RESUMO
A 72-year-old right-handed female patient was operated on for left-sided acute subdural hematoma responsible for coma. Two weeks afterward, her neurological status had improved with a Glasgow Coma Scale score of 14 and a paradoxical left-sided hemiparesis. The brain magnetic resonance imaging displayed a diffusion-restricting, hyper fluid-attenuated inversion recovery lesion of the right cerebral peduncle facing the tentorial notch, and the patient was diagnosed with Kernohan-Woltman notch phenomenon. This allowed to focus the neurological rehabiliation on the ipsilateral motor deficit as well as the hemineglect.
Assuntos
Pedúnculo Cerebral , Hematoma Subdural Agudo , Humanos , Feminino , Idoso , Hematoma Subdural Agudo/diagnóstico por imagem , Hematoma Subdural Agudo/etiologia , Hematoma Subdural Agudo/cirurgia , Encéfalo/patologia , Imageamento por Ressonância Magnética/métodos , Cabeça/patologiaRESUMO
OBJECTIVES: Nigrostriatal dopaminergic neuron loss is essential in pathogenesis of Parkinson's disease (PD). The purpose of this study was to evaluate nigrostriatal structures including the putamen, cerebral peduncle, widths of interpeduncular cistern, and ambient cistern around the midbrain with conventional cranial magnetic resonance images (MRI) in patients with PD. METHODS: The MRI of 56 subjects was included, which was selected from the radiological data system for this retrospective study. The 29 patients with idiopathic PD were included and their disease duration, Hoehn&Yahr stage, and Levodopa equivalent dose (LED) were recorded. The 27 controls had a normal neurologic examination and cranial MRI. All subjects in the patient and control groups had right-hand dominance. Putamen and cerebral peduncle areas and widths of interpeduncular and ambient cisterns were measured in T2 sequences of MRI. Further statistical analysis was applied to exclude gender and age effect on areas. RESULTS: The areas of putamen and cerebral peduncles were significantly reduced in patients with PD compared to the control bilaterally (p < 0.001). Enlargement of interpeduncular and ambient cisterns in patients was higher than in controls, and it was significant (p < 0.001). A correlation was not observed between measurement results and clinical characteristics of patients with PD. Only the cerebral peduncle area/ambient cistern width ratio was significantly correlated with disease duration positively (right r = 0.46 p = 0.012, left r = 0.389 p = 0.037). CONCLUSION: Clinicians should be careful with conventional MRIs of patients with idiopathic PD in practice. It may be different from controls without any neurological disorder, particularly putamen, cerebral peduncles, interpeduncular, and ambient cisterns.
The areas of putamen and cerebral peduncles were significantly reduced in patients with PDEnlargement of interpeduncular and right ambient cisterns were detected in patients with PDCerebral peduncle area/ambient cistern width ratio was significantly correlated with disease duration positivelyMRIs of patients with idiopathic PD may be different from controls without any neurological disorder, particularly putamen, cerebral peduncles, interpeduncular, and ambient cisterns.
Assuntos
Pedúnculo Cerebral , Doença de Parkinson , Humanos , Doença de Parkinson/diagnóstico , Putamen/diagnóstico por imagem , Putamen/patologia , Estudos Retrospectivos , Imageamento por Ressonância Magnética/métodos , Pedúnculo Cerebral/patologia , Substância Negra/patologiaRESUMO
PURPOSE: This works comprehensively analyses a modern cohort of patients with ipsilateral hemiparesis (IH) and discusses the pathophysiological theories elaborated to explain this paradoxical neurological sign according to the findings from contemporary neuroimaging and neurophysiological techniques. METHODS: A descriptive analysis of the epidemiological, clinical, neuroradiological, neurophysiological, and outcome data in a series of 102 case reports of IH published on since the introduction of CT/MRI diagnostic methods (years 1977-2021) was performed. RESULTS: IH mostly developed acutely (75.8%) after traumatic brain injury (50%), as a consequence of the encephalic distortions exerted by an intracranial haemorrhage eventually causing contralateral peduncle compression. Sixty-one patients developed a structural lesion involving the contralateral cerebral peduncle (SLCP) demonstrated by modern imaging tools. This SLCP showed certain variability in its morphology and topography, but it seems pathologically consistent with the lesion originally described in 1929 by Kernohan & Woltman. The study of motor evoked potentials was seldom employed for the diagnosis of IH. Most patients underwent surgical decompression, and a 69.1% experienced some improvement of the motor deficit. CONCLUSIONS: Modern diagnostic methods support that most cases in the present series developed IH following the KWNP model. The SLCP is presumably the consequence of either compression or contusion of the cerebral peduncle against the tentorial border, although focal arterial ischemia may also play a contributing role. Some improvement of the motor deficit should be expected even in the presence of a SLCP, provided the axons of the CST were not completely severed.
