RESUMEN
Purpose: Glaucoma is a disorder that involves visual field loss caused by retinal ganglion cell damage. Previous diffusion magnetic resonance imaging (dMRI) studies have demonstrated that retinal ganglion cell damage affects tissues in the optic tract (OT) and optic radiation (OR). However, because previous studies have used a simple diffusion tensor model to analyze dMRI data, the microstructural interpretation of white matter tissue changes remains uncertain. In this study, we used a multi-contrast MRI approach to further clarify the type of microstructural damage that occurs in patients with glaucoma. Methods: We collected dMRI data from 17 patients with glaucoma and 30 controls using 3-tesla (3T) MRI. Using the dMRI data, we estimated three types of tissue property metrics: intracellular volume fraction (ICVF), orientation dispersion index (ODI), and isotropic volume fraction (IsoV). Quantitative T1 (qT1) data, which may be relatively specific to myelin, were collected from all subjects. Results: In the OT, all four metrics showed significant differences between the glaucoma and control groups. In the OR, only the ICVF showed significant between-group differences. ICVF was significantly correlated with qT1 in the OR of the glaucoma group, although qT1 did not show any abnormality at the group level. Conclusions: Our results suggest that, at the group level, tissue changes in OR caused by glaucoma might be explained by axonal damage, which is reflected in the intracellular diffusion signals, rather than myelin damage. The significant correlation between ICVF and qT1 suggests that myelin damage might also occur in a smaller number of severe cases.
Asunto(s)
Glaucoma de Ángulo Abierto/diagnóstico por imagen , Imágenes de Resonancia Magnética Multiparamétrica , Tracto Óptico/diagnóstico por imagen , Vías Visuales/diagnóstico por imagen , Sustancia Blanca/diagnóstico por imagen , Adulto , Anciano , Femenino , Glaucoma de Ángulo Abierto/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Tracto Óptico/fisiopatología , Trastornos de la Visión/fisiopatología , Campos Visuales/fisiología , Vías Visuales/fisiopatología , Sustancia Blanca/fisiopatología , Adulto JovenRESUMEN
The retinogeniculate visual pathway (RGVP) conveys visual information from the retina to the lateral geniculate nucleus. The RGVP has four subdivisions, including two decussating and two nondecussating pathways that cannot be identified on conventional structural magnetic resonance imaging (MRI). Diffusion MRI tractography has the potential to trace these subdivisions and is increasingly used to study the RGVP. However, it is not yet known which fiber tracking strategy is most suitable for RGVP reconstruction. In this study, four tractography methods are compared, including constrained spherical deconvolution (CSD) based probabilistic (iFOD1) and deterministic (SD-Stream) methods, and multi-fiber (UKF-2T) and single-fiber (UKF-1T) unscented Kalman filter (UKF) methods. Experiments use diffusion MRI data from 57 subjects in the Human Connectome Project. The RGVP is identified using regions of interest created by two clinical experts. Quantitative anatomical measurements and expert anatomical judgment are used to assess the advantages and limitations of the four tractography methods. Overall, we conclude that UKF-2T and iFOD1 produce the best RGVP reconstruction results. The iFOD1 method can better quantitatively estimate the percentage of decussating fibers, while the UKF-2T method produces reconstructed RGVPs that are judged to better correspond to the known anatomy and have the highest spatial overlap across subjects. Overall, we find that it is challenging for current tractography methods to both accurately track RGVP fibers that correspond to known anatomy and produce an approximately correct percentage of decussating fibers. We suggest that future algorithm development for RGVP tractography should take consideration of both of these two points.
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Imagen de Difusión Tensora/métodos , Cuerpos Geniculados/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador/métodos , Quiasma Óptico/diagnóstico por imagen , Nervio Óptico/diagnóstico por imagen , Tracto Óptico/diagnóstico por imagen , Retina/diagnóstico por imagen , Vías Visuales/diagnóstico por imagen , Adulto , Femenino , Humanos , Masculino , Adulto JovenRESUMEN
Posterior reversible encephalopathy syndrome (PRES) is a neurological syndrome manifesting with acute focal signs, and concomitant neuroimaging findings of vasogenic oedema. It affects the parieto-occipital regions in a vast majority of cases, although atypical variants have been described comprising the brainstem, basal ganglia or spinal cord. We report the case of a 41-year-old woman, admitted for persistent headache and inferior altitudinal field defect in the right eye. She presented with severe, non-medicated, hypertension. Brain MRI showed findings compatible with atypical PRES, involving the brainstem and optic pathways. With antihypertensive therapy the headache remitted, although visual field remained and was interpreted in the context of a vascular aetiology-non-arteritic anterior ischaemic optic neuropathy. MRI was repeated 3 weeks later and showed almost complete reversal of the previous changes.
