The impact of multiple sclerosis on the size and morphology of corpus callosum: an MRI-based retrospective study / Impacto de la esclerosis múltiple en el tamaño y la morfología del cuerpo calloso: un estudio retrospectivo basado en resonancia magnética

SUMMARY: The corpus callosum (CC) includes the majority of fibers linking the two brain hemispheres. Several cross sectional studies showed an association between callosal atrophy and malfunction and neurodegenerative diseases, which may play a role in their pathological manifestations. As a result, the accurate quantification of the corpus callosum is important to have normative values according to sex, age and ethnicity. The purpose of this study is to determine the size of CC in patients suffering from multiple sclerosis, and compare it to CC size in healthyindividuals. Midsagittal size of CC were recorded prospectively from 404 routine MR brain examinations in normal individuals. The internal skull surface was measured to calculate CC/ internal skull surface ratio. Two groups of patients were studied: 200 (100 male /100 female) healthy individuals and 204 (101 males/103 females) with multiple sclerosis (MS). Mean surface area of CC in controls was 6.58±1.04 cm2 and there was no significant difference between males and females (P< 0.627). CC/ internal skull surface ratio was 4.44±0.77 %. MS patients showed a significant decrease in CC size compared to normal controls. Using MR imaging, we measured the mean sizes of the various portions of the CC in normal individuals, in addition to MS patients; these values may provide a useful basis to determine changes occurring in CC structures.

El cuerpo calloso (CC) incluye la mayoría de las fibras que unen los dos hemisferios cerebrales. Varios estudios transversales mostraron una asociación entre la atrofia y el mal funcionamiento calloso y las enfermedades neurodegenerativas, lo que puede desempeñar un papel en sus manifestaciones patológicas. En consecuencia, la cuantificación precisa del cuerpo calloso es importante para tener valores normativos según sexo, edad y etnia. El propósito de este estudio fue determinar el tamaño de CC en pacientes que padecen esclerosis múltiple y compararlo con el tamaño de CC en individuos sanos. El tamaño sagital medio del CC se registró prospectivamente a partir de 404 exámenes cerebrales de RM de rutina en individuos normales. Se midió la superficie interna del cráneo para calcular la relación CC/superficie interna del cráneo. Se estudiaron dos grupos de pacientes: 200 (100 hombres/100 mujeres) sanos y 204 (101 hombres/103 mujeres) con esclerosis múltiple (EM). El área superficial media de CC en los controles fue de 6,58±1,04 cm2 y no hubo diferencia significativa entre hombres y mujeres (P< 0,627). La relación CC/superficie interna del cráneo fue de 4,44±0,77 %. Los pacientes con EM mostraron una disminución significativa en el tamaño de CC en comparación con los controles normales. Usando imágenes de RM, medimos los tamaños medios de las diversas porciones del CC en individuos normales, además de pacientes con EM; estos valores pueden proporcionar una base útil para determinar los cambios que ocurren en las estructuras CC.

Anatomía del cuerpo calloso en ratas sometidas a estrés prenatal crónico / Anatomy of corpus callosum in rats submitted to chronic prenatal stress