Assuntos
Encefalopatias , Pedúnculo Cerebral , Humanos , Encefalopatias/complicações , Encéfalo , Imageamento por Ressonância Magnética , Paresia/diagnóstico , Paresia/etiologiaRESUMO
The projection neurons of the striatum, the principal nucleus of the basal ganglia, belong to one of the following two major pathways: the striatopallidal (indirect) pathway or the striatonigral (direct) pathway. Striatonigral axons project long distances and encounter ascending tracts (thalamocortical) while coursing alongside descending tracts (corticofugal) as they extend through the internal capsule and cerebral peduncle. These observations suggest that striatal circuitry may help to guide their trajectories. To investigate the developmental contributions of striatonigral axons to internal capsule formation, we have made use of Sox8-EGFP (striatal direct pathway) and Fezf2-TdTomato (corticofugal pathway) BAC transgenic reporter mice in combination with immunohistochemical markers to trace these axonal pathways throughout development. We show that striatonigral axons pioneer the internal capsule and cerebral peduncle and are temporally and spatially well positioned to provide guidance for corticofugal and thalamocortical axons. Using Isl1 conditional knock-out (cKO) mice, which exhibit disrupted striatonigral axon outgrowth, we observe both corticofugal and thalamocortical axon defects with either ventral forebrain- or telencephalon-specific Isl1 inactivation, despite Isl1 not being expressed in either cortical or thalamic projection neurons. Striatonigral axon defects can thus disrupt internal capsule formation. Our genome-wide transcriptomic analysis in Isl1 cKOs reveals changes in gene expression relevant to cell adhesion, growth cone dynamics, and extracellular matrix composition, suggesting potential mechanisms by which the striatonigral pathway exerts this guidance role. Together, our data support a novel pioneering role for the striatal direct pathway in the correct assembly of the ascending and descending axon tracts within the internal capsule and cerebral peduncle.SIGNIFICANCE STATEMENT The basal ganglia are a group of subcortical nuclei with established roles in the coordination of voluntary motor programs, aspects of cognition, and the selection of appropriate social behaviors. Hence, disruptions in basal ganglia connectivity have been implicated in the motor, cognitive, and social dysfunction characterizing common neurodevelopmental disorders such as attention-deficit/hyperactivity disorder, autism spectrum disorder, obsessive-compulsive disorder, and tic disorder. Here, we identified a novel role for the striatonigral (direct) pathway in pioneering the internal capsule and cerebral peduncle, and in guiding axons extending to and from the cortex. Our findings suggest that the abnormal development of basal ganglia circuits can drive secondary internal capsule defects and thereby may contribute to the pathology of these disorders.
