Anterior Optic Pathway Research Articles

Target delineation and optimal radiosurgical dose for pituitary tumors.

Stereotactic radiosurgery (SRS) delivered as either single-fraction or multi-fraction SRS (2–5 fractions) is frequently employed in patients with residual or recurrent pituitary adenoma. The most common delivery systems used for SRS include the cobalt-60 system Gamma Knife, the CyberKnife (CK) robotic radiosurgery system, or a modified conventional radiotherapy machine (linear accelerator, LINAC). Tumor control and normalization of hormone hypersecretion have been reported in 75–100 % and 25–80 % of patients, respectively. Hypopituitarism is the most commonly reported late complication of radiation treatment, whereas other toxicities occur less frequently. We have provided an overview of the recent available literature on SRS in patients with a pituitary adenoma. Critical aspects of pituitary irradiation, including target delineation and doses to organs at risk, optimal radiation dose, as well as the long-term efficacy and toxicity of SRS for either nonfunctioning or secreting pituitary adenomas are discussed. Single-fraction SRS represents an effective treatment for patients with a pituitary adenoma; however, caution should be used for lesions > 2.5–3 cm in size and/or involving the anterior optic pathway. Future studies will be necessary to optimize target doses and critical organ dose constrains in order to reduce the long-term toxicity of treatments while maintaining high efficacy.

Multisession Radiosurgery for Sellar and Parasellar Benign Meningiomas: Long-term Tumor Growth Control and Visual Outcome.

Concern about radiation-induced optic neuropathy (RION) has governed recent thinking about the role of radiation therapy in the treatment of meningiomas involving the anterior optic pathways. Despite this concern, during the last few years, the use of radiosurgery for such lesions has increased steadily. To define both the tumor control rate and the risk of RION over a long-term follow-up period in a large cohort of patients treated with multisession radiosurgery. The local control and visual outcome of 143 patients who underwent multisession radiosurgery (mRS) were evaluated. Neurological outcome was also analyzed. The data for the present study were obtained from a prospectively maintained database. The mean follow-up was 44 months (range, 12-113 months). All patients underwent mRS. The median prescription dose was 25 Gy delivered in 3 to 5 fractions. The prescription isodose, which typically encompassed at least 95% of the tumor, ranged from 65% to 86% (median, 80%). The mean tumor volume was 11.0 cm (range, 0.1-126.3 cm; median, 8 cm). The progression-free survival at 3, 5, and 8 years was 100%, 93%, and 90%, respectively. Compared with baseline, visual function improved in 36% of patients, whereas 7.4% experienced a worsening in visual function (5.1% excluding the patients with progressive disease). Good local control rate and a low risk of RION indicate that mRS is a safe and effective treatment option in cases of large meningiomas.

Glioblastoma multiforme of the optic chiasm: A rare case of common pathology.

Background:Malignant optic and chiasmatic gliomas are extremely rare, and are classified pathologically as anaplastic astrocytoma or glioblastoma multiforme (GBM). Approximately 40 cases of optic GBM in adults have been reported in the literature, and only five of them were described to originate from the optic chiasm.Case Description:An 82-year-old male patient with a past medical history of diabetes mellitus type 2, melanoma, and bladder cancer presented with gradual vision loss of the left eye in a period of 1 month. After neuro-ophthalmological examination, the decision of thither magnetic resonance imaging (MRI) studies was made. It showed a contrast enhancing mass in the region of the optic chiasm. In this case, imaging study was not enough to establish an accurate diagnosis and a left pterional craniotomy for biopsy and resection of the optic chiasmal mass was performed. After histological evaluation of the mass tissue, the diagnosis of GBM was made. Taking into account the patient's poor condition and unfavorable prognosis he was moved to inpatient hospice. The patient deceased within 2 months after surgery.Conclusion:Chiasmal GBM is an extremely rare condition where a biopsy is necessary for accurate diagnosis and optimal treatment. Differential diagnosis for such lesions can be very difficult and include demyelinating optic neuritis and non-demyelinating inflammatory optic neuropathy (e.g., sarcoid), vascular lesions (e.g., cavernoma), compressive lesions of the optic apparatus, metastatic malignancy, and primary tumors of the anterior optic pathway. The role of chemotherapy and radiotherapy including novel stereotaxic radiosurgery methods is still unclear and will need to be evaluated.