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Tronco Encefálico/diagnóstico por imagen , Tracto Óptico/diagnóstico por imagen , Síndrome de Leucoencefalopatía Posterior/complicaciones , Síndrome de Leucoencefalopatía Posterior/diagnóstico , Adulto , Femenino , Humanos , Imagen por Resonancia Magnética , Síndrome de Leucoencefalopatía Posterior/terapiaRESUMEN
Previous studies suggest that long-term supplementation and dietary intake of omega-3 polyunsaturated fatty acids (PUFAs) may have neuroprotective effects following brain injury. The objective of this study was to investigate potential neuroprotective effects of omega-3 PUFAs on white matter following closed-head trauma. The closed-head injury model of engineered rotational acceleration (CHIMERA) produces a reproducible injury in the optic tract and brachium of the superior colliculus in mice. Damage is detectable using diffusion tensor imaging (DTI) metrics, particularly fractional anisotropy (FA), with sensitivity comparable to histology. We acquired in vivo (n = 38) and ex vivo (n = 41) DTI data in mice divided into sham and CHIMERA groups with two dietary groups: one deficient in omega-3 PUFAs and one adequate in omega-3 PUFAs. We examined injury effects (reduction in FA) and neuroprotection (FA reduction modulated by diet) in the optic tract and brachium. We verified that diet did not affect FA in sham animals. In injured animals, we found significantly reduced FA in the optic tract and brachium (~10% reduction, p < 0.001), and Bayes factor analysis showed strong evidence to reject the null hypothesis. However, Bayes factor analysis showed substantial evidence to accept the null hypothesis of no diet-related FA differences in injured animals in the in vivo and ex vivo samples. Our results indicate no neuroprotective effect from adequate dietary omega-3 PUFA intake on white matter damage following traumatic brain injury. Since damage from CHIMERA mainly affects white matter, our results do not necessarily contradict previous findings showing omega-3 PUFA-mediated neuroprotection in gray matter.
Asunto(s)
Lesiones Traumáticas del Encéfalo/diagnóstico por imagen , Dieta , Ácidos Grasos Omega-3/uso terapéutico , Fármacos Neuroprotectores/uso terapéutico , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/lesiones , Animales , Teorema de Bayes , Imagen de Difusión Tensora , Sustancia Gris/patología , Traumatismos Cerrados de la Cabeza/diagnóstico por imagen , Masculino , Ratones , Ratones Endogámicos C57BL , Tracto Óptico/diagnóstico por imagen , Tracto Óptico/lesiones , Colículos Superiores/diagnóstico por imagen , Colículos Superiores/lesionesAsunto(s)
Hemianopsia/etiología , Síndromes de Compresión Nerviosa/complicaciones , Tracto Óptico/patología , Enfermedades de la Retina/etiología , Células Ganglionares de la Retina/patología , Anciano , Femenino , Humanos , Imagen por Resonancia Magnética , Síndromes de Compresión Nerviosa/diagnóstico por imagen , Nariz , Tracto Óptico/diagnóstico por imagen , Pruebas del Campo Visual , Campos VisualesRESUMEN
OBJECTIVE: Preoperative tumor-related edema of the optic tract (EOT) is often found along the white matter tract of the visual system. However, the relationship of EOT with visual function and outcome remains unclear. Therefore we aimed to elucidate whether the presence of EOT is associated with visual outcome in patients with sellar and suprasellar tumors. METHODS: A total of 212 eyes of 106 patients who underwent endoscopic endonasal surgery for sellar and suprasellar tumors at our institution between March 2016 and August 2018 were included in this retrospective study. Data on patient characteristics, preoperative magnetic resonance imaging findings, and ophthalmologic evaluations were collected. Patients were assigned to 2 groups depending on preoperative magnetic resonance imaging findings (EOT group = 19 [17.9%], non-EOT group = 87 [82.1%]). Visual acuity, visual field (VF), global visual function score, VF index, VF mean deviation, and retinal nerve fiber layer thickness as determined by optical coherence tomography were compared between the groups before and after treatment. RESULTS: In the EOT group, 4 patients had pituitary adenoma, 8 had craniopharyngioma, and 7 had other pathologies. There was no significant difference of pathologies between the groups. Preoperatively, EOT group showed significantly lower values of global visual function score, VF index, mean deviation, and retinal nerve fiber layer thickness than did the non-EOT group (P < 0.001). Postoperatively, the EOT group showed worse visual outcomes than did the non-EOT group. CONCLUSIONS: This study reveals that EOT caused by sellar and suprasellar tumors is associated with worse visual function and poor improvement postoperatively.
