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1.
Neuroimage ; 238: 118208, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34089872

RESUMO

The study of local cortical folding patterns showed links with psychiatric illnesses as well as cognitive functions. Despite the tools now available to visualize cortical folds in 3D, manually classifying local sulcal patterns is a time-consuming and tedious task. In fact, 3D visualization of folds helps experts to identify different sulcal patterns but fold variability is so high that the distinction between these patterns sometimes requires the definition of complex criteria, making manual classification difficult and not reliable. However, the assessment of the impact of these patterns on the functional organization of the cortex could benefit from the study of large databases, especially when studying rare patterns. In this paper, several algorithms for the automatic classification of fold patterns are proposed to allow morphological studies to be extended and confirmed on such large databases. Three methods are proposed, the first based on a Support Vector Machine (SVM) classifier, the second on the Scoring by Non-local Image Patch Estimator (SNIPE) approach and the third based on a 3D Convolution Neural Network (CNN). These methods are generic enough to be applicable to a wide range of folding patterns. They are tested on two types of patterns for which there is currently no method to automatically identify them: the Anterior Cingulate Cortex (ACC) patterns and the Power Button Sign (PBS). The two ACC patterns are almost equally present whereas PBS is a particularly rare pattern in the general population. The three models proposed achieve balanced accuracies of approximately 80% for ACC patterns classification and 60% for PBS classification. The CNN-based model is more interesting for the classification of ACC patterns thanks to its rapid execution. However, SVM and SNIPE-based models are more effective in managing unbalanced problems such as PBS recognition.


Assuntos
Córtex Cerebral/diagnóstico por imagem , Aprendizado de Máquina , Reconhecimento Automatizado de Padrão/métodos , Bases de Dados Factuais , Humanos , Imageamento por Ressonância Magnética , Máquina de Vetores de Suporte
2.
Stroke ; 51(3): 944-951, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31906829

RESUMO

Background and Purpose- Dexterous object manipulation, requiring generation and control of finger forces, is often impaired after stroke. This study aimed to describe recovery of precision grip force control after stroke and to determine clinical and imaging predictors of 6-month performance. Methods- Eighty first-ever stroke patients with varying degrees of upper limb weakness were evaluated at 3 weeks, 3 months, and 6 months after stroke. Twenty-three healthy individuals of comparable age were also studied. The Strength-Dexterity test was used to quantify index finger and thumb forces during compression of springs of varying length in a precision grip. The coordination between finger forces (CorrForce), along with Dexterity-score and Repeatability-score, was calculated. Anatomical magnetic resonance imaging was used to calculate weighted corticospinal tract lesion load (wCST-LL). Results- CorrForce, Dexterity-score, and Repeatability-score in the affected hand were dramatically lower at each time point compared with the less-affected hand and the control group, even in patients with mild motor impairment according to Fugl-Meyer assessment. Improved performance over time occurred in CorrForce and Dexterity-score but not in Repeatability-score. The Fugl-Meyer assessment hand subscale, sensory function, and wCST-LL best predicted CorrForce and Dexterity-score status at 6 months (R2=0.56 and 0.87, respectively). wCST-LL explained substantial variance in CorrForce (R2=0.34) and Dexterity-score (R2=0.50) at 6 months; two-point discrimination and Fugl-Meyer score accounted for considerable additional variance. Absence of recovery in CorrForce was predicted by wCST-LL >4 cc and in Dexterity-score by wCST-LL >6 cc. Conclusions- Findings highlight persisting deficits in the ability to grasp and control finger forces after stroke. wCST-LL was the strongest predictor of performance at 6 months, but early two-point discrimination and Fugl-Meyer score had substantial additional predictive value. Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT02878304.


Assuntos
Força da Mão , Acidente Vascular Cerebral/fisiopatologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Polegar/fisiopatologia , Fatores de Tempo
3.
Radiology ; 293(3): 633-643, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31592732

RESUMO

Background Tumor location is a main prognostic parameter in patients with glioblastoma. Probabilistic MRI-based brain atlases specifying the probability of tumor location associated with important demographic, clinical, histomolecular, and management data are lacking for isocitrate dehydrogenase (IDH) wild-type glioblastomas. Purpose To correlate glioblastoma location with clinical phenotype, surgical management, and outcomes by using a probabilistic analysis in a three-dimensional (3D) MRI-based atlas. Materials and Methods This retrospective study included all adults surgically treated for newly diagnosed IDH wild-type supratentorial glioblastoma in a tertiary adult surgical neuro-oncology center (2006-2016). Semiautomated tumor segmentation and spatial normalization procedures to build a 3D MRI-based atlas were validated. The authors performed probabilistic analyses by using voxel-based lesion symptom mapping technology. The Liebermeister test was used for binary data, and the generalized linear model was used for continuous data. Results A total of 392 patients (mean age, 61 years ± 13; 233 men) were evaluated. The authors identified the preferential location of glioblastomas according to subventricular zone, age, sex, clinical presentation, revised Radiation Therapy Oncology Group-Recursive Partitioning Analysis class, Karnofsky performance status, O6-methylguanine DNA methyltransferase promoter methylation status, surgical management, and survival. The superficial location distant from the eloquent area was more likely associated with a preserved functional status at diagnosis (348 of 392 patients [89%], P < .05), a large surgical resection (173 of 392 patients [44%], P < .05), and prolonged overall survival (163 of 334 patients [49%], P < .05). In contrast, deep location and location within eloquent brain areas were more likely associated with an impaired functional status at diagnosis (44 of 392 patients [11%], P < .05), a neurologic deficit (282 of 392 patients [72%], P < .05), treatment with biopsy only (183 of 392 patients [47%], P < .05), and shortened overall survival (171 of 334 patients [51%], P < .05). Conclusion The authors identified the preferential location of isocitrate dehydrogenase wild-type glioblastomas according to parameters of interest and provided an image-based integration of multimodal information impacting survival results. This suggests the role of glioblastoma location as a surrogate and multimodal parameter integrating several known prognostic factors. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Huang in this issue.


