A locus for radiation-induced gastroschisis on mouse Chromosome 7

A 4-year-old boy with bilateral optic sheath enlargement and progressive optic atrophy and blindness is presented. Computed tomography demonstrated hydrocephalus and enlargement of the optic nerve sheath complex. The child died during an attempted repair of hypoplastic atrioventricular valves. Autopsy demonstrated a patulous perioptic subarachnoid space and optic atrophy. This condition has been described in the literature but has not had radiologic-pathologic correlation. With the availability of magnetic resonance imaging, this diagnosis may be made prospectively, thus, it is important for the radiologist to be aware of this entity because optic atrophy and blindness may be prevented by early diagnosis and surgery.     

Protracted posttraumatic optic disc swelling

BACKGROUND: Optic disc swelling is a rare sequela of blunt ocular trauma. METHODS: The authors examined three young patients who had an unusual post-traumatic optic neuropathy in which protracted swelling of the optic nerve head was the salient clinical feature. RESULTS: Associated choroidal ruptures in two patients suggested a contrecoup mechanism of injury to the optic nerve at its junction with the globe. All patients had partial recovery of vision over months, concurrent with resolution of the nerve head swelling and development of optic disc pallor. CONCLUSION: Despite its protracted course, posttraumatic optic disc swelling appears to be associated with a favorable prognosis for visual recovery.     

Deglutition in patients treated with reconstructive laryngectomy]

BACKGROUND: Chronic papilledema may lead to irreversible damage of optic nerve fibers. To preserve visual functions, a decompression of the optic nerve is recommended by means of a fenestration of the optic nerve sheath. In this study long-term results after optic nerve sheath fenestration in patients with idiopathic pseudotumor cerebri are reported. PATIENTS AND METHODS: 14 patients were re-examined 15 to 145 months (mean 62 months) after a fenestration of the retrobulbar optic nerve sheath on 23 eyes by a transconjunctival approach. Surgery was done to treat progressive visual loss or in severe obscurations. The patient's symptoms, visual acuity, visual fields, and ophthalmoscopic findings of the optic nerve head and the central fundus were compared to the preoperative status. RESULTS: Re-examination revealed improvement or stabilisation of objective and subjective findings in 17 eyes, one of them was operated on the more involved contralateral side only. Six eyes showed a recurrence of the papilledema without a functional change for the worse after an interval of 7 to 121 months. Three eyes of two patients ended up with optic atrophy and extensive visual loss. Preoperatively, these eyes had shown cotton wool spots in the optic nerve head and a rapid deterioration of vision. CONCLUSIONS: Fenestration of the retrobulbar optic nerve sheath can prevent further visual loss in most patients with pseudotumor cerebri, unless the eye has already become nearly blind. Postoperatively, ophthalmological controls are necessary at regular intervals because relapses after successful surgery can occur after months or years.     

Optic disc morphology in eyes after nonarteritic anterior ischemic optic neuropathy

PURPOSE: Parapapillary chorioretinal atrophy, neuroretinal rim loss, and a decrease of retinal vessel diameter have been described to occur in glaucomatous eyes. This study was conducted to evaluate the frequency and degree of these signs in nonarteritic anterior ischemic optic neuropathy (AION). METHODS: We evaluated morphometrically and compared stereo color optic disc photographs of 17 patients after AION, 184 patients with primary open-angle glaucoma, and 98 normal subjects. RESULTS: The optic disc area and retinal vessel diameter were significantly smaller and the visibility of the retinal nerve fiber bundles was significantly reduced in patients after nonarteritic AION compared with that of the normal subjects. The optic disc shape, area, and form of zones alpha and beta of the parapapillary chorioretinal atrophy and the size and form of the neuroretinal rim did not differ significantly between these two groups. In the group of eyes with glaucoma, the neuroretinal rim was significantly smaller and the parapapillary chorioretinal atrophy was significantly larger than in the group of eyes with AION. Visibility of the retinal nerve fiber bundles and retinal vessel caliber did not differ statistically between the eyes with AION and those with glaucoma. CONCLUSIONS: These results indicate that the parapapillary chorioretinal atrophy is not larger in eyes after nonarteritic AION compared with normal eyes. They show that the area and shape of the neuroretinal rim, as determined planimetrically, may not markedly change after nonarteritic AION. They confirm previous reports on a small optic disc size as a risk factor for nonarteritic AION. They agree with findings of a reduced retinal vessel caliber in eyes with optic nerve damage, independently of the cause.     

