cause related to choroidal osteoma. All of seven cases of choroidal osteoma were manifested as calcified mass which were located in the posterior wall of the eyeball near the juxtapapillary region. Calcification ranged in size from 1 to 2 cm and had curvilinear shape. Both US and CT were equally useful to evaluate choroidal osteoma. CONCLUSION: By depicting the characteristic calcification, US and CT are useful imaging modalities in evaluating choroidal osteoma.

Comparison of Orbital Pseudotumor and Lymphoma: Clinical and Radiological Findings

PURPOSE: To compare the clinical and radiological findings of orbital pseudotumor with those of orbital lymphoma. MATERIALS AND METHODS: The clinical and radiological features of 12 orbital pseudotumors were compared with those of 17 orbital lymphomas, the nature of all lesions being confirmed by tissue biopsy. Twenty-four CT scans and nine MR images were retrospectively reviewed and compared, with special focus on the location of a tumor in the orbit, the invasion of periorbital structures, tumor margin, bilaterality, and signal intensity. The initial symptoms at admission were also classified and compared. RESULTS: In 50% of cases, orbital pseudotumors were located in both extraconal and intraconal space; 75% involved two or more extraocular muscles, and 33% involved the optic nerve. Margins were either infiltrative (75%) or ill-defined (92%). As for orbital lymphomas, 64% occupied extraconal space, invading one or less extraocular muscle (76%) and conjunctiva (29%). Seventy-one percent had a sharp margin, and 65% were lobulated or round. In pseudotumors, orbital pain and visual loss were major symptoms, while in lymphomas a painless orbital mass was the initial symptom. CONCLUSION: CT or MR image analysis of lesion location, margin, and the involvement of adjacent extra-ocular muscle or optic nerves may help differentiate between orbital lymphoma and orbital pseudo tumor.

CT Findings of Orbital Langerhans Cell Histiocytosis

PURPOSE: To evaluate the CT findings in patients with Langerhans cell histiocytosis (LCH) involving the orbit. MATERIALS AND METHODS: Orbital CT scans of six children with pathologically proven LCH were retrospectively analyzed. Follow-up CT (n = 5) and MR (n = 1) imaging findings were also revi ewed. RESULTS: Initial CT scans revealed varying degree of bone destruction with soft-tissue masses, and on nonenhanced images the mean attenuation value was 44 Hounsfield units(HU). All masses showed mild to moderate enhancement with a mean attenuation value of 74 HU. The bony margins abutting onto soft tissue masses were irregular but clearly demarcated. No evidence of calcification or periosteal reaction was noted. Suprasellar mass and rib involvement was noted in one patient and hepatos-plenomegaly in two. Follow-up CT and MR images showed that the soft tissue masses were almost completely resolve d, with bone remodeling and reossification. CONCLUSION: A soft tissue mass with irregular but clearly demarcated bone destruction is thought to be a characteristic finding of LCH involving the orbit. Follow-up images after treatment showed bone remodeling and reossification.

Ultrasonic Measurement of the Extraocular Muscles: A Comparison with CT

PURPOSE: To compare the usefulness of orbital ultrasound measurements of extraocular muscle thickness with that of CT measurements in patients with thyroid ophthalmopathy. MATERIALS AND METHODS: Fourteen patients with thyroid ophthalmopathy underwent orbital ultrasound and CT scanning, and 19 normal volunteers underwent ultrasound. For orbital ultrasound, a 5-10 MHz small part probe was applied to bilateral closed eyelids. The medial and lateral rectus muscles were measured on transverse scan, and the superior rectus complex and inferior rectus muscles on longitudinal scan. On orbital CT, the medial and lateral rectus muscles were measured on axial scan, and the superior rectus complex and inferior rectus muscle on coronal scan. The maximum thickness of the belly of each muscle was measured on both ultrasound and CT. The ultrasound detection rates for each measurable muscle were assessed in both the thyroid ophthalmopathy and normal control group, and the statistical significance of the thickness of extraocular muscles measured by ultrasound and CT was evalvated. RESULTS: In patients with thyroid ophthalmopathy and in the normal control group, all medial and lateral rec-tus muscles were successfully measured by ultrasound. The detection rate for the superior rectus complex was 60.7 % in the thyroid ophthalmopathy group and 63.1% in the normal control group, and for the inferior rectus muscle, 78.6% and 39.5% in the two respective groups. A comparison of measurements of the thickness of extraocular muscle using orbital ultrasound and CT showed no statistically significant difference between the medial rectus muscle and the superior rectus complex, but a significant difference between the lateral and inferior rectus muscle. CONCLUSION: In these patients, all medial rectus muscles were easy measurable by ultrasound, and the thickness thus determined was not different from that determined by CT. Orbital ultrasound is thus a useful method for diagnosis and follow-up in patients with thyroid ophthalmopathy in whom the medial rectus mus-cle is thickened.