Assuntos
Mapeamento Encefálico/métodos , Neoplasias Encefálicas/diagnóstico por imagem , Glioblastoma/diagnóstico por imagem , Imageamento Tridimensional , Imageamento por Ressonância Magnética/métodos , Atlas como Assunto , Neoplasias Encefálicas/enzimologia , Neoplasias Encefálicas/cirurgia , Feminino , Glioblastoma/enzimologia , Glioblastoma/cirurgia , Humanos , Isocitrato Desidrogenase , Masculino , Pessoa de Meia-Idade , Fenótipo , Estudos Retrospectivos
4.
Front Neurol ; 10: 836, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31456734

RESUMO

Objective: This longitudinal observational study investigated how neural stretch-resistance in wrist and finger flexors develops after stroke and relates to motor recovery, secondary complications, and lesion location. Methods: Sixty-one patients were assessed at 3 weeks (T1), three (T2), and 6 months (T3) after stroke using the NeuroFlexor method and clinical tests. Magnetic Resonance Imaging was used to calculate weighted corticospinal tract lesion load (wCST-LL) and to perform voxel-based lesion symptom mapping. Results: NeuroFlexor assessment demonstrated spasticity (neural component [NC] >3.4N normative cut-off) in 33% of patients at T1 and in 51% at T3. Four subgroups were identified: early Severe spasticity (n = 10), early Moderate spasticity (n = 10), Late developing spasticity (n = 17) and No spasticity (n = 24). All except the Severe spasticity group improved significantly in Fugl-Meyer Assessment (FMA-HAND) to T3. The Severe and Late spasticity groups did not improve in Box and Blocks Test. The Severe spasticity group showed a 25° reduction in passive range of movement and more frequent arm pain at T3. wCST-LL correlated positively with NC at T1 and T3, even after controlling for FMA-HAND and lesion volume. Voxel-based lesion symptom mapping showed that lesioned white matter below cortical hand knob correlated positively with NC. Conclusion: Severe hand spasticity early after stroke is negatively associated with hand motor recovery and positively associated with the development of secondary complications. Corticospinal tract damage predicts development of spasticity. Early quantitative hand spasticity measurement may have potential to predict motor recovery and could guide targeted rehabilitation interventions after stroke.

5.
Neuroradiology ; 61(10): 1137-1144, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31197413

RESUMO

PURPOSE: In patients with ICA stenosis, increased peak systolic velocity is a marker of stenosis at risk of ischemic stroke. 4DFlow MRI is a reproducible technique to evaluate velocities in ICA stenosis, although it seems to underestimate velocities as compared with Doppler ultrasonography. The purpose of our study was to confirm that velocities were underestimated on a new set of data acquired with a clinical 4DFlow sequence, and to devise optimal acquisition parameters for ICA stenosis exploration based on a numerical simulation. METHODS: After review board approval, 15 healthy controls and 12 patients presenting ICA stenosis were explored with Doppler ultrasonography and 4DFlow MRI. We created a 2-dimensional simulation of ICA stenosis and its corresponding 4DFlow acquisition, and compared its mean peak systolic velocity underestimation to real MRI and Doppler. We then simulated the acquisition for voxel size ranging from 0.5 to 1.25 mm and number of phases per cardiac cycle ranging from 10 to 25. RESULTS: On acquired data, 4DFlow MR underestimated peak systolic velocities (mean difference between Doppler and 4DFlow: - 35 cm/s), especially high velocities. With spatial and temporal resolutions equivalent to MR acquisition, our simulation yielded similar underestimation (mean difference: - 31 cm/s, P = 0.30). Simulations showed that 0.7-mm resolution and 20 phases per cardiac cycle would be necessary to record peak systolic velocities up to 250 cm/s. CONCLUSION: Higher spatial resolution can provide accurate peak systolic velocities measurement with 4DFlow MRI, thus allowing better ICA stenosis assessment. Further studies are needed to validate the proposed parameters.


