Neuro-ophthalmic evaluation and management of pituitary disease.

Neuro-ophthalmic evaluation is a crucial component of the diagnostic and prognostic assessment of pituitary disease and compressive chiasmopathy, and can inform the timing of vision-restoring tumour resection surgery. The most common disease affecting the pituitary with neuro-ophthalmic implications are pituitary adenomas. Neuro-ophthalmic manifestations include decreased vision, abnormal colour vision and impaired visual field or diplopia. The recognition of these syndromes is critical to achieve early diagnosis and treatment and to improve prognosis. The pattern of vision loss in chiasmal compression is determined by the anatomical relationship between the pituitary lesion and optic chiasm, and potential visual field defects include bitemporal deficits, junctional scotomas, monocular cecocentral defects, and incongruous homonymous hemianopias. Rarer neuro-ophthalmic manifestations of pituitary disease include ophthalmoplegia, nystagmus, and obstructive hydrocephalus. There is growing evidence that demonstrates the strong diagnostic utility of optical coherence tomography (OCT) parameters in detecting the presence of compressive chiasmopathy, as well as the prognostic ability to predict the rate and degree of visual recovery following decompression surgery. Long-term neuro-ophthalmic monitoring is critical for detecting delayed vision loss following resection surgery, which may represent tumour recurrence or secondary complications.

Morning Glory Disc Anomaly: Expanding the MR Phenotype.

BACKGROUND AND PURPOSE: Morning glory disc anomaly (MGDA) is a congenital malformation characterized by a funnel-shaped optic disc excavation with radiating vessels and a central glial tuft. Imaging is essential to evaluate associated cephalocele and steno-occlusive vasculopathy. The goal of this study was to assess optic nerve, chiasmatic, and sphenoid bone morphology in MGDA. MATERIALS AND METHODS: This retrospective study examined all subjects with funduscopically confirmed MGDA diagnosed and imaged with brain MR imaging between 2008 and 2023. RESULTS: Thirty-two children met inclusion criteria. Ocular involvement was unilateral in 29 subjects and bilateral in 3. Segmental optic nerve enlargement ipsilateral to the MGDA was seen in 21 subjects, with 3 also demonstrating a segmental reduction in the size of the ipsilateral optic nerve. Segmental reduction in the size of the ipsilateral optic nerve was present in 3 additional subjects, one with bilateral MGDA. The optic chiasm appeared asymmetrically thickened in 21 subjects, often with deformity. The optic nerves appeared normal in signal intensity in all subjects, with faint peripheral chiasmatic enhancement in 4 of 20 patients who received contrast. Optic nerve findings were stable in 15 subjects with multiple examinations. A persistent craniopharyngeal canal was identified in 17 subjects with sphenoid cephalocele in 1 and mild inferior pituitary gland displacement in 4. Tubular or nodular nasopharyngeal lesions were seen in 10 subjects. One subject had an off-midline sphenoid bone cleft, midbrain deformity, and abnormal thickening of and enhancement around the left oculomotor nerve; the oculomotor nerve finding was present in 1 additional patient. CONCLUSIONS: MGDA often manifests with ipsilateral optic nerve thickening, leading to a potential misdiagnosis as optic glioma. MGDA is also commonly associated with a persistent craniopharyngeal canal with variable pituitary gland and infundibular deformity, cephalocele, and tubular or nodular nasopharyngeal lesions.

Pearls & Oy-sters: Case Report of a Ruptured Suprasellar Dermoid Cyst Presenting With Junctional Scotoma of Traquair.

A 27-year-old woman with a known suprasellar dermoid cyst and stable idiopathic intracranial hypertension (IIH) presented with new monocular vision change and new-onset headaches. Formal visual field testing accurately identified progressive chiasmal compression due to her suprasellar dermoid cyst before radiographic change was appreciable on magnetic resonance imaging. Accurate interpretation of her visual field findings avoided the common pitfall of attributing new visual symptoms to her IIH diagnosis. This case highlights the value of recognizing visual field changes that localize to the chiasm even in patients with history of other ophthalmologic conditions.

Nerve fibre organisation in the human optic nerve and chiasm: what do we really know?

