ABSTRACT
Wallerian degeneration (WD) is defined as progressive anterograde disintegration of axons and accompanying demyelination after an injury to the proximal axon or cell body. Since the 1980s and 1990s, conventional magnetic resonance imaging (MRI) sequences have been shown to be sensitive to changes of WD in the subacute to chronic phases. More recently, advanced MRI techniques, such as diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI), have demonstrated some of earliest changes attributed to acute WD, typically on the order of days. In addition, there is increasing evidence on the value of advanced MRI techniques in providing important prognostic information related to WD. This article reviews the utility of conventional and advanced MRI techniques for assessing WD, by focusing not only on the corticospinal tract but also other neural tracts less commonly thought of, including corticopontocerebellar tract, dentate-rubro-olivary pathway, posterior column of the spinal cord, corpus callosum, limbic circuit, and optic pathway. The basic anatomy of these neural pathways will be discussed, followed by a comprehensive review of existing literature supported by instructive clinical examples. The goal of this review is for readers to become more familiar with both conventional and advanced MRI findings of WD involving important neural pathways, as well as to illustrate increasing utility of advanced MRI techniques in providing important prognostic information for various pathologies.
Subject(s)
Corpus Callosum/diagnostic imaging , Pyramidal Tracts/diagnostic imaging , Wallerian Degeneration/diagnostic imaging , Corpus Callosum/pathology , Diffusion Magnetic Resonance Imaging , Diffusion Tensor Imaging/methods , Humans , Magnetic Resonance Imaging/methods , Neural Pathways/diagnostic imaging , Neural Pathways/pathology , Prognosis , Pyramidal Tracts/pathology , Wallerian Degeneration/pathologySubject(s)
Kallmann Syndrome/complications , Kallmann Syndrome/pathology , Movement Disorders/etiology , Pyramidal Tracts/pathology , Adult , Diffusion Tensor Imaging , Extracellular Matrix Proteins/genetics , Humans , Imaging, Three-Dimensional , Kallmann Syndrome/diagnostic imaging , Kallmann Syndrome/genetics , Male , Motor Cortex/diagnostic imaging , Movement Disorders/diagnostic imaging , Mutation/genetics , Nerve Tissue Proteins/genetics , Psychomotor Performance/physiology , Pyramidal Tracts/diagnostic imagingABSTRACT
INTRODUCTION: Spinal cord and peripheral nerves are classically known to be damaged in Friedreich's ataxia, but the extent of cerebral involvement in the disease and its progression over time are not yet characterized. The aim of this study was to evaluate longitudinally cerebral damage in Friedreich's ataxia. METHODS: We enrolled 31 patients and 40 controls, which were evaluated at baseline and after 1 and 2 years. To assess gray matter, we employed voxel-based morphometry and cortical thickness measurements. White matter was evaluated using diffusion tensor imaging. Statistical analyses were both cross-sectional and longitudinal (corrected for multiple comparisons). RESULTS: Group comparison between patients and controls revealed widespread macrostructural differences at baseline: gray matter atrophy in the dentate nuclei, brainstem, and precentral gyri; and white matter atrophy in the cerebellum and superior cerebellar peduncles, brainstem, and periventricular areas. We did not identify any longitudinal volumetric change over time. There were extensive microstructural alterations, including superior cerebellar peduncles, corpus callosum, and pyramidal tracts. Longitudinal analyses identified progressive microstructural abnormalities at the corpus callosum, pyramidal tracts, and superior cerebellar peduncles after 1 year of follow-up. CONCLUSION: Patients with Friedreich's ataxia present more widespread gray and white matter damage than previously reported, including not only infratentorial areas, but also supratentorial structures. Furthermore, patients with Friedreich's ataxia have progressive microstructural abnormalities amenable to detection in a short-term follow-up.