Assuntos
Artéria Carótida Interna/diagnóstico por imagem , Estenose das Carótidas/diagnóstico por imagem , Hemodinâmica/fisiologia , Imageamento Tridimensional/métodos , Angiografia por Ressonância Magnética/métodos , Adulto , Idoso , Velocidade do Fluxo Sanguíneo/fisiologia , Artéria Carótida Interna/fisiopatologia , Estenose das Carótidas/fisiopatologia , Simulação por Computador , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valores de Referência , Fatores de Risco , Sensibilidade e Especificidade , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/fisiopatologia , Sístole/fisiologia , Ultrassonografia Doppler de Pulso
6.
Stroke ; 50(4): 867-872, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30908160

RESUMO

Background and Purpose- In acute stroke patients with large vessel occlusion, the goal of intravenous thrombolysis (IVT) is to achieve early recanalization (ER). Apart from occlusion site and thrombus length, predictors of early post-IVT recanalization are poorly known. Better collaterals might also facilitate ER, for instance, by improving delivery of the thrombolytic agent to both ends of the thrombus. In this proof-of-concept study, we tested the hypothesis that good collaterals independently predict post-IVT recanalization before thrombectomy. Methods- Patients from the registries of 6 French stroke centers with the following criteria were included: (1) acute stroke with large vessel occlusion treated with IVT and referred for thrombectomy between May 2015 and March 2017; (2) pre-IVT brain magnetic resonance imaging, including diffusion-weighted imaging, T2*, MR angiography, and dynamic susceptibility contrast perfusion-weighted imaging; and (3) ER evaluated ≤3 hours from IVT start on either first angiographic run or noninvasive imaging. A collateral flow map derived from perfusion-weighted imaging source data was automatically generated, replicating a previously validated method. Thrombus length was measured on T2*-based susceptibility vessel sign. Results- Of 224 eligible patients, 37 (16%) experienced ER. ER occurred in 10 of 83 (12%), 17 of 116 (15%), and 10 of 25 (40%) patients with poor/moderate, good, and excellent collaterals, respectively. In multivariable analysis, better collaterals were independently associated with ER ( P=0.029), together with shorter thrombus ( P<0.001) and more distal occlusion site ( P=0.010). Conclusions- In our sample of patients with stroke imaged with perfusion-weighted imaging before IVT and intended for thrombectomy, better collaterals were independently associated with post-IVT recanalization, supporting our hypothesis. These findings strengthen the idea that advanced imaging may play a key role for personalized medicine in identifying patients with large vessel occlusion most likely to benefit from IVT in the thrombectomy era.


Assuntos
Encéfalo/diagnóstico por imagem , Circulação Colateral , Acidente Vascular Cerebral/terapia , Trombectomia , Terapia Trombolítica/métodos , Administração Intravenosa , Idoso , Idoso de 80 Anos ou mais , Feminino , Fibrinolíticos/uso terapêutico , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Sistema de Registros , Acidente Vascular Cerebral/diagnóstico por imagem , Ativador de Plasminogênio Tecidual/uso terapêutico , Resultado do Tratamento
7.
Neurophysiol Clin ; 49(2): 149-164, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30391148

RESUMO

OBJECTIVES: In this longitudinal pilot study, we investigated how manual dexterity recovery was related to corticospinal tract (CST) injury and excitability, in six patients undergoing conventional rehabilitation. METHODS: Key components of manual dexterity, namely finger force control, finger tapping rate and independence of finger movements, were quantified. Structural MRI was obtained to calculate CST lesion load. CST excitability was assessed by measuring rest motor threshold (RMT) and the amplitude of motor evoked potentials (MEPs) using transcranial magnetic stimulation (TMS). Measurements were obtained at two weeks, three and six months post-stroke. RESULTS: At six months post-stroke, complete recovery of hand gross motor impairment (i.e., maximal Fugl-Meyer score for hand) had occurred in three patients and four patients had recovered ability to accurately control finger force. However, tapping rate and independence of finger movements remained impaired in all six patients at six months. Recovery in hand gross motor impairment and finger force control occurred in patients with smaller CST lesion load and almost complete recovery of CST excitability, although RMT or MEP size remained slightly altered in the stroke-affected hemisphere compared to the unaffected hemisphere. The two patients with poorest recovery showed persistent absence of MEPs and greatest structural injury to CST. DISCUSSION: The findings support good motor recovery being overall correlated with smaller CST lesion, and with almost complete recovery of CST excitability. However, impairment of manual dexterity persisted despite recovery in gross hand movements and grasping abilities, suggesting involvement of additional brain structures for fine manual tasks.


Assuntos
Destreza Motora , Tratos Piramidais/patologia , Tratos Piramidais/fisiopatologia , Recuperação de Função Fisiológica , Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral/patologia , Acidente Vascular Cerebral/fisiopatologia , Idoso , Potencial Evocado Motor , Feminino , Dedos , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos , Tratos Piramidais/lesões , Estimulação Magnética Transcraniana , Resultado do Tratamento
8.
Stroke ; 47(10): 2553-8, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27625381