Anterior Optic Pathway Compression Due to Internal Carotid Artery Aneurysms: Neurosurgical Management and Outcomes.

Background and PurposeCompression of the anterior optic pathway results in visual deficits that can lead to the detection of unruptured aneurysms in the internal carotid artery (ICA). The general types of treatment modalities for aneurysms and visual deficits include surgery and endosaccular coiling. This study retrospectively analyzed and compared the resolution of visual deficits following surgery or endosaccular coiling.MethodsWe reviewed data on 33 patients with unruptured ICA aneurysms who presented with visual field deficits caused by mass effects over the anterior optic pathway. Statistical analyses were performed to identify the variables associated with the recovery of visual symptoms.ResultsEighteen patients underwent aneurysm clipping, 2 underwent bypass surgery with endovascular trapping, and 2 underwent endovascular trapping without bypass surgery (group A). Ten patients received endosaccular coiling (group B). The visual outcomes included the following: in group A, 17 patients (73.9%) demonstrated improvement and 6 patients (26.1%) demonstrated no changes or worse outcomes; in group B, 2 patients (20.0%) demonstrated improvement and 8 patients (80.0%) demonstrated no changes or worse outcomes. Group A was associated with a higher rate of favorable outcome than group B (P = 0.007). According to the multivariate analysis, treatment without endosaccular coiling (group A) was the only variable significantly associated with improvement of visual outcome (P = 0.005; OR = 28.523; 95% CI = 2.683-303.171).ConclusionsTreatment modality was the only predictor of improvement in visual deficits. Treatment without endosaccular coiling resulted in visual improvement significantly more often in comparison with endosaccular coiling.

Optic pathway glioma in children: does visual deficit correlate with radiology in focal exophytic lesions?

Unlike pilocytic astrocytomas in other parts of the brain, optic pathway gliomas (OPG) are usually diffuse lesions involving the anterior optic pathways and hypothalamus. Their infiltrative nature often precludes complete surgical resection. We sought to determine whether careful magnetic resonance (MR) analysis, correlated with visual deficits, could be sufficient to identify those focal lesions that may be amenable to more aggressive surgical resection at presentation. We retrospectively reviewed the medical records of patients from two sites: children under 20 years of age treated for OPG between 1985 and 2009 at St Jude's Children's Research Hospital and children under 16 years of age treated at Great Ormond Street Hospital, London, UK, between 1984 and 2011. Patients with isolated optic nerve tumors were excluded. Visual acuity and visual field data at presentation were reviewed and correlated with MR characteristics, including extent of optic pathway involvement, symmetry, and lateral extension. Two hundred and one children were treated for OPG between 1984 and 2011 in the two institutions; 74 had neurofibromatosis 1 (NF1). At presentation, visual loss was symmetrical in 132 patients and asymmetrical in 69. Potential correlation between pattern of visual loss and tumor characteristics on routine MRI was found in only 13 patients with asymmetrical vision. There was no difference between patients with and without NF1. The decision for aggressive surgical resection for optic pathway gliomas should be based on clinical criteria, particularly in children with good vision in one eye and poor vision in the other, as current MRI results do not reliably predict visual field deficits.