RESUMEN: El cuerpo calloso (CC), es la mayor comisura de sustancia blanca del encéfalo de los mamíferos placentados, constituida por numerosos haces de fibras transversales que conectan áreas corticales de ambos hemisferios cerebrales. Por otro lado, el estrés se define como una respuesta general del organismo ante demandas externas o internas, inicialmente amenazantes, que consiste en movilizar recursos fisiológicos y psicológicos para poderlas afrontar. Dada la importancia del cuerpo calloso en las conexiones cortico-corticales, el objetivo del presente estudio, fue evaluar el efecto en ratas, de un estrés prenatal crónico por inmovilización, sobre la anatomía macroscópica del CC. Se utilizaron seis ratas preñadas de la cepa Wistar de 250 g, de las cuales tres fueron sometidas, a partir del octavo día postconcepción, a una restricción de movimiento por diez días (2h/día). Posteriormente, las madres prosiguieron su gestación, parto y lactancia. Al nacimiento, las camadas fueron ajustadas a seis crías machos por madre (n=36), destetadas a los 21 días y sacrificadas a los 45-52 días de edad. Los encéfalos fueron seccionados a través de la cisura interhemisférica y ambos hemisferios fotografiados por su cara medial. Las imágenes fueron digitalizadas y analizadas mediante el programa Scion Image®, para la medición del área total, parciales (tercio anterior, medio, posterior y quinto posterior) y perímetro callosal. Es así como, el estrés prenatal por inmovilización, afectó significativamente (p<0,01), la morfología macroscópica del cuerpo calloso. Evidenciándose una disminución del área total, áreas parciales y perímetro callosal, en los animales sometidos a restricción prenatal. Estableciendo una relación directa entre número de axones y área callosal e inversa entre diámetro y densidad axonal; lo observado podría tener incidencia en la transferencia interhemisférica.

SUMMARY: The Corpus Callosum (CC) is the largest white matter commissure in the brain of placental mammals, consisting of numerous transverse fiber bundles that connect cortical areas of both cerebral hemispheres. On the other hand, stress is defined as a general response of the organism to external or internal demands, initially threatening, which consists of mobilizing physiological and psychological resources to be able to face them. Given the importance of CC in cortico-cortical connections, the aim of the present study, was to evaluate the effect of chronic pre-natal immobilization stress on the macroscopic anatomy of CC in rats. Six 250g pregnant rats of the Wistar strain were used, of which three were subjected, starting on the eighth post-conception day, to movement restriction for ten days (2h/day). Subsequently, the mothers continued their gestation, delivery and lactation. At birth, litters were adjusted to six male offspring per mother (n=36), which were weaned at 21 days and slaughtered at 45-52 days of age. The brains were fixed, and later sectioned through the interhemispheric fissure and both hemispheres photographed by their medial aspect. The images were digitized and analyzed using the Scion Image® program, for the measurement of the total area, partial area (ante- rior, middle and posterior thirds, as well as posterior fifth) and callosal perimeter. Thus, prenatal stress due to immobilization significantly affected (p<0.01), the macroscopic morphology of the CC. Evidence shows a decrease in the total area, partial areas and callosal perimeter in the animals subjected to prenatal restraint, as compared to normal animals. Establishing a direct relationship between number of axons and callosal area and an inverse relationship between diameter and axonal density, what was observed may have an impact on interhemispheric transfer.

Fetal akinesia deformation sequence with pontocerebellar hypoplasia, and migration and gyration defects

Fetal akinesia deformation sequence (FADS), or Pena-Shokeir phenotype is a constellation of deformational changes resulting from decreased or absent fetal movement, and include arthrogryposis, and craniofacial and central nervous system anomalies. We report an autopsy case of a 36-6/7week female neonate with a normal female karyotype and chromosome microarray demonstrating findings consistent with FADS. We provide a detailed examination of the severe and complex central nervous system abnormalities, including marked pontocerebellar hypoplasia and cortical and cerebellar migration and gyration defects. This case represents a rare detailed examination of the central nervous system of a patient with FADS.

Altered white matter microarchitecture in Parkinson's disease: a voxel-based meta-analysis of diffusion tensor imaging studies / 医学前沿