RESUMO

BACKGROUND AND PURPOSE: Rapid and reliable assessment of the perfusion-weighted imaging (PWI)/diffusion-weighted imaging (DWI) mismatch is required to promote its wider application in both acute stroke clinical routine and trials. We tested whether an evaluation based on the Alberta Stroke Program Early CT Score (ASPECTS) reliably identifies the PWI/DWI mismatch. METHODS: A total of 232 consecutive patients with acute middle cerebral artery stroke who underwent pretreatment magnetic resonance imaging (PWI and DWI) were retrospectively evaluated. PWI-ASPECTS and DWI-ASPECTS were determined blind from manually segmented PWI and DWI volumes. Mismatch-ASPECTS was defined as the difference between PWI-ASPECTS and DWI-ASPECTS (a high score indicates a large mismatch). We determined the mismatch-ASPECTS cutoff that best identified the volumetric mismatch, defined as VolumeTmax>6s/VolumeDWI≥1.8, a volume difference≥15 mL, and a VolumeDWI<70 mL. RESULTS: Inter-reader agreement was almost perfect for PWI-ASPECTS (κ=0.95 [95% confidence interval, 0.90-1]), and DWI-ASPECTS (κ=0.96 [95% confidence interval, 0.91-1]). There were strong negative correlations between volumetric and ASPECTS-based assessments of DWI lesions (ρ=-0.84, P<0.01) and PWI lesions (ρ=-0.90, P<0.01). Receiver operating characteristic curve analysis showed that a mismatch-ASPECTS ≥2 best identified a volumetric mismatch, with a sensitivity of 0.93 (95% confidence interval, 0.89-0.98) and a specificity of 0.82 (95% confidence interval, 0.74-0.89). CONCLUSIONS: The mismatch-ASPECTS method can detect a true mismatch in patients with acute middle cerebral artery stroke. It could be used for rapid screening of patients with eligible mismatch, in centers not equipped with ultrafast postprocessing software.


Assuntos
Isquemia Encefálica/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Imageamento por Ressonância Magnética , Imagem de Perfusão , Idoso , Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/cirurgia , Feminino , Fibrinolíticos/uso terapêutico , Humanos , Infarto da Artéria Cerebral Média/tratamento farmacológico , Infarto da Artéria Cerebral Média/cirurgia , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Trombectomia , Ativador de Plasminogênio Tecidual/uso terapêutico , Resultado do Tratamento
9.
Front Hum Neurosci ; 10: 410, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27582700

RESUMO

A major feature of the human cortex is its huge morphological variability. Although a comprehensive literature about the sulco-gyral pattern of the central region is available from post-mortem data, a reliable and reproducible characterization from in vivo data is still lacking. The aim of this study is to test the reliability of morphological criteria of the central region sulci used in post-mortem data, when applied to in vivo magnetic resonance imaging (MRI) data. Thirty right-handed healthy individuals were included in the study. Automated segmentation and three dimensional (3D) surface-based rendering were obtained from clinical 3D T1-weighted MRI. Two senior radiologists labeled the three sulci composing the central region (precentral [PreCS], central [CS] and postcentral [PostCS]) and analyzed their morphological variations using 47 standard criteria derived from Ono's atlas based on post-mortem data. For each criterion, inter-rater concordance and comparison with the occurrence frequency provided in Ono's atlas were estimated. Overall, the sulcal pattern criteria derived from MRI data were highly reproducible between the raters with a high mean inter-rater concordance in the three sulci (CS: κ = 0.92 in left hemisphere/κ = 0.91 in right hemisphere; PreCS: κ = 0.91/κ = 0.93; PostCS: κ = 0.84/0.79). Only a very limited number of sulcal criteria significantly differed between the in vivo and the post-mortem data (CS: 2 criteria in the left hemisphere/3 criteria in the right hemisphere; PreCS: 3 in the left and right hemispheres; PostCS: 3 in the left hemisphere and 5 in the right hemisphere). Our study provides a comprehensive description of qualitative sulcal patterns in the central region from in vivo clinical MRI with high agreement with previous post-mortem data. Such identification of reliable sulcal patterns of the central region visible with standard clinical MRI data paves the way for the detection of subtle variations of the central sulcation associated with variations of normal or pathological functioning.

10.
Stroke ; 47(4): 1005-11, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26979862

RESUMO

BACKGROUND AND PURPOSE: Whether to withhold recanalization treatment when the diffusion-weighted imaging (DWI) lesion exceeds a given volume is unsettled. Our aim was to assess the impact of recanalization on outcome in patients with baseline DWI lesion ≥70 mL (DWI≥70 mL) treated ≤4.5 hours from onset. We hypothesized that recanalization is beneficial in a sizeable fraction of these patients and that this is associated with a larger DWI lesion reversal. METHODS: We analyzed 267 consecutive patients treated with intravenous recombinant tissue-type plasminogen activator for middle cerebral artery territory stroke in whom an occlusion was present on magnetic resonance angiography and 24-hour recanalization and 90-day clinical outcome could be assessed. After stratification relative to the 70-mL DWI lesion cut point, we calculated the odds ratio for recanalization of the primary arterial occlusive lesion (AOL score ≥2) to predict favorable outcome (modified Rankin scale score ≤2). DWI lesion reversal was compared between recanalizers with DWI≥70 mL with favorable and unfavorable outcomes. RESULTS: Median (interquartile range) DWI lesion volume was 22 mL (10-60), and median onset time to imaging was 116 minutes (86-151). Twelve (22%) of the 54 patients with DWI≥70 mL experienced favorable outcome, of which 9 had recanalized. In patients with DWI≥70 mL, recanalization was significantly associated with favorable outcome after adjustment for age and National Institutes of Health Stroke Scale (odds ratio =4.72 [1.09-20.32]; P=0.0375). Among recanalizers with DWI≥70 mL, absolute and relative DWI reversal volumes were larger in those with favorable as compared with unfavorable outcome (18.8 mL [12.2-47.6] versus 8.5 mL [4.3-31.1]; P=0.17; and 19.6% [10.9-62.8] versus 8.7% [3.9-16.5], respectively; P=0.049). CONCLUSIONS: Patients with DWI lesion volume ≥70 mL can benefit from recanalization after intravenous recombinant tissue-type plasminogen activator. This may partly reflect a larger amount of DWI lesion reversal.