Radiological differentiation of optic neuritis with myelin oligodendrocyte glycoprotein antibodies, aquaporin-4 antibodies, and multiple sclerosis

Background: Recognizing the cause of optic neuritis (ON) affects treatment decisions and visual outcomes. Objective: We aimed to define radiological features of first-episode demyelinating ON. Methods: We performed blinded radiological assessment of 50 patients presenting with first-episode myelin oligodendrocyte glycoprotein (MOG) antibody-associated ON (MOG-ON; n=19), aquaporin-4 (AQP4) antibody-associated ON (AQP4-ON; n=11), multiple sclerosis (MS)-associated ON (MS-ON; n=13), and unclassified ON (n=7). Results: Bilateral involvement was more common in MOG-ON and AQP4-ON than MS-ON (84% vs. 82% vs. 23%), optic nerve head swelling was more common in MOG-ON (53% vs. 9% vs. 0%), chiasmal involvement was more common in AQP4-ON (5% vs. 64% vs. 15%), and bilateral optic tract involvement was more common in AQP4-ON (0% vs. 45% vs. 0%). Retrobulbar involvement was more common in MOG-ON, whereas intracranial involvement was more common in AQP4-ON. MOG-ON and AQP4-ON had longer lesion lengths than MS-ON. The combination of two predictors, the absence of magnetic resonance imaging brain abnormalities and a higher lesion extent score, showed a good ability to discriminate between an autoantibody-associated ON (MOG or AQP4) and MS. AQP4-ON more frequently had severe and sustained visual impairment. Conclusion: MOG-ON and AQP4-ON are more commonly bilateral and longitudinally extensive. MOG-ON tends to involve the anterior optic pathway, whereas AQP4-ON the posterior optic pathway.

Distributed abnormalities of brain white matter architecture in patients with dominant optic atrophy and OPA1 mutations.

Using advanced MRI techniques, we investigated the presence and topographical distribution of brain grey matter (GM) and white matter (WM) alterations in dominant optic atrophy (DOA) patients with genetically proven OPA1 mutation as well as their correlation with clinical and neuro-ophthalmologic findings. Nineteen DOA patients underwent neurological, neuro-ophthalmologic and brainstem auditory evoked potentials (BAEP) evaluations. Voxel-wise methods were applied to assess regional GM and WM abnormalities in patients compared to 20 healthy controls. Visual acuity was reduced in 16 patients. Six DOA patients (4 with missense mutations) had an abnormal I peripheral component (auditory nerve) at BAEP. Compared to controls, DOA patients had significant atrophy of the optic nerves (p < 0.0001). Voxel-based morphometry (VBM) analysis showed that, compared to controls, DOA patients had significant WM atrophy of the chiasm and optic tracts; whereas no areas of GM atrophy were found. Tract-based spatial statistics (TBSS) analysis showed that compared to controls, DOA patients had significantly lower mean diffusivity, axial and radial diffusivity in the WM of the cerebellum, brainstem, thalamus, fronto-occipital-temporal lobes, including the cingulum, corpus callosum, corticospinal tract and optic radiation bilaterally. No abnormalities of fractional anisotropy were detected. No correlations were found between volumetric and diffusivity abnormalities quantified with MRI and clinical and neuro-ophthalmologic measures of disease severity. Consistently with pathological studies, tissue loss in DOA patients is limited to anterior optic pathways reflecting retinal ganglion cell degeneration. Distributed abnormalities of diffusivity indexes might reflect abnormal intracellular mitochondrial morphology as well as alteration of protein levels due to OPA1 mutations.

Decision Making for Patients With Concomitant Pituitary Macroadenoma and Ophthalmologic Comorbidity: A Clinical Controversy

Coexisting complex visual field defects and serious ophthalmologic comorbidities make the management of the pituitary macroadenomas more challenging. Diffusion tensor imaging (DTI) magnetic resonance imaging that tracks neural fibers in the white matter has been used recently to visualize the impact of different pathologies on cranial nerves. This study explains application of anterior optic pathway tractography for patients with ophthalmologic comorbidities and pituitary adenoma. Two patients with atypical visual field defects caused by nonfunctional pituitary macroadenoma and simultaneous ophthalmologic morbidities (one glaucoma and the other giant cell arteritis) were selected for surgical decompression of the anterior optic apparatus. Standard perimetry and optic pathway DTI were done preoperatively, intraoperatively, and 3 months after surgery. The nontypical pattern of visual field defect could not differentiate between the ophthalmologic disease and the chiasmatic compression attributable to pituitary macroadenoma as the main cause. Preoperative visual pathway DTI tractography showed lack of decussating chiasmatic fibers in both of the patients. DTI tractography revealed the reappearance of these fibers intraoperatively in one and postoperatively in the other one. Three months after surgery, the visual field and acuity improved and DTI tractography confirmed presence of crossing chiasmatic fibers. Visual pathway DTI tractography is a promising adjunct to the standard perimetry in preoperative assessment of pituitary macroadenoma with serious ophthalmologic comorbidities. It also may be useful in the intraoperative determination of the optic pathway decompression and for following the visual outcome of these patients after surgery.