A recent anatomical study of the human optic chiasm cast doubt on the widespread assumption that nerve fibres travelling in the human optic nerve and chiasm are arranged retinotopically. Accordingly, a scoping literature review was performed to determine what is known about the nerve fibre arrangement in these structures. Meta-analysis suggested that the average number of fibres in each optic nerve was 1.023 million with an inter-individual range of approximately 50% of the mean. Loss of nerve fibres with age (approximately 3,400 fibres/year) could not account for this variability. The review suggested that there might be a retinotopic arrangement of nerve fibres in the orbital portion of the optic nerve but that this arrangement is most likely to be lost posteriorly with a more random distribution of nerve fibres at the chiasm. Limited studies have looked at nerve fibre arrangement in the chiasm. In summary, the chiasm is more 'H-shaped' than 'X-shaped': nerve fibre crossings occur paracentrally with nerves in the centre of the chiasm travelling coronally and in parallel. There is interaction between crossed and uncrossed fibres which are widely distributed. The review supports the non-existence of Wilbrand's knee. Considerable further work is required to provide more precise anatomical information, but this review suggests that the assumed preservation of retinotopy in the human optic nerve and chiasm is probably not correct.

Optic chiasm involvement in multiple sclerosis, aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein-associated disease.

BACKGROUND: Optic neuritis (ON) is a common feature of inflammatory demyelinating diseases (IDDs) such as multiple sclerosis (MS), aquaporin 4-antibody neuromyelitis optica spectrum disorder (AQP4 + NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). However, the involvement of the optic chiasm (OC) in IDD has not been fully investigated. AIMS: To examine OC differences in non-acute IDD patients with (ON+) and without ON (ON-) using magnetisation transfer ratio (MTR), to compare differences between MS, AQP4 + NMOSD and MOGAD and understand their associations with other neuro-ophthalmological markers. METHODS: Twenty-eight relapsing-remitting multiple sclerosis (RRMS), 24 AQP4 + NMOSD, 28 MOGAD patients and 32 healthy controls (HCs) underwent clinical evaluation, MRI and optical coherence tomography (OCT) scan. Multivariable linear regression models were applied. RESULTS: ON + IDD patients showed lower OC MTR than HCs (28.87 ± 4.58 vs 31.65 ± 4.93; p = 0.004). When compared with HCs, lower OC MTR was found in ON + AQP4 + NMOSD (28.55 ± 4.18 vs 31.65 ± 4.93; p = 0.020) and MOGAD (28.73 ± 4.99 vs 31.65 ± 4.93; p = 0.007) and in ON- AQP4 + NMOSD (28.37 ± 7.27 vs 31.65 ± 4.93; p = 0.035). ON+ RRMS had lower MTR than ON- RRMS (28.87 ± 4.58 vs 30.99 ± 4.76; p = 0.038). Lower OC MTR was associated with higher number of ON (regression coefficient (RC) = -1.15, 95% confidence interval (CI) = -1.819 to -0.490, p = 0.001), worse visual acuity (RC = -0.026, 95% CI = -0.041 to -0.011, p = 0.001) and lower peripapillary retinal nerve fibre layer (pRNFL) thickness (RC = 1.129, 95% CI = 0.199 to 2.059, p = 0.018) when considering the whole IDD group. CONCLUSION: OC microstructural damage indicates prior ON in IDD and is linked to reduced vision and thinner pRNFL.

Longitudinal changes in optic disc cupping from the baseline in chiasmal lesion optic neuropathy and glaucoma.

We aimed to investigate the changes in cupping in chiasmal lesion optic neuropathy (chON) compared to baseline optic disc and glaucoma. We used a novel study design to enroll patients who had fundus photographs incidentally taken during routine health check-ups prior to the onset of optic neuropathy. In 31 eyes (21 patients) with chON and 33 eyes (30 patients) with glaucoma, we investigated the change in cup-to-disc (C/D) area from the baseline to overt cupping using flicker analysis. Compared to the baseline, 23 eyes (74.2%) had increased cup size and 3 (9.7%) had vascular configuration changes in the chONgroup; in contrast, all glaucoma eyes exhibited changes in cup size and vascular configuration. The increase in C/D area ratio was significantly smaller in chON (0.04 ± 0.04) compared to glaucoma (0.10 ± 0.04, P < 0.001); the minimum residual neuroretinal rim width showed a more pronounced difference (29.7 ± 8.2% vs 7.1 ± 3.9%, P < 0.001). The changes distributed predominantly towards the nasal direction in chON, contrasting the changes to the arcuate fibers in glaucoma. In conclusion, our results provide the first longitudinal evidence of true pathological cupping in chONcompared to photographically disease-free baseline. The marked difference in the residual minimum rim width reaffirms the importance of rim obliteration in the differential diagnosis between the two diseases.