Assuntos
Isquemia Encefálica/patologia , Encéfalo/patologia , Fibrinolíticos/uso terapêutico , Acidente Vascular Cerebral/patologia , Terapia Trombolítica , Ativador de Plasminogênio Tecidual/uso terapêutico , Idoso , Idoso de 80 Anos ou mais , Isquemia Encefálica/tratamento farmacológico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Prognóstico , Acidente Vascular Cerebral/tratamento farmacológico , Resultado do Tratamento
11.
Med Image Anal ; 30: 11-29, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26849421

RESUMO

Segregating the human cortex into distinct areas based on structural connectivity criteria is of widespread interest in neuroscience. This paper presents a groupwise connectivity-based parcellation framework for the whole cortical surface using a new high quality diffusion dataset of 79 healthy subjects. Our approach performs gyrus by gyrus to parcellate the whole human cortex. The main originality of the method is to compress for each gyrus the connectivity profiles used for the clustering without any anatomical prior information. This step takes into account the interindividual cortical and connectivity variability. To this end, we consider intersubject high density connectivity areas extracted using a surface-based watershed algorithm. A wide validation study has led to a fully automatic pipeline which is robust to variations in data preprocessing (tracking type, cortical mesh characteristics and boundaries of initial gyri), data characteristics (including number of subjects), and the main algorithmic parameters. A remarkable reproducibility is achieved in parcellation results for the whole cortex, leading to clear and stable cortical patterns. This reproducibility has been tested across non-overlapping subgroups and the validation is presented mainly on the pre- and postcentral gyri.


Assuntos
Córtex Cerebral/anatomia & histologia , Conectoma/métodos , Imagem de Tensor de Difusão/métodos , Interpretação de Imagem Assistida por Computador/métodos , Técnica de Subtração , Substância Branca/anatomia & histologia , Algoritmos , Feminino , Humanos , Aumento da Imagem/métodos , Masculino , Rede Nervosa/anatomia & histologia , Reconhecimento Automatizado de Padrão/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto Jovem
12.
Stroke ; 47(2): 424-7, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26732567

RESUMO

BACKGROUND AND PURPOSE: Fluid-attenuated inversion recovery vascular hyperintensities (FVH) beyond the boundaries of diffusion-weighted imaging (DWI) lesion (FVH-DWI mismatch) have been proposed as an alternative to perfusion-weighted imaging (PWI)-DWI mismatch. We aimed to establish whether FVH-DWI mismatch can identify patients most likely to benefit from recanalization. METHODS: FVH-DWI mismatch was assessed in 164 patients with proximal middle cerebral artery occlusion before intravenous thrombolysis. PWI-DWI mismatch (PWITmax>6sec/DWI>1.8) was assessed in the 104 patients with available PWI data. We tested the associations between 24-hours complete recanalization on magnetic resonance angiography and 3-month favorable outcome (modified Rankin Scale score ≤2), stratified on FVH-DWI (or PWI-DWI) status. RESULTS: FVH-DWI mismatch was present in 121/164 (74%) patients and recanalization in 50/164 (30%) patients. The odds ratio for favorable outcome with recanalization was 16.2 (95% confidence interval, 5.7-46.5; P<0.0001) in patients with FVH-DWI mismatch and 2.6 (95% confidence interval, 0.6-12.1; P=0.22) in those without FVH-DWI mismatch (P=0.048 for interaction). Recanalization was associated with favorable outcome in patients with PWI-DWI mismatch (odds ratios, 9.9; 95% confidence interval, 3.1-31.3; P=0.0001) and in patients without PWI-DWI mismatch (odds ratios, 7.0; 95% confidence interval, 1.1-44.1; P=0.047), P=0.76 for interaction. CONCLUSION: The FVH-DWI mismatch may rapidly identify patients with proximal occlusion most likely to benefit from recanalization.


Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , Infarto da Artéria Cerebral Média/diagnóstico , Sistema de Registros , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Fibrinolíticos/uso terapêutico , Humanos , Infarto da Artéria Cerebral Média/tratamento farmacológico , Angiografia por Ressonância Magnética , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Seleção de Pacientes , Estudos Retrospectivos , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/tratamento farmacológico , Fatores de Tempo , Ativador de Plasminogênio Tecidual/uso terapêutico , Resultado do Tratamento
13.
Neurobiol Aging ; 36(8): 2360-9, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26058839

RESUMO

Prospective memory (PM) refers to a complex cognitive ability that underpins the delayed execution of previously formulated intentions. PM performance declines early in normal aging and this process is accentuated in Alzheimer's disease. The left frontopolar cortex (BA10) has been consistently assigned a major role in PM functioning, but whether it can be noninvasively modulated to enhance PM performance in aged people has not been addressed so far. Here, we investigated the effects of modulating left BA10 by means of theta burst stimulation (TBS), using either excitatory (intermittent TBS), inhibitory (continuous TBS) or control (vertex) TBS in healthy aged subjects. The behavioral effects were assessed using a reliable and ecological virtual reality PM task that included both event- and time-based retrievals. As compared with vertex stimulation, event-based PM performance significantly improved after excitatory stimulation, whereas inhibitory stimulation had no significant effect. Additionally, and across the different types of stimulation, performance for congruent links between the event-based PM cue and the action to be performed was significantly better as compared with incongruent links. In conclusion, intermittent TBS might provide a relevant interventional strategy to counteract the decline of cognitive functions and memory abilities in normal aging.