Biomechanical aspects of the subarachnoid space and cervical cord in healthy individuals examined with kinematic magnetic resonance imaging

STUDY DESIGN: In vivo flexion-extension magnetic resonance imaging studies of the cervical spine were performed inside a positioning device. OBJECTIVE: To determine the functional changes of the cervical cord and the subarachnoid space that occur during flexion and extension of the cervical spine in healthy individuals. SUMMARY OF BACKGROUND DATA: As an addition to static magnetic resonance imaging examinations, kinematic magnetic resonance imaging studies of the cervical spine were performed to obtain detailed information about functional aspects of the cervical cord and the subarachnoid space. The results were compared with published data of functional flexion-extension myelograms of the cervical spine. METHODS: The cervical spines of 40 healthy individuals were examined in a whole-body magnetic resonance scanner from 50 degrees of flexion to 30 degrees of extension, using a positioning device. At nine different angle positions, sagittal T1-weighted spin-echo sequences were obtained. The images were analyzed with respect to the segmental motion, the diameter of the subarachnoid space, and the diameter of the cervical cord. RESULTS: The segmental motion between flexion and extension was 11 degrees at C2-C3, 12 degrees at C3-C4, 15 degrees at C4-C5, 19 degrees at C5-C6, and 20 degrees at C6-C7. At flexion, a narrowing of the ventral subarachnoid space of up to 43% and a widening of the dorsal subarachnoid space of up to 89% (compared with the neutral position, 0 degrees) were observed. At extension, an increase in the diameter of the ventral subarachnoid space of up to 9% was observed, whereas the dorsal subarachnoid space was reduced to 17%. At flexion, there was a reduction in the sagittal diameter of the cervical cord of up to 14%, and, at extension, there was an increase of up to 15%, compared with the neutral position (0 degrees; these values varied depending on the cervical segment. Statistically significant differences (P < 0.05) were found between flexion and extension in the diameter of the ventral and dorsal subarachnoid space and in the diameter of the cervical cord. CONCLUSIONS: Compared with the results of previous studies using functional cervical myelograms, kinematic magnetic resonance imaging provides additional noninvasive data concerning the physiologic changes of the cervical subarachnoid space and the cervical cord during flexion and extension in healthy individuals.     

Primary carcinoma of the female urethra

A 26-year-old man went blind as part of a multifocal central nervous system disease. Bilateral optic nerve head pallor developed four weeks later. There had been no papilledema. In this setting, the appearance of optic atrophy without preceding papilledema in part led to the clinical diagnosis of severe disseminated encephalomyelitis. At autopsy multiple brain abscesses were found, including an area of inflammation within the chiasm.     

The MRI appearance of the optic nerve sheath following fenestration for benign intracranial hypertension

Optic nerve fenestration is carried out in cases of severe benign intracranial hypertension. This study aimed to monitor the optic nerve sheath appearances and orbital changes that occur following this procedure. The eight patients were all female with an average age of 37.3 years and a range of 20-58 years. The duration of symptoms was 2-6 years. Symptoms included headaches, diplopia and visual obscurations. Examination revealed severe papilledema. All investigations, including MRI, biochemical and immunological tests, were negative. Patients had fenestration of a 2 mm x 3 mm segment of the medial aspect of the optic nerve sheath. Imaging was obtained with a 1 T MRI machine using a head coil. Coronal, axial and sagittal 3 mm contiguous sections using STIR sequences with TR 4900 ms, IT 150 ms and TE 60 ms were obtained. Five patients showed clinical improvement. The post-operative MRI findings in four of these included a decreased volume of cerebrospinal fluid (CSF) around the optic nerve sheaths and a localized collection of fluid within the orbit. There were no MRI changes in the three patients with no clinical improvement. Decreased CSF volume around the optic nerve and a fluid collection within the orbit may indicate a favorable outcome in optic nerve fenestration.     