Assuntos
Transtorno do Espectro Autista , Pedúnculo Cerebral , Animais , Transtorno do Espectro Autista/metabolismo , Axônios/fisiologia , Córtex Cerebral/metabolismo , Cápsula Interna , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Vias Neurais/fisiologia , TálamoRESUMO
OBJECTIVE: Schizencephaly is a rare congenital malformation that causes motor impairment. To determine the treatment strategy, each domain of the motor functions should be appropriately evaluated. We correlated a color map of diffusion tensor imaging (DTI) and transcranial magnetic stimulation (TMS) with the hand function test (HFT) to identify the type of hand function that each test (DTI and TMS) reflects. Further, we attempted to demonstrate the motor neuron organization in schizencephaly. METHOD: This retrospective study was conducted on 12 patients with schizencephaly. TMS was conducted in the first dorsal interosseous (FDI), biceps (BB), and deltoid muscles of the upper extremity, and contralateral MEP (cMEP) and ipsilateral MEP (iMEP) were recorded. The HFT included the grip strength, box and block (B&B), and 9-hole peg test. The schizencephalic cleft was confirmed using magnetic resonance imaging, and the corticospinal tract (CST) was identified using the color map of DTI. The symmetry indices for the peduncle and CST at pons level were calculated as the ratios of the cross-sectional area of the less-affected side and that of the more-affected side. RESULT: In the more-affected hemisphere TMS, no iMEP was obtained. In the less-affected hemisphere TMS, the iMEP response was detected in 9 patients and cMEP in all patients, which was similar to the pattern observed in unilateral lesion. Paretic hand grip strength was strongly correlated with the presence of iMEP (p = 0.044). The symmetry index of the color map of DTI was significantly correlated with the B&B (p = 0.008, R 2 = 0.416), whereas the symmetry index of the peduncle was not correlated with all HFTs. CONCLUSION: In patients with schizencephaly, the iMEP response rate is correlated with the hand function related to strength, while the symmetricity of the CST by the color map of DTI is correlated with the hand function associated with dexterity. Additionally, we suggest the possible motor organization pattern of schizencephaly following interhemispheric competition.
Assuntos
Pedúnculo Cerebral/patologia , Mãos/fisiopatologia , Córtex Motor/patologia , Ponte/patologia , Transtornos Psicomotores/patologia , Tratos Piramidais/patologia , Esquizencefalia/patologia , Adolescente , Adulto , Mapeamento Encefálico , Pedúnculo Cerebral/diagnóstico por imagem , Pedúnculo Cerebral/fisiopatologia , Criança , Pré-Escolar , Imagem de Tensor de Difusão/métodos , Feminino , Força da Mão/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Córtex Motor/diagnóstico por imagem , Córtex Motor/fisiopatologia , Músculo Esquelético/inervação , Músculo Esquelético/fisiopatologia , Ponte/diagnóstico por imagem , Ponte/fisiopatologia , Transtornos Psicomotores/diagnóstico por imagem , Transtornos Psicomotores/fisiopatologia , Tratos Piramidais/diagnóstico por imagem , Tratos Piramidais/fisiopatologia , Estudos Retrospectivos , Esquizencefalia/diagnóstico por imagem , Esquizencefalia/fisiopatologia , Estimulação Magnética Transcraniana/métodosRESUMO
Patients with the ciliopathy Joubert syndrome present with physical anomalies, intellectual disability, and a hindbrain malformation described as the "molar tooth sign" due to its appearance on an MRI. This radiological abnormality results from a combination of hypoplasia of the cerebellar vermis and inappropriate targeting of the white matter tracts of the superior cerebellar peduncles. ARL13B is a cilia-enriched regulatory GTPase established to regulate cell fate, cell proliferation, and axon guidance through vertebrate Hedgehog signaling. In patients, mutations in ARL13B cause Joubert syndrome. To understand the etiology of the molar tooth sign, we used mouse models to investigate the role of ARL13B during cerebellar development. We found that ARL13B regulates superior cerebellar peduncle targeting and these fiber tracts require Hedgehog signaling for proper guidance. However, in mouse, the Joubert-causing R79Q mutation in ARL13B does not disrupt Hedgehog signaling nor does it impact tract targeting. We found a small cerebellar vermis in mice lacking ARL13B function but no cerebellar vermis hypoplasia in mice expressing the Joubert-causing R79Q mutation. In addition, mice expressing a cilia-excluded variant of ARL13B that transduces Hedgehog normally showed normal tract targeting and vermis width. Taken together, our data indicate that ARL13B is critical for the control of cerebellar vermis width as well as superior cerebellar peduncle axon guidance, likely via Hedgehog signaling. Thus, our work highlights the complexity of ARL13B in molar tooth sign etiology.
