Imaging for neuro-ophthalmic and orbital disease - a review

Qualitative and Quantitative Magnetic Resonance Imaging in Bacterial Orbital Cellulitis

PURPOSE

To summarise the qualitative and quantitative parameters of bacterial orbital cellulitis (OC) on magnetic resonance imaging (MRI) and explore their clinical correlations.

METHODS

Multi-centre retrospective study with inclusion of patients of all ages with OC who underwent MRI. Patients with isolated pre-septal cellulitis, bilateral disease and poor-quality scans were excluded. An enlargement ratio for extraocular muscles (EOMs) was calculated by dividing maximal EOM measurements from the affected side by the contralateral side.

RESULTS

Twenty MRI scans from twenty patients (Mean age: 40.8 ± 24.3 years old, M: F = 15:5) between 2011 and 2022 were analysed. Three (15.0%) cases were paediatric patients (<18 years old). All cases had both pre-septal and orbital fat involvement. The EOM were affected in nineteen cases, with the superior muscle complex (18/19, 94.7%) most commonly affected. Mean enlargement ratio (1.30, Range: 1.04-1.82) was greatest for the medial rectus on axial views on T1 and fat-suppressed contrast-enhanced T1 (FS CE T1). Optic peri-neuritis was present in eleven (55.0%) patients, whilst two (9.5%) cases had optic neuritis. A greater degree of proptosis was observed in patients with optic neuropathy and those who underwent surgical intervention compared to those without (p = .002 and p = .002, respectively).

CONCLUSION

MRI remains an important imaging modality for evaluating complicated OC. However, qualitative features may lack accuracy and is not a reproducible means of analysis. Simple quantitative parameters, such as proptosis and EOM measurements, correlate with high-risk clinical features and may have utility in predicting clinical course.

A retrospective analysis of the management and surgical treatment of orbital lesions: Outcomes and rationale

The orbital cavity is a subject of interest for various specialists, and achieving optimal outcomes requires comprehensive, multidisciplinary management. This study aims to report 10 years of experience in the preoperative, surgical, and postoperative care of patients with orbital lesions, examining their clinical, radiological, and anatomopathological features and outcomes. A retrospective review of 125 patients who underwent surgical treatment for intraorbital masses between January 2012 and December 2021 was performed. Outcome measures included postoperative diplopia, exophthalmos, decimal visual acuity, eyeball position, ocular motility, operative time, complications, and aesthetic results. A total of 107 patients were included. All cases were discussed with a neuroradiologist to determine the best therapeutic approach based on preoperative imaging. Preoperative diplopia was linked to extraconal (p = 0.03) and anterior (p = 0.001) lesions, and exophthalmos and visual acuity deterioration were associated with intraconal (p = 0.02; p = 0.03) and retrobulbar (p = 0.001; p = 0.02) lesions. Complications (11.2%) included diplopia, worsened visual acuity, postoperative blepharoptosis, and postoperative ectropion. Of the patients, 80.4% reported an "excellent" aesthetic outcome. This study underscores the importance of a multidisciplinary approach based on a thorough analysis of preoperative imaging. Periorbital approaches tailored to the lesion's three-dimensional location enables safe access to most intraorbital lesions, resulting in minimal complications and good aesthetic results.

Prevalence of significant pathology on MRI of brain and orbits in patients presenting with visual disturbance

PURPOSE

The aim of our study was to determine the frequency and variety of abnormalities detected on MRI studies of the brain and orbits (MRBO), in patients referred for investigation of visual disturbance from a tertiary ophthalmology centre in Ireland. A secondary objective was to assess the various imaging pathologies identified in this cohort of patients.

METHODS

The inclusion criteria were patients who underwent an Magnetic resonance imaging (MRI) brain or MRI brain and orbits over a 12-month period for investigation of first episode of visual disturbance, who were over 18 years of age, with visual disturbance of unknown aetiology. Statistical analysis was performed to calculate the percentage of abnormalities and corresponding 95% confidence interval (CI). Additionally, logistic regression was used to investigate any association between age, gender and the pathologies which presented.