The cupped disc. Who needs neuroimaging?

OBJECTIVE: To determine the incidence of positive neuroradiologic studies in consecutive patients with glaucoma associated with normal intraocular pressure and to compare the psychophysical and clinical characteristics of these eyes with eyes with disc cupping associated with intracranial masses. DESIGN: Retrospective case-controlled study. PARTICIPANTS: Fifty-two eyes of 29 patients with glaucoma associated with normal intraocular pressure and 44 eyes of 28 control patients with compressive lesions were reviewed. INTERVENTION: The medical records of consecutive glaucoma patients with normal intraocular pressure who underwent brain magnetic resonance imaging or computed tomography scanning as part of a diagnostic evaluation between January 1, 1985, and July 1, 1995, were reviewed. A masked reading of optic nerve photographs and visual fields was performed by one observer. A similar analysis was performed on a control group of consecutive patients with nonglaucomatous optic nerve cupping with known intracranial mass lesions. MAIN OUTCOME MEASURES: The neuroradiologic findings, clinical characteristics, optic nerve head appearance, and patterns of visual field loss were compared between groups. RESULTS: None of the patients diagnosed with glaucoma had neuroradiologic evidence of a mass lesion involving the anterior visual pathway. Compared to control subjects, patients with glaucoma were older (P = 0.0001), had better visual acuity (P = 0.002), greater vertical loss of neuroretinal rim tissue (P = 0.0001), more frequent optic disc hemorrhages (P = 0.01), less neuroretinal rim pallor (P = 0.0001), and more nerve fiber bundle visual field defects aligned at the horizontal midline (P = 0.0001). Visual acuity less than 20/40, vertically aligned visual field defects, optic nerve pallor in excess of cupping, and age younger than 50 years were 77%, 81%, 90%, and 93% specific for nonglaucomatous cupping associated with compressive lesions, respectively. CONCLUSIONS: Anterior visual pathway compression is an uncommon finding in the neuroradiologic evaluation of patients with a presumptive diagnosis of normal-tension glaucoma. Younger age, lower levels of visual acuity, vertically aligned visual field defects, and neuroretinal rim pallor may increase the likelihood of identifying an intracranial mass lesion.     

Aging changes of the optic nerve head in relation to open angle glaucoma

AIMS: To determine the age related changes in optic nerve head structure in a group of normal subjects and assess the significance of any changes in relation to those found in open angle glaucoma. METHODS: A group of 88 white volunteers and friends and spouses of patients with a normal visual field and normal intraocular pressure was studied. Two different imaging and measurement devices were used (computer assisted planimetry and scanning laser ophthalmoscopy), and the results from each were compared. Measurements were made of the optic disc, optic cup, and neuroretinal rim areas, and the vertical optic disc diameter and cup/disc diameter ratio. RESULTS: Neuroretinal rim area declined at the rate of between 0.28% and 0.39% per year. Vertical optic cup diameter and optic cup area increased with age. The mean cup/disc diameter ratio increased by about 0.1 between the ages of 30 and 70 years. CONCLUSIONS: Age related changes are significant and measurable, and should be taken into account when assessing the glaucoma suspect, and when estimating the rate of progression of glaucomatous optic neuropathy in patients with established disease.     

Autoantibodies and pregnancy loss

Patients with neurofibromatosis type 1 (NF-1) have an increased incidence of optic glioma. Although spinal dural ectasia or meningocele is well represented in the NF-1 literature, radiologists are not as familiar with dural ectasia of the optic nerve sheath as spinal dural ectasia. This is a report of a pediatric patient with NF-1 with dural ectasia of the optic nerve sheath. This is the second reported case of dural ectasia of the optic nerve sheath demonstrated by magnetic resonance imaging.     