Assuntos
Fatores de Ribosilação do ADP/metabolismo , Anormalidades Múltiplas/genética , Cerebelo/anormalidades , Pedúnculo Cerebral/metabolismo , Anormalidades do Olho/genética , Doenças Renais Císticas/genética , Retina/anormalidades , Receptor Smoothened/metabolismo , Fatores de Ribosilação do ADP/genética , Animais , Orientação de Axônios , Pedúnculo Cerebral/embriologia , Camundongos , Camundongos Endogâmicos C57BL , Mutação de Sentido Incorreto , Receptor Smoothened/genéticaRESUMO
We describe the anatomical landmarks and surgical feasibility of a novel 'safe' brainstem entry zone to approach ventrally placed intra-axial midbrain tumors. The anatomy of the brainstem was specifically studied to evaluate safe surgical entry zone in the midbrain on two formalin fixed silicon injected cadaver head specimens. A novel entry point through the lateral one - fifth of the cerebral peduncle was identified to be 'safe' to approach lesions of the ventral midbrain. Three patients, having oculomotor schwannoma, peduncular glioma and a peduncular cavernoma were operated using this safe entry zone. To approach the midbrain, retrosigmoid lateral supracerebellar route was used in two patients and a basal subtemporal avenue was deployed in one patient. On the basis of fine microanatomical dissection on cadavers, a novel entry point through the lateral one-fifth of the cerebral peduncle, 5 mm anterior to the lateral mesencephalic sulcus and approximately 5 mm superior to the fourth nerve was identified. The proposed brainstem entry point traverses the parieto-temporo-occipital pontine fibers and the trajectory is between the corticospinal tracts ventrally and the substantia nigra dorsally. Three patients were operated successfully using the approach. There were no post-operative motor, sensory or extra-pyramidal deficits. The corridor through the lateral one-fifth of the cerebral peduncle presents a safe and relative 'easy' surgical route to approach ventrally placed intra-axial midbrain tumors.
Assuntos
Neoplasias do Tronco Encefálico/diagnóstico por imagem , Neoplasias do Tronco Encefálico/cirurgia , Pedúnculo Cerebral/diagnóstico por imagem , Pedúnculo Cerebral/cirurgia , Craniotomia/métodos , Microcirurgia/métodos , Adulto , Cadáver , Feminino , Humanos , Masculino , Adulto JovemRESUMO
OBJECTIVES: To set age-specific normal reference values for brainstem, cerebellar vermis, and peduncles measurements and characterize values' variations according to gender, age, and age by gender interaction. METHODS: 565 normal brain magnetic resonance examinations with normal anatomy and signal intensity of the supra- and infratentorial structures were categorized into six age groups (infant, child, adolescent, young adult, middle-age adult, and old aged adults). Patients with congenital malformations, gross pathology of the supra- or infratentorial brain, brain volume loss, developmental delay, metabolic disorders, and neuropsychological disorders (n = 2.839) were excluded. On midsagittal T1 weighted and axial T2 weighted images specific linear diameters and ratios of the brainstem, cerebellar vermis, and peduncles were attained. Two observers assessed a random sample of 100 subjects to evaluate the inter- and intraobserver reproducibility. Intraclass correlation coefficients, means ± standard deviation, one and two-way analysis of variance tests were used in the statistical analysis. RESULTS: Good to excellent inter- and intraobserver measurements' reproducibility were observed, except for the transverse diameter of the midbrain, the anteroposterior diameter of the medulla oblongata at the pontomedullary and cervicomedullary junctions, cerebellar vermis anteroposterior diameter, and thickness of the superior cerebellar peduncle. Age-specific mean values of the investigated measurements were established. A significant gender-related variation was recorded in the anteroposterior diameter of the basis pontis (p = 0.044), the anteroposterior diameter of the medulla oblongata at the cervicomedullary junction (p = 0.044), and cerebellar vermis height (p = 0.018). A significant age-related change was detected in all measurements except the tectal ratio. Age by gender interaction had a statistically significant effect on the tectal ratio, inferior, and middle cerebellar peduncles' thickness (p = 0.001, 0.022, and 0.028, respectively). CONCLUSION: This study provides age-specific normal mean values for various linear dimensions and ratios of the posterior fossa structures with documentation of measurements' variability according to gender, age, and their interaction. ADVANCES IN KNOWLEDGE: It provides a valuable reference in the clinical practice for easier differentiation between physiological and pathological conditions of the posterior fossa structures especially various neurodegenerative diseases and congenital anomalies.