Chapter 22 - Auditory synesthesias

Synesthesia is experienced when sensory stimulation of one sensory modality (the inducer) elicits an involuntary or automatic sensation in another sensory modality or different aspect of the same sensory modality (the concurrent). Auditory synesthesias (AS) occur when auditory stimuli trigger a variety of concurrents, or when non-auditory sensory stimulations trigger auditory synesthetic perception. The AS are divided into three types: developmental, acquired, and induced. Developmental AS are not a neurologic disorder but a different way of experiencing one's environment. They are involuntary and highly consistent experiences throughout one's life. Acquired AS have been reported in association with neurologic diseases that cause deafferentation of anterior optic pathways, with pathologic lesions affecting the central nervous system (CNS) outside of the optic pathways, as well as non-lesional cases associated with migraine, and epilepsy. It also has been reported with mood disorders as well as a single idiopathic case. Induced AS has been reported in experimental and postsurgical blindfolding, as well as intake of hallucinogenics or psychedelics. In this chapter the three different types of synesthesia, their characteristics, and phenomologic differences, as well as their possible neural mechanisms are discussed.

Ga-68-DOTA-TATE PET/CT for Discrimination of Tumors of the Optic Pathway

Purpose: Symptomatic tumors of the optic nerve pathway may endanger vision. They are difficult to classify by imaging alone and biopsy may damage visual function. Tumor pathology influences treatment decision and a diagnostic tool with a high sensitivity and specificity would therefore be invaluable. We hypothesized that Ga-68-DOTA-TATE PET/CT may help in discriminating optic nerve tumors as uptake of somatostatin is elevated in meningiomas.Material and Methods: Ga-68-DOTA-TATE PET/CT was used to examine 13 patients with ambiguous, symptomatic lesions of the optic pathway for treatment planning. The presence or absence of meningioma was validated by histopathology or supplementary diagnostic work-up.Results: Ga-68-DOTA-TATE PET/CT identified 10 meningiomas (en plaque = 1, optic nerve sheath = 4, sphenoidal = 5) correctly via increased SSTR (somatostatin receptor) expression (mean SUVmax (maximum standardized uptake value) = 14.3 ± 15.4). 3 tumors did not show elevated Ga-68-DOTA-TATE uptake (SUVmax = 2.1 ± 1.0). Subsumizing all clinical-radiological follow-up tools available, these lesions were classified as an intracerebral metastasis of an advanced gastric carcinoma, histologically proven inflammatory collagenous connective tissue and presumed leukemic infiltration of a newly diagnosed chronic lymphocytic leukemia. In this case series, Ga-68-DOTA-TATE PET/CT demonstrated both a sensitivity and specificity of 100%. Yet, the golden standard of histopathology was only available in a subset of patients included.Conclusion: Ga-68-DOTA-TATE PET/CT proved to be a valuable diagnostic tool for the correct classification of equivocal, symptomatic tumors of the anterior optic pathway requiring therapy. PET/CT results influenced therapy decision essentially in all cases.