Subject(s)
Corpus Callosum/pathology , Diffusion Tensor Imaging , Friedreich Ataxia/pathology , Gray Matter/pathology , Pyramidal Tracts/pathology , Adult , Age of Onset , Cross-Sectional Studies , Disease Progression , Female , Humans , Image Processing, Computer-Assisted , Longitudinal Studies , Male , Retrospective Studies , Severity of Illness Index , Statistics as Topic , Young AdultABSTRACT
OBJECTIVES: To measure both fractional anisotropy (FA) values in the corticospinal tracts (CSTs) and volume of the thalami in preterm infants with cystic periventricular leukomalacia (c-PVL) and to compare these measurements with control infants. STUDY DESIGN: Preterm infants with c-PVL and controls with magnetic resonance imaging data acquired between birth and term equivalent age (TEA) were retrospectively identified in 2 centers. Tractography of the CST and segmentation of the thalamus were performed, and values from infants with c-PVL and controls were compared. RESULTS: Thirty-three subjects with c-PVL and 31 preterm controls were identified. All had at least 1 scan up to TEA, and multiple scans were performed in 31 infants. A significant difference in FA values of the CST was found between cases and controls on the scans both before and at TEA. Absolute thalamic volumes were significantly reduced at TEA but not on the earlier scans. Data acquired in infancy showed lower FA values in infants with c-PVL. CONCLUSIONS: Damage to the CST can be identified on the early scan and persists, whereas the changes in thalamic volume develop in the weeks between the early and term equivalent magnetic resonance imaging. This may reflect the difference between acute and remote effects of the extensive injury to the white matter caused by c-PVL.
Subject(s)
Leukomalacia, Periventricular/pathology , Pyramidal Tracts/pathology , Thalamus/pathology , Anisotropy , Diffusion Tensor Imaging/methods , Female , Gestational Age , Humans , Infant, Newborn , Infant, Premature , Magnetic Resonance Imaging/methods , Male , Retrospective StudiesABSTRACT
Stimulating the dorsal anterior pretectal nucleus (dAPtN) in rats is more effective than stimulating the ventral APtN (vAPtN) at reducing tail-flick latency, whereas stimulation of the vAPtN is more effective at reducing postoperative pain behaviour. This study examines whether a cell lesion caused by injecting N-methyl-D-aspartate into the dAPtN or vAPtN changes the withdrawal threshold of a rat hind paw during different phases of the tactile hypersensitivity induced by a chronic constriction injury (CCI) of the contralateral sciatic nerve. The number of Fos immunoreactive cells in the APtN was also evaluated. The rats whose vAPtN was lesioned 2 days before CCI had more intense tactile hypersensitivity 2 days after CCI than that of the control group, but the groups were not different 7 days after the CCI. The rats whose vAPtN was lesioned 5 days after CCI had withdrawal thresholds that did not differ significantly 7 days after the CCI. The tactile hypersensitivity of the rats whose dAPtN was lesioned 2 days before or 5 days after CCI was not different from that of the control on the second and seventh days after the CCI. The number of Fos immunoreactive cells in the vAPtN and dAPtN increased 2 days after CCI, but did not differ from that in the control 7 days after CCI. We conclude that vAPtN and dAPtN cells are activated by nerve injury; the vAPtN exerts inhibitory control of the initial phase of neuropathic pain whereas the dAPtN does not appear to exert an inhibitory effect in neuropathic processing.
Subject(s)
Neuralgia/metabolism , Pain Measurement/methods , Pretectal Region/metabolism , Pyramidal Tracts/metabolism , Animals , Male , Neuralgia/pathology , Pretectal Region/pathology , Pyramidal Tracts/pathology , Rats , Rats, WistarABSTRACT
The principal motor tract involved in mammalian locomotor activities is known as the corticospinal tract (CST), which starts in the brain motor cortex (upper motor neuron), extends its axons across the brain to brainstem and finally reaches different regions of spinal cord, contacting the lower motor neurons. Visualization of the CST is essential to carry out studies in different kinds of pathologies such as spinal cord injury or multiple sclerosis. At present, most studies of axon structure and/or integrity that involve histological tissue sectioning present the problem of finding the region where the CST is predominant. To solve this problem, one could use a novel technique to make the tissues transparent and observe them directly without histological sectioning. However, the disadvantage of this procedure is the need of costly and nonconventional equipment, such as two-photon fluorescence microscopy or ultramicroscopy to perform the image acquisition. Here, we show that labeling the CST with FluoroRuby in the motor cortex and then performing the clearing technique, the z-acquisition of the entire CST in unsectioned tissue followed by three-dimensional reconstruction can be carried out by standard one-photon confocal microscopy, with yields similar to those obtained by two-photon microscopy. In addition, we present an example of the application of this method in a spinal cord injury model, where the disruption of CST is shown at the lesion site.