Asunto(s)
Adenoma/cirugía , Craneofaringioma/cirugía , Edema/diagnóstico por imagen , Tracto Óptico/diagnóstico por imagen , Neoplasias Hipofisarias/cirugía , Trastornos de la Visión/fisiopatología , Adenoma/complicaciones , Adolescente , Adulto , Anciano , Niño , Craneofaringioma/complicaciones , Edema/etiología , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Cavidad Nasal , Cirugía Endoscópica por Orificios Naturales , Neuroendoscopía , Disco Óptico/diagnóstico por imagen , Disco Óptico/patología , Tamaño de los Órganos , Neoplasias Hipofisarias/complicaciones , Pronóstico , Retina/diagnóstico por imagen , Retina/patología , Estudios Retrospectivos , Tomografía de Coherencia Óptica , Trastornos de la Visión/etiología , Agudeza Visual , Campos Visuales , Adulto JovenRESUMEN
PURPOSE OF REVIEW: Optic pathway gliomas are low-grade neoplasms that affect the precortical visual pathway of children and adolescents. They can affect the optic nerve, optic chiasm, optic tracts and radiations and can either be sporadic or associated with neurofibromatosis type one. Gliomas isolated to the optic nerve (ONG) represent a subgroup of optic pathway gliomas, and their treatment remains controversial. New developments in ONG treatment have emerged in recent years, and it is necessary for clinicians to have a current understanding of available therapies. RECENT FINDINGS: The current review of the literature covers the background of and recent developments in ONG treatment, with a focus on standard chemotherapy, new molecularly targeted therapies, radiation therapy and surgical resection and debulking. SUMMARY: Although standard chemotherapy remains the mainstay of ONG treatment, newer molecularly targeted therapies such as mitogen-activated protein kinase kinase inhibitors and bevacizumab represent a promising new treatment modality, and clinical studies are ongoing.
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Quiasma Óptico/patología , Glioma del Nervio Óptico/terapia , Neoplasias del Nervio Óptico/terapia , Tracto Óptico/patología , Adolescente , Antineoplásicos/uso terapéutico , Niño , Femenino , Humanos , Masculino , Terapia Molecular Dirigida , Procedimientos Quirúrgicos Oftalmológicos , Quiasma Óptico/diagnóstico por imagen , Glioma del Nervio Óptico/diagnóstico por imagen , Glioma del Nervio Óptico/patología , Neoplasias del Nervio Óptico/diagnóstico por imagen , Neoplasias del Nervio Óptico/patología , Tracto Óptico/diagnóstico por imagen , RadioterapiaRESUMEN
Purpose: Explore in vivo whether there is direct communication between the cerebrospinal fluid (CSF) and extravascular compartment of human visual pathway structures. Methods: A prospective and observational study included 10 subjects who underwent intrathecal gadolinium-enhanced magnetic resonance imaging (MRI) for suspected CSF circulation disorder, but with a negative result and with no known ophthalmic diseases. After precontrast T1-weighted MRI, 0.5 mL of gadobutrol (Gadovist, 1.0 mmol/mL) was injected intrathecally. Gadobutrol distributes in the extravascular space, and served as a CSF tracer. Consecutive MRI scans were obtained throughout 24 to 48 hours. To assess gadobutrol contrast enrichment, regions of interest (ROIs) were placed at multiple locations along the visual pathway, from the primary visual cortex to the eye's vitreous body. CSF tracer dependent T1 signal was measured in each ROI. A linear mixed-model was used for statistical analyses. Results: CSF tracer enrichment was found within the optic nerve, optic chiasm, optic tract, and primary visual cortex (P < 0.001). Peak tracer enrichment in the visual pathway generally occurred after 24 hours and was preceded by peak enhancement in the prechiasmatic cistern after 4 to 6 hours. Conclusions: The results indicate direct communication between CSF of subarachnoid space and the extravascular space of the human visual pathway. Extravascular entry of the CSF tracer is a prerequisite for a glymphatic system, the present findings may suggest its presence. The existence of a glymphatic system in the human visual pathway could bring novel perspectives on the pathophysiology and treatment of ophthalmic diseases.