Assuntos
Envelhecimento/psicologia , Lobo Frontal/fisiologia , Memória Episódica , Ritmo Teta/fisiologia , Estimulação Magnética Transcraniana/métodos , Idoso , Transtornos Cognitivos/psicologia , Transtornos Cognitivos/terapia , Feminino , Humanos
14.
Eur Radiol ; 25(11): 3230-7, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25916388

RESUMO

OBJECTIVE: HYPR flow is a 3D dynamic contrast-enhanced MRA technique providing isotropic sub-millimetre resolution with half-second temporal resolution. We compared HYPR flow and time-resolved imaging of contrast kinetics (TRICKS) MRA for the characterization of cerebral arteriovenous malformations (cAVMs), using catheter DSA as reference. METHODS: Twenty-two patients underwent HYPR flow and TRICKS MRA within 15 days of DSA. HYPR flow and TRICKS datasets were reviewed separately by two readers for image quality, Spetzler-Martin grade, venous ectasia, and deep venous drainage. RESULTS: Image quality was better for HYPR flow than for TRICKS (narrower full width at half maximum; larger arterial diagnostic window; greater number of arterial frames, P ≤ 0.05). Using HYPR flow, inter-reader agreement was excellent for all cAVM characteristics. The agreement with DSA for the overall Spetzler-Martin grade was excellent for HYPR flow (ICC = 0.96 and 0.98, depending on the reader) and TRICKS (ICC = 0.82 and 0.95). In comparison to TRICKS, HYPR flow showed higher concordance with DSA for the identification of venous ectasia and deep venous drainage. CONCLUSION: Owing to an excellent agreement with DSA with respect to depiction of the vascular architecture of cAVMs, HYPR flow could be useful for the non-invasive characterization of cAVMs. KEY POINTS: • Dynamic MRA is used for cerebral AVM depiction and follow-up • HYPR flow is a new, highly-resolved dynamic MRA sequence • HYPR flow provides whole brain coverage • HYPR flow provides excellent agreement with the Spetzler-Martin grade • Compared to TRICKS MRA, HYPR flow improves cerebral AVM characterization.


Assuntos
Malformações Arteriovenosas Intracranianas/patologia , Adulto , Angiografia Digital/métodos , Cateterismo/métodos , Angiografia Cerebral/métodos , Meios de Contraste , Feminino , Hemodinâmica/fisiologia , Humanos , Imageamento Tridimensional/métodos , Malformações Arteriovenosas Intracranianas/fisiopatologia , Cinética , Angiografia por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Adulto Jovem
15.
PLoS One ; 10(3): e0122252, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25822985

RESUMO

OBJECTIVE: Focal cortical dysplasias (FCDs) are mainly located in the frontal region, with a particular tropism for the central sulcus. Up to 30% of lesions are undetected (magnetic resonance [MR]-negative FCD patients) or belatedly diagnosed by visual analysis of MR images. We propose an automated sulcus-based method to analyze abnormal sulcal patterns associated with central FCD, taking into account the normal interindividual sulcal variability. METHODS: We retrospectively studied 29 right-handed patients with FCD in the central region (including 12 MR negative histologically-confirmed cases) and 29 right-handed controls. The analysis of sulcal abnormalities from T1-weighted MR imaging (MRI) was performed using a graph-based representation of the cortical folds and an automated sulci recognition system, providing a new quantitative criterion to describe sulcal patterns, termed sulcus energy. RESULTS: Group analysis showed that the central sulcus in the hemisphere ipsilateral to the FCD exhibited an abnormal sulcal pattern compared with controls (p = 0.032). FCDs were associated with abnormal patterns of the central sulci compared with controls (p = 0.006), a result that remained significant when MR-negative and MR-positive patients were considered separately, while the effects of sex, age and MR-field were not significant. At the individual level, sulcus energy alone failed to detect the FCD lesion. We found, however, a significant association between maximum z-scores and the site of FCD (p = 0.0046) which remained significant in MR-negative (p = 0.024) but not in MR-positive patients (p = 0.058). The maximum z-score pointed to an FCD sulcus in four MR-negative and five MR-positive patients. CONCLUSIONS: We identified abnormal sulcal patterns in patients with FCD of the central region compared with healthy controls. The abnormal sulcal patterns ipsilateral to the FCD and the link between sulcus energy and the FCD location strengthen the interest of sulcal abnormalities in FCD patients.