RESULTS

135 MRI brain and orbit examinations fulfilled the inclusion criteria. Abnormalities were identified on 86 of the 135 examinations (63.7%; 95% CI: 55.3% to 71.3%). Nonspecific T2 hyperintensities were identified on 28 (20.7%) of the examinations, 13 (9.6%) examinations showed images suggestive of demyelination and 11 (8.1%) showed optic neuropathy. The logistic regression analysis showed no evidence of an association between age (p = 0.223), gender (p = 0.307) and abnormalities in this study.

CONCLUSION

This represents a relatively high detection rate of abnormalities on MRBO when compared with similar studies and shows the important role MRI has in patients with a visual disturbance.

Advances in magnetic resonance imaging of orbital disease

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

Trends in optical coherence tomography angiography use in university clinic and private practice setting between 2014-2018

BACKGROUND

The aim was to assess the trends in optical coherence tomography angiography (OCTA) use compared with fluorescein angiography (FA).

METHODS

A bilateral patient's exam on a single day was considered one examination. A total of 3680 and 700 OCTA examinations and 3387 and 439 FA examinations were performed between 2014 and 2018 in a university clinic and private practice, respectively. A regression analysis was completed.

RESULTS

The use of OCTA procedures grew 17-fold from 2015 till 2018. In a university clinic, ultrawide-field FA accounted for 2% of all FA examinations performed in 2015, and its use increased to 68% in 2018 while the number of narrow-field FA examinations dropped from 617 in 2014 to 220 in 2018. This decrease inversely correlated with the rise of diabetic retinopathy cases diagnosed with FA (R= -0.86, p= 0.02). In private practice, the increase in the use of OCTA was a primary driver of the decline of the FA use from 127 in 2015 to 27 in 2018, while the number of OCTA examinations was 344 in 2018 (R= -0.99, p= 0.06).

CONCLUSION

The results of the study indicate that OCTA is a valuable tool capable of replacing FA in some selected cases.

The Diagnostic Yield and Cost of Radiologic Imaging for Urgent and Emergent Ocular Conditions in an Eye Emergency Room

Objective The aim of this study is to assess the diagnostic yield and economic cost of radiologic imaging for urgent and emergent ophthalmic conditions in an emergency room (ER) setting

Design Retrospective, consecutive case series.

Methods Charts of all patients who underwent radiologic imaging in a dedicated eye ER over a single year were reviewed. Data collected included age, patient reported chief complaint, visual acuity, principal examination finding, indication for imaging, imaging modalities performed, and the current procedural terminology (CPT) codes billed for the imaging performed. Imaging results were classified into three groups with binary outcomes: normal or abnormal; significant if it led to a change in patient management, and relevant if the imaging findings were related to the chief complaint or principal examination finding. Imaging costs were calculated using the billed CPT codes.

Results A total of 14,961 patients were evaluated during the 1-year study and 1,371 (9.2%) patients underwent imaging. Of these, 521 patients (38.0%) had significant findings. A majority of this group had significant and relevant findings (469, 34.2% of total). Subgroup analysis was performed based upon patient chief complaint, principal examination finding, and indication for imaging. Overall, the total cost of imaging was $656,078.34 with an average cost of $478.54 per patient.

Conclusion Imaging for urgent and emergent ophthalmic conditions in an eye ER resulted in significant management changes in 38.0% of patients. Radiographic imaging contributes to healthcare expenditures; however, these costs must be weighed against the substantial costs of delayed and misdiagnoses, especially when patients present with acute ophthalmological symptoms.