Comparison of MRI findings of hypothalamic-optic chiasmatic gliomas and craniopharyngiomas.

BACKGROUND: Differential diagnosis of hypothalamic-optic chiasmatic gliomas (HOCGs) and craniopharyngiomas on magnetic resonance imaging (MRI) can be quite challenging. PURPOSE: To compare the MRI features of HOCGs and cranipharyngiomas. MATERIAL AND METHODS: Patients diagnosed with HOCG or craniopharyngioma in histopathological evaluation between 2012 and 2022 and who underwent preoperative contrast-enhanced brain MRI were included. Various MRI features were retrospectively evaluated for each lesion: T2-weighted imaging and fluid attenuation inversion recovery hyperintensity, calcification, cystic change, T1-weighted (T1W) imaging hyperintensity of the cystic component, hemorrhage, involvement of sellar, suprasellar or other adjacent structures, lobulated appearance, presence of hydrocephalus, and contrast enhancement pattern. Apparent diffusion coefficient (ADC) values were also evaluated and compared. RESULTS: Among 38 patients included, 13 (34%) had HOCG and 25 (66%) had craniopharyngioma. Craniopharyngiomas had a significantly higher rate of cystic changes, calcification, and T1W imaging hyperintensity of the cystic component than HOCGs (P <0.05). Of HOCGs, 92% had chiasm involvement, 23% had optic nerve involvement, and 31% had brain stem involvement. On the other hand, chiasm involvement was observed in 8% of craniopharyngiomas, but none had optic nerve and/or brain stem involvement (P <0.05). While 62% (8/13) of HOCGs had diffuse homogeneous enhancement, 80% (20/25) of craniopharyngiomas had a diffuse heterogeneous enhancement pattern. Mean ADC values were significantly higher in craniopharyngiomas compared to HOCGs (2.1 vs. 1.6 ×10-3mm2/s, P <0.05). CONCLUSION: Although some neuroimaging findings may overlap, features such as presence of cyst and calcification, brain stem and optic pathway involvement, different enhancement patterns, and ADC values may be helpful in the differential diagnosis of HOCGs and craniopharyngiomas.

Role of PKN1 in Retinal Cell Type Formation.

We recently identified PKN1 as a developmentally active gatekeeper of the transcription factor neuronal differentiation-2 (NeuroD2) in several brain areas. Since NeuroD2 plays an important role in amacrine cell (AC) and retinal ganglion cell (RGC) type formation, we aimed to study the expression of NeuroD2 in the postnatal retina of WT and Pkn1-/- animals, with a particular focus on these two cell types. We show that PKN1 is broadly expressed in the retina and that the gross retinal structure is not different between both genotypes. Postnatal retinal NeuroD2 levels were elevated upon Pkn1 knockout, with Pkn1-/- retinae showing more NeuroD2+ cells in the lower portion of the inner nuclear layer. Accordingly, immunohistochemical analysis revealed an increased amount of AC in postnatal and adult Pkn1-/- retinae. There were no differences in horizontal cell, bipolar cell, glial cell and RGC numbers, nor defective axon guidance to the optic chiasm or tract upon Pkn1 knockout. Interestingly, we did, however, see a specific reduction in SMI-32+ α-RGC in Pkn1-/- retinae. These results suggest that PKN1 is important for retinal cell type formation and validate PKN1 for future studies focusing on AC and α-RGC specification and development.

Optochiasmatic Cavernomas: Updated systematic review and proposal of a novel classification with surgical approaches.

