Navegando por Palavras-chave "magnetic resonance spectroscopy"
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- ItemAcesso aberto (Open Access)Contribuição do índice de intensidade de sinal na sequência t1 desvio químico associado à espectroscopia por ressonância magnética no diagnóstico dos adenomas adrenais(Universidade Federal de São Paulo (UNIFESP), 2016-12-15) Dalavia, Claudio Carvalho [UNIFESP]; Ajzen, Sergio Aron [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)OBJECTIVE. To investigate the advantages of using modified signal intensity measurements on chemical shift imaging alone or correlate with proton spectroscopy in the differential diagnosis of adrenal adenomas. SUBJECTS AND METHODS. 97 patients (69 adenomas, 8 carcinomas, 14 pheochromocytomas, 4 metastasis, 1 myelolipoma and 1 granulomatous lesion) underwent chemical shift imaging and spectroscopy. Signal intensity index was calculated as [(signal intensity on in-phase image ? signal intensity on out-of-phase image) / (signal intensity on in-phase image)] × 100%. The averages of three minimum, mean, and maximum signal intensity values measured on three consecutive images, in the smaller lesions if not possible we use one or two images, with the region of interest covering one-half to two-thirds of the mass. All indexes were compared with spectroscopy metabolite ratios (lactate/creatine, glutamine-glutamate/creatine, choline/creatine, choline/lipid, 4.0?4.3 ppm/creatine, and lipid/creatine) for each type of adrenal mass. RESULTS. All signal intensity measurements and spectroscopy metabolite ratios were significant to the differentiation between adenomas and no adenomas, except Lip/Cr and Cho/Lip. Was not possible to apply the spectroscopy in 37,75% of the cases. CONCLUSION. The signal intensity index and spectroscopy metabolite ratios increased the accuracy of the differential diagnosis of adrenal adenomas.
- ItemAcesso aberto (Open Access)Espectroscopia por ressonância magnética de prótons em epilepsia mioclônica juvenil sugere o comprometimento de uma rede neuronal específica(Liga Brasileira de Epilepsia (LBE), 2008-09-01) Lin, Katia [UNIFESP]; Carrete Junior, Henrique [UNIFESP]; Lin, Jaime [UNIFESP]; Peruchi, M.m. [UNIFESP]; Araujo Filho, Gerardo Maria de [UNIFESP]; Pascalicchio, T.f. [UNIFESP]; Guaranha, Mirian Salvadori Bittar [UNIFESP]; Guilhoto, Laura Maria de Figueiredo Ferreira [UNIFESP]; Yacubian, Elza Márcia Targas [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)OBJECTIVES: The neuroanatomical basis and the neurochemical abnormalities that underlay juvenile myoclonic epilepsy (JME) are not fully defined. While the thalamus plays a central role in synchronization of widespread regions of the cerebral cortex during a seizure, emerging evidence suggests that all cortical neurons may not be homogeneously involved. The purpose of this study was to investigate the cerebral metabolic differences between patients with JME and normal controls. METHODS: All patients had a JME diagnosis based on seizure history and semiology, EEG recording, normal magnetic resonance neuroimaging (MRI) and video-EEG. Forty JME patients (JME-P) were submitted to 1.5 T MRI proton spectroscopy (1H-MRS), multi-voxel with PRESS sequence (TR/TE = 1500/30 ms) over the following locations: prefrontal cortex (PC), frontal cortex (FC), thalamus, basal nuclei, posterior cingulate gyrus (PCG), insular, parietal and occipital cortices. We determined ratios for integral values of N-acetyl aspartate (NAA) and glutamine-glutamate (GLX) over creatine-phosphocreatine (Cr). The control group (CTL) consisted of 20 age and sex-matched healthy volunteers. RESULTS: Group analysis demonstrated a tendency for lower NAA/Cr ratio of JME-P compared to CTL predominantly on FC, PC, thalamus and occipital cortex. When compared to CTL, JME-P had a statistically significant difference in GLX/Cr on FC, PC, insula, basal nuclei, PCG and on thalamus. When evaluating the relationship among the various components of this epileptic network among JME-P, the strongest correlation occurred between thalamus and PC. Also, we found a significant negative correlation between NAA/Cr and duration of epilepsy. CONCLUSION: Reductions in NAA may represent loss or injury of neurons and/or axons, as well as metabolic dysfunction while glutamate is considered to be an excitatory neurotransmitter in the brain which is involved in the pathogenesis of epileptogenic seizures.
- ItemSomente MetadadadosLactate detection by MRS in mitochondrial encephalopathy: Optimization of technical parameters(Blackwell Publishing, 2008-01-01) Rocha, Antonio Jose da; Braga, Flavio Tulio; Maia Junior, Antonio Carlos Martins [UNIFESP]; Silva, Carlos Jorge da; Toyama, Carlos; Pinto Gama, Hugo Pereira; Kok, Fernando [UNIFESP]; Gomes, Helio Rodrigues [UNIFESP]; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP); Fleury Diagnost CtrMitochondriopathies are a heterogeneous group of diseases with variable phenotypic presentation, which can range from subclinical to lethal forms. They are related either to DNA mutations or nuclear-encoded mitochondrial genes that affect the integrity and function of these organelles, compromising adenosine triphosphate (ATP) synthesis. Magnetic resonance (MR) is the most important imaging technique to detect structural and metabolic brain abnormalities in mitochondriopathies, although in some cases these studies may present normal results, or the identified brain abnormalities may be nonspecific. Magnetic resonance spectroscopy (MRS) enables the detection of high cerebral lactate levels, even when the brain has normal appearance by conventional MR scans. MRS is a useful tool for the diagnosis of mitochondriopathies, but must be correlated with clinical, neurophysiological, biochemical, histological, and molecular data to corroborate the diagnosis. Our aim is to clarify the most relevant issues related to the use of MRS in order to optimize its technical parameters, improving its use in the diagnosis of mitochondriopathies, which is often a challenge.
- ItemSomente MetadadadosLeukoencephalopathy with vanishing white matter: report of four cases from three unrelated Brazilian families(Elsevier B.V., 2002-06-01) Rosemberg, S.; Leite, C. D.; Arita, Fernando Norio [UNIFESP]; Kliemann, S. E.; Lacerda, MTC; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)Four patients with leukoencephalopathy with vanishing white matter from three unrelated Brazilian families are reported. in all cases the initial symptoms occurred in the three first years of life. in three cases the onset was acute and at least in two patients the involvement of the white matter preceded the clinical symptoms. Only cerebellar and pyramidal signs were present and persisted throughout the evolution. An episodic course with worsening of the symptoms during febrile illnesses was noted in one patient. in three patients a significant deceleration of the head growth was noted. in one family. brother and sister were affected but the twin brother of the boy was free from the disease. in another family, the patient had a sister who died at 13 years of age from an identical disease not diagnosed at that time. in one family, the parents were first cousins. in all patients, serial magnetic resonance imaging and magnetic resonance spectroscopy showed the characteristic picture of the involvement of the white matter with increasing signal intensity close to that of the cerebrospinal fluid. (C) 2002 Elsevier Science B.V. All rights reserved.