The New Ophthalmology Internship: A Trainee Curricular Survey

Background The American Academy of Ophthalmology, in conjunction with the Accreditation Council of Graduate Medical Education (ACGME), has mandated the creation of a linked ophthalmology internship year for all programs by 2021. This mandate provides a unique opportunity to tailor a curriculum specific to the ophthalmology trainee. This study reports the results of a national survey of ophthalmology residents and fellows regarding the relevance and applicability of extramural content to their ophthalmology training.

Methods Using the online portal SurveyMonkey, an anonymous survey was sent to 119 ACGME-accredited ophthalmology residencies. It consisted of nine questions formulated to measure the perceived applicability and relevance of other specialties to ophthalmology training. Responses were summarized with descriptive statistics. Outcomes were compared by one-way analysis of variance with Tukey's post hoc analysis for between group differences and Benjamini–Hochberg for multiple comparisons.

Results Ninety-four respondents (residents and fellows) completed the survey (January–February 2020); 52.1% completed an internal medicine internship, 42.6% transitional, and 5.3% general surgery. Overall, prior internship experience was rated favorably. Otolaryngology and radiology were deemed the most relevant to ophthalmology training. Intensive care unit (ICU) was considered the least beneficial, followed by general surgery, primary care, and pediatrics. Neuroradiology was overwhelmingly preferred over general radiology. The majority of respondents reported minimal exposure to oral and maxillofacial surgery (OMFS) in medical school/internship. When choosing a reason for inclusion in the new curriculum, respondents reported a high level of surgical overlap with otolaryngology, OMFS, and plastic surgery; clinical overlap with neurology; and ophthalmic consultation with emergency medicine.

Conclusion Several specialties—notably otolaryngology, radiology, and neurology—were considered highly relevant but lacking in preresidency exposure. The preference for neuroradiology was almost unanimous. In contrast, general surgery and ICU were found to be minimally relevant. Overall, ophthalmology residents reported a high level of satisfaction with their internship experience, an important consideration when building a curriculum that will appeal to potential applicants. The findings of this survey provide a framework to build a curricular plan based on current resident and fellow experience.

Imaging of Nontraumatic Orbital and Neuro-ophthalmological Emergencies

Emergency department (ED) visits for eye and vision-related concerns are common. In most cases, accurate diagnosis is made using clinical history and physical exam findings without the need for emergent imaging. When orbital imaging is performed in the ED, it is often in patients with orbital trauma where CT is used to assess for orbital fractures and associated injuries. However, CT or MR imaging can also be critical to appropriately diagnose and manage certain ED patients with nontraumatic eye and vision-related conditions. The purpose of this article is to review the imaging findings and differential diagnoses for nontraumatic orbital and neuro-ophthalmological emergencies from a practical, clinical perspective, based on a patient's typical presenting symptoms. The more commonly imaged clinical indications will be discussed including periorbital swelling, proptosis, eye pain, diplopia, and visual disturbances. In addition, rare but easily overlooked and clinically important diagnoses for the emergency radiologist to recognize will be highlighted.

Anatomical, histological and computed tomography comparisons of the eye and adnexa of crab-eating fox (Cerdocyon thous) to domestic dogs

An understanding of species' morphological and physiological parameters is crucial to developing conservation strategies for wild animals kept in human care. Detailed information is lacking for crab-eating fox (Cerdocyon thous) eyes and adnexa. Therefore, the aim of this study was to describe anatomical, histological and computed tomography (CT) features of the eye and adnexa in crab-eating fox, compared to domestic dogs. CT of the eye and adnexa of one live animal and a frozen specimen was performed for anatomical identification. In addition, the heads of five animals of each species were fixed in 10% buffered formalin for gross anatomical description of the eye and adnexa using topographic dissection and exenteration techniques. All steps were photographed and features such as location, shape, and distances and relationships between structures were described. For histological evaluation, two eyes of each species were fixed in 10% buffered formalin, processed by routine paraffin inclusion technique and stained with hematoxylin and eosin. The CT scan was difficult to evaluate, mainly that of the frozen head, which did not provide good definition of the soft tissues; nevertheless, it demonstrated the potential for structure visualization and description. The gross anatomical and histological evaluations showed the presence of eyelashes on the upper eyelid and of upper and lower lacrimal points, an incomplete orbit with supraorbital ligament, slightly exposed sclera with discretely pigmented limbus and pigmentation throughout the conjunctiva, and a slit-shaped pupil. Hematoxylin and eosin staining demonstrated structural similarities between the crab-eating fox and domestic dog. Thus, the possibility of using the domestic dog as a study model for the preventive and therapeutic management of wild dogs kept in human care is demonstrated.