This study aimed to define the most consistent white matter microarchitecture pattern in Parkinson's disease (PD) reflected by fractional anisotropy (FA), addressing clinical profiles and methodology-related heterogeneity. Web-based publication databases were searched to conduct a meta-analysis of whole-brain diffusion tensor imaging studies comparing PD with healthy controls (HC) using the anisotropic effect size-signed differential mapping. A total of 808 patients with PD and 760 HC coming from 27 databases were finally included. Subgroup analyses were conducted considering heterogeneity with respect to medication status, disease stage, analysis methods, and the number of diffusion directions in acquisition. Compared with HC, patients with PD had decreased FA in the left middle cerebellar peduncle, corpus callosum (CC), left inferior fronto-occipital fasciculus, and right inferior longitudinal fasciculus. Most of the main results remained unchanged in subgroup meta-analyses of medicated patients, early stage patients, voxel-based analysis, and acquisition with 30 diffusion directions. The subgroup meta-analysis of medication-free patients showed FA decrease in the right olfactory cortex. The cerebellum and CC, associated with typical motor impairment, showed the most consistent FA decreases in PD. Medication status, analysis approaches, and the number of diffusion directions have an important impact on the findings, needing careful evaluation in future meta-analyses.

Anatomical and ultrastructural sex differences in mean diameter and thickness of myelinated axons in adult rat corpus callosum / Diferencias sexuales anatómicas y ultraestructurales del diámetro medio y grosor de los axones mielinizados en el cuerpo calloso de ratas adultas

Sexual dimorphism exists at all levels of the nervous system. These sex differences could underlie genderrelated differences in behavior and neuropsychological function, as well as the gender differences in the prevalence of various mental disorders such as autism, attention deficit disorders, and schizophrenia. Myelination, on the other hand, is a unique cellular process that can have a dramatic impact on the structure and physiology of an axon and its surrounding tissue. The corpus callosum (CC) is the largest of the brain commissures, which connects the cerebral cortices of the two hemispheres, and provides interhemispheric connectivity for information transfer and processing between cortical regions. Variation in the axonal properties of CC will alter the interhemispheric connectivity. The CC consists of myelinated and unmyelinated axons, glial cells and blood vessels. Several functional studies have reported that the function of CC is associated with its axons density and myelination properties. The sexual dimorphism in the axonal content of the CC has always been controversial; hence, the aim of this study was to analyze the differences in axons' diameter and myelin sheath thickness of the CC between male and female rats. For this purpose, five pairs of adult male and female rats were perfused and the CC were removed and sectioned. Four sections from different subregions of the corpus callosum that represent the genu, anterior body, posterior body, and splenium of the CC were stained and electron microscopic images were captured using stereological guidelines. Later, the axons diameter and myelin sheath thickness for each subregion were calculated and compared between males and females. Our preliminary findings of the present study indicated region specific differences in the myelinated axon thickness and diameter in the CC between male and female rats.

El dimorfismo sexual existe en todos los niveles del sistema nervioso. Estas diferencias de sexo podrían ser la base de las diferencias de comportamiento y función neuropsicológica relacionadas con el sexo, así como las diferencias en la prevalencia de diversos trastornos mentales, como el autismo, los trastornos por déficit de atención y la esquizofrenia. La mielinización, por otro lado, es un proceso celular único que puede tener un impacto dramático en la estructura y fisiología de un axón y su tejido circundante. El cuerpo calloso (CC) es la mayor comisura cerebral, que conecta las cortezas cerebrales de ambos hemisferios, y proporciona la conectividad interhemisférica para la transferencia y el procesamiento de información entre regiones corticales. La variación en las propiedades axonales de CC alterará la conectividad interhemisférica. El CC consiste en axones mielinizados y no mielinizados, células gliales y vasos sanguíneos. Varios estudios funcionales han informado que la función de CC está asociada con la densidad de axones y las propiedades de mielinización. El dimorfismo sexual en el contenido axonal del CC siempre ha sido controvertido; por lo tanto, el objetivo de este estudio fue analizar las diferencias en el diámetro de los axones y el grosor de la vaina de mielina del CC entre ratas macho y hembra. Para este propósito, se perfundieron cinco pares de ratas macho y hembra adultas y se extrajeron y seccionaron las CC. Se tiñeron cuatro secciones de diferentes subregiones del cuerpo calloso que representan el genu, el cuerpo anterior, el cuerpo posterior y el esplenio y se capturaron imágenes de microscopía electrónicas utilizando referencias estereológicas. Posteriormente se calculó el diámetro de los axones y el grosor de la vaina de mielina para cada subregión y se compararon entre machos y hembras. Nuestros hallazgos preliminares del presente estudio indicaron diferencias específicas en el grosor y diámetro del axón mielinizado en el CC entre ratas macho y hembra.