Quantitative evaluation of papilledema in pseudotumor cerebri

PURPOSE: To determine the feasibility of adapting confocal scanning laser (CSL) tomography of the optic disc for quantitative evaluation of papilledema in pseudotumor cerebri (PTC). METHODS: Confocal scanning laser tomography of the optic disc was performed in 11 patients with diagnosed PTC and 12 visually normal control subjects of similar age. In five patients with active papilledema, CSL tomography was performed serially over several months. To quantify optic disc characteristics, surface topography was measured in 0.1-mm steps along the horizontal and vertical meridians and four oblique meridians. Best fit polynomial functions, describing surface topography along each meridian, were derived using linear regression analysis. RESULTS: Third-order polynomials provided excellent fits (significantly better than the second-order functions) to the surface topography for all meridians in the control subjects and patients with PTC. In control subjects and PTC patients an asymmetry in the slope of the optic disc contours was evident along the horizontal but not the vertical meridian. In patients with active papilledema a significant elevation of the center of the disc was accompanied by a change in overall surface topography. Each of the PTC patients followed up serially had a pronounced posterior deformation of the disc (i.e., a reduction in papilledema) that was initially apparent in the temporal meridian and did not proceed uniformly across all meridians. CONCLUSIONS: Confocal scanning laser tomography can quantify the magnitude and monitor the resolution of papilledema in PTC. Studies of optic nerve head topography may provide further insight into optic nerve compliance with elevated intracranial pressure.     

Bilateral optic nerve meningioma. Case report

A case of bilateral optic nerve meningioma is reported. The onset of the clinical symptoms, at age 27, resembled unilateral optic neuritis with papilledema, leading to bilateral amaurosis with optic atrophy 4 years later. Skull X-ray revealed a "blistering' type of bone reaction. In the carotid angiogram, the ophthalmic artery appeared quite enlarged and displaced. The CT scan showed a fusiform enlargement of both optic nerves. Pathological diagnosis was based upon an optic nerve biopsy. Including the present case, only 12 instances of bilateral optic nerve meningioma have been reported.     

Bilateral optic disk pallor after unilateral internal carotid artery occlusion

Bilateral pallor of the optic disks was observed in a 52-year-old man after dissection of an internal carotid artery. Diffuse pallor of the ipsilateral optic disk reflected infarction of the ipsilateral optic nerve and "bow-tie" atrophy of the contralateral optic disk reflected infarction of the ipsilateral optic tract. The findings were due to an occlusion of the internal carotid artery proximal to the origin of the ophthalmic artery, resulting also in insufficiency in the area of supply of the anterior choroidal artery.     

Ultrasound of extracerebral spaces in infants: standardized examination technique

High resolution ultrasound (5/7.5 MHz, linear array) allows imaging of the extracerebral space in infants. A standardised state-of-the-art imaging technique is described that can be performed during routine cranial sonography. Diagnosing dilated subarachnoid space is possible by comparison to normal values. Pathological findings of the subarachnoid and subdural space can be differentiated. Evaluation of the following conditions is possible: external hydrocephalus, cortical atrophy, pyogenic meningitis, subdural hematoma and hygroma. High resolution ultrasound can add helpful information in situations in which magnetic resonance imaging or computed tomography were previously needed. Since it is a noninvasive method, ultrasound is ideal for follow-up studies and hence the method of choice.     

Does the use in animals of antimicrobial agents, including glycopeptide antibiotics, influence the efficacy of antimicrobial therapy in humans?