Imaging in Neuro-ophthalmology

PURPOSE OF REVIEW

This article discusses an approach to imaging in patients with neuro-ophthalmologic disorders, with emphasis on the clinical-anatomic localization of lesions affecting afferent and efferent visual function.

RECENT FINDINGS

Advances in MRI, CT, ultrasound, and optical coherence tomography have changed how neuro-ophthalmic disorders are diagnosed and followed in the modern clinical era.

SUMMARY

The advantages, disadvantages, and indications for various imaging techniques for neuro-ophthalmologic disorders are discussed, with a view to optimizing how these tools can be used to enhance patient care.

How accurate is the clinical and radiological evaluation of orbital lesions in comparison to surgical orbital biopsy?

AIMS

The purpose of the present study is to determine the overall and disease-related accuracy of clinical and radiological diagnosis when compared to the histology result of the surgical orbital biopsy.

METHODS

A retrospective case notes analysis of patients who underwent surgical orbital biopsy during a 12-year period involving more than 100 orbital lesions. The accuracy of clinical and radiological diagnosis was compared with histological diagnosis.

RESULTS

A total of 112 orbital biopsies were carried out in 104 eyes of 101 patients between 2003 and 2015. Correct diagnosis was reached in <50% of cases by both ophthalmologists and radiologists alike. Vascular lesions exhibit characteristic clinical and imaging features that allow for accurate diagnosis and can often be managed conservatively. The greatest challenge, both clinically and on imaging was in differentiating between inflammatory and haematological orbital lesions which represented half of our cases. There was no operative mortality and there were no post-operative complications recorded.

CONCLUSION

Surgical orbital biopsy is a safe and accurate diagnostic tool for orbital lesions of unknown aetiology and, in our opinion, remains the gold standard.

Diagnostic imaging in neuro-ophthalmology

Neuro-ophthalmology is a field combining neurology and ophthalmology that studies diseases that affect the visual system and the mechanisms that control eye movement and pupil function. Imaging tests make it possible to thoroughly assess the relevant anatomy and disease of the structures that make up the visual pathway, the nerves that control eye and pupil movement, and the orbital structures themselves. This article is divided into three sections (review of the anatomy, appropriate imaging techniques, and evaluation of disease according to clinical symptoms), with the aim of providing useful tools that will enable radiologists to choose the best imaging technique for the differential diagnosis of patients' problems to reach the correct diagnosis of their disease.

Apparent Diffusion Coefficient (ADC) of the vitreous humor and Susceptibility Weighted Imaging (SWI) of the retina in abused children with retinal hemorrhages

This study speculated that the apparent diffusion coefficient (ADC) of the vitreous humor might be altered in the setting of abusive head trauma (AHT) with retinal hemorrhages (RH). Fourty-four subjects were analyzed (n=20 AHT cases; n=24 controls). There was no statistically significant difference in normalized ADC values between the cases and controls (-0.14 and -0.08 respectively, p=0.46), but analysis of RH by susceptibility weighted imaging (SWI) compared to dilated funduscopic exam demonstrated statistically significant correlation (p=0.003 and 0.012). Our results suggest that SWI serves as a more sensitive diagnostic tool for detection of ocular injury in AHT than ADC.