Subject(s)
Axons/pathology , Pyramidal Tracts/pathology , Spinal Cord Injuries/pathology , Animals , Brain/pathology , Image Processing, Computer-Assisted , Imaging, Three-Dimensional , Male , Mice , Mice, Inbred C57BL , Microscopy, Confocal , Motor Cortex/pathology , Pyramidal Cells/pathologyABSTRACT
INTRODUCTION: Functional magnetic resonance imaging is a noninvasive technique that allows mapping and visualizing of brain connectivity networks. The hemiparesis after a stroke is a good biological model to study changes in brain connectivity. This model can be expanded if information is obtained before and after neurorehabilitation therapy. OBJECTIVE: To present the functional neuroimaging findings in a patient with stroke before and after performing neurorehabilitation therapy. MATERIALS AND METHODS: As part of the neurorehabilitation protocol, resonance imaging was performed before and after treatment with an equipment operating at 1.5 T. Volumetric T1-weighted images, diffusion images for tractography, functional resonance images with the patient at rest and with the patient performing pincer movement with the right hand were obtained. RESULTS: Functional maps before and after therapy were obtained, which are presented together with structural connectivity images obtained by tractography. Clinical changes can be seen accompanied by changes in activation patterns obtained by functional magnetic resonance imaging. CONCLUSION: The versatility of magnetic resonance imaging allows further knowledge of the structural and functional state of the brain generating new possibilities for diagnosis and prognosis in patients undergoing neurorehabilitation therapy. Neurological rehabilitation processes can be quantified and they can reveal certain postlesional neuroplasticity dynamic processes that the central nervous system possesses.
Subject(s)
Brain Mapping/methods , Diffusion Tensor Imaging/methods , Infarction, Middle Cerebral Artery/complications , Magnetic Resonance Imaging/methods , Paresis/rehabilitation , Pyramidal Tracts/pathology , Child , Dominance, Cerebral , Hand/physiopathology , Humans , Male , Motor Activity/physiology , Paresis/etiology , Physical Therapy Modalities , Reflex, Abnormal , Sepsis/complicationsABSTRACT
Introducción. La resonancia magnética funcional es una técnica no invasiva que permite el mapeo cerebral y la visualización de redes de conectividad. La hemiparesia posterior a un accidente cerebrovascular constituye un buen modelo biológico para estudiar los cambios en la conectividad cerebral. El uso de este modelo se puede expandir si se obtiene información antes y después de la rehabilitación neurológica. Objetivo. Presentar los hallazgos por neuroimágenes funcionales de un paciente con accidente cerebrovascular antes y después del tratamiento de rehabilitación neurológica. Materiales y métodos. Como parte del protocolo de rehabilitación neurológica se tomaron imágenes de resonancia antes y después del tratamiento con un equipo que operaba a 1,5 T. Se obtuvieron imágenes volumétricas potenciadas en T1, imágenes de difusión para tractografía, imágenes de resonancia funcional con el paciente en reposo y haciendo movimientos de pinza con la mano derecha. Resultados. Se obtuvieron mapas funcionales antes y después de la terapia, los cuales se presentan conjuntamente con las imágenes de conectividad estructural obtenidas mediante tractografía. Se observó que los cambios clínicos estaban acompañados de cambios en los patrones de activación obtenidos por resonancia magnética funcional. Conclusión. La versatilidad que ofrece la resonancia magnética permite conocer el estado funcional y estructural del cerebro, generando así nuevas posibilidades de diagnóstico y pronóstico en pacientes que reciben rehabilitación neurológica, con lo que se pueden cuantificar y develar ciertos procesos dinámicos de plasticidad neuronal posteriores a una lesión, que son propios del sistema nervioso central.
