Orbital Magnetic Resonance Research Articles

Normative measurements of orbital structures on magnetic resonance images; a cross-sectional study with mini review of the literature.

Awareness of normative values of extra orbital structures would provide useful information to interpret the radiological images better and use them for diagnostic purposes. This study aimed to reveal the average values of major extraocular structures measured on magnetic resonance images. In this retrospective cross-sectional study, magnetic resonance (MR) images of 256 orbits of 128 patients were re-interpreted regarding the measurements of major orbital structures. Extraocular muscles, superior ophthalmic vein, and optic nerve-sheath complex were measured on orbital MR images of these patients. The data distributions were presented by box-plot analyses for each parameter, and the measurement results were analyzed regarding gender and age groups. Lateral rectus muscle thickness (LR), inferior rectus muscle thickness (IR), globe position (GP), and interzygomatic line (IZL) values were higher in the male group than in the female group (p values were < 0.001, 0.003, 0.020, and < 0.001 respectively). LR, the thickness of the superior group muscles (SUP GR), IR, superior oblique muscle thickness (SOBL), and the thickness of optic nerve-sheath complex (ON) values indicated a significant relationship between age groups. There was a significant, positive, and low-level correlation between age and LR, SUP GR, and IR values (p values were < 0.001, 0.001, and < 0.001, respectively). This study provides quantitative data on normative values of orbital structures with gender and age group comparisons. Clinicians or surgeons can easily use the measured values to gather diagnostic information from the orbital region.

Supraequatorial displacement with lateral rectus myopexy for treatment of myopic sagging/heavy eye

PurposeTo describe the outcome of the patients diagnosed of sagging/heavy eye associated to myopia, that were operated on with the supra-equatorial displacement with LR myopexy. MethodsA retrospective study of 9 cases between 2017−2023. The following data were analyzed: horizontal and vertical deviation, diplopia, amblyopia, ductions, ocular torsion, sensorial test, macular pathology, and the orbital magnetic resonance. Treatment was considered Successful if the diplopia was improved or eliminated and a final vertical deviation (VD) ≤5 prism diopters (PD). ResultsThe mean age (SD) was: 62.11 (4.6) years (100% women). A total of 88.88% presented diplopia. The mean preoperative hypotropia was: 11.33 PD (SD 3.16), and the mean final VD 3.44 PD (SD 3.05). After surgery, the hypotropia was overcorrected in one case, under corrected in 5, and orthophoria was achieved in another three. The technique was associated with surgery of another rectus muscle in 4 subjects. The mean follow-up time after surgery was 34 months (SD 34.62). Six of the 9 patients improved with a vertical deviation ≤5 PD. In 3 patients, the diplopia was eliminated, while in 5 it remained intermittent (three with macular pathology). ConclusionSupra-equatorial displacement with LR myopexy for treatment of myopic sagging/heavy eye, is a therapeutic option if hypotropia is less than 12 PD or the Yokoyama technique is not indicated. A good result was obtained in most cases, although diplopia could only be totally suppressed in three, and another five remained intermittent.

Miopexia supra-ecuatorial del recto lateral en el tratamiento del síndrome «sagging/heavy eye» miópico

PurposeTo describe the outcome of the patients diagnosed of sagging/heavy eye associated to myopia, that were operated on with the supra-equatorial displacement with lateral rectus myopexy. MethodsA retrospective study of 9 cases between 2017 and 2023. The following data were analyzed: horizontal and vertical deviation, diplopia, amblyopia, ductions, ocular torsion, sensorial test, macular pathology, and the orbital magnetic resonance. Treatment was considered successful if the diplopia was improved or eliminated and a final vertical deviation≤5prism diopters (PD). ResultsThe mean age (SD) was: 62.11 (4.6) years (100% women). A total of 88.88% presented diplopia. The mean preoperative hypotropia was: 11.33PD (SD 3.16), and the mean final VD 3.44PD (SD 3.05). After surgery, the hypotropia was overcorrected in one case, under corrected in 5, and orthophoria was achieved in another 3. The technique was associated with surgery of another rectus muscle in 4 subjects. The mean follow-up time after surgery was 34 months (SD 34.62). Six of the 9 patients improved with a vertical deviation≤5PD. In 3 patients, the diplopia was eliminated, while in 5 it remained intermittent (3 with macular pathology). ConclusionSupra-equatorial displacement with lateral rectus myopexy for treatment of myopic sagging/heavy eye is a therapeutic option if hypotropia is less than 12PD or the Yokoyama technique is not indicated. A good result was obtained in most cases, although diplopia could only be totally suppressed in three, and another five remained intermittent.