Cavernomas are histologically benign vascular malformations found at different sites in the brain. A rare site for such cavernomas, however, is the anterior optic pathway, comprising the optic nerve, chiasma, and optic tract-called optochiasmatic cavernomas (OCC). These lesions usually present with sudden onset or progressive vision loss, headache, and features mimicking pituitary apoplexy. In this paper, we describe a case of OCC operated at our center. We carry out an updated review of literature depicting cases of OCC, their clinical presentation, management, and postoperative complications. We also propose a novel classification system based on lesion location and further analyze these cavernoma types with respect to the surgical approach used and visual outcome. A 30-year-old lady had presented with a 3-week history of progressive bilateral vision loss and headache. Based on imaging, she was suspected to have a cavernous angioma of the chiasma and left optic tract. Due to progressive vision deterioration, the lesion was surgically excised using pterional craniotomy. Postoperatively, her visual symptoms improved, but she developed diabetes insipidus. Clinical and radiological follow-up has been done for 18 months after surgery. A total of 81 cases have been described in the literature, including the present case. Chiasmal apoplexy is the most common presentation. Surgical excision is the standard of care. Our analysis based on lesion location shows the most appropriate surgical approach to be used for each cavernoma type. Visual outcome correlates with the preoperative visual status. Visual outcome is good in patients presenting with acute chiasmal apoplexy, and when complete surgical excision is performed. The endonasal endoscopic approach was found to provide the best visual outcome. In addition to preoperative visual status, complete surgical excision predicts favorable visual outcomes in OCC. Our proposed classification system guides the appropriate surgical approach required for a particular location of the cavernoma.

Microsurgical Resection of a Parachiasmatic Craniopharyngioma via a Left-Sided Pterional Transsylvian Approach.

Craniopharyngiomas are histologically benign tumors that originate from squamous rests along the pituitary stalk. They make up approximately 1.2% to 4.6% of all intracranial tumors and do not show significant differences in occurrence based on sex. Adamantinomatous craniopharyngiomas have 2 peaks of incidence, commonly observed in patients from ages 5 to 15 years and again from 45 to 60 years. In contrast, papillary craniopharyngiomas mainly affect adults in their fifth and sixth decades of life.1 The "malignancy" of craniopharyngiomas is attributed to their location and the challenges associated with achieving complete removal because they can manifest in the sellar, parachiasmatic, and intraventricular regions or a combination of these.2,3 Various approaches have been used to resect these tumors.4,5 Radical resection offers the most promising option for disease control, potential cure, and the ability to transform the disease from lethal to survivable in children, allowing for a functional adult life.2,3 Meticulous evaluation is crucial to determine the appropriate approach and side, with particular emphasis on closely examining the relationship between the tumor and optic pathways (nerve, chiasm, tract), which are frequently involved. This assessment should also include the tumor's relationship with other crucial structures, such as the hypothalamus and adjacent arteries, to ensure that the strategy is adjusted accordingly to further minimize the risk of postoperative morbidity. Video 1 demonstrates a left-sided pterional transsylvian approach to remove a parachiasmatic craniopharyngioma involving the left optic chiasm and tract.

Biometry extraction and probabilistic anatomical atlas of the anterior Visual Pathway using dedicated high-resolution 3-D MRI.

Anterior Visual Pathway (aVP) damage may be linked to diverse inflammatory, degenerative and/or vascular conditions. Currently however, a standardized methodological framework for extracting MRI biomarkers of the aVP is not available. We used high-resolution, 3-D MRI data to generate a probabilistic anatomical atlas of the normal aVP and its intraorbital (iOrb), intracanalicular (iCan), intracranial (iCran), optic chiasm (OC), and tract (OT) subdivisions. We acquired 0.6 mm3 steady-state free-precession images from 24 healthy participants using a 3 T scanner. aVP masks were obtained by manual segmentation of each aVP subdivision. Mask straightening and normalization with cross-sectional area (CSA) preservation were obtained using scripts developed in-house. A probabilistic atlas ("aVP-24") was generated by averaging left and right sides of all subjects. Leave-one-out cross-validation with respect to interindividual variability was performed employing the Dice Similarity Index (DSI). Spatially normalized representations of the aVP subdivisions were generated. Overlapping CSA values before and after normalization demonstrate preservation of the aVP cross-section. Volume, length, CSA, and ellipticity index (ε) biometrics were extracted. The aVP-24 morphology followed previous descriptions from the gross anatomy. Atlas spatial validation DSI scores of 0.85 in 50% and 0.77 in 95% of participants indicated good generalizability across the subjects. The proposed MRI standardization framework allows for previously unavailable, geometrically unbiased biometric data of the entire aVP and provides the base for future spatial-resolved, group-level investigations.

Is the OCT a predictive tool to assess visual impairment in optic chiasm compressing syndrome in pituitary macroadenoma? A prospective longitudinal study.