Hereditary spastic paraplegia: a clinical and epidemiological study of a Brazilian pediatric population / Paraplegia espástica hereditária: estudo clínico e epidemiológico em uma população pediátrica brasileira

ABSTRACT Aims: To investigate hereditary spastic paraplegia (HSP) in a pediatric Brazilian sample. Methods: Epidemiological, clinical, radiological and laboratory data were analyzed in 35 patients. Results: Simple HSP (HSP-S) was detected in 12 patients, and complicated HSP (HSP-C) was detected in 23 patients. The mean age of onset of symptoms was 2.9 years in HSP-S and 1.6 years in HSP-C (p = 0.023). The disease was more severe in HSP-C. There were no differences in sex, ethnic background, or family history between groups. Intellectual disability was the most frequent finding associated with HSP-C. Peripheral axonal neuropathy was found in three patients. In the HSP-C group, MRI was abnormal in 13 patients. The MRI abnormalities included nonspecific white matter lesions, cerebellar atrophy, thinning of the corpus callosum and the "ear of the lynx sign". Conclusions: In children with spastic paraplegia, HSP must be considered whenever similar pathologies, mainly diplegic cerebral palsy, are ruled out.

RESUMO Objetivo: Investigar paraplegia espástica hereditária (PEH) em uma amostra brasileira de pacientes pediátricos. Métodos: Foram colhidos dados clínicos, epidemiológicos, radiológicos e laboratoriais de 35 pacientes. Resultados: Doze pacientes foram classificados como PEH simples (PEH-S), e 23 como PEH complicada (PEH-C). A média de idade de início dos sintomas foi de 2,9 anos na PEH-S e 1,6 anos na PEH-C (p = 0,023). A doença foi mais grave na PEH-C. Não houve diferença de sexo, etnia e histórico familial entre os dois grupos. Deficiência intelectual foi a associação clínica mais frequente na PEH-C. Neuropatia periférica axonal foi encontrada em três pacientes. A RM foi normal em 13 casos de PEH-C. Anormalidades de RM incluiram alterações inespecíficas da substância branca, atrofia de cerebelo, afilamento de corpo caloso e o "sinal da orelha de lince". Conclusões: PEH deve ser considerada em crianças com paraparesia espástica sempre que descartadas condições patológicas similares, principalmente paralisia cerebral.

An Autopsy Proven Case of CSF1R-mutant Adult-onset Leukoencephalopathy with Axonal Spheroids and Pigmented Glia (ALSP) with Premature Ovarian Failure

Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a progressive degenerative white matter disorder caused by mutations in the tyrosine kinase domain of the CSF1R gene. ALSP is often misdiagnosed as other diseases due to its rarity and various clinical presentations such as Parkinsonism, pyramidal signs, cognitive impairment and/or psychiatric symptoms. We describe an autopsy case of ALSP with a CSF1R mutation. A 61-year-old woman presented insidious-onset gait difficulty for 12 years since her age of 49, and premature ovarian failure since her age of 35. At initial hospital visit, brain magnetic resonance imaging revealed hydrocephalus. Initially, Parkinson's syndrome was diagnosed, and she was prescribed L-dopa/carbidopa because of spasticity and rigidity of extremities, which had worsened. Subsequently, severe neuropsychiatric symptoms and cognitive impairment developed and radiologically, features of leukoencephalopathy or leukodystrophy were detected. She showed a down-hill course and died, 12 years after initial diagnosis. At autopsy, the brain showed severe symmetric atrophy of bilateral white matter, paper-thin corpus callosum, thin internal capsule, and marked hydrocephalus. Microscopically, diffuse loss of white matter, relatively preserved subcortical U-fibers, and many eosinophilic bulbous neuroaxonal spheroids were noted, but there was no calcification. Pigmented glia with brown cytoplasmic pigmentation were readily found in the white matter, which were positive for Periodic acid-Schiff, p62, and CD163 stains, but almost negative for CD68. Whole-exome and Sanger sequencing revealed a CSF1R mutation (c.2539G>A, p.Glu847Lys) which was reported in prior one ALSP case. This example demonstrates that ALSP could be associated with premature ovarian failure.