Introduction: Functional magnetic resonance imaging is a noninvasive technique that allows mapping and visualizing of brain connectivity networks. The hemiparesis after a stroke is a good biological model to study changes in brain connectivity. This model can be expanded if information is obtained before and after neurorehabilitation therapy. Objective: To present the functional neuroimaging findings in a patient with stroke before and after performing neurorehabilitation therapy. Materials and methods: As part of the neurorehabilitation protocol, resonance imaging was performed before and after treatment with an equipment operating at 1.5 T. Volumetric T1-weighted images, diffusion images for tractography, functional resonance images with the patient at rest and with the patient performing pincer movement with the right hand were obtained. Results: Functional maps before and after therapy were obtained, which are presented together with structural connectivity images obtained by tractography. Clinical changes can be seen accompanied by changes in activation patterns obtained by functional magnetic resonance imaging. Conclusion: The versatility of magnetic resonance imaging allows further knowledge of the structural and functional state of the brain generating new possibilities for diagnosis and prognosis in patients undergoing neurorehabilitation therapy. Neurological rehabilitation processes can be quantified and they can reveal certain postlesional neuroplasticity dynamic processes that the central nervous system possesses.
Subject(s)
Child , Humans , Male , Brain Mapping/methods , Diffusion Tensor Imaging/methods , Infarction, Middle Cerebral Artery/complications , Magnetic Resonance Imaging/methods , Paresis/rehabilitation , Pyramidal Tracts/pathology , Dominance, Cerebral , Hand/physiopathology , Motor Activity/physiology , Physical Therapy Modalities , Paresis/etiology , Reflex, Abnormal , Sepsis/complicationsABSTRACT
A 23-year-old woman presented to our hospital with 9 months history of progressive ataxia, visual loss since childhood due to retinitis pigmentosa and primary amenorrhea. On examination, there were also sparse scalp hair, very long and curled upwards eyelashes and short stature. Oliver-McFarlane syndrome was suspected. Brain MRI disclosed cerebellar atrophy and hyperintense signal in corticospinal tracts on FLAIR and T2-weighted images. Therefore, brain imaging must be thoroughly investigated in patients with suspected Oliver-McFarlane syndrome, in order to determinate whether cerebellar atrophy and hyperintense signal in corticospinal tracts are part of this neurological condition.
Subject(s)
Blepharoptosis/congenital , Blepharoptosis/pathology , Dwarfism/pathology , Hypertrichosis/congenital , Hypertrichosis/pathology , Intellectual Disability/pathology , Magnetic Resonance Imaging/methods , Pyramidal Tracts/pathology , Retinitis Pigmentosa/congenital , Retinitis Pigmentosa/pathology , Adult , Atrophy/pathology , Developmental Disabilities/pathology , Female , HumansABSTRACT
OBJECTIVE: To assess speech abilities in adolescents born preterm and investigate whether there is an association between specific speech deficits and brain abnormalities. STUDY DESIGN: Fifty adolescents born prematurely (<33 weeks' gestation) with a spectrum of brain injuries were recruited (mean age, 16 years). Speech examination included tests of speech-sound processing and production and speech and oromotor control. Conventional magnetic resonance imaging and diffusion-weighted imaging was acquired in all adolescents born preterm and 30 term-born control subjects. Radiological ratings of brain injury were recorded and the integrity of the primary motor projections was measured (corticospinal tract and speech-motor corticobulbar tract [CST/CBT]). RESULTS: There were no clinical diagnoses of developmental dysarthria, dyspraxia, or a speech-sound disorder, but difficulties in speech and oromotor control were common. A regression analysis revealed that presence of a neurologic impairment, and diffusion-weighted imaging abnormalities in the left CST/CBT were significant independent predictors of poor speech and oromotor outcome. These left-lateralized abnormalities were most evident at the level of the posterior limb of the internal capsule. CONCLUSION: Difficulties in speech and oromotor control are common in adolescents born preterm, and adolescents with injury to the CST/CBT pathways in the left-hemisphere may be most at risk.