Specialized Diagnostic Investigations to Assess Ocular Status in Hypertensive Diseases of Pregnancy

This review describes specialized diagnostic investigations to assess ocular status in hypertensive diseases of pregnancy. Ocular assessment can aid in early detection for prompt multidisciplinary treatment, obstetric intervention and follow-up. The investigations accurately predict the possible causes of blindness in hypertensive diseases of pregnancy. The investigations include fluorescein angiography, ophthalmodynamometry, fluorophotometry, imaging modalities, OCT, ultrasonography, doppler velocimetry and blood chemistry analysis. The review includes a summary of imaging techniques and related recent developments to assess the neuro-ophthalmic aspects of the disease. The imaging modalities have been instrumental in understanding the complex neuropathophysiological mechanisms of eclamptic seizures. The importance of blood chemistry analysis in hypertensive diseases of pregnancy has been emphasized. The investigations have made a significant contribution in improving the standards of antenatal care and reducing maternal and fetal morbidity and mortality.

Orbital tumours and tumour-like lesions: exploring the armamentarium of multiparametric imaging

Although the orbit is a small anatomical space, the wide range of structures present within it are often the site of origin of various tumours and tumour-like conditions, both in adults and children. Cross-sectional imaging is mandatory for the detection, characterization, and mapping of these lesions. This review focuses on multiparametric imaging of orbital tumours. Each tumour is reviewed in relation to its clinical presentation, compartmental location, imaging characteristics, and its histological features. We herein describe orbital tumours as lesions of the globe (retinoblastoma, uveal melanoma), optic nerve sheath complex (meningioma, optic nerve glioma), conal-intraconal compartment (hemangioma), extraconal compartment (dermoid/epidermoid, lacrimal gland tumours, lymphoma, rhabdomysarcoma), and bone and sinus compartment (fibrous dysplasia). Lesions without any typical compartmental localization and those with multi-compartment involvement (veno-lymphatic malformation, plexiform neurofibroma, idiopathic orbital pseudotumour, IgG4 related disease, metastases) are also reviewed. We discuss the role of advanced imaging techniques, such as MR diffusion-weighted imaging (DWI), diffusion tensor imaging, fluoro-2-deoxy-D-glucose positron emission tomography CT (FDG-PET CT), and positron emission tomography MRI (MRI PET) as problem-solving tools in the evaluation of those orbital masses that present with non-specific morphologic imaging findings. Main messages/Teaching points • A compartment-based approach is essential for the diagnosis of orbital tumours. • CT and MRI play a key role in the work-up of orbital tumours. • DWI, PET CT, and MRI PET are complementary tools to solve diagnostic dilemmas. • Awareness of salient imaging pearls and diagnostic pitfalls avoids interpretation errors.

Imaging of the Postoperative Orbit

Imaging evaluation of the postoperative orbit remains challenging even for the expert neuroradiologist. This article provides a simplified framework for understanding the complex postoperative appearances of the orbit, in an attempt to enhance the diagnostic accuracy of postoperative computed tomography and MR imaging of the orbit. Readers are familiarized with the normal appearances of common eye procedures and orbit reconstructions to help avoid interpretative pitfalls. Also reviewed are imaging features of common surgical complications, and evaluation of residual/recurrent neoplasm in the setting of oncologic imaging surveillance.

Infrared pupillometry, the Neurological Pupil index and unilateral pupillary dilation after traumatic brain injury: implications for treatment paradigms