Visual dysfunction is a prevalent symptom in patients with non-functioning pituitary macroadenoma (NFPM); the role of OCT in such patients has not been yet determined. This is a prospective longitudinal observational study over a period of 6 years, on 20 patients presenting a radiological compression of the optic chiasma without visual acuity (VA) and visual field (VF) disturbances. The primary endpoint was to evaluate the impact of NFPA on neuro-axonal loss by measuring RNFL thickness using OCT at inclusion (T0), 12 months (T1), 24 months (T2), and 36 months (T3), respectively. The secondary endpoint was to monitor the evolution of OCT over time and assess any relationship between the degree of OCT alteration and the degree of radiological and clinical optic chiasm compression syndrome. Among the 20 patients included, eight (40%) showed an altered RNFL-OCT at diagnosis, while the remaining 12 (60%) showed a normal pattern. During a mean ophthalmologic follow-up of 60 months, 4 patients (20%) presented an asymptomatic reduction of RNFL-OCT thickness although all 20 had a VA/VF stable. To our knowledge, this study represents the first attempt to longitudinally evaluate the natural history and evolution of RNFL-OCT in patients with radiologically asymptomatic chiasmatic compression syndrome. The results do not clearly demonstrate the role of the OCT as an early prognostic factor for visual dysfunction.

Optic chiasm manual and automated measurements in sub-acute optic neuritis with OCT and MRI correlations.

PURPOSE: The optic chiasm (OC) is a central structure in the visual pathway and can be visualized in conventional MRI, but no consensus regarding its measurement has been defined. We aim to investigate the most reproducible manual approach to OC measurement and to explore associations of OC with optical coherence tomography (OCT) parameters, and automatic brain segmentation (FreeSurfer) in subacute optic neuritis (sON), multiple sclerosis without optic neuritis (MSwoON), and healthy subjects (HS). MATERIALS AND METHODS: We reproduced two previously reported methodologies and implemented a new proposed simplified approach, entitled optic chiasm mean area (OCMA). The intra and inter-rater reliability and reproducibility were assessed through the intraclass correlation (ICC) and Dice similarity (DSC) coefficients. Partial correlations were calculated to gauge the associations between OCMA fraction (OCMA divided by total intracranial volume), brain regional segmentations derived from FreeSurfer, and OCT parameters. RESULTS: We have analysed 43 sON, 20 MSwoON, and 20 HS. OCMA presented better results for reliability in both intra- and inter-rater analysis (excellent ICC and DSC with over 80% overlap between masks), as compared to the other two approaches. OCMA fraction was associated with OC volume fraction obtained with Freesurfer in all groups, brain parenchymal fraction, and OCT parameters in MSwoON. CONCLUSIONS: The OCMA is a simplified approach to measure OC atrophy, has a higher reliability than the current approaches and shows association with an automated method. OC-derived measures seem to reflect diffuse neurodegenerative damage, whereas, in patients with subacute ON, it may be associated with local damage.

Prechiasmatic Transection of the Unilateral Dodge Class â Optic Pathway Glioma without Neurofibromatosis Type 1: Technical Description and Clinical Prognosis.

OBJECTIVE: For unilateral Dodge Class Ⅰ optic pathway glioma (OPG-uDCⅠ) without neurofibromatosis type 1, unilateral isolated optic nerve gliomas before the optic chiasm have been confirmed to possibly cause visual deterioration and poor prognosis. For this type of highly selective localized tumor, we explored surgery as the only treatment method. This article retrospectively analyzed and summarized the clinical data of this case series, with the aim of exploring the main technical details and clinical prognosis. METHODS: Included were patients with OPG-uDCⅠ without neurofibromatosis type 1 and experiencing vision loss on the affected side. The fronto-orbital approach was used, which was mainly divided into 3 parts: intraorbital, optic canal, and intracranial. All patients underwent prechiasmatic resection without any adjuvant treatments. The follow-up period was 3 months after surgery, and magnetic resonance imaging and contralateral visual acuity were reviewed annually after surgery. RESULTS: All OPG-uDCⅠ cases were completely removed without any adjuvant treatments, and there was no recurrence during the follow-up period. Pathological results showed that, except for 1 adult patient with pilomyxoid astrocytoma (World Health Organization grade Ⅱ), the others all had pilocytic astrocytoma (World Health Organization grade Ⅰ). Five patients experienced transient ptosis, and all recovered 3 months after surgery. CONCLUSIONS: For OPG-uDCⅠ without neurofibromatosis type 1, radical prechiasmatic resection of the tumor is possible, without the need for postoperative radiotherapy and chemotherapy.