Subject(s)
Brain Injury, Chronic/complications , Premature Birth , Pyramidal Tracts/pathology , Speech Disorders/diagnosis , Adolescent , Brain Injury, Chronic/pathology , Brain Injury, Chronic/physiopathology , Diffusion Magnetic Resonance Imaging , Follow-Up Studies , Hearing Loss/etiology , Humans , Magnetic Resonance Imaging , Psychomotor Performance , Speech Disorders/etiology , Speech Disorders/physiopathology , Speech Perception , Speech Production MeasurementSubject(s)
Brain/physiology , Infant, Premature/physiology , Premature Birth/physiopathology , Adaptation, Physiological/physiology , Birth Weight/physiology , Brain/growth & development , Child Development/physiology , Diffusion Tensor Imaging , Humans , Infant, Newborn , Paired-Associate Learning/physiology , Pyramidal Tracts/pathology , Verbal Learning/physiologyABSTRACT
OBJECTIVE: To evaluate the impact of early brain injury and neonatal illness on corticospinal tract (CST) development in premature newborns serially studied with diffusion tensor tractography. STUDY DESIGN: Fifty-five premature newborns (median 27.6 weeks postmenstrual age) were scanned with magnetic resonance imaging (MRI) early in life and at term-equivalent age. Moderate-severe brain abnormalities (abnormal-MRI) were characterized by moderate-severe white matter injury or ventriculomegaly. Diffusion tensor tractography was used to measure CST diffusion parameters which reflect microstructural development: fractional anisotropy (FA) and average diffusivity (D(av)). The effect of abnormal-MRI and neonatal illness on FA and D(av) were assessed with multivariate regression for repeated measures adjusting for age at scan. RESULTS: Twenty-one newborns (38%) had abnormal-MRI on either scan. FA increased with age significantly slower in newborns with abnormal-MRI (0.008/week) relative to newborns without these MRI abnormalities (0.011/wk) (interaction term P = .05). D(av) was higher in newborns with abnormal-MRI (1.5 x 10(-5) mm(2)/sec; P < .001) for any given age at scan. In the 23 newborns (42%) with postnatal infection, FA increased more slowly (interaction term P = .04), even when adjusting for the presence of abnormal-MRI. CONCLUSIONS: CST microstructural development is significantly impaired in premature newborns with abnormal-MRI or postnatal infection, with a pattern of diffusion changes suggesting impaired glial cell development.
Subject(s)
Diffusion Tensor Imaging , Infant, Premature , Pyramidal Tracts/pathology , Humans , Infant, Newborn , Infant, Newborn, Diseases/pathology , Infections/pathology , Neuroglia/pathology , Premature Birth/physiopathology , Prospective StudiesABSTRACT
BACKGROUND AND PURPOSE: There are 2 main hypotheses concerning the cause of mirror movements (MM) in Kallmann syndrome (KS): abnormal development of the primary motor system, involving the ipsilateral corticospinal tract; and lack of contralateral motor cortex inhibitory mechanisms, mainly through the corpus callosum. The purpose of our study was to determine white and gray matter volume changes in a KS population by using optimized voxel-based morphometry (VBM) and to investigate the relationship between the abnormalities and the presence of MM, addressing the 2 mentioned hypotheses. MATERIALS AND METHODS: T1-weighted volumetric images from 21 patients with KS and 16 matched control subjects were analyzed with optimized VBM. Images were segmented and spatially normalized, and these deformation parameters were then applied to the original images before the second segmentation. Patients were divided into groups with and without MM, and a t test statistic was then applied on a voxel-by-voxel basis between the groups and controls to evaluate significant differences. RESULTS: When considering our hypothesis a priori, we found that 2 areas of increased gray matter volume, in the left primary motor and sensorimotor cortex, were demonstrated only in patients with MM, when compared with healthy controls. Regarding white matter alterations, no areas of altered volume involving the corpus callosum or the projection of the corticospinal tract were demonstrated. CONCLUSION: The VBM study did not show significant white matter changes in patients with KS but showed gray matter alterations in keeping with a hypertrophic response to a deficient pyramidal decussation in patients with MM. In addition, gray matter alterations were observed in patients without MM, which can represent more complex mechanisms determining the presence or absence of this symptom.