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Espacio Subaracnoideo/fisiología , Vías Visuales/fisiología , Adulto , Líquido Cefalorraquídeo/fisiología , Medios de Contraste/administración & dosificación , Femenino , Sistema Glinfático/fisiología , Humanos , Inyecciones Espinales , Imagen por Resonancia Magnética , Masculino , Quiasma Óptico/diagnóstico por imagen , Quiasma Óptico/fisiología , Nervio Óptico/diagnóstico por imagen , Nervio Óptico/fisiología , Tracto Óptico/diagnóstico por imagen , Tracto Óptico/fisiología , Compuestos Organometálicos/administración & dosificación , Estudios Prospectivos , Espacio Subaracnoideo/diagnóstico por imagen , Corteza Visual/diagnóstico por imagen , Corteza Visual/fisiología , Vías Visuales/diagnóstico por imagenRESUMEN
BACKGROUND: MOG antibody disease is an autoimmune disease of the central nervous system (CNS) characterized by the presence of a serological antibody against myelin oligodendrocyte glycoprotein (MOG). MRI is instrumental in distinguishing neuromyelitis optica spectrum disorder (NMOSD) from multiple sclerosis (MS), but MRI features of MOG disease appear to overlap with NMOSD and MS. OBJECTIVES: In this study we aim to characterize the radiological features of MOG antibody disease and compare the findings with those previously described. METHODS: This is a retrospective study of 26 MOG positive patients. We aim to describe their brain, spinal and orbital MRI features and compare our findings with those previously reported in the literature. RESULTS: The majority of the abnormal findings was located on orbital MRIs, with more involvement of the anterior structures and bilateral involvement of the optic nerves. Brain abnormalities were distinct from both NMOSD and MS lesions. Spinal cord was the least affected. CONCLUSIONS: This is a dedicated radiological study aiming to characterize the features of MOG antibody disease which might aid in the proper investigation of cases presenting with acquired demyelinating disorders.
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Autoanticuerpos/sangre , Encéfalo/diagnóstico por imagen , Enfermedades Autoinmunes Desmielinizantes SNC/diagnóstico por imagen , Enfermedades Autoinmunes Desmielinizantes SNC/inmunología , Glicoproteína Mielina-Oligodendrócito/inmunología , Nervio Óptico/diagnóstico por imagen , Tracto Óptico/diagnóstico por imagen , Médula Espinal/diagnóstico por imagen , Adulto , Encéfalo/patología , Enfermedades Autoinmunes Desmielinizantes SNC/sangre , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Esclerosis Múltiple/diagnóstico por imagen , Mielitis Transversa/diagnóstico por imagen , Neuromielitis Óptica/diagnóstico por imagen , Nervio Óptico/patología , Tracto Óptico/patología , Estudios Retrospectivos , Médula Espinal/patologíaRESUMEN
In a patient with an optic tract syndrome, we describe the loss of retinal nerve fiber layer and retinal microvasculature using enface and optical coherence tomography angiography image analyses.