A Patient with Corpus Callosum Infarction Accompanying Infective Endocarditis

No abstract available.

Corpus Callosum Hemorrhage Secondary to Reversible Cerebral Vasoconstriction Syndrome

No abstract available.

Clinical and neuroimaging determinants of minimally conscious and persistent vegetative states after acute stroke

BACKGROUND: Patients with persistent vegetative state (PVS) show no evidence of awareness of self or their environment, and those with minimally conscious state (MCS) have severely impaired consciousness with minimal but definite behavioral evidence of self or environmental awareness after stroke. Neuroimaging and clinical characteristics separating these two close consciousness states after stroke were insufficiently studied. METHODS: We conducted a hospital-based cohort study of all patients with stroke (2011 to 2017) who underwent 3T magnetic resonance imaging and consciousness assessment after 3 months of inclusion. Univariate and multivariate regression analyses were used to estimate the relative risk of neuroimaging markers for differentiation of PVS and MCS. RESULTS: Of 3,600 eligible subjects, 323 patients (0.09%) had PVS and 93 (0.02%) had MCS (mean age, 62.25±13.4 years). Higher stroke volume was strongly associated with PVS compared to MCS (odds ratio [OR], 0.99; 95% confidence interval [CI], 0.98 to 1.00; P=0.001). On univariate analysis, cingulate gyrus (OR, 2.7; 95% CI, 1.62 to 4.36; P=0.001) and corpus callosum (OR, 2.1; 95% CI, 1.28 to 3.44; P=0.003) involvement was significantly associated with PVS. However, on multivariate analysis, only cingulate gyrus involvement was independently associated with PVS (OR, 2.2; 95% CI, 1.33 to 3.72; P=0.002). CONCLUSION: Our results indicate that PVS and MCS are different consciousness states according to clinical and neuroimaging findings. To predict outcome, cognitive performance of these patients should be well questioned after stroke.

Effect of Ghrelin on Memory Impairment in a Rat Model of Vascular Dementia / 간호학회지

PURPOSE: The purpose of this study was to identify the effect of ghrelin on memory impairment in a rat model of vascular dementia induced by chronic cerebral hypoperfusion. METHODS: Randomized controlled groups and the posttest design were used. We established the representative animal model of vascular dementia caused by bilateral common carotid artery occlusion and administered 80 µg/kg ghrelin intraperitoneally for 4 weeks. First, behavioral studies were performed to evaluate spatial memory. Second, we used molecular biology techniques to determine whether ghrelin ameliorates the damage to the structure and function of the white matter and hippocampus, which are crucial to learning and memory. RESULTS: Ghrelin improved the spatial memory impairment in the Y-maze and Morris water maze test. In the white matter, demyelination and atrophy of the corpus callosum were significantly decreased in the ghrelin-treated group. In the hippocampus, ghrelin increased the length of hippocampal microvessels and reduced the microvessels pathology. Further, we confirmed angiogenesis enhancement through the fact that ghrelin treatment increased vascular endothelial growth factor (VEGF)-related protein levels, which are the most powerful mediators of angiogenesis in the hippocampus. CONCLUSION: We found that ghrelin affected the damaged myelin sheaths and microvessels by increasing angiogenesis, which then led to neuroprotection and improved memory function. We suggest that further studies continue to accumulate evidence of the effect of ghrelin. Further, we believe that the development of therapeutic interventions that increase ghrelin may contribute to memory improvement in patients with vascular dementia.

