RESUMEN
The details of brain metabolism in chronic cerebral infarcts have not been clarified. Using proton MR spectroscopy (1H-MRS) at 1.5 T, we measured biochemical changes in 16 patients with large infarcts involving the motor cortex in the chronic phase (median 293.9 days) and related the findings to clinical data. Localised spectra were obtained using point-resolved spectroscopy, with an echo time of 270 ms. Regions of interest were placed on the frontal lobe, including the precentral gyrus and central sulcus. Motor function was assessed by the manual muscle power test at the time of the 1H-MRS study. Only three patients with severe paresis had no signal in the lesions and a lactate signal was obtained in 13 cases. N-acetyl aspartate (NAA) was observed in 4 cases with recanalisation of an occluded vessel. Motor function correlated strongly with the NAA/choline-containing compounds (Cho) ratio (P < 0.01) and lactate/Cho ratio (P < 0.01). We found various metabolic patterns, reflecting residual neurological function.
Asunto(s)
Infarto Cerebral/diagnóstico , Metabolismo Energético/fisiología , Espectroscopía de Resonancia Magnética , Examen Neurológico , Adulto , Anciano , Anciano de 80 o más Años , Infarto Cerebral/fisiopatología , Enfermedad Crónica , Dominancia Cerebral/fisiología , Femenino , Lóbulo Frontal/fisiopatología , Hemiplejía/diagnóstico , Hemiplejía/fisiopatología , Humanos , Ácido Láctico/metabolismo , Masculino , Persona de Mediana Edad , Corteza Motora/fisiopatologíaRESUMEN
Proton magnetic resonance spectroscopy (1H MRS) was evaluated for distinguishing between radiation necrosis and recurrent glioma in 11 patients after high-dose radiotherapy. Six patients had a histological diagnosis of recurrent glioma. Four patients had a histological diagnosis of radiation necrosis and one had a clinical course consistent with the diagnosis of radiation necrosis. 1H MRS showed cases of radiation necrosis had two characteristic 1H MRS patterns: markedly increased lactate/creatine and phosphocreatine (Cr) ratio and decreased choline-containing compounds/Cr ratio compared to that of recurrent glioma; or all the major metabolites were completely diminished. The N-acetyl aspartate signal was not helpful for differential diagnosis. 1H MRS is a potentially useful method for differentiating tumor recurrence from radiation necrosis in patients treated for malignant glioma.