Assuntos
Córtex Cerebral/patologia , Lobo Frontal/patologia , Malformações do Desenvolvimento Cortical/patologia , Adolescente , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Estudos Retrospectivos , Adulto Jovem
16.
Neurology ; 84(6): 560-8, 2015 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-25589667

RESUMO

OBJECTIVE: To evaluate the accuracy of functional MRI (fMRI) at 3T, as currently used in the preoperative mapping of language areas, compared with direct cortical stimulation (DCS) during awake surgery, in patients with supratentorial gliomas; and to identify clinical, histopathologic,and radiologic factors associated with fMRI/DCS discrepancies. METHODS: Language mapping with fMRI and DCS of 40 consecutive patients with gliomas(24 low-grade, 16 high-grade) in functional areas were retrospectively analyzed. Three block designed tasks were performed during fMRI (letter word generation, category word generation,semantic association). During awake surgery, eloquent areas were mapped using DCS, blinded to fMRI. A site-by-site comparison of the 2 techniques was performed using a cortical grid. fMRI sensitivity and specificity were calculated using DCS as the reference. Associations of clinical,histopathologic, and radiologic features (including relative cerebral blood volume [rCBV] measured with dynamic susceptibility contrast MRI) with fMRI false-positive and false-negative occurrence were assessed using hierarchical logistic regressions. RESULTS: Of 2,114 stimulated cortical sites, 103 were positive for language during DCS. Sensitivity and specificity of language fMRI combining the 3 tasks reached 37.1% (95% confidence interval [CI] 20.7­57.2) and 83.4% (95% CI 77.1­88.3), respectively. Astrocytoma subtype(odds ratio [OR] 2.50 [1.32­4.76]; p 5 0.007), tumor rCBV ,1.5 (OR 2.17 [1.08­4.35]; p 50.03), higher cortical rCBV (OR 2.22 [1.15­4.17]; p 5 0.02), and distance to tumor .1 cm (OR2.46 [1.82­3.32]; p # 0.001) were independently associated with fMRI false-positive occurrence. CONCLUSIONS: There are pitfalls in preoperative fMRI as currently used in preoperative language mapping in glioma patients, made more complicated when high-grade and hyperperfused tumors are evaluated.


Assuntos
Mapeamento Encefálico/métodos , Neoplasias Encefálicas/cirurgia , Córtex Cerebral/fisiopatologia , Estimulação Elétrica , Glioma/cirurgia , Idioma , Imageamento por Ressonância Magnética , Procedimentos Neurocirúrgicos/métodos , Adulto , Idoso , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/fisiopatologia , Córtex Cerebral/patologia , Meios de Contraste , Feminino , Glioma/patologia , Glioma/fisiopatologia , Humanos , Modelos Logísticos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Razão de Chances , Estudos Retrospectivos , Sensibilidade e Especificidade , Resultado do Tratamento , Vigília
17.
Radiology ; 274(2): 500-7, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25243540

RESUMO

PURPOSE: To compare the occurrence of several central sulcus variants and to assess the reproducibility of a sulcal pattern named the power button sign (PBS) in patients with type 2 focal cortical dysplasia (FCD2) and healthy control subjects. MATERIALS AND METHODS: The local institutional review board approved the study, and written informed consent was waived for patients and was obtained from control subjects. Four readers reviewed three-dimensional (3D) T1-weighted magnetic resonance (MR) images in 37 patients (13 with negative MR imaging findings) with histologically proven FCD2 of the central region and 44 control subjects on the basis of a visual analysis of a 3D reconstruction of cortical folds. They searched for central sulcus variations (interruptions, side branches, and connections) and for a particular sulcal pattern, namely, the interposition of a precentral sulcal segment between the central sulcus and one of its hook-shaped anterior ascending branches (ie, PBS). Inter- and intraobserver reliability, specificity, and sensitivity were calculated. RESULTS: The central sulcus showed a greater number of side branches (P < .001) and was more frequently connected to the precentral sulcus (P < .001) in patients with FCD2 than in control subjects. The PBS was found in 23 (62%) of 37 total patients with FCD2, in six (46%) of 13 with negative MR imaging findings, and in only one control subject. Inter- and intraobserver rates were excellent (0.88 and 0.93, respectively) for the detection of PBS. FCD2 was located either in the depth of the ascending branch of the central sulcus (14 of 23, 61%) or in its immediate vicinity (nine of 23). CONCLUSION: Given its excellent reproducibility and specificity, the PBS, when present, could become a useful qualitative diagnostic MR criterion of FCD2 in the central region.


Assuntos
Imageamento por Ressonância Magnética , Malformações do Desenvolvimento Cortical/diagnóstico , Neuroimagem/métodos , Adulto , Feminino , Humanos , Masculino , Malformações do Desenvolvimento Cortical/classificação , Reprodutibilidade dos Testes , Estudos Retrospectivos , Adulto Jovem
18.
Radiology ; 270(1): 261-8, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24029646