An MRI-Based Quantification for Correlation of Imaging Biomarker and Clinical Performance in Chronic Phase of Carbon Monoxide Poisoning

PURPOSE: The purpose of this study was to determine the relation between quantitative magnetic resonance imaging biomarkers, and clinical performances in chronic phase of carbon monoxide intoxication. MATERIALS AND METHODS: Eighteen magnetic resonance scans and cognitive evaluations were performed, on patients with carbon monoxide intoxication in chronic phase. Apparent diffusion coefficient (ADC) ratios of affected versus unaffected centrum semiovale, and corpus callosum were obtained. Signal intensity (SI) ratios between affected centrum semiovale, and normal pons in T2-FLAIR (fluid-attenuated inversion recovery) images were obtained. The Mini-Mental State Exam, and clinical outcome scores were assessed. Correlation coefficients were calculated, between MRI and clinical markers. Patients were further classified into poor-outcome and good-outcome groups based on clinical performance, and imaging parameters were compared. T2-SI ratio of centrum semiovale was compared, with that of 18 sex-matched and age-matched controls. RESULTS: T2-SI ratio of centrum semiovale was significantly higher in the poor-outcome group, than that in the good-outcome group and was strongly inversely correlated, with results from the Mini-Mental State Exam. ADC ratios of centrum semiovale were significantly lower in the poor outcome group than in the good outcome group, and were moderately correlated with the Mini-Mental State Exam score. CONCLUSION: A higher T2-SI and a lower ratio of ADC values in the centrum semiovale, may indicate presence of more severe white matter injury and clinical impairment. T2-SI ratio and ADC values in the centrum semiovale, are useful quantitative imaging biomarkers for correlation with clinical performance in individuals with carbon monoxide intoxication.

Utility of white matter to gray matter signal intensity ratio in comatose patients treated by targeted temperature management after cardiac arrest: a preliminary study

OBJECTIVE: This study examined the efficacy of the white matter (WM) to gray matter (GM) signal intensity ratio (SIR) in predicting the clinical prognosis of cardiac arrest patients. METHODS: Thirty-one patients who were resuscitated from cardiac arrest and underwent brain magnetic resonance imaging (MRI) were investigated retrospectively. Thirty one subjects with normal brain MRI findings served as the controls. The signal intensities (SI) were measured on T2-weighted image (T2WI). The circular regions of measurement (2–10 mm²) were placed over the regions of interest, and the average signals in GM and WM were recorded in the caudate nucleus (CN), putamen, anterior limb of the internal capsule, corpus callosum (CC), and in the cortex and WM of the frontal lobe. Cerebral performance category (CPC) 1–2 were classified as a good prognosis, and CPC 3–5 were classified as a poor prognosis. RESULTS: Most combinations of the SIR of WM to GM and most SIs of GM, except the frontal cortex, were significantly different between the two groups. On the other hand, the SI of WM was insignificant between both groups. In receiver operating characteristic (ROC) curve analysis, the SIR of the CC to CN had an area under the ROC curve (AUROC) of 1.00 for a cut-off value of 1.59 (sensitivity, 100%; specificity, 100%), the SIR of the CC to putamen had also an AUROC of 1.00 for a cut-off value of 1.43 (sensitivity, 100%; specificity, 100%). CONCLUSION: The SIR of WM to GM measured on a T2WI is related to the neurological outcome after a cardiac arrest.

