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1.
J Cereb Blood Flow Metab ; 37(4): 1251-1263, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27381824

RESUMO

Inflammation may play a role in the development of epilepsy after brain insults. [11C]-( R)-PK11195 binds to TSPO, expressed by activated microglia. We quantified [11C]-( R)-PK11195 binding during epileptogenesis after pilocarpine-induced status epilepticus (SE), a model of temporal lobe epilepsy. Nine male rats were studied thrice (D0-1, D0 + 6, D0 + 35, D0 = SE induction). In the same session, 7T T2-weighted images and DTI for mean diffusivity (MD) and fractional anisotropy (FA) maps were acquired, followed by dynamic PET/CT. On D0 + 35, femoral arterial blood was sampled for rat-specific metabolite-corrected arterial plasma input functions (AIFs). In multiple MR-derived ROIs, we assessed four kinetic models (two with AIFs; two using a reference region), standard uptake values (SUVs), and a model with a mean AIF. All models showed large (up to two-fold) and significant TSPO binding increases in regions expected to be affected, and comparatively little change in the brainstem, at D0 + 6. Some individuals showed increases at D0 + 35. AIF models yielded more consistent increases at D0 + 6. FA values were decreased at D0 + 6 and had recovered by D0 + 35. MD was increased at D0 + 6 and more so at D0 + 35. [11C]-( R)-PK11195 PET binding and MR biomarker changes could be detected with only nine rats, highlighting the potential of longitudinal imaging studies.


Assuntos
Encéfalo/diagnóstico por imagem , Proteínas de Transporte/metabolismo , Epilepsia/imunologia , Imageamento por Ressonância Magnética/métodos , Microglia/imunologia , Tomografia por Emissão de Pósitrons/métodos , Receptores de GABA-A/metabolismo , Animais , Encéfalo/imunologia , Encéfalo/metabolismo , Radioisótopos de Carbono , Modelos Animais de Doenças , Epilepsia/diagnóstico por imagem , Epilepsia/metabolismo , Isoquinolinas , Estudos Longitudinais , Masculino , Microglia/metabolismo , Pilocarpina , Ligação Proteica , Ratos Sprague-Dawley
2.
Neuroimage Clin ; 7: 122-31, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25610774

RESUMO

PURPOSE: We have previously shown that an imaging marker, increased periventricular [(11)C]flumazenil ([(11)C]FMZ) binding, is associated with failure to become seizure free (SF) after surgery for temporal lobe epilepsy (TLE) with hippocampal sclerosis (HS). Here, we investigated whether increased preoperative periventricular white matter (WM) signal can be detected on clinical [(18)F]FDG-PET images. We then explored the potential of periventricular FDG WM increases, as well as whole-brain [(11)C]FMZ and [(18)F]FDG images analysed with random forest classifiers, for predicting surgery outcome. METHODS: Sixteen patients with MRI-defined HS had preoperative [(18)F]FDG and [(11)C]FMZ-PET. Fifty controls had [(18)F]FDG-PET (30), [(11)C]FMZ-PET (41), or both (21). Periventricular WM signal was analysed using Statistical Parametric Mapping (SPM8), and whole-brain image classification was performed using random forests implemented in R (http://www.r-project.org). Surgery outcome was predicted at the group and individual levels. RESULTS: At the group level, non-seizure free (NSF) versus SF patients had periventricular increases with both tracers. Against controls, NSF patients showed more prominent periventricular [(11)C]FMZ and [(18)F]FDG signal increases than SF patients. All differences were more marked for [(11)C]FMZ. For individuals, periventricular WM signal increases were seen at optimized thresholds in 5/8 NSF patients for both tracers. For SF patients, 1/8 showed periventricular signal increases for [(11)C]FMZ, and 4/8 for [(18)F]FDG. Hence, [(18)F]FDG had relatively poor sensitivity and specificity. Random forest classification accurately identified 7/8 SF and 7/8 NSF patients using [(11)C]FMZ images, but only 4/8 SF and 6/8 NSF patients with [(18)F]FDG. CONCLUSION: This study extends the association between periventricular WM increases and NSF outcome to clinical [(18)F]FDG-PET, but only at the group level. Whole-brain random forest classification increases [(11)C]FMZ-PET's performance for predicting surgery outcome.


Assuntos
Epilepsia do Lobo Temporal/diagnóstico por imagem , Epilepsia do Lobo Temporal/cirurgia , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos , Adulto , Radioisótopos de Carbono , Feminino , Flumazenil , Fluordesoxiglucose F18 , Hipocampo/diagnóstico por imagem , Hipocampo/patologia , Hipocampo/cirurgia , Humanos , Interpretação de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos , Esclerose/patologia , Resultado do Tratamento , Adulto Jovem
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