Subject(s)
Brain/pathology , Functional Laterality/physiology , Image Processing, Computer-Assisted/methods , Kallmann Syndrome/diagnosis , Magnetic Resonance Imaging/methods , Motor Cortex/pathology , Movement Disorders/diagnosis , Pyramidal Tracts/pathology , Adolescent , Adult , Child , Corpus Callosum/pathology , Dominance, Cerebral/physiology , Humans , Male , Middle Aged , Neural Inhibition/physiology , Neurologic Examination , Organ Size/physiology , Somatosensory Cortex/physiologyABSTRACT
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects the corticospinal tract. ALS functional rating scale (ALSFRS) is a questionnaire that quantifies motor deficits, while diffusion tensor imaging (DTI) evaluates the integrity of fibers through the fractional anisotropy (FA). In the present study, seven ALS patients were evaluated by ALSFRS and immediately submitted to DTI, getting FA values in the following regions: cerebral peduncle (PC), internal capsule (CI) and the white matter under the primary motor cortex (M1), secondary motor cortex (M2) and somesthetic cortex (SI). A control group was constituted by twelve healthy individuals. FA values in patients were significantly lower when compared with controls, with a tendency to higher reductions in the right hemisphere and more inferior regions. Interestingly, FA values were reduced in somesthetic area. No correlation was observed between symptoms duration and FA values. Despite the correlation observed between ALSFRS scores and degeneration in PC and CI, our results suggest that this subjective scale is not a good parameter for the evaluation of the structural damage in encephalic portions of the corticospinal tract.
Subject(s)
Amyotrophic Lateral Sclerosis/pathology , Diffusion Magnetic Resonance Imaging , Pyramidal Tracts/pathology , Surveys and Questionnaires , Case-Control Studies , Female , Humans , Male , Middle Aged , Reproducibility of ResultsABSTRACT
A esclerose lateral amiotrófica (ELA) é doença neurodegenerativa que afeta o trato córtico-espinhal. A escala funcional de avaliação em ELA (ALSFRS) é um questionário que quantifica clinicamente as perdas motoras, enquanto a imagem por tensor de difusão (DTI) avalia a integridade das fibras através da fração de anisiotropia (FA). No presente estudo, sete pacientes com ELA definida foram avaliados pela ALSFRS e imediatamente submetidos à DTI, obtendo valores de FA nas regiões: pedúnculo cerebral (PC), cápsula interna (CI) e substância barnca subjacente às áreas motora primária (M1), motora secundária (M2) e somestésica (SI). Um grupo controle foi constituído de doze indivíduos saudáveis. Os pacientes apresentaram valores de FA significativamente menores que os controles, com tendência à maior redução à direita e nas regiões mais caudais. Curiosamente, os valores de FA estavam reduzidos na área somestésica. Não foi observada correlação entre a duração dos sintomas e os valores de FA. Apesar da correlação entre os valores da ALSFRS e a degeneração em PC e CI, nossos resultados sugerem que essa escala subjetiva não é um bom parâmetro para a avaliação do dano estrutural nas porções encefálicas do trato corticoespinhal.
