RESUMO
A 1.4-T magnetic resonance (MR) imager was modified to perform MR spectroscopy measurements. The implementation involved only a few additions in hardware and practically no change in software. Procedures for acquiring the MR spectra are similar to those for MR images. Both sensitivity and homogeneity were found to be adequate over a region 12 cm in diameter. Typical scanning times are 4.5 minutes for human brain, 2.8 minutes for muscle, and 20-35 minutes for solid tumors. Preliminary spectral studies of the metabolism of human brains, tumors, and a muscle of the forearm during exercise obtained with the modified system are presented.
Assuntos
Espectroscopia de Ressonância Magnética/instrumentação , Trifosfato de Adenosina/análise , Adulto , Animais , Encéfalo/metabolismo , Carcinoma de Células Escamosas/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Espectroscopia de Ressonância Magnética/métodos , Masculino , Melanoma/metabolismo , Camundongos , Contração Muscular , Músculos/metabolismo , Fosfatos/análise , Fosfocreatina/análise , Software , Extratos de Tecidos/análiseRESUMO
Computed tomography (CT) has proven useful in diagnosing inflammatory and neoplastic disease of the pancreas. Neoplasms of the pancreas produce enlargement of the gland and loss of surrounding fat planes. Acute pancreatitis also produces enlargement but correct diagnosis can be made with the clinical correlation. The usefulness of CT in chronic pancreatitis depends upon the state of the disease. Distinction between an inflammatory and a neoplastic mass is not possible on the basis of a CT scan alone. CT is also useful for needle guidance for aspiration biopsy of the pancreas.
Assuntos
Pâncreas/diagnóstico por imagem , Tomografia por Raios X/métodos , Adenocarcinoma/diagnóstico por imagem , Angiografia , Colangiografia , Computadores , Humanos , Linfoma/diagnóstico por imagem , Linfoma Difuso de Grandes Células B/diagnóstico por imagem , Linfoma não Hodgkin/diagnóstico por imagem , Neoplasias Pancreáticas/diagnóstico por imagem , Pancreatite/diagnóstico por imagem , UltrassonografiaRESUMO
Spatial resolution of the EMI and Delta computed tomographic scanners has been measured by recording the response to a nylon and water sunburst phantom (Siemens star) and calculating the modulation transfer function at radii corresponding to various spatial frequencies. The resolution appears to be related primarily to the size of the matrix element, and exhibits an upper cut-off frequency somewhat in excess of 3 cycles/cm.