PURPOSE: To determine if the cerebral cortical vain sign seen on magnetic resonance (MR) images can be used with color Doppler ultrasound (US) to differentiate enlarged subarachnoid space from subdural collection. MATERIALS AND METHODS: Eighteen infants with pericerebral fluid collection were prospectively examined with color Doppler US and MR imaging. Patients were classified into two groups: group A, with positive cortical vein sign (visualization of color-coded cortical veins that cross fluid collections at cerebral convexities); and group B, without the sign. RESULTS: Positive cortical vein sign was seen at US in 12 patients (group A): nine with benign enlargement of subarachnoid spaces, two with brain atrophy, and one with meningococcal meningitis. The veins were displaced and embedded within the echogenic pia-arachnoid that surrounds the brain or were trapped in the subarachnoid spaces between the neo-membrane and cortical surface (group B, negative cortical vein sign) in four patients with meningitis, two victims of child abuse, and one patient with leukemia. Findings from subsequent MR imaging confirmed the color Doppler US findings. CONCLUSION: Color Doppler US depiction of the cortical vain sign appears to be as effective as MR imaging in differentiating enlargement of the subarachnoid fluid space from subdural effusion.     

Gradual painless visual loss: chronic optic neuropathies

The clinician must be the ultimate medical detective when dealing with chronic optic neuropathies. History taking is crucial. Clinical examination may require supplementation with visual field testing, fluorescein angiography, ocular and orbital ultrasound imaging, CT and MR imaging, blood test data, and cerebrospinal fluid or tissue biopsy data to determine the specific diagnosis. This supplementation is labor-intensive and time-consuming; the visual loss usually will progress throughout the process, frustrating and frightening the patient and physician. The final common pathway is gradual optic atrophy; the appearance of the optic nerve is rarely adequate to determine the cause of the visual loss. This article includes tables that review diagnostic aids and therapies, and lists the frequency with which several disease entities were encountered over 15 years in one tertiary care neuro-ophthalmic practice. If a specific cause is discernible, then a specific therapy may be available. This approach has the best chance of saving the patient's vision with the least toxicity caused by erroneous trials. By necessity, the work-up for these patients is expensive, but the cost of not pursuing the cause is irrevocable, permanent blindness.     

MRI of the anterior optic pathways following enucleation

We examined five patients who had enucleation of one eye for inflammatory or neoplastic disease, using MRI at 1.5 Tesla. None had symptoms referable to the enucleated orbit. In addition, age- and-sex matched individuals were imaged as control subjects, and a further 15 subjects, referred for other than orbital disease, were reviewed. Measurements were made retrospectively of the dimensions of the optic chiasm to establish normal values. All five patients showed abnormalities on MRI following enucleation: abnormal signal within the optic nerve remnant on short tau inversion recovery (STIR) images, and atrophy of the nerve remnant and the chiasm. These findings were not apparent in the control or normal subjects. Such findings are to be expected following enucleation and should not be interpreted as indicating active pathology.     

Clinical and ultrastructural ocular histopathologic studies of adult-onset metachromatic leukodystrophy

A twin brother and sister with adult-onset metachromatic leukodystrophy developed progressive central acuity loss and optic disk pallor. Both had normal electroretinograms and fluorescein angiography. Postmortem examination of the sister's eyes by histochemistry and electron microscopy revealed ganglion cell loss and optic atrophy. Cerebroside sulfate had accumulated in optic nerve glial cells. Optic atrophy was more advanced than in previously reported cases of infantile-onset metachromatic leukodystrophy. The pathologic process seemed to be retrograde optic nerve degeneration due to abnormal myelin metabolism.     

Profile of some risk factors for coronary heart disease in a developing country: Nigeria

We examined visual evoked potentials and pattern electroretinograms in a patient with Tolosa-Hunt syndrome associated with optic nerve involvement. The 82-year-old woman developed unilateral painful ophthalmoplegia and visual loss in the right eye. Magnetic resonance imaging showed an abnormal soft-tissue area in the right cavernous sinus and the right orbital apex. Symptoms responded rapidly to treatment with corticosteroid. Visual evoked potentials to flash and pattern stimuli were both remarkably reduced and delayed in the right eye in the acute stage; however they improved to almost normal after steroid therapy. The pattern electroretinogram recorded in the acute stage was normal bilaterally. These results indicate that optic nerve involvement in Tolosa-Hunt syndrome can be mild and reversible.