P06.09 * LONG TERM VISUAL OUTCOME AFTER RADIOSURGERY IN 97 PATIENTS AFFECTED BY ANTERIOR SKULL BASE BENIGN MENINGIOMAS

INTRODUCTION. The concern about radiation induced optic neuropathy (RION) strongly characterized the recent past. This has probably been the main limit to a wider diffusion of radiotherapy and radiosurgery as treatment of meningiomas involving the anterior optic pathways. In spite of this consideration, during the last few years the radiotherapy activity for such lesions is continuously increasing. The aim of the present study is to define the risk of RION on a medium to long term follow-up period in a large series of patients treated by radiosurgery. The efficacy of the treatment is also investigated. MATERIALS AND METHODS: The visual outcome of 97 patients which underwent radiosurgery due to a meningioma involving the anterior optic pathways has been retrospectively evaluated. Patients with a minimum follow-up period longer than 12 months were included. Sixteen patients had a single session radiosurgery (sSRS) with a mean dose of 12 Gy (range 8-13 Gy; median 13 Gy). In these cases the mean tumour volume was 4,9 cc (range 0,3-10,5 cc; median 3.6 cc) Eighty-one patients underwent a multi-session radiosurgery (mSRS). The mean prescription dose was 24 Gy (range 15-30Gy; median 25Gy), the mean tumour volume was 9,5 cc (range 0,5-65 cc; median 6,5 cc) The visual outcome was evaluated in all cases. All the included patients had at least a pre-treatment and a last follow-up visual function assessment. Furthermore local control has been analyzed. RESULTS: The mean follow-up is 43 months (range 12-96 months; 56 patients f-up ≥ 36 monts; 23 patients f-up ≥ 60 months) Compared to the baseline the visual function improved in 24 patients (24 %) and was unchanged in 65 (68 %). Seven patients worsened 8 (8 %). Three out of these experienced a tumour progression. Only two patients with no progression disease developed a “de novo” visual deficit. At the analysis time, the overall local control was 94 %. Eighteen lesions (18%) showed a partial shrinkage, seventy-three (72%) were stable and 6 patients (6%) experienced a progression of the disease. When observed, the tumour progression always occurred later than 36 months post-treatment. CONCLUSIONS: The study confirms the low risk of radiation induced optic neuropathy both in case of sSRS and mSRS. Multisession radiosurgery makes also the larger lesions manageable. The high local control rate and the low toxicity suggest that radiosurgery could be proposed also as a primary treatment.

Paradoxical Growth of Presumed Optochiasmatic Tuberculomas Following Medical Therapy

Tuberculosis is an endemic infectious disease in developing countries. Patients receiving treatment for systemic tuberculosis may develop paradoxical growth of tuberculomas in the brain, which can lead to vision loss. We describe 3 patients who had paradoxical development of tuberculomas in the anterior optic pathway during treatment for tuberculosis and presented with acute vision loss. These optochiasmatic tuberculomas were not present at the initial presentation of tuberculosis and appeared on brain magnetic resonance imaging at the time of presentation with vision loss. Vision improved on instituting systemic corticosteroids in addition to antituberculous treatment. As there was visual recovery after patients began receiving systemic corticosteroids and there was no worsening of the systemic condition, it is reasonable to assume that the optochiasmatic tuberculomas resulted from a paradoxical reaction. It is important to recognize this condition and initiate prompt treatment to reduce visual morbidity.

Third Ventricular and Interpeduncular Fossa Tubercular Abscess With Triventriculomegaly - Ventriculoscopic Surgical Management

Intracranial tuberculomas are rather common lesions in developing world.Tuberculomas are usually located in cerebellum, basal ganglia and cerebral hemispheres, particularly in frontoparietal region.Less common sites include the corpus callosum, quadrigeminal plate,the cerebellopontine angle, the retro-orbital region, the anterior optic pathway and the supraseller region.The central nervous system (CNS) involvement comprises approximately 10–15% of all tuberculous infections. Brain tuberculosis is usually parenchymal. Intraventricular tuberculosis is very rare and only little number of cases has been reported. Intraventricular tubercular abscess is further rarer. Here we report a case of third ventricular tubercular abscess with triventriculomegaly that was managed by ventriculoscopic drainage and third ventriculostomy though preoperative diagnosis &amp; surgical planning was different. DOI: http://dx.doi.org/10.3329/jom.v14i1.11415 J MEDICINE 2013; 14 : 72-73

Optic nerve assessment identifies biomarkers of axonal pathology in multiple sclerosis