Orbital anatomy magnetic resonance imaging in diplopic versus non-diplopic patients after glaucoma drainage device placement.

New-onset persistent diplopia has become a common complication after glaucoma drainage device (GDD) placement. Understanding the orbital anatomy of such patients may provide information regarding risk of diplopia, GDD selection, and post-operative management. The purpose of this study was to examine the orbital anatomic differences in diplopic and non-diplopic patients after GDD implantation using high-resolution MRI. Seven eyes (N = 4 with diplopia and N = 3 without diplopia after GDD placement) of seven patients that had undergone placement of Baerveldt 250 (B250), Baerveldt 350 (B350), or Ahmed FP7 (FP7) GDD were prospectively enrolled at a single institution. All patients underwent a 3.0T orbital MRI with 3D volumetric T1 and T2 weighted sequence. Images were analyzed for orbital volume, axial length, orbital distances, presence of superior rectus-lateral rectus (SR-LR) band, position of GDD, and SR-LR angles. Patients with diplopia had smaller mean ± SD orbital axial (911.5 ± 111.8 mm3 vs 931.7 ± 79.7 mm3) and coronal volumes (1162.5 ± 145.5 mm3 vs 1180 ± 34.6 mm3) compared to non-diplopic patients. Average orbital rim distances were larger for the diplopic group. The SR-LR displacement angle for diplopic patients was larger (101.6° ± 8.1 vs 94.7° ± 17.6) while the SR-LR quadrantic angle (86.6° ± 4.2 vs 89.1° ± 4.3) was smaller. SR-LR band was present and intact in all patients. GDD malpositioning was not evident in any patient. The decreased orbital axial and coronal volumes as well as increased orbital rim distances in diplopic patients suggests the need for further studies to understand the role of orbital anatomy in occurrence of diplopia. Dynamic MRI imaging may be helpful in identifying differences in extraocular muscle function that reveal an etiology of diplopia in patients with GDD implantation.

Radiologic imaging shows variable accuracy in diagnosing orbital inflammatory disease and assessing its activity

Radiologic orbital imaging provides important information in the diagnosis and management of orbital inflammation. However, the diagnostic value of orbital imaging is not well elucidated. This study aimed to investigate the diagnostic accuracy of orbital imaging to diagnose orbital inflammatory diseases and its ability to detect active inflammation. We collected 75 scans of 52 patients (49 computed tomography (CT) scans; 26 magnetic resonance (MR) imaging scans). Clinical diagnoses included thyroid eye disease (TED) (41 scans, 31 patients), non-specific orbital inflammation (NSOI) (22 scans, 14 patients), sarcoidosis (4 scans, 3 patients), IgG4-related ophthalmic disease (IgG4-ROD) (5 scans, 3 patients), and granulomatosis with polyangiitis (GPA) (3 scans, 1 patient). Two experienced neuroradiologists interpreted the scans, offered a most likely diagnosis, and assessed the activity of inflammation, blinded to clinical findings. The accuracy rate of radiological diagnosis compared to each clinical diagnosis was evaluated. Sensitivity and specificity in detecting active inflammation were analyzed for TED and NSOI. The accuracy rate of radiologic diagnosis was 80.0% for IgG4-ROD, 77.3% for NSOI, and 73.2% for TED. Orbital imaging could not diagnose sarcoidosis. Orbital CT had a sensitivity of 50.0% and a specificity of 75.0% to predict active TED using clinical assessment as the gold standard. The sensitivity/specificity of orbital MR was 83.3/16.7% for the detection of active NSOI. In conclusion, orbital imaging is accurate for the diagnosis of IgG4, NSOI, and TED. Further studies with a large number of cases are needed to confirm this finding, especially with regard to uncommon diseases. Orbital CT showed moderate sensitivity and good specificity for identifying active TED.