Ultrasonic Measurement of the Extraocular Muscles: A Comparison with CT

PURPOSE: To compare the usefulness of orbital ultrasound measurements of extraocular muscle thickness with that of CT measurements in patients with thyroid ophthalmopathy. MATERIALS AND METHODS: Fourteen patients with thyroid ophthalmopathy underwent orbital ultrasound and CT scanning, and 19 normal volunteers underwent ultrasound. For orbital ultrasound, a 5-10 MHz small part probe was applied to bilateral closed eyelids. The medial and lateral rectus muscles were measured on transverse scan, and the superior rectus complex and inferior rectus muscles on longitudinal scan. On orbital CT, the medial and lateral rectus muscles were measured on axial scan, and the superior rectus complex and inferior rectus muscle on coronal scan. The maximum thickness of the belly of each muscle was measured on both ultrasound and CT. The ultrasound detection rates for each measurable muscle were assessed in both the thyroid ophthalmopathy and normal control group, and the statistical significance of the thickness of extraocular muscles measured by ultrasound and CT was evalvated. RESULTS: In patients with thyroid ophthalmopathy and in the normal control group, all medial and lateral rec-tus muscles were successfully measured by ultrasound. The detection rate for the superior rectus complex was 60.7 % in the thyroid ophthalmopathy group and 63.1% in the normal control group, and for the inferior rectus muscle, 78.6% and 39.5% in the two respective groups. A comparison of measurements of the thickness of extraocular muscle using orbital ultrasound and CT showed no statistically significant difference between the medial rectus muscle and the superior rectus complex, but a significant difference between the lateral and inferior rectus muscle. CONCLUSION: In these patients, all medial rectus muscles were easy measurable by ultrasound, and the thickness thus determined was not different from that determined by CT. Orbital ultrasound is thus a useful method for diagnosis and follow-up in patients with thyroid ophthalmopathy in whom the medial rectus mus-cle is thickened.

Intraorbital Wood Foreign Body Mimicking Air at CT: A Case Report

Computed tomography revealed variable sized small areas of extremely low attenuation in the right orbit of a45-year-old woman who had fallen face down. The appearance and attenuation of the areas suggested air, but on widewindow-width images attenuation was seen to be higher than that of sinus air. We report a case involvingintraorbital wood foreign bodies which on CT mimicked the appearance of air and which were surgically removed.

A Case of Oribital Myositis / 대한류마티스학회지

No abstract available.

CT Findings of Orbital Blow-out Fracture

PURPOSE: To evaluate the usefulness and radiologic findings of CT in the diagnosis of orbital blow-outfracture. MATERIALS AND METHODS: Forty-four patients with orbital blow-out fractures diagnosed by clinicalfindings and CT were evaluated retrospectively. On CT images, we evaluated the site and frequency of fracture,herniation of orbital fat, extraocular muscle abnormality, intraorbital hematoma, and intrasinus hemorrhage. RESULTS: Forty-eight sites of orbital wall fractures were seen. Of these, 25(52.1%) were observed at the medialwall and 18(37.5%) at the inferior wall. Combined fracture of the medial and inferior wall was seen in fivecases(10.4%), and orbital fat herniation to adjacent sinuses in 25. Associated extraocular muscle abnormalitieswere seen at the medial rectus (n=20) and inferior rectus muscle(n=18). Intrasinus hemorrhage was seen in 15cases, and intraorbital hematoma in five. CONCLUSION: CT is a useful diagnostic modality for the evaluation oforbital blow-out fracture and associated soft tissue abnormalities.