Our aim was to identify possible correlations between physical disabilities assessed by expanded disability status score (EDSS) and neurodegenerative process measured by retinal nerve fibers thickness, and also with demyelization process measured by visual evoked potential with P100 wave latency at optic nerve level on patients diagnosed with multiple sclerosis (MS). This study aimed to find a structural biomarker at central nerve system (CNS) level which could correlate with clinical disability. The optic nerve is an accessible structure of CNS easy to investigate. We analyzed a population of 111 patients diagnosed with different clinical forms of multiple sclerosis based on 2005 revised Mc Donald criteria, for whom we assessed clinical disability by EDSS, and by different subscales of multiple sclerosis composite (MSFC) as timed to walk 25 foot (TW25F) and nine hole peg test (9HPT). Optic nerve involvement was assessed for each eye measuring visual acuity (VA) (Snellen chart), P100 wave latency by visual evoked potential (VEP) and retinal nerve fiber layer thickness (RNFL) by optical coherence tomography (OCT). The medium age of our population was 38.09 and the medium EDSS was 3.3. – 76 out of 111 were women. 79 patients were diagnosed with relapsing remitting (RR) MS, 7 with clinically isolated syndrome (CIS), the other were diagnosed with progressive form of MS: 7 with primary progressive MS and one with primary progressive with relapse MS. We obtained positive correlations, and statistically significant between EDSS and 9HPT for dominant hand (r=0.58, p = 0.0001) and also for non dominant hand (r = 0.66, p = 0.0001) using Pearson correlation. EDSS score correlates statistically significant with P100 wave latency and visual acuity for both eyes using Pearson correlation, so we obtained negative correlation between EDSS and VA for right eye (r = -0.45, p = 0.0001), and for left eye (r = -0.49, p = 0.0001). We also observed statistically significant positive correlation between EDSS and P100 wave latency for right eye (r = 0.405, p = 0.0001), and left eye (r = 0.400, p = 0.0001). RNFL doesn’t correlate with EDSS, VA or P100 wave latency. Using chi square correlation between EDSS score (we choose a cut of value of 3) and pathological value of RNFL by OCT we didn’t obtain a statistical significant result. The results were : for right eye phi = 0.01, p = 0.9), and for left eye (phi = -0.1, p = 0.3). Similar results were obtained for EDSS of 4.0. The results were: for right eye (phi=-0.009, p= 0.9), and for left eye (phi = 0.017, p = 0.8). In conclusion, in order to understand the pathology of multiple sclerosis the anterior optic nerve pathway offers an attractive model. Optic nerve assessment can be realized through non-invasive complementary methods. Functional and structural data of optic nerve can be obtained by VA measurement, VEP and OCT assessments. Our study showed that axonal pathology of the optic nerve (part of CNS exclusively composed by white matter) correlates with clinical disability measured by EDSS, suggesting that P100 latency is a functional biomarker of the disease. A prospective study to validate such a marker of the progression of the disease is needed.

Delineation of Optic Nerves and Chiasm in Close Proximity to Large Suprasellar Tumors with Contrast-enhanced FIESTA MR Imaging