Assuntos
Mapeamento Encefálico/métodos , Tronco Encefálico/anatomia & histologia , Vermis Cerebelar/anatomia & histologia , Imageamento por Ressonância Magnética/métodos , Córtex Olfatório/anatomia & histologia , Adolescente , Adulto , Fatores Etários , Idoso , Pedúnculo Cerebral/anatomia & histologia , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Pedúnculo Cerebelar Médio/anatomia & histologia , Valores de Referência , Reprodutibilidade dos Testes , Adulto JovemRESUMO
BACKGROUND: Lesions arising at the ventral thalamopeduncular junction are difficult to resect. In addition to being relatively inaccessible, these lesions are located in one of the most sensitive areas of the brain. A critical question is whether new approaches could be developed to allow surgeons to adequately resect these lesions with reasonable outcomes. In the present report, we describe our approach to resect lesions in this region of the brain using an eyebrow craniotomy approach with a trajectory through the supracarotid triangle. METHODS: Through retrospective data collection, we present a small series of patients who had undergone an eyebrow, supracarotid triangle approach to resect lesions located at the thalamopeduncular junction. We describe our surgical technique and report patient outcomes using this approach. RESULTS: Three patients had undergone an eyebrow, supracarotid approach for resection of a lesion arising at the ventral thalamopeduncular junction. Two patients had presented with a cavernoma and one with a pilocytic astrocytoma. Complete resection of all 3 lesions was achieved during surgery without any intraoperative complications. No patient developed permanent contralateral weakness despite entering the peduncle during surgery. One patient developed permanent paresthesia in his left hand. CONCLUSIONS: Lesions arising at the ventral thalamopeduncular junction can be adequately resected with reasonable outcomes using an eyebrow, supracarotid triangle approach. This operative technique establishes another potential operative corridor by which neurosurgeons can resect lesions arising within this relatively inaccessible part of the brain.
Assuntos
Astrocitoma/cirurgia , Neoplasias do Tronco Encefálico/cirurgia , Pedúnculo Cerebral/cirurgia , Craniotomia/métodos , Sobrancelhas , Tálamo/cirurgia , Adulto , Astrocitoma/diagnóstico por imagem , Neoplasias do Tronco Encefálico/diagnóstico por imagem , Pedúnculo Cerebral/diagnóstico por imagem , Feminino , Humanos , Masculino , Estudos Retrospectivos , Tálamo/diagnóstico por imagem , Adulto JovemRESUMO
CASE 1: A 9-yr-old boy presents with right subdural hematoma and ipsilateral hemiparesis. Clinical presentation and imaging are consistent with Kernohan-Woltman notch phenomenon. CASE 2: A 19-yr-old man presents with right subdural hematoma and ipsilateral hemiparesis. Clinical presentation is consistent with Kernohan-Woltman notch phenomenon. CLINICAL PEARL: Kernohan-Woltman notch phenomenon is a false-localizing neurologic sign that presents with hemiparesis ipsilateral to the primary lesion. It occurs in the setting of transtentorial herniation, during which the contralateral cerebral peduncle is compressed against the free edge of the tentorium, causing compression of descending corticospinal tract fibers.
Assuntos
Hematoma Subdural/complicações , Hematoma Subdural/diagnóstico por imagem , Paresia/diagnóstico por imagem , Paresia/etiologia , Pedúnculo Cerebral/diagnóstico por imagem , Criança , Dura-Máter/diagnóstico por imagem , Humanos , Masculino , Tratos Piramidais/diagnóstico por imagem , Adulto JovemRESUMO
Background: Holmes tremor (HT) arises from disruption of the cerebellothalamocortical pathways. A lesion can interrupt the projection at any point, resulting in this tremor. We describe a case of HT due to the rare artery of Percheron infarct and its successful treatment using deep brain stimulation. Case report: A 62-year-old woman with a right medial cerebral peduncle and bilateral thalamic stroke developed HT. Ventral intermediate nucleus (Vim) zona incerta (ZI) deep brain stimulation (DBS) surgery was performed, with improvement in her tremor. Discussion: Our case supports the theory that the more caudal ZI target in combination with Vim is beneficial in treating poorly DBS-responsive tremors such as HT.