Analysis of clinical characteristics of demyelinating optic neuritis in children under the age of 16

Objective To observe the clinical characteristics of demyelinating optic neuritis (DON) in Chinese children under the age of 16. Methods A retrospective review of the medical charts of 42 pediatric patients with DON was conducted in this study. Twenty-two patients (52.4%) were male, and 20 patients(47.6%) were female. The patients aged from 3 to 15 years, with the mean age of (9.5±2.3) years. There were 35 bilateral patients and 7 unilateral patients. Twenty-seven patients (64.3%) had prodromal symptoms before onset. All patients underwent visual function and imaging tests, such as best corrected visual acuity (BCVA), fundus photography, visual evoked potential (VEP), visual field, MRI. The patients were tested for serum levels of antibodies for aquaporin 4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) with a cell-based assay. All patients were received corticosteroid therapy. The mean follow-up was (1.17±0.42) years. The children who had coordination ability and with BCVA≥0.3 were received examination of Humphery automatic perimeter. Data were collected on the age, gender, clinical features, neuroimaging, serological specific antibodies, treatment and vision prognosis. Results 23.8% of the children were bilateral optic neuritis in onset stages. 64.2% were recurrent optic neuritis and 83.3% exhibited bilateral diseases eventually. BCVA had decreased to ≤0.1 in 87.0%% eyes and disc swelling was observed in 77.9% eyes during the onset stages. All eyes had visual field defects and abnormal VEP exam results, with delayed latency of P100 and P2, and varying degrees of amplitude reduction. Serum AQP4 antibody and MOG antibody were tested by cell-based assay, 2/42 children (4.7%) were positive for AQP4 antibody and 5/24 children (20.8%) were positive for MOG antibody. All of anti-AQP4+ and anti- MOG+ cases relapsed. All children underwent orbital magnetic resonance imaging (MRI), 40 cases (95.2%) showed demyelination features of optic nerve, and 5 cases (11.9%) showed long segments lesion (more than 1/2 length of the optic nerve). There were 2 anti-AQP4+ cases and 3 anti- MOG+ cases from the 5 cases with long segments lesion. MRI also showed brain demyelinating lesions in 4 children (3 of them were anti- MOG+) or spinal cord demyelinating lesions in 3 children (2 of them were anti- MOG+). After treatment with glucocorticoid, visual acuity improved in all eyes, of which 84.4% with BCVA≥0.5. Forty-eight eyes of 26 children accept dynamic visual field during the course of treatment, showed the vision abnormalities associated with optic nerve damage. Conclusions Children under the age of 16 with DON can experience severe visual impairment, higher recurrence tendencies, and higher rate of disc involvement, but good response to glucocorticoid therapy. AQP4 or MOG antibodies positive might be concurrent with brain and (or) spinal cord demyelinating lesions and indicated a poorer prognosis. Key words: Optic neuritis; Demyelinating diseases; Child; Disease attributes

Bilateral lacrimal caruncle lesions.

ABSTRACTA 65-year-old man was referred to our hospital for the treatment of a lesion on the medial lacrimal canthus of both eyes. He had a history of perinuclear anti-neutrophil cytoplasmic antibodies, i.e., pANCA-positive interstitial pneumonia. Orbital magnetic resonance imaging excluded space occupying lesions, and laboratory testing excluded thyroid-related diseases. The masses were excised, and histopathological examinations showed sebaceous gland hyperplasia and inflammatory changes around the gland. In addition, the specimen from the left eye showed a retention cyst possibly caused by an infection. It was also possible that the use of steroid was involved in the development of the lesions. A relationship between the ANCA and the lesions was not completely eliminated.

Diagnosis and stage of Graves' ophthalmopathy: Efficacy of quantitative measurements of the lacrimal gland based on 3-T magnetic resonance imaging.

The aim of the present study was to determine the efficacy of quantitative measurements of the lacrimal gland based on 3-T magnetic resonance (MR) imaging in the diagnosis and staging of Graves' ophthalmopathy (GO). The study retrospectively enrolled 33 patients with GO (the GO group) and 24 healthy volunteers [the healthy control (HC) group] with orbit MR imaging performed using a 3-T MR scanner. Quantitative parameters of the lacrimal gland, including axial length, axial width, axial area, coronal length, coronal width, coronal area, volume and signal intensity ratio (SIR) of the lacrimal gland to the ipsilateral temporal muscle were measured. The difference of quantitative parameters between the GO and HC groups, or between active and inactive GO groups were evaluated using a Student's t-test. Receiver operating characteristic analyses were used to evaluate the diagnostic value of the significant parameters in discriminating patients with GO from healthy controls, or discriminating active from inactive GO. All the quantitative measurements of the GO patients were significantly larger than those of the healthy controls (P<0.05), with the exception of the coronal length (P=0.150). Axial and coronal width had the best efficacy in discriminating patients with GO from healthy controls. Only SIR was found to be different between the active and inactive GO groups (P=0.001). Setting a SIR of 2.57 as the threshold value, the optimal efficacy was achieved (area under the curve, 0.711; sensitivity, 57.7%; specificity, 77.5%) in discriminating between active and inactive GO. Quantitative measurements of the lacrimal gland based on 3-T MR imaging may assist in the diagnosis and stage of GO.