Pupillary dysfunction, a concerning finding in the neurologic examination of the patient with an acute traumatic brain injury often dictates the subsequent treatment paradigm. Patients were monitored closely with an infrared pupillometer, with NPi technology, for acute changes in pupillary function. NPi technology applies a scalar value to pupillary function. A retrospective chart review was performed of traumatic brain injury patients with acute unilateral pupillary dilation, admitted to Legacy Emanuel Medical Center’s NeuroTrauma Unit, Portland, OR, and followed as outpatients, between January 2012 and December 2013. Clinical exam findings of pupillary size, NPi scores, and brain Magnetic Resonance Imaging and Computed Tomography images were analyzed. Five traumatic brain injury patients were identified with unilateral pupillary dysfunction with long-term follow-up after the initial injury. Each patient was monitored closely in the trauma bay for neurological deterioration with a pupillometer and the clinical exam. Two patients underwent subsequent intracranial pressure monitoring based on a deteriorating clinical scenario, including consistent abnormal unilateral NPi scores. One patient with consistent abnormal NPi scores and an improved clinical exam did not undergo invasive interventions. Two patients showed early improvement in NPi scores correlating with the normalization of their pupillary reactivity. Anisocoria improved in all patients despite concurrent abnormal NPi scores. Magnetic Resonance Imaging and Computed Tomography imaging studies, with a focus on the third nerve, revealed focal abnormalities consistent with the clinical findings. A unilateral blown pupil and abnormal NPi score in a traumatic brain injury patient are not necessarily indicative of intracranial pressure issues, and must be correlated with the entire clinical scenario, to determine the etiology of the third nerve injury and direct potential therapeutic interventions. Early NPi score normalization suggests pupillary function may improve. We found that NPi scores, as a component of the clinical exam, provide a sensitive, noninvasive and quantitative means of following pupillary function acutely and chronically after a traumatic brain injury.

Imaging of adult ocular and orbital pathology--a pictorial review

Orbital pathology often presents a diagnostic challenge to the reporting radiologist. The aetiology is protean, and clinical input is therefore often necessary to narrow the differential diagnosis. With this manuscript, we provide a pictorial review of adult ocular and orbital pathology.

Neuroimaging in ophthalmology

In the past three decades, there have been countless advances in imaging modalities that have revolutionized evaluation, management, and treatment of neuro-ophthalmic disorders. Non-invasive approaches for early detection and monitoring of treatments have decreased morbidity and mortality. Understanding of basic methods of imaging techniques and choice of imaging modalities in cases encountered in neuro-ophthalmology clinic is critical for proper evaluation of patients. Two main imaging modalities that are often used are computed tomography (CT) and magnetic resonance imaging (MRI). However, variations of these modalities and appropriate location of imaging must be considered in each clinical scenario. In this article, we review and summarize the best neuroimaging studies for specific neuro-ophthalmic indications and the diagnostic radiographic findings for important clinical entities.

Neuroimaging in patients referred to a neuro-ophthalmology service: the rates of appropriateness and concordance in interpretation

OBJECTIVE

Neuroimaging studies frequently are ordered to investigate neuro-ophthalmic symptoms. When misused, these studies are expensive and time consuming. This study describes the type and frequency of neuroimaging errors in patients referred to an academic neuro-ophthalmology service and measures how frequently these neuroimaging studies were reinterpreted.

DESIGN

Prospective cohort study.

PARTICIPANTS

Eighty-four consecutive patients referred to an academic neuro-ophthalmology practice.

METHODS

From November 2009 through July 2010, 84 consecutive new patients who had undergone a neuroimaging study in the last 12 months specifically to evaluate their presenting neuro-ophthalmic symptoms were enrolled prospectively. Participants then underwent a complete neuro-ophthalmic evaluation, followed by a review of prior neuroimaging. Questions regarding appropriateness of the most recent imaging, concordance of radiologic interpretation, and re-evaluation of referring diagnoses were answered by the attending physician.

MAIN OUTCOME MEASURES

The frequency and types of errors committed in the use of neuroimaging and the frequency of reinterpretation of prereferral neuroimaging studies after neuro-ophthalmic history and examination.