RESUMO

PURPOSE: To assess the feasibility of a selective flow-tracking cartographic procedure applied to four-dimensional (4D) flow imaging and to demonstrate its usefulness in the characterization of dural arteriovenous fistulas (DAVFs). MATERIALS AND METHODS: Institutional review board approval was obtained, and all patients provided written informed consent. Eight patients (nine DAVFs) underwent 3.0-T magnetic resonance (MR) imaging and digital subtraction angiography (DSA). Imaging examinations were performed within 24 hours of each other. 4D flow MR imaging was performed by using a 4D radial phase-contrast vastly undersampled isotropic projection reconstruction pulse sequence with an isotropic spatial resolution of 0.86 mm (5 minutes 35 seconds). Two radiologists independently reviewed images from MR flow-tracking cartography and reported the location of arterial feeder vessels and the venous drainage type and classified DAVFs according to the risk of rupture (Cognard classification). These results were compared with those at DSA. Quadratic weighted κ statistics with their 95% confidence intervals (CIs) were used to test intermodality agreement in the identification of arterial feeder vessels, draining veins, and Cognard classification. RESULTS: Interreader agreement for shunt location on MR images was perfect (κ = 1), with good-to-excellent interreader agreement for arterial feeder vessel identification (κ = 0.97; 95% CI = 0.92, 1.0), and matched in all cases with shunt location defined at DSA. There was good-to-excellent agreement between MR cartography and DSA in the definition of the main feeding arteries (κ = 0.92; 95% CI = 0.83, 1.0), presence of retrograde flow in dural sinuses (κ = 1), presence of retrograde cortical venous drainage (κ = 1), presence of venous ectasia (κ = 1), and final Cognard classification of DAVFs (κ = 1, standard error = 0.35). CONCLUSION: MR selective flow-tracking cartography enabled the noninvasive characterization of cranial DAVFs.


Assuntos
Malformações Vasculares do Sistema Nervoso Central/diagnóstico , Angiografia por Ressonância Magnética/métodos , Adulto , Idoso , Angiografia Digital , Velocidade do Fluxo Sanguíneo , Circulação Cerebrovascular , Meios de Contraste , Estudos de Viabilidade , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Masculino , Meglumina/análogos & derivados , Pessoa de Meia-Idade , Compostos Organometálicos , Estudos Prospectivos
19.
Epilepsia ; 55(1): 117-22, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24237393

RESUMO

PURPOSE: Type 2 focal cortical dysplasia (FCD2) is one of the main causes of refractory partial epilepsy, but often remains overlooked by MRI. This study aimed to elucidate whether 3T MRI offers better detection and characterization of FCD2 than 1.5T, using similar coils and acquisition time. METHODS: Two independent readers reviewed the 1.5T and 3T MR images of 25 patients with histologically proven FCD2. For both magnetic fields, the ability to detect a lesion was analyzed. We compared the identification of each of the five criteria typical of FCD2 (cortical thickening, blurring, cortical signal changes, subcortical signal changes, and "transmantle" sign) and artifacts, using a four-point scale (0-3). Interobserver reliability for lesion detection was calculated. KEY FINDINGS: Seventeen lesions (68%) were detected at 3T, two of which were overlooked at 1.5T. Interobserver reliability was better at 3T (κ = 1) than at 1.5T (κ = 0.83). The transmantle sign was more clearly identified at 3T than 1.5T (mean visualization score: 1.72 vs. 0.56; p = 0.002). SIGNIFICANCE: The use of 3T MRI in patients suspected of type 2 FCD improves the detection rate and the lesion characterization owing to the transmantle sign being more clearly seen at 3T. This point is of interest, since this feature is considered as an MR signature of FCD2.


Assuntos
Encefalopatias/diagnóstico , Encéfalo/patologia , Malformações do Desenvolvimento Cortical/diagnóstico , Neuroimagem/métodos , Adolescente , Adulto , Encefalopatias/patologia , Epilepsia , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Malformações do Desenvolvimento Cortical/patologia , Malformações do Desenvolvimento Cortical do Grupo I , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Adulto Jovem
20.
J Neuroradiol ; 40(3): 158-63, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23806365

RESUMO

BACKGROUND AND PURPOSE: Our aim was to estimate the prevalence of negative diffusion-weighted imaging (DWI) with total perfusion-diffusion mismatch in a large series of anterior circulation stroke patients treated with thrombolysis and to describe the characteristics of these patients. MATERIALS AND METHODS: From January 2006 to December 2010, a retrospective search was made for total perfusion-diffusion (PWI-DWI) mismatch patterns on pretreatment 1.5-T MRI scans of 166 consecutive thrombolyzed patients taken<4.5 h after onset of anterior stroke. A total mismatch profile corresponded to an absence of initial DWI signal changes with hypoperfusion (T(max)>6 s) on PWI. Clinical and MRI characteristics were compared between DWI+ and DWI- patients. RESULTS: Five (3%) patients had a normal initial DWI. All had stable substantial clinical deficits (NIHSS scores ≥ 6) and large perfusion abnormalities - in other words, 'total mismatch' - and infarcts in the acutely hypoperfused area on follow-up imaging. While DWI- and DWI+ patients did not significantly differ in any of the pretreatment imaging or clinical variables except for the extent of PWI-DWI mismatch, DWI- patients had lower NIHSS scores at 24 h, and were more likely to show early neurological improvement (Δ0-24 h NIHSS ≥ 8) and good outcomes (mRS ≤ 2) at the time of hospital discharge. CONCLUSION: Total mismatch i.e. failure of DWI to reveal any ischemic tissue despite a large perfusion defect, can be observed before thrombolysis even in stroke patients with stable substantial neurological deficits. However, this rare MRI profile is associated with a favorable outcome after thrombolysis.


Assuntos
Isquemia Encefálica/fisiopatologia , Encéfalo/fisiopatologia , Acidente Vascular Cerebral/fisiopatologia , Terapia Trombolítica/métodos , Idoso , Encéfalo/patologia , Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/patologia , Circulação Cerebrovascular , Imagem de Difusão por Ressonância Magnética , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Acidente Vascular Cerebral/tratamento farmacológico , Acidente Vascular Cerebral/patologia
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