Relationship between the levels and variation of CXCL12, PDGF, CXCL14 in cerebrospinal fluid of optic neuritis and neuromyelitis optica

To explore the predictive value of the prognosis and outcome for optic neuritis (ON) and neuromyelitis optica (NMO) by investigating the levels and variation of CXCL12, PDGF and CXCL14 in CSF of patients with ON and NMO. Retrospective study. Thirty-five patients with ON, 10 patients with NMO and 10 patients with cerebral venous sinus thrombosis (CVST) were scheduled in the research unit from September 2012 to September 2013 in Neuro-Ophthalmology Department of PLA General Hospital. Clinical data and cerebrospinal fluid (CSF) parameters were collected. CXCL12, PDGF and CXCL14 concentrations were measured in CSF using enzyme linked immunosorbent assay (ELISA). The CXCL12, PDGF and CXCL14 levels in CSF were compared by using ANOVA in different diseases with different phases and recurrent cases found by MRI. Multiple comparisons were used by LSD method. The comparison of positive rate for MRI in ON different phases was used by exact probability. Meanwhile, correlation analysis was conducted between CXCL12, PDGF, CXCL14 and white blood cells (WBC), IgG and protein in CSF. Compared with NMO group (3.69±0.35, 2.04±0.24, 7.05±0.94), the CXCL12, PDGF and CXCL14 levels in CSF were higher in ON (4.39±0.51, 2.51±0.39, 8.65±1.55) and CVST(4.84± 0.49, 2.79±0.47, 10.53±1.11) group (F=14.593, 10.060, 10.003,P<0.001, <0.001, <0.001), especially the CXCL12, PDGF and CXCL14 levels in CSF of CVST group patients were higher than that in ON group. Among them, the CXCL12 and PDGF levels in CSF were higher in acute phase of ON (4.63±0.50, 2.65±0.40) and CVST(4.84±0.49, 2.79±0.47) group than stationary phase of ON (4.13±0.39, 2.34±0.32) group (F=8.823, 4.906, P=0.001, 0.012). In addition, 28 of 35 ON patients were conducted the cerebral or orbital magnetic resonance imaging (MRI). The result showed that the CXCL12 and PDGF levels in CSF of patients with positive finding in MRI (3.96±0.30, 2.23±0.16) were higher than those patients with negative finding in MRI (4.64±0.42, 2.62±0.42) (t=-4.754, -2.977, all P<0.01). Besides that, there was higher correlation between the CXCL12 level and PDGF in CSF (P<0.01). Reduced concentration of cytokine that promoted remyelination such as CXCL12 and PDGF in cerebrospinal fluid of the ON and NMO patients may predict a bad myelin regeneration.

The diagnostic value of orbital magnetic resonance imaging T2-Mapping in patients with active Graves' ophthalmopathy