To evaluate whether contrast material-enhanced (CE) fast imaging employing steady-state acquisition (FIESTA) can depict the anterior optic pathways in patients with large suprasellar tumors. Institutional review board approval was obtained. Twenty-eight patients with large suprasellar tumors undergoing surgical treatment (19 pituitary adenomas, six meningiomas, and three additional miscellaneous tumors) underwent preoperative magnetic resonance (MR) imaging, including CE FIESTA, at 3.0 T. Two radiologists assessed the visibility of five segments of the optic pathways (bilateral optic nerves and optic tracts, optic chiasm) with CE FIESTA and conventional MR imaging, including thin-section coronal T2-weighted imaging and CE T1-weighted imaging, by using a three-point scale. Moreover, the preoperative signal intensity of the optic pathways was correlated with pre- and postoperative visual impairment to determine whether high signal intensity at CE FIESTA is predictive of persistence of visual impairment after surgery. The χ(2) test was used to compare scores assigned to CE FIESTA and conventional MR images. The percentage of anterior optic pathways rated as visible was significantly higher with CE FIESTA than with conventional MR imaging (100% [140 of 140 segments] vs 78% [109 of 140 segments], P < .05). Thirty-one of the 140 segments (22%) were not depicted with conventional MR imaging; all of these 31 segments were visualized with CE FIESTA. For 12 patients who underwent transcranial surgery, the anatomic locations of the optic pathways at CE FIESTA were compatible with the surgical findings. CE FIESTA helped predict persistent visual impairment after surgical treatment with a sensitivity of 75% (three of four patients) and a specificity of 96% (23 of 24 patients). The accuracy of CT FIESTA in the prediction of visual loss was significantly higher than that of T2-weighted imaging (93% [26 of 28 patients] vs 50% [14 of 28 patients], P < .05). CE FIESTA is useful for the preoperative localization of the anterior optic pathways in patients with large suprasellar tumors and offers the potential to predict persistent visual impairment after decompression.

Functional magnetic resonance imaging evaluation of visual cortex activation in patients with anterior visual pathway lesions.

The aim of this study was to examine the secondary visual cortex functional disorder in patients with glaucoma and large pituitary adenoma by functional magnetic resonance imaging, and to determine the correlation between visual field defect and primary visual cortex activation. Results showed that single eye stimulation resulted in bilateral visual cortex activation in patients with glaucoma or large pituitary adenoma. Compared with the normal control group, the extent and intensity of visual cortex activation was decreased after left and right eye stimulation, and functional magnetic resonance imaging revealed a correlation between visual field defects and visual cortex activation in patients with glaucoma and large pituitary adenoma. These functional magnetic resonance imaging data suggest that anterior optic pathway lesions can cause secondary functional disorder of the visual cortex, and that visual defects are correlated with visual cortex activation.

Compression optochiasmatique par un clip refoulé par une hydrocéphalie chronique après traitement chirurgical d’un anévrisme rompu de l’artère communicante antérieure

Chronic hydrocephalus is a classic and recognized complication that affects 6 to 37% of patients with aneurysmal subarachnoid haemorrhage. The diagnosis is often mentioned due to the delayed onset of gait disturbance and slower psychomotor performance. The CT-scan confirms the diagnosis by showing an enlargement of the ventricles. In case of symptomatic hydrocephalus, a ventriculo-peritoneal shunt is often required. The authors report a rare case of chronic hydrocephalus presenting with visual symptoms, due to the delayed mobilisation of a surgical clip with direct mass effect over the anterior optic pathways. The treatment of hydrocephalus led to a rapid and complete regression of symptoms.

Intraoperative magnetic resonance imaging and early prognosis for vision after transsphenoidal surgery for sellar lesions

Sellar lesions with suprasellar extension may cause loss of visual acuity and visual field damage due to compression of the optic chiasm. Using intraoperative MR (iMR) imaging to detect symptomatic lesion remnants adjacent to the optic chiasm (that may be resected in the same procedure) may positively affect the functional outcome of patients with these lesions. The aim of this study was to evaluate the correlation between visual improvement and optic nerve decompression detected by iMR imaging in patients undergoing transsphenoidal resection of pituitary lesions. A total of 32 patients (23 men and 9 women) who underwent transsphenoidal resection of sellar lesions causing visual impairment were included in this study. Tumor volume ranged from 0.9 cm(3) to 55.7 cm(3) (mean 9.8 ± 11.7 cm(3)). Preoperative assessment showed visual field damage in 31 patients (97%) and loss of visual acuity in 28 patients (88%). The latency period between the appearance of symptoms and transsphenoidal decompression was 14.9 ± 19.5 weeks. Intraoperative MR imaging was performed after the resection was believed to be complete, or if further tumor removal was not safely possible due to changed conditions in the surgical field. Complete resection was detected on these initial scans in 17 patients (53%). Partial resection was achieved in 9 patients (28%) and tumor debulking in 6 (19%). Additional resection was possible in 8 (53%) of these 15 patients. Four (50%) of these 8 cases had suprasellar remnants and the optic chiasm was subsequently decompressed. In 5 cases optimal decompression of the optic chiasm was not possible. On early follow-up within 1 month after surgery, overall improvement of visual field damage was observed in 27 patients (87%). In 23 patients (74%), the Goldmann perimetry demonstrated complete recovery. Improvement of visual acuity was noted in 24 patients (86%). Eighteen patients (64%) regained full visual acuity. Identification of a decompressed optic chiasm on iMR imaging was significantly correlated with visual field improvement (p = 0.0007; positive predictive value 0.96, 95% CI 0.81-0.99) and relief of visual acuity deficits (p = 0.0002; positive predictive value 0.96, 95% CI 0.79-0.99). Two patients needed transcranial procedures for symptomatic tumor remnants detected on iMR imaging. Intraoperative MR imaging findings correlate with prognosis of visual deficits after transsphenoidal decompression of the anterior optic pathways. The use of iMR imaging may prevent revision surgery for unexpected symptomatic remnants.