RESULTS

Most study participants (84.5%; 71/84) underwent magnetic resonance imaging before referral; 15.5% (13/84) underwent only computed tomography. The rate of suboptimal neuroimaging studies was 38.1% (32/84). The 3 most common reasons for suboptimal studies were incomplete area of imaging (34.4%; 11/32), wrong study type (28.1%; 9/32), and poor image quality (21.9%; 7/32). Twenty-four of 84 subjects (28.6%) required additional neuroimaging. The authors agreed with the radiology interpretation of the prior neuroimaging studies in most patients (77.4%; 65/84). The most common anatomic locations for discordance in interpretation were the intraorbital optic nerve (35%; 7/20) and the brainstem (20%; 4/20).

CONCLUSIONS

There was a high rate of suboptimal neuroimaging studies performed in patients referred for neuro-ophthalmology examination. These findings have significant implications given the increasing attention to resource use currently and in the near future.

Diffusion changes in the vitreous humor of the eye during aging

BACKGROUND AND PURPOSE

The inability to image the vitreous humor of the eye adequately hinders a complete understanding of its normal structure and the changes occurring in aging and disease. The purpose of the present study was to reveal normative data and age-related changes of the vitreous humor by using DWI.

MATERIALS AND METHODS

A total of 160 patients were enrolled in the present study. Patients were divided into 8 groups according to decade of age, and each group was of equal size with 20 patients. The ADCs were determined for each vitreous humor. Each determination was obtained by using average regions of interest of 50 ± 2 mm(2). ADC values were then plotted against age.

RESULTS

The ADC values obtained from group 0 (0-10 years of age) were statistically different from those of all other groups (P < .05). Group 1 (11-20 years of age) was statistically different from groups 3, 5, 6, and 7 (P < .05). A trend toward increased ADC values with increasing age was not statistically significant.

CONCLUSIONS

Besides the statistically significant difference between pediatric and adult patients, a statistically insignificant trend of increased ADC values among aging adults has been demonstrated. These normative data contribute to our understanding of how DWI can aid in the diagnosis of age-related changes in eye health and function.

Role of imaging in the management of neuro-ophthalmic disorders

Advancements in physics, computers, and imaging science in the last century have seen neuro-imaging evolving from a plain X-ray to computed tomography, magnetic resonance imaging scans, noninvasive angiography, and special sequences such as fat suppression, fluid attenuation recovery and diffusion-weighted imaging. A prompt prescription of an appropriate imaging modality and the most suitable sequence can increase the diagnostic yield, and in many instances, it can be a sight-saving and even a life-saving decision. This article discusses basic principles of neuro-imaging, its common indications, and the appropriate application in an ophthalmology practice.

Sixth nerve palsy as the presenting symptom of metastatic colon carcinoma

Isolated cranial mononeuropathies in patients over 50 years of age most commonly result from microvascular ischemic demyelination. A 51-year-old female without vasculopathic risk factors presented with isolated sixth nerve palsy. Magnetic resonance imaging (MRI) of the brain and orbits revealed a cavernous sinus lesion that was diagnosed as a meningioma. Laboratory tests showed abnormal liver function, and an abdominal computerized tomogram demonstrated an obstructive colonic mass with liver metastasis. The pathology tests of specimens taken during a laparotomy diagnosed colon adenocarcinoma. The MRI interpretation was changed to cavernous sinus metastasis from a primary adenocarcinoma of the colon. This case had common cranial nerve symptoms but with a very rare etiology, emphasizing the importance of a high index of suspicion of remote origins in patients with isolated sixth nerve palsy and no atherosclerotic risk factors.

Imaging in neuro-ophthalmology: An overview

Advances in neuroimaging and interventional techniques have revolutionized the early diagnosis, prognosis, and treatment of neuro-ophthalmic disorders. These techniques include computed tomography (CT), magnetic resonance imaging (MRI), CT and MR angiographic techniques, catheter digital subtraction angiography, functional MRI, positron emission tomography, and single photon emission computed tomography. In this review, the value of current techniques in the diagnosis, localization, and treatment of various neuro-ophthalmic disorders is described.