Objective To study the clinical value of orbital magnetic resonance imaging(MRI) in diagnosis and making a judgment about the curative effect of glucocorticoid in patients with Graves' ophthalmopathy(GO). Methods A total of 106 patients with GO were divided into active GO group or inactive GO group according to whether clinical activity score(CAS)≥3 or not, respectively. T2 relaxation times(T2RTs)(ms) and areas(mm2) of four extra-ocular muscles (EOMs) (superior, inferior, medial, and lateral rectus) were directly measured by MRI T2-Mapping. Correlation analysis of T2RTs and areas with eyeball motility, diplopia, exophthalmus, visual acuity and intraocular pressure(IOP) were also performed. The T2RTs and areas of EOMs before and after intravenous methylprednisolone(iv MP) pulse therapy were recorded, respectively. Results The mean T2RTs(88.9±13.8) and mean areas(58.1±23.8) of EOMs in active GO were significantly greater than those in inactive GO(80.6±10.0 and 46.2±18.6, respectively), bing both significantly greater than those in volunteers with normal eyes(76.2±4.7 and 30.3±6.1, respectively)(P<0.01). Maximal T2RTs and maximal areas of EOMs showed significant positive correlation(P<0.01), and both were positively correlated weakly with CAS, reduced movement of eyeball, diplopia, exophthalmus and loss of visual acuity(P<0.01). On the contrary, maximal T2RTs and maximal areas of EOMs showed negative correlation or no correlation with spontaneous retrobulbar pain, painful eye movement, redness of eyelids and abnormal IOP. Even if 1≤CAS<3, ophthalmic symptoms and signs also showed a positive responses to iv MP in patients with moderate to severe GO as long as prolonged T2RTs occurred at least in one of EOMs. The maximal T2RTs, maximal areas, mean T2RTs and mean areas of EOMs were significantly decreased at the end of iv MP treatment, meanwhile ophthalmic symptoms and signs were obviously improved. Conclusions Prolonged T2RTs, especially accompanied by enlarged area on the identical EOMs is an remarkable symbols of acute inflamed muscles. The findings suggested that the use of prolonged T2RTs can improve diagnostic sensitivity and predict the curative effect of iv MP in patients with moderate to severe GO and CAS≥1. (Chin J Endocrinol Metab, 2015, 31: 327-332) Key words: Graves' ophthalmopathy; Magnetic resonance imaging; Methylprednisolone

Ultrahigh field magnetic resonance and colour Doppler real-time fusion imaging of the orbit – a hybrid tool for assessment of choroidal melanoma

A combination of magnetic resonance images with real-time high-resolution ultrasound known as fusion imaging may improve ophthalmologic examination. This study was undertaken to evaluate the feasibility of orbital high-field magnetic resonance and real-time colour Doppler ultrasound image fusion and navigation. This case study, performed between April and June 2013, included one healthy man (age, 47 years) and two patients (one woman, 57 years; one man, 67 years) with choroidal melanomas. All cases underwent 7.0-T magnetic resonance imaging using a custom-made ocular imaging surface coil. The Digital Imaging and Communications in Medicine volume data set was then loaded into the ultrasound system for manual registration of the live ultrasound image and fusion imaging examination. Data registration, matching and then volume navigation were feasible in all cases. Fusion imaging provided real-time imaging capabilities and high tissue contrast of choroidal tumour and optic nerve. It also allowed adding a real-time colour Doppler signal on magnetic resonance images for assessment of vasculature of tumour and retrobulbar structures. The combination of orbital high-field magnetic resonance and colour Doppler ultrasound image fusion and navigation is feasible. Multimodal fusion imaging promises to foster assessment and monitoring of choroidal melanoma and optic nerve disorders. • Orbital magnetic resonance and colour Doppler ultrasound real-time fusion imaging is feasible • Fusion imaging combines the spatial and temporal resolution advantages of each modality • Magnetic resonance and ultrasound fusion imaging improves assessment of choroidal melanoma vascularisation.

Congenital fibrosis of the extraocular muscles: magnetic resonance imaging findings and surgical treatment

Purpose: We analyzed findings of orbital and cranial magnetic resonance imaging (MRI) in patients with congenital fibrosis of the extraocular muscles (CFEOM). We described surgery and its outcome.Material and method: Nine out of 10 patients with clinical findings of CFEOM underwent orbital and cranial MRI to perform a study of the extraocular muscles and cranial nerves. A multimodality workstation platform developed by the imaging laboratory of our hospital for PC computer allowed us to visualize and measure the cross sections of the extraocular muscles in a coronal section. Surgery was indicated to resolve strabismus. Outcome was considered favorable if the final deviation was <10 pd in the primary position without head turn.Results: In 8 cases (6 males, 5 unilateral [3 left eye]), MRI revealed atrophy of at least 1 of the extraocular muscles supplied by the third nerve. Five patients had third nerve aplasia or hypoplasia. Clinical findings were compatible with a probable diagnosis of CFEOM in all 10 patients. Four patients underwent ptosis surgery before being diagnosed with CFEOM. Four patients underwent surgery to correct strabismus and, of these, 2 required multiple interventions (1 needed 4 interventions). Outcome was successful in only 2 cases.Conclusion: Orbital and cranial MRI provided useful information about extraocular muscles and cranial nerves in CFEOM. Surgery must be performed on an individual basis; the number of reoperations is high. The outcome of surgery was favorable in half of the cases.