Assuntos
Infarto Cerebral/diagnóstico por imagem , Estimulação Encefálica Profunda/métodos , Tremor/terapia , Núcleos Ventrais do Tálamo , Zona Incerta , Infarto Cerebral/complicações , Pedúnculo Cerebral/irrigação sanguínea , Pedúnculo Cerebral/diagnóstico por imagem , Feminino , Humanos , Pessoa de Meia-Idade , Tálamo/irrigação sanguínea , Tálamo/diagnóstico por imagem , Tremor/etiologiaRESUMO
BACKGROUND: Cases of Wallerian degeneration of bilateral cerebral peduncles after acute carbon monoxide poisoning have not yet been reported. To date, most of the delayed encephalopathy after acute carbon monoxide poisoning (DEACMP) lesions captured in magnetic resonance imaging (MRI) has been located in the subcortical white matter and basal ganglia. Here we report two cases of DEACMP with abnormalities in the bilateral cerebral peduncles. The etiology of abnormalities, which were strictly confined to the bilateral cerebral peduncles, was Wallerian degeneration secondary to upstream nerve axonal damage, making this the first report on such bilateral cerebral peduncle abnormalities after DEACMP. CASE PRESENTATION: In this report, we present two cases of DEACMP with abnormal signals in the bilateral cerebral peduncles captured during brain MRIs. Case 1 was of a 68-year-old man who presented with paroxysmal disturbance of the consciousness, left limb weakness for 16 days, and lagging responses for 2 days. Case 2 was of a 55-year-old man who was unconscious for 6 h. In addition to the above mentioned characteristics on the brain MRIs, the electroencephalography of case 1 indicated that his forehead scans had a mixture of wide sharp, sharp, and three-phase waves. Brain diffusion tensor imaging of case 2 further proved that the bilateral cerebral anomalies represented Wallerian degeneration secondary to upstream axonal damage. After the definitive diagnosis, the patients returned to the local hospital for hyperbaric oxygen therapy. CONCLUSIONS: Wallerian degeneration of the bilateral cerebral peduncles after acute carbon monoxide poisoning has never been reported before. The abnormal signals in the bilateral cerebral peduncles captured during brain MRIs indicated Wallerian degeneration secondary to upstream axonal damage; thus, these two cases may further our understanding of DEACMP imaging.
Assuntos
Intoxicação por Monóxido de Carbono/complicações , Pedúnculo Cerebral/patologia , Degeneração Walleriana/etiologia , Idoso , Gânglios da Base/patologia , Encefalopatias/patologia , Imagem de Tensor de Difusão , Eletroencefalografia , Humanos , Oxigenoterapia Hiperbárica , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Inconsciência , Substância Branca/patologiaRESUMO
INTRODUCTION: The inferior cerebellar peduncle (ICP) is a major neural tract in the cerebellum and is involved in coordination of movement and proprioceptive; therefore, ICP injury can be accompanied by poor coordination of movement, including ataxia. In this study, using diffusion tensor tractography (DTT), we investigated the relationship between ataxia and ICP injury in patients with cerebral infarct. METHODS: We recruited 14 stroke patients with ataxia after the onset of stroke and 12 normal subjects. The Score of Assessment and Rating of Ataxia (SARA) was used to evaluate ataxia. The values of fractional anisotropy (FA), apparent diffusion coefficient, and fiber number (FN) of the ICP were measured for the diffusion tensor imaging parameters. RESULTS: Significant differences were observed in the FA and FN values of the ICP in the affected hemisphere between the patient and control groups (Pâ<â.05). In addition, the FN value of the ICP in the affected hemisphere showed a negative correlation with SARA (râ=â-0.538, Pâ<â.05). However, parameters of the ICP in the unaffected hemisphere or the FN value in the unaffected hemisphere showed no correlation with SARA (Pâ>â.05). CONCLUSION: We found that the ataxia severity was closely related to the severity of ICP injury in patients with cerebral infarct. Our results suggest that evaluation of the ICP using DTT would be useful for patients with ataxia after cerebral infarct.