Asunto(s)
Fibras Nerviosas/patología , Disco Óptico/irrigación sanguínea , Enfermedades del Nervio Óptico/patología , Tracto Óptico/patología , Células Ganglionares de la Retina/patología , Vasos Retinianos/patología , Tomografía de Coherencia Óptica , Adulto , Capilares/diagnóstico por imagen , Capilares/patología , Angiografía con Fluoresceína , Humanos , Presión Intraocular , Masculino , Disco Óptico/diagnóstico por imagen , Enfermedades del Nervio Óptico/diagnóstico por imagen , Tracto Óptico/diagnóstico por imagen , Vasos Retinianos/diagnóstico por imagen , Campos VisualesRESUMEN
AIM: The aim of this study was to assess parameters of retinal morphology by using high-definition optical coherence tomography (OCT) in patients with Wolfram syndrome (WFS) and their relation to optic tract atrophy in magnetic resonance imaging (MRI). METHOD: High-definition OCT and MRI parameters were evaluated in 12 patients with WFS (three males, nine females; median age at examination 12y 8mo, range 10y 2mo-15y 11mo) and referred to 30 individuals with type 1 diabetes (T1D) (12 males, 18 females; median age at examination 20y 5mo, range 16y 8mo-21y 4mo) and 33 typically developing comparison participants (10 males, 23 females; median age at examination 20y 7mo, range 13y-22y 4mo). RESULTS: Total thickness and quadrant thickness of the retinal nerve fibre layer (RNFL), macular full-thickness parameters and macular ganglion cell layer/inner plexiform layer, intraorbital and intracranial thickness of the optical nerve, as well as the optic chiasm and visual tracts were significantly reduced in patients with WFS compared with those having T1D and the typically developing comparison participants. Optic chiasm thickness correlated negatively in patients with WFS with both age (r=-0.79; p=0.002) and duration of diabetes (r=-0.62; p=0.032). Thickness of the intraorbital parts of the optic nerves in patients with WFS correlated positively with thickness of the superior RNFL (r=0.73; p=0.006). INTERPRETATION: High-definition OCT in combination with MRI could become an important tool for evaluating the effectiveness of therapeutic trials in patients with WFS. WHAT THIS PAPER ADDS: Provides evidence of significant reduction of retinal parameters and optic nerves in patients with Wolfram syndrome (WFS). Shows correlations between magnetic resonance imaging parameters and retinal morphology parameters in patients with WFS.
Asunto(s)
Vías Visuales/diagnóstico por imagen , Síndrome de Wolfram/diagnóstico por imagen , Adolescente , Niño , Preescolar , Femenino , Humanos , Lactante , Imagen por Resonancia Magnética , Masculino , Nervio Óptico/diagnóstico por imagen , Tracto Óptico/diagnóstico por imagen , Retina/diagnóstico por imagen , Tomografía de Coherencia Óptica , Adulto JovenRESUMEN
Adult male C57BL/6J mice have previously been reported to have motor and memory deficits after experimental closed head traumatic brain injury (TBI), without associated gross pathologic damage or neuroimaging changes detectable by magnetic resonance imaging or diffusion tensor imaging protocols. The presence of neurologic deficits, however, suggests neural damage or dysfunction in these animals. Accordingly, we undertook a histologic analysis of mice after TBI. Gross pathology and histologic analysis using Nissl stain and NeuN immunohistochemistry demonstrated no obvious tissue damage or neuron loss. However, Luxol Fast Blue stain revealed myelin injury in the optic tract, while Fluoro Jade B and silver degeneration staining revealed evidence of axonal neurodegeneration in the optic tract as well as the lateral geniculate nucleus of the thalamus and superior colliculus (detectable at 7 days, but not 24 hours, after injury). Fluoro Jade B staining was not detectable in other white matter tracts, brain regions or in cell somata. In addition, there was increased GFAP staining in these optic tract, lateral geniculate, and superior colliculus 7 days post-injury, and morphologic changes in optic tract microglia that were detectable 24 hours after injury but were more prominent 7 days post-injury. Interestingly, there were no findings of degeneration or gliosis in the suprachiasmatic nucleus, which is also heavily innervated by the optic tract. Using micro-computed tomography imaging, we also found that the optic canal appears to decrease in diameter with a dorsal-ventral load on the skull, which suggests that the optic canal may be the site of injury. These results suggest that there is axonal degeneration in the optic tract and a subset of directly innervated areas, with associated neuroinflammation and astrocytosis, which develop within 7 days of injury, and also suggest that this weight drop injury may be a model for studying indirect traumatic optic neuropathy.