Isolated Trochlear Nerve Palsy in Tolosa-Hunt Syndrome

A 67-year-old Japanese woman without contributory medical history developed acute onset of left-sided trochlear nerve palsy (TNP) with persistent and severe periorbital pain. There were no other neurological abnormalities. Funduscopic findings were normal. Cranial and orbital magnetic resonance (MR) imaging, and cranial MR angiography demonstrated no abnormalities. By administration of prednisolone 40 mg/day from the day after onset, periorbital pain was resolved within 24 hours, and TNP within 5 days. Thereafter, prednisolone was gradually tapered off. She remained asymptomatic under no medication. In the English language literature, this is the first reported case of Tolosa-Hunt syndrome presenting with isolated TNP.

Chronic progressive external ophthalmoplegia without ptosis

Abstract Purpose Chronic progressive external ophthalmoplegia (CPEO) is a rare mitochondrial myopathy characterized by slowly progressive paralysis of the extraocular muscles with onset around the age of 20. Patients usually experience bilateral ptosis before developing symmetric, multidirectional external ophthalmoplegia. Methods 31‐year‐old woman with 10 year history of slowly progressive paralysis of the extraocular muscles was referred to our institute. Every action of extraocular muscles was reduced in both eyes. She could not adduct and elevate, there was only a slight abduction and depression function in both eyes. Patient had no ptosis or exophthalmus. BCVA was 20/20 in both eye. Slit lamp examination was normal. Dilated funduscopic examination revealed slight pigment disturbance in the periphery. Visual field and color vision tests were normal. Electroretinography showed lower borderline scotopic b‐wave amplitudes. Laboratory tests showed increased lactic acid and creatine phosphokinase values. The results of liver and kidney function, autoimmun and serologic tests were normal. All thyroid function tests yielded negative results. Urinalysis, chest x‐ray, heart ultrasound, brain and orbital magnetic resonance, nasal sinus CT scans were normal. Tensilon test excluded myasthenia gravis. Results We considered the case as CPEO clinically, mitochondrial DNA analysis is in process. Conclusion In CPEO, slowly progressive paralysis of the extraocular muscles may develop without ptosis. A careful differential diagnosis is very important.

Orbital magnetic resonance imaging combined with clinical activity score can improve the sensitivity of detection of disease activity and prediction of response to immunosuppressive therapy for Graves' ophthalmopathy

The aim of this study was to demonstrate that the addition of orbital magnetic resonance (MR) imaging can provide improvement in sensitivity of detection of active disease and the prediction of the response to intravenous glucocorticoid therapy (ivGC), over clinical activity score (CAS) alone. A prospective case series was studied at our institution. Forty eight patients were examined by CAS and orbital MR imaging. The maximum of T2 relaxation times of extraocular muscles (maxT2RT) and other parameters were evaluated by MR imaging. Thirty five of 48 patients underwent ivGC. Twenty of 35 patients, whose CAS was 2 points or less, were evaluated for the response to ivGC. The correlation between CAS and maxT2RT was evaluated. Differentiation of active and inactive GO was performed by CAS and orbital MR imaging. The response to ivGC was evaluated by CAS, orbital MR imaging and ophthalmic parameters. As a result, CAS and maxT2RT showed significant positive correlation (r=0.58, p<0.0001), and 15 patients were positive by CAS and orbital MR imaging. However, 20 patients were positive by only MR imaging. In those 20 patients, there was significant improvement after ivGC. We concluded that orbital MR imaging combined with CAS could improve the sensitivity of detection of active disease and the prediction of the response to ivGC. In addition, even if only one parameter of CAS is positive, further examination with orbital MR imaging is advised.

Retinoblastoma: Abnormal gadolinium enhancement of anterior segment of eyes at MR imaging with clinical and histopathologic correlation.