Primary retinal pathology in multiple sclerosis as detected by optical coherence tomography

Sir, We read the recent Brain publication by Saidha et al. (2011) with great interest. In their manuscript, the authors suggested that primary retinal pathology detectable by optical coherence tomography (OCT) defines a subset of patients with multiple sclerosis (Saidha et al ., 2011). This subgroup of patients, which they termed ‘macular thinning predominant phenotype’, was reported to exist in ∼10% of the entire multiple sclerosis cohort examined by spectral domain OCT (Cirrus) at the authors’ centres. The macular thinning predominant OCT phenotype was defined by a combination of average macular thickness below the 5th percentile, with ipsilateral normal average retinal nerve fibre layer (RNFL) thicknesses (between the 5th and 95th percentiles of RNFL values from the manufacturer's normative database), in one or both eyes, in the absence of a history of acute optic neuritis in affected eyes (Saidha et al ., 2011). Sixty-two per cent (31/50) of patients fulfilling the macular thinning predominant OCT criteria had a macular thickness below the 1st percentile. In addition, there was a remarkable male preponderance among patients with the macular thinning predominant phenotype (70% male versus 30% female), a difference that was even more pronounced (77.4% male versus 22.6% female) among those patients with very low macular thicknesses (<1st percentile). These in vivo findings are in line with a recent post-mortem analysis reporting retinal pathology in multiple sclerosis beyond damage to the RNFL and the ganglion cell layer (Green et al ., 2010). These data are intriguing in that they point to a novel concept of primary retinal damage in multiple sclerosis. They indicate that retinal pathology might not only develop as a consequence of inflammatory attacks to the anterior optic pathway causing …

Nerve Growth Factor Eye Drop Administration Improves Visual Function in a Patient With Optic Glioma

Background. Spontaneous visual improvement in people with an optic glioma (OG) of the anterior or retrochiasmatic optic pathways is rare. Objective. To evaluate the effects on visual function of nerve growth factor (NGF) eye drop administration in a patient with severe visual impairment due to a low-grade OG. Methods. A 45-year-old woman with OG and long-standing optic nerve atrophy was assessed before and after 2 NGF treatment courses. The drug used was 2.5S murine NGF. One milligram of NGF, diluted in saline solution, was administered onto the conjunctiva of both eyes for 10 consecutive days 3 times a day for each treatment. The follow-up was performed by clinical, neuroradiologic, and electrophysiological tests (electroretinogram and visual evoked potentials [VEPs]) at the end of each treatment and 30 and 60 days later. Results. A repeated subjective and objective improvement of visual function (>3 lines visual acuity; >40° visual field; >50% VEP amplitude increase, Wilcoxon test P < .01) was recorded after NGF treatment. These measures tended to deteriorate toward baseline values 60 days from the end of each NGF treatment. No ocular or systemic side effects were observed throughout treatment. Conclusions. Conjunctival NGF may be a beneficial adjunct therapy for visual loss in patients with OG, possibly exerting its effects on residual viable optic pathways.