Increased white matter diffusivity associated with phantom limb pain / 대한통증학회지

BACKGROUND: We utilized diffusion tensor imaging (DTI) to evaluate the cerebral white matter changes that are associated with phantom limb pain in patients with unilateral arm amputation. It was anticipated that this would complement previous research in which we had shown that changes in cerebral blood volume were associated with the cerebral pain network. METHODS: Ten patients with phantom limb pain due to unilateral arm amputation and sixteen healthy age-matched controls were enrolled. The intensity of phantom limb pain was measured by the visual analogue scale (VAS) and depressive mood was assessed by the Hamilton depression rating scale. Diffusion tensor-derived parameters, including fractional anisotropy, mean diffusivity, axial diffusivity (AD), and radial diffusivity (RD), were computed from the DTI. RESULTS: Compared with controls, the cases had alterations in the cerebral white matter as a consequence of phantom limb pain, manifesting a higher AD of white matter in both hemispheres symmetrically after adjusting for individual depressive moods. In addition, there were associations between the RD of white matter and VAS scores primarily in the hemispheres related to the missing hand and in the corpus callosum. CONCLUSIONS: The phantom limb pain after unilateral arm amputation induced plasticity in the white matter. We conclude that loss of white matter integrity, particularly in the hemisphere connected with the missing hand, is significantly correlated with phantom limb pain.

Multicystic Encephalomalacia:Report of One Case / 中国医学科学院学报

The magnetic resonance imaging findings of multicystic encephalomalacia are featured by bilateral frontal large cystic lesion with corpus callosum involvement,evident heterogeneous enhancement of the lesion margin,ring hyperintensity on diffusion weighted imaging,and high choline peak and low N-acetylaspartate peak of the enhanced lesion margin on magnetic resonance spectroscopy.This article reports a case of multicystic encephalomalacia.

Bilateral Occipital Lobe Infarction Presenting as Bilateral Inferior Altitudinal Defects

PURPOSE: Horizontal visual field defects are generally caused by lesions before the optic chiasm, but we report a case with bilateral inferior altitudinal defects secondary to bilateral occipital lobe infarction. CASE SUMMARY: A 57-year-old male with a history of diabetes and hypertension presented with a month of blurring in the inferior visual field. His corrected visual acuity was 1.0 in the right eye and 0.63 in the left eye, and the intraocular pressure was normal in each eye. Pupillary response, ocular movement, and color vision tests were normal in both eyes. There was no specific finding of the optic disc and macula on fundus examination. Visual field examination revealed an inferior congruous homonymous hemianopia with horizontal meridian sparing and a left incongruous homonymous quadrantanopia. Optical coherence tomography for peripapillary retinal nerve fiber layer thickness revealed a mild decrease in the inferior disc of both eyes. Brain magnetic resonance imaging confirmed the presence of an acute infarction confined with upper medial calcarine fissures of bilateral occipital lobe and the right splenium of the corpus callosum, which were consistent with inferior altitudinal hemianopia and left superior incongruous quadrantanopia, respectively. Brain magnetic resonance angiography showed multiple stenosis of bilateral posterior cerebral arteries. CONCLUSIONS: The altitudinal visual field defects could be caused by the occipital lesion medial to the calcarine fissure, and unusual visual defects could be due to a combination of multiple lesions.

Crossed Aphasia after Right Corpus Callosum Infarction: a Case Report

Crossed aphasia (CA) is defined as language impairment following right-hemispheric brain lesion in right-handed person. Exact mechanism responsible for CA is ambiguous, and recently several brain lesions have been proposed to be associated with aphasia using lesion mapping method. Corpus callosum has dual bloody supply which makes it less vulnerable to infarction. Speech difficulties such as stuttering after corpus callosum infarction have been reported in the past, but aphasia is rare, which makes CA more unique. We report an extraordinary case of CA after right corpus callosum infarction. A 74-year-old female patient with a previous history of right thalamus infarction with no neurologic sequela has developed language disturbance without apraxia 1 month ago and a diffusion-weighted magnetic resonance imaging showed newly developed infarction at right corpus callosum. The aphasia quotient of the Korean version of the Western Aphasia Battery was 2.5, implying severe global aphasia. Positron emission tomography-computed tomography showed decreased metabolism in right corpus callosum and left frontal and temporal cortex, suggesting that interhemispheric diaschisis may be responsible for the CA. This is an extraordinary case report of an isolated manifestation of CA secondary to right corpus callosum infarction.