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Lesiones Traumáticas del Encéfalo/complicaciones , Traumatismos Cerrados de la Cabeza/complicaciones , Traumatismos del Nervio Óptico/etiología , Animales , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Lesiones Traumáticas del Encéfalo/diagnóstico por imagen , Lesiones Traumáticas del Encéfalo/patología , Modelos Animales de Enfermedad , Gliosis/diagnóstico por imagen , Gliosis/etiología , Gliosis/patología , Traumatismos Cerrados de la Cabeza/diagnóstico por imagen , Traumatismos Cerrados de la Cabeza/patología , Masculino , Ratones Endogámicos C57BL , Enfermedades Neurodegenerativas/diagnóstico por imagen , Enfermedades Neurodegenerativas/etiología , Enfermedades Neurodegenerativas/patología , Traumatismos del Nervio Óptico/diagnóstico por imagen , Traumatismos del Nervio Óptico/patología , Tracto Óptico/diagnóstico por imagen , Tracto Óptico/patologíaRESUMEN
BACKGROUND: Hemangioblastomas usually occur in the cerebellum and are often a component of von Hippel-Lindau disease. Edema-like changes along the optic tract are commonly observed in association with tumors in the sellar and suprasellar regions, such as craniopharyngiomas and pituitary adenomas. Here, we describe a case of sporadic suprasellar hemangioblastoma with edema-like changes along the optic tract that completely resolved after surgery. CASE DESCRIPTION: The patient was a 28-year-old woman with failing vision and a bitemporal hemianopia. Magnetic resonance imaging revealed a tumor accompanied by a 10-mm cyst. Fluid-attenuated inversion recovery axial magnetic resonance imaging revealed a hyperintense region along the optic tract. Other regions of the central nervous system were normal. Endoscopic transsphenoidal surgery was performed, and the histopathologic findings confirmed hemangioblastoma. Six months after surgery, the edema-like change along the optic tract had disappeared. The patient is doing well without pituitary insufficiency, pituitary hormone medications, or signs of tumor recurrence. In addition, the genetic test was negative for von Hippel-Lindau mutations. CONCLUSIONS: When examining a patient with suprasellar tumor, clinicians must consider the possibility of hemangioblastoma. Adequate treatment can improve the edematous change and visual disturbance.
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Edema Encefálico/diagnóstico por imagen , Neoplasias Cerebelosas/diagnóstico por imagen , Hemangioblastoma/diagnóstico por imagen , Tracto Óptico/diagnóstico por imagen , Adulto , Edema Encefálico/complicaciones , Edema Encefálico/cirugía , Neoplasias Cerebelosas/complicaciones , Neoplasias Cerebelosas/cirugía , Femenino , Hemangioblastoma/complicaciones , Hemangioblastoma/cirugía , Humanos , Tracto Óptico/cirugíaRESUMEN
BACKGROUND: To investigate and quantify the impact of intracranial lesions at different locations within the visual pathway on the ganglion cell layer-inner plexiform layer (GCL-IPL) complex and the retinal nerve fiber layer (RNFL). METHODS: Patients with intracranial lesions affecting the optic chiasm (Group I) or the optic tract and/or lateral geniculate nucleus (Group II) were included. All patients received kinetic visual field assessment and underwent spectral domain optical coherence tomography. Peripapillary and papillomacular bundle (PMB) RNFL and macular GCL-IPL thickness in 4 perifoveal areas were measured and compared with normal values derived from 52 age-matched healthy control subjects. Z-scores for each parameter of every patient were calculated and compared with the normative data. Z-scores less than -2.0 (e.g., -2.5) were considered as being statistically significant. RESULTS: Twenty-two patients (Group I and II: 13 and 9, respectively) were included. Ten of 13 patients in Group I showed significant binasal GCL-IPL thinning, with associated temporal sector thinning in 8 patients. In Group II, all 9 patients showed significant reduction of the GCL-IPL corresponding to the homonymous visual field defect, but only 4 demonstrated RNFL thinning. Contralateral RNFL thinning within the PMB clinically similar to bow-tie atrophy was evident in all patients in Group II. GCL-IPL and RNFL thinning varied in severity from mild (isolated PMB RNFL thickness reduction) to severe (bilateral asymmetrical reduction of PMB RNFL associated with asymmetric, predominantly nasal reduction of GCL-IPL) in Group I. CONCLUSION: Clinical abnormalities in patients with visual pathway lesions are more likely to demonstrate abnormalities of GCL-IPL than global peripapillary RNFL thickness. However, PMB thickness measurement appears to be a valuable tool to detect abnormalities of the anterior visual pathways. If peripapillary RNFL measurements are performed in such patients, PMB thickness should be considered the most useful quantitative parameter.