Assuntos
Ataxia Cerebelar/complicações , Infarto Cerebral/etiologia , Pedúnculo Cerebral/lesões , Adulto , Idoso , Ataxia Cerebelar/diagnóstico , Ataxia Cerebelar/epidemiologia , Infarto Cerebral/epidemiologia , Infarto Cerebral/fisiopatologia , Pedúnculo Cerebral/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Diffusion tensor imaging (DTI) can be used to index white matter integrity of the corticospinal tract (CST) after stroke; however, the psychometric properties of DTI-based measures of white matter integrity are unknown. The purpose of this study was to examine test-retest reliability as determined by intraclass correlation coefficients (ICC) and calculate minimal detectable change (MDC) of DTI-based measures of CST integrity using three different approaches: a Cerebral Peduncle approach, a Probabilistic Tract approach, and a Tract Template approach. Eighteen participants with chronic stroke underwent DTI on the same magnetic resonance imaging scanner 4 days apart. For the Cerebral Peduncle approach, a researcher hand drew masks at the cerebral peduncle. For the Probabilistic Tract approach, tractography was seeded in motor areas of the cortex to the cerebral peduncle. For the Tract Template approach, a standard CST template was transformed into native space. For all approaches, the researcher performing analyses was blind to participant number and day of data collection. All three approaches had good to excellent test-retest reliability for fractional anisotropy (FA; ICCs >0.786). Mean diffusivity, axial diffusivity, and radial diffusivity were less reliable than FA. The ICC values were highest and MDC values were the smallest for the most automated approach (Tract Template), followed by the combined manual/automated approach (Probabilistic Tract) then the manual approach (Cerebral Peduncle). The results of this study may have implications for how DTI-based measures of CST integrity are used to define impairment, predict outcomes, and interpret change after stroke.
Assuntos
Imagem de Tensor de Difusão/métodos , Tratos Piramidais/patologia , Acidente Vascular Cerebral/patologia , Adulto , Idoso , Pedúnculo Cerebral/diagnóstico por imagem , Doença Crônica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tratos Piramidais/diagnóstico por imagem , Reprodutibilidade dos Testes , Acidente Vascular Cerebral/diagnóstico por imagemRESUMO
Diffusion tensor imaging is often used to assess white matter (WM) changes following traumatic brain injury (TBI), but is limited in voxels that contain multiple fibre tracts. Fixel-based analysis (FBA) addresses this limitation by using a novel method of analysing high angular resolution diffusion-weighted imaging (HARDI) data. FBA examines three aspects of each fibre tract within a voxel: tissue micro-structure (fibre density [FD]), tissue macro-structure (fibre-bundle cross section [FC]) and a combined measure of both (FD and fibre-bundle cross section [FDC]). This study used FBA to identify the location and extent of micro- and macro-structural changes in WM following TBI. A large TBI sample (Nmild = 133, Nmoderate-severe = 29) and control group (healthy and orthopaedic; N = 107) underwent magnetic resonance imaging with HARDI and completed reaction time tasks approximately 7 months after their injury (range: 98-338 days). The TBI group showed micro-structural differences (lower FD) in the corpus callosum and forceps minor, compared to controls. Subgroup analyses revealed that the mild TBI group did not differ from controls on any fixel metric, but the moderate to severe TBI group had significantly lower FD, FC and FDC in multiple WM tracts, including the corpus callosum, cerebral peduncle, internal and external capsule. The moderate to severe TBI group also had significantly slower reaction times than controls, but the mild TBI group did not. Reaction time was not related to fixel findings. Thus, the WM damage caused by moderate to severe TBI manifested as fewer axons and a reduction in the cross-sectional area of key WM tracts.
