RESUMO
Contrast material-enhanced three-dimensional (3D) magnetic resonance (MR) angiography of the supraaortic arteries with randomly segmented central k-space ordering (ie, contrast-enhanced timing-robust angiography [CENTRA]) was performed in 16 patients. CENTRA enabled reliable depiction of the aortic arch up to the circle of Willis at high spatial resolution (true voxel size, 0.81 x 0.81 x 1.0 mm(3)). With CENTRA, the divergent demands of high spatial resolution, wide anatomic coverage, and arterial phase imaging have been reconciled. The random order of central k-space acquisition may minimize artifacts in contrast-enhanced 3D MR angiography caused by unstable contrast material opacification at the initiation of sampling.
Assuntos
Aorta Torácica/patologia , Isquemia Encefálica/diagnóstico , Encéfalo/irrigação sanguínea , Aumento da Imagem/métodos , Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Angiografia por Ressonância Magnética/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Artéria Carótida Interna/patologia , Estenose das Carótidas/diagnóstico , Artérias Cerebrais/patologia , Veias Cerebrais/patologia , Círculo Arterial do Cérebro/patologia , Meios de Contraste , Feminino , Gadolínio DTPA , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Sensibilidade e EspecificidadeRESUMO
OBJECTIVE: To detect regional metabolic changes that resemble the expected spatial pattern of neuronal loss in patients with Alzheimer disease (AD). METHODS: Thirty-four patients with AD and 22 healthy control subjects were included in the study. Single-slice fast proton spectroscopic imaging was performed in parallel angulation to the temporal lobes. Proton spectra were selected from the hippocampus, the lateral temporal lobe, and the occipital lobe of both hemispheres to determine metabolite concentration of N-acetylaspartate (NAA), total creatine (tCr), including phosphocreatine and creatine, and choline-containing compounds (Cho). The metabolic ratios of NAA/tCr and Cho/tCr were calculated and compared between patients with AD and healthy volunteers. RESULTS: The NAA/tCr ratios were significantly reduced in the left (F(1,1) = 4.34, P =.04) and right hippocampus (F(1,1) = 9.96, P =.003) in patients with AD. The Cho/tCr ratios remained unchanged in both hippocampi. There was no significant change of either NAA/tCr or Cho/tCr in the lateral temporal and occipital lobes of patients with AD. CONCLUSION: This study provides evidence that fast proton spectroscopic imaging may detect the regional pattern of disturbed neuronal integrity in patients with AD with high spatial resolution in a short acquisition time.