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Cuerpos Geniculados/patología , Fibras Nerviosas/patología , Quiasma Óptico/patología , Enfermedades del Nervio Óptico/diagnóstico , Tracto Óptico/patología , Células Ganglionares de la Retina/patología , Vías Visuales/patología , Adulto , Femenino , Cuerpos Geniculados/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Quiasma Óptico/diagnóstico por imagen , Tracto Óptico/diagnóstico por imagen , Tomografía de Coherencia Óptica/métodos , Trastornos de la Visión/diagnóstico , Agudeza Visual , Campos Visuales , Vías Visuales/diagnóstico por imagen , Adulto JovenRESUMEN
Hemianopia after traumatic brain injury is not infrequent and results from retro-chiasmatic lesions. Differentiating optic pathway lesions can be challenging with classic imaging. Advanced imaging techniques as an investigational tool for posttraumatic hemianopia are discussed and their pitfalls highlighted through an illustrative case study. In a patient with posttraumatic hemianopia, MRI at 8 weeks and 2 years after trauma were analyzed. Diffusion tensor imaging (DTI) and morphometric analysis of the primary visual cortex (V1) were performed. Optical coherence tomography (OCT) was performed 2 years after trauma. DTI at 8 weeks showed a decrease in fractional anisotropy (FA) of the left optic tract together with a decrease in FA in the right optic tract and optic radiation. At 2 years, an isolated decrease of the left optic tract FA values was noticed together with signs of Wallerian degeneration on classic MR imaging. OCT showed thinning of the retina congruent with the visual field deficit. While DTI abnormalities were also present in the early scan, they were more diffuse and also encompassed functionally intact structures. Results of advanced imaging techniques need to be interpreted with caution and can vary according to the timing of imaging due to Wallerian degeneration.
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Lesiones Traumáticas del Encéfalo/complicaciones , Hemianopsia/etiología , Tracto Óptico/patología , Degeneración Walleriana/etiología , Degeneración Walleriana/patología , Adulto , Anisotropía , Imagen de Difusión Tensora , Estudios de Seguimiento , Lateralidad Funcional , Hemianopsia/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética , Masculino , Tracto Óptico/diagnóstico por imagen , Tomografía de Coherencia Óptica , Corteza Visual/diagnóstico por imagen , Pruebas del Campo VisualRESUMEN
Vertebrobasilar dolichoectasia (VBD) is characterized by significant dilation, elongation, and tortuosity of the vertebrobasilar system. We present a unique case of VBD, confirmed by neuroimaging studies, showing vascular compression of the right optic tract and lower cranial nerves leading to an incongruous left homonymous inferior quadrantanopia and glossopharyngeal neuralgia.
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Enfermedades del Nervio Glosofaríngeo/etiología , Hemianopsia/etiología , Tracto Óptico/diagnóstico por imagen , Insuficiencia Vertebrobasilar/complicaciones , Anciano de 80 o más Años , Diagnóstico Diferencial , Enfermedades del Nervio Glosofaríngeo/diagnóstico , Hemianopsia/diagnóstico , Humanos , Angiografía por Resonancia Magnética , Masculino , Oftalmoscopía , Síndrome , Insuficiencia Vertebrobasilar/diagnósticoRESUMEN
Some studies have used diffusion tensor imaging (DTI) to investigate white matter development of the visual pathway in humans and animals after visual deprivation. However, the alterations in the bilateral optic tract after the transection of unilateral optic nerve have not been well explored. In this study, we attempted to investigate the structural integrity of and pathological changes to the bilateral optic tract after transection of the unilateral optic nerve in rats using DTI. Eight healthy male Sprague-Dawley (SD) rats were randomly divided into 2 groups, with 4 in each group. Group A served as a control group. Transection of the unilateral (right) optic nerve was performed in the four rats in group B at seven days after birth to establish the early monocular blind model. Four months after the operation, MnCl2 was injected into the left eyes of all rats, and MRI examinations were performed 24h after injection. We detect the fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) values of the bilateral optic tract in all rats. In a comparison of the ipsilateral optic tract of group B with group A, a significant decrease in FA (P<0.001) and an increase in RD (P<0.01) of the left optic tract were found in group B, while no significant difference was found in the right optic tract. In group B, the FA and RD values of the left optic tract were significantly lower (P<0.01) and significantly higher (P<0.05), respectively, than those of the right optic tract. Consequently, transection of the right optic nerve can lead to structural integrity damage of and pathological changes to the left optic tract in rats. Some DTI-derived parameters (such as FA and RD) may serve as biomarkers of optic tract degeneration.