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects the corticospinal tract. ALS functional rating scale (ALSFRS) is a questionnaire that quantifies motor deficits, while diffusion tensor imaging (DTI) evaluates the integrity of fibers through the fractional anisotropy (FA). In the present study, seven ALS patients were evaluated by ALSFRS and immediately submitted to DTI, getting FA values in the following regions: cerebral peduncle (PC), internal capsule (CI) and the white matter under the primary motor cortex (M1), secondary motor cortex (M2) and somestetic cortex (SI). A control group was constituted by twelve healthy individuals. FA values in patients were significantly lower when compared with controls, with a tendency to higher reductions in the right hemisphere and more inferior regions. Interestingly, FA values were reduced in somestetic area. No correlation was observed between symptoms duration and FA values. Despite the correlation observed between ALSFRS scores and degeneration in PC and CI, our results suggest that this subjective scale is not a good parameter for the evaluation of the structural damage in encephalic portions of the corticospinal tract.
Subject(s)
Female , Humans , Male , Middle Aged , Amyotrophic Lateral Sclerosis/pathology , Diffusion Magnetic Resonance Imaging , Pyramidal Tracts/pathology , Surveys and Questionnaires , Case-Control Studies , Reproducibility of ResultsABSTRACT
Experimental studies in nonhuman primates have questioned the selectivity of pyramidal tract damage in giving rise to the classical pyramidal syndrome in humans, characterized by permanent spastic hemiplegia (PSH). According to this view, concomitant injury of extrapyramidal pathways is necessary for the development of both hemiplegia and spasticity. In this study we used conventional magnetic resonance imaging and diffusion tensor imaging tractography to characterize the anatomical correlates of PSH in a patient with a rare and discrete unilateral lesion of the medullary pyramid. Our findings support the hypothesis that damage confined to the medullary pyramid/pyramidal tract is sufficient to produce PSH. In contrast to nonhuman primates, the human 'pyramidal' and 'pyramid' syndromes are equivalent clinico-anatomic concepts.
Subject(s)
Hemiplegia/pathology , Pyramidal Tracts/pathology , Aged , Diffusion Magnetic Resonance Imaging/methods , Female , Hemiplegia/physiopathology , Humans , Imaging, Three-Dimensional , Male , Middle Aged , Neuropsychological Tests , Pyramidal Tracts/physiopathology , SyndromeABSTRACT
The clinical features of multiple system atrophy (MSA) include four domains: autonomic failure/urinary dysfunction, Parkinsonism, cerebellar ataxia, and corticospinal tract dysfunction. Although the diagnosis of definite MSA requires pathological confirmation, magnetic resonance imaging (MRI) studies have been shown to contribute to the diagnosis of MSA. Although pyramidal tract dysfunction is frequent in MSA patients, signs of pyramidal tract involvement are controversially demonstrated by MRI. We evaluated the pyramidal involvement in 10 patients (7 women) with clinically probable MSA, detecting the presence of spasticity, hyperreflexia, and Babinski sign, as well as demonstrating degeneration of the pyramidal tract and primary motor cortex by MRI in all of them. Our article also discusses key radiological features of this syndrome. In MSA, pyramidal tract involvement seems to be more frequent than previously thought, and the clinicoradiological correlation between pyramidal tract dysfunction and degeneration may contribute to the understanding of the clinical hallmarks of MSA. MRI may also add information regarding the differential diagnosis of this syndrome.
Subject(s)
Magnetic Resonance Imaging , Multiple System Atrophy/pathology , Nerve Degeneration/pathology , Pyramidal Tracts/pathology , Female , Humans , Male , Middle Aged , Multiple System Atrophy/complications , Multiple System Atrophy/physiopathology , Nerve Degeneration/complications , Nerve Degeneration/physiopathology , Parkinson Disease, Secondary/diagnosis , Parkinson Disease, Secondary/etiology , Parkinson Disease, Secondary/physiopathology , Reflex, Abnormal/physiology , Severity of Illness IndexABSTRACT
Inherited prion diseases are characterized by mutations in the PRNP gene encoding the prion protein (PrP). We report a novel missense mutation in the PRNP gene (resulting in a G114V mutation in PrP) in members of a Uruguayan family with clinical and histopathologic features of prion disease. Affected individuals were characterized by an early age at onset, initial neuropsychiatric symptoms, late dementia with prominent pyramidal and extrapyramidal symptoms, and long disease duration.