To evaluate abnormal gadolinium enhancement of the anterior segment of eyes harboring retinoblastoma at magnetic resonance (MR) imaging and correlate this finding with clinical and histopathologic information. Three neuroradiologists examined 46 eyes with 34 retinoblastomas in 25 children on gadolinium-enhanced T1-weighted orbital MR images obtained shortly after contrast material injection for evidence of abnormally high signal intensity in the anterior segment. Twenty-two of the 34 affected eyes were enucleated, and six of these 22 eyes were treated with preenucleation adjuvant therapy. Thus, correlation of the clinical, MR imaging, and histopathologic findings in 16 eyes was performed. Statistical analysis was performed with nonparametric methods (Fisher exact test). P <.05 indicated a statistically significant difference. Fourteen of the 34 affected eyes showed abnormal gadolinium enhancement of the anterior segment. Regarding the 16 eyes evaluated for statistical analysis, a significant correlation (P =.011) between abnormal gadolinium enhancement of the anterior segment and histopathologically documented optic nerve infiltration was noted. A trend toward an association between abnormal enhancement and elevated intraocular pressure (P =.215), tumor growth beyond the equator at MR imaging (P =.125), and histopathologically proved iris neoangiogenesis (P =.182) also was noted. Histopathologic evidence of optic nerve and/or choroid infiltration correlated significantly (P =.001; sensitivity, 100% [nine of nine eyes]; specificity, 86% [six of seven eyes]) with abnormal enhancement. Abnormal gadolinium enhancement of the anterior segments of eyes harboring retinoblastoma seems to indicate more aggressive tumor behavior.

Twist mode in spherical alkali metal clusters.

A remarkable orbital quadrupole magnetic resonance, so-called twist mode, is predicted in alkali metal clusters where it is represented by Ipi = 2(-) low-energy excitations of valence electrons with strong M2 transitions to the ground state. We treat the twist by both macroscopic and microscopic ways. In the latter case, the shell structure of clusters is fully exploited, which is crucial for the considered size region ( 8<or=N(e)<or=1314). The energy-weighted sum rule is derived for the pseudo-Hamiltonian. In medium and heavy spherical clusters, the twist dominates over its spin-dipole counterpart and becomes the most strong multipole magnetic mode.

The evaluation of congenital double elevator palsy with magnetic resonance imaging

Orbital and cranial magnetic resonance imaging (MRI) was performed in nine patients with congenital double elevator palsy. On orbital MRI examination, superior rectus (SR) and inferior rectus (IR) muscles were specifically evaluated with sagittal and coronal views. Bell’s phenomenon was present in three cases and four patients had positive forced duction tests. The vertical recti did not show any difference in either size or signal intensity when compared to controls. There was no denervation atrophy in the SR muscle. On cranial MRI examination, we were unable to demonstrate any abnormal signal intensity. The results of this study suggest that a paretic SR muscle is unlikely to be responsible for the clinical picture in congenital double elevator palsy, since a paretic SR muscle causing such a severe limitation of upgaze would be expected to have denervation atrophy.

Diagnosis and management of orbital inflammation and infections secondary to foreign bodies: a clinical review

Orbital inflammation and secondary infections may be caused by many types of foreign bodies, including organic and inorganic matter, non-autogenous surgical implants and allografts, and surgical hardware and materials utilized in reconstructive surgery. In penetrating injury patients, the nature of the foreign body determines the clinical behavior; inert objects such as steel and glass may not cause significant inflammation to warrant their removal. Removal of organic foreign bodies, however, is mandatory since these objects usually lead to secondary infection with abscess and fistula formation. This paper reviews salient points related to history-taking and physical examination, diagnostic workup, and medical and surgical treatment in foreign body-induced orbital inflammation and infections. It is emphasized that practically every case of orbital trauma should be approached with a high index of suspicion for penetrating injury with possible intraorbital foreign body. The investigational tools to detect orbital foreign bodies, including ultrasonography, computed tomography and magnetic resonance imaging, are reviewed. The principles of the management, including antimicrobial therapy, surgical indications and techniques, are also discussed.

Artifacts and pitfalls in MR imaging of the orbit: a clinical review.

High-resolution magnetic resonance (MR) imaging of the orbit has become widely accepted as a valuable diagnostic technique. However, there are a number of artifacts and pitfalls associated with orbital MR imaging. Chemical shift artifacts may be induced by orbital fat or silicone oil used to treat retinal detachment. Motion artifacts are caused primarily by unavoidable globe motion during imaging. Artifacts due to a nonuniform magnetic field are particularly noticeable at air-tissue interfaces but may also be caused by incomplete fat saturation or highly magnetic materials near the orbit. Protocol errors may cause artifacts such as saturation, phase wraparound, truncation, shading, and partial-volume artifacts. This information can be used to improve orbital image quality and avoid misinterpretation of image artifacts. Use of fat saturation, silicone saturation, and careful patient screening for metal near the eyes and instruction to reduce motion can help reduce the occurrence of artifacts. In addition, optimal imaging technique is essential and should include use of proper surface coils, plane of section, and pulse sequences.