Asunto(s)
Ceguera/patología , Imagen de Difusión Tensora , Lateralidad Funcional/fisiología , Tracto Óptico/diagnóstico por imagen , Animales , Modelos Animales de Enfermedad , Procesamiento de Imagen Asistido por Computador , Masculino , Distribución Aleatoria , Ratas , Ratas Sprague-DawleyRESUMEN
OBJECTIVES: We investigated changes in the optic tract and optic radiation in patients with multiple sclerosis (MS) by comparing unilateral and bilateral optic nerve damage assessed based on visual evoked potentials (VEPs) using advanced diffusion MR metrics. METHODS: In 21 MS patients, diffusion MRI was performed. Maps of fractional anisotropy, apparent diffusion coefficient (ADC), and mean kurtosis (MK) were computed. On the basis of the P100 latency in VEPs, the MS patients were divided into three groups: bilateral (n=7), unilateral (n=7), and no abnormality (n=7). Their optic tracts and optic radiations were analyzed with diffusion MRI-based fiber tracking. We also investigated the correlations between diffusion parameters and VEPs (n=21). RESULTS: In the optic tract, the diffusion changes in each of the three groups showed step-like changes. The diffusion changes in the optic radiations of the unilateral group were similar to those in the normal VEP group. Only the bilateral group showed significantly higher ADC and lower MK relative to the other two groups (P<0.05, Steel-Dwass multiple-comparison test). A significant positive correlation between VEP latency and ADC and a significant negative correlation between VEP latency and MK were observed (P<0.01, Spearman's correction). CONCLUSIONS: We first evaluated the relationship between VEPs and DKI and concluded that the lateral geniculate nucleus may compensate for unilateral damage in the pre-geniculate optic pathway via neural plasticity.
Asunto(s)
Imagen de Difusión por Resonancia Magnética/métodos , Potenciales Evocados Visuales , Esclerosis Múltiple/diagnóstico por imagen , Nervio Óptico/diagnóstico por imagen , Tracto Óptico/diagnóstico por imagen , Adulto , Anisotropía , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Fibras Nerviosas/patología , Índice de Severidad de la EnfermedadRESUMEN
BACKGROUND: To extract DTI parameters from a specific structure, a region of interest (ROI) must be defined. ROI selection in small structures is challenging; the final measurement results could be affected due to the significant impact of small geometrical errors. In this study the optic tracts were analyzed with the aim to assess differences in DTI parameters due to ROI method and to identify the most reliable method. METHODS: Images of 20 healthy subjects were acquired. Fractional anisotropy (FA) was extracted from the optic tracts by four different ROI methods. Manual tracing was performed in 1) the b0 image and 2) a T1-weighted image registered to the FA image. Semi-automatic segmentation was performed based on 3) tractography and 4) the FA-skeleton algorithm in the tract-based spatial statistics (TBSS) framework. Results were analyzed with regard to ROI method as well as to inter-scan, intra-rater and inter-rater reliability. RESULTS: The resulting FA values divided the ROI methods into two groups that differed significantly: 1) the FA-skeleton and the b0 methods showed higher FA values compared to 2) the tractography and the T1-weighted methods. The intra- and inter-rater variabilities were similar for all methods, except for the tractography method where the inter-rater variability was higher. The FA-skeleton method had a better reproducibility than the other methods. CONCLUSION: Choice of ROI method was found to be highly influential on FA values when the optic tracts were analyzed. The FA-skeleton method performed the best, yielding low variability and high repeatability.
Asunto(s)
Imagen de Difusión por Resonancia Magnética/métodos , Imagen de Difusión Tensora/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Tracto Óptico/diagnóstico por imagen , Adulto , Algoritmos , Anisotropía , Femenino , Voluntarios Sanos , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los ResultadosRESUMEN
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.