Subject(s)
Amyloid/genetics , Brain/physiopathology , Genetic Predisposition to Disease/genetics , Mutation/genetics , Prion Diseases/genetics , Protein Precursors/genetics , Adolescent , Adult , Age of Onset , Amino Acid Substitution/genetics , Biopsy , Brain/metabolism , Brain/pathology , Chromosome Aberrations , DNA Mutational Analysis , Dementia/genetics , Dementia/pathology , Dementia/physiopathology , Disease Progression , Fatal Outcome , Female , Frontal Lobe/metabolism , Frontal Lobe/pathology , Frontal Lobe/physiopathology , Genetic Testing , Humans , Male , Personality Disorders/genetics , Personality Disorders/pathology , Personality Disorders/physiopathology , Prion Diseases/pathology , Prion Diseases/physiopathology , Prion Proteins , Prions , Pyramidal Tracts/metabolism , Pyramidal Tracts/pathology , Pyramidal Tracts/physiopathology , UruguayABSTRACT
BACKGROUND AND PURPOSE: Hyperintensity in the posterior limb of the internal capsule at T2-weighted MR imaging, consistent with corticospinal tract (CST) degeneration, is described in amyotrophic lateral sclerosis (ALS). However, the lack of specific tests or biological markers hinders confirmation of the diagnosis, especially in the early stages. We investigated the CST in ALS with MR imaging. METHODS: We examined 25 patients (14 men, 11 women; mean age, 49.1 years; range, 29-68 years) and 21 age- and sex-matched control subjects without upper motor neuron signs. According to the revised El Escorial criteria, 22 patients had definite ALS; two, probable ALS; and one, suspected ALS. Fluid-attenuated inversion recovery (FLAIR; TR/TE/TI, 11,000/140/2600) and T1-weighted spin-echo (SE)/magnetization transfer contrast-enhanced (MTC; TR/TE, 510/12) imaging was performed at 1 T. Two experienced neuroradiologists blinded to the patients' history independently evaluated the CST. RESULTS: T1-weighted SE MTC imaging allowed visualization of the CST in both patients and control subjects. T1-weighted SE MTC images showed hypointensity along the CST and bilateral subcortical regions of the precentral gyri in all control subjects and hyperintensity in 80% of patients with ALS (P < .05). FLAIR images showed hyperintensity in these areas in both groups, with no significant difference. CONCLUSION: T1-weighted SE MTC imaging is sensitive and accurate in depicting CST lesions in ALS, whereas FLAIR imaging is not. T1-weighted SE MTC imaging is useful in diagnosing ALS by showing hyperintense areas along the CST, which separates patients from control subjects. This sequence should be included in the workup of patients with weakness and pyramidal signs.
Subject(s)
Image Enhancement , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Motor Neuron Disease/diagnosis , Nerve Degeneration/diagnosis , Pyramidal Tracts/pathology , Adult , Aged , Cerebral Cortex/pathology , Female , Humans , Internal Capsule/pathology , Male , Middle Aged , Sensitivity and SpecificityABSTRACT
Twenty-six patients with syringomyelia were studied with polysomnography to determine the frequency of periodic limb movements (PLM) and its relationship to the presence of a Chiari anomaly, the severity of corticospinal tract involvement, and localization of the syrinx. Sixteen patients showed PLM in stages I and II of non-REM sleep and three PLM also while awake. There were no statistically significant differences in overall disability, corticospinal signs, presence of an associated Chiari anomaly, and disease duration between patients with and without PLM, although there was a trend for patients with PLM to have more severe disease. There was preservation of the lumbosacral enlargement of the spinal cord by the syrinx in all patients with PLM. The latency delay between lower and upper limb muscles was suggestive of conduction along propriospinal pathways. Syringomyelia may lead to an abnormal state of spinal hyperexcitability favoring the appearance of PLM. Detailed magnetic resonance image studies of patients with different localizations of the syrinx cavities may help to determine which tracts are involved in the production of PLM.