Assuntos
Lesões Encefálicas Traumáticas/patologia , Lesões Encefálicas Traumáticas/fisiopatologia , Pedúnculo Cerebral/patologia , Corpo Caloso/patologia , Imagem de Difusão por Ressonância Magnética/métodos , Cápsula Externa/patologia , Cápsula Interna/patologia , Tempo de Reação/fisiologia , Substância Branca/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Concussão Encefálica/diagnóstico por imagem , Concussão Encefálica/patologia , Concussão Encefálica/fisiopatologia , Lesões Encefálicas Traumáticas/diagnóstico por imagem , Pedúnculo Cerebral/diagnóstico por imagem , Corpo Caloso/diagnóstico por imagem , Cápsula Externa/diagnóstico por imagem , Feminino , Seguimentos , Escala de Coma de Glasgow , Humanos , Cápsula Interna/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Substância Branca/diagnóstico por imagem , Adulto JovemAssuntos
Pedúnculo Cerebral/diagnóstico por imagem , Doenças do Nervo Oculomotor/fisiopatologia , Acidente Vascular Cerebral/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Doenças do Nervo Oculomotor/etiologia , Acidente Vascular Cerebral/complicaçõesRESUMO
BACKGROUND: To evaluate the presence of Wallerian degeneration and its relationship with sensorimotor deficits following childhood-onset arterial ischemic stroke (AIS). METHODS: Children surviving unilateral AIS older than one month of age were assessed for severity of sensorimotor neurological deficit with the Pediatric Stroke Outcome Measure at least one year post stroke (mean follow-up = 2.9 years, S.D. = ±1.6). The area (mm3) of each cerebral peduncle was measured on T2-weighted magnetic resonance images to calculate an Asymmetry Index (AI). The AI between patients with childhood stroke (cases) and controls (children with normal MRI) was compared. In the stroke group, the AI between patients with good and poor motor outcome, and the correlation between the AI and motor outcome was calculated. RESULTS: Asymmetry was compared in 52 children with stroke (cases) and 20 controls (normal brain MRIs). The AI was greater in patients with stroke (mean = 6.8%, S.D. = ±5.9) compared with controls (mean = 3.4%, S.D. = ±3.5, P < 0.02). Patients with poor outcome had an AI of 10% or greater compared with patients with good outcome (mean 10.4 versus 4, P < 0.001), and the AI was moderately correlated with motor deficit severity (r = 0.582, P = 0.001). CONCLUSIONS: Asymmetry of the cerebral peduncle is a feasible method of assessing Wallerian degeneration in children with unilateral AIS. The degree of asymmetry in the cerebral peduncles was moderately correlated with neurological outcome severity and reflects the degree of motor deficit in children following stroke.
Assuntos
Isquemia Encefálica , Doenças Arteriais Cerebrais , Pedúnculo Cerebral/diagnóstico por imagem , Transtornos Motores , Avaliação de Resultados em Cuidados de Saúde , Paresia , Convulsões , Acidente Vascular Cerebral , Degeneração Walleriana/diagnóstico por imagem , Adolescente , Isquemia Encefálica/complicações , Isquemia Encefálica/diagnóstico por imagem , Isquemia Encefálica/patologia , Isquemia Encefálica/fisiopatologia , Doenças Arteriais Cerebrais/complicações , Doenças Arteriais Cerebrais/diagnóstico por imagem , Doenças Arteriais Cerebrais/patologia , Doenças Arteriais Cerebrais/fisiopatologia , Pedúnculo Cerebral/patologia , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Lactente , Imageamento por Ressonância Magnética , Masculino , Transtornos Motores/etiologia , Transtornos Motores/patologia , Transtornos Motores/fisiopatologia , Paresia/etiologia , Paresia/patologia , Paresia/fisiopatologia , Estudos Retrospectivos , Convulsões/etiologia , Convulsões/patologia , Convulsões/fisiopatologia , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/patologia , Acidente Vascular Cerebral/fisiopatologiaRESUMO
Brainstem cavernous malformations are challenging lesions considering the numerous eloquent structures frequently related. Surgical resection is the preferred treatment if the patient is symptomatic and the lesion can be safely resected. We present the case of a right-handed 38-yr-old female, presenting with progressive impairment of her handwriting. Physical examination showed a right-sided grade 4/5 hemiparesis. Preoperative imaging was suggestive of a left cerebral peduncle cavernous malformation with a recent area of hemorrhage. The most superficial portion of the lesion was on the surface of the brainstem in the supratrigeminal safe entry zone of the pons. A frontotemporal craniotomy was performed, followed by a pretemporal transtentorial approach. Prior to performing brainstem incision, the area was stimulated, and no motor evoked potential was recorded. The hematoma was then evacuated, and the cavernous malformation was dissected and removed. The capsule was also dissected and removed, using neurophysiological monitoring to guide this procedure. The lesion was completely resected, and the patient was discharged on postoperative day 7 with a right-sided hemiparesis grade 3/5, which improved to grade 5/5 after 4 mo. The patient presented an improvement of her symptoms, with no new neurological deficits. Brainstem cavernomas can be safely removed in selected cases, using the adequate safe entry zone and the appropriate surgical approach. The pretemporal route can be used to reach the anterolateral aspect of the upper part of the brainstem, as it combines the advantages of both transsylvian and subtemporal approaches. An informed consent was obtained from the patient for publication of this operative video.