Ai-Ling Lin, Hanzhang Lu, Peter T Fox, Timothy Q Duong
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引用次数: 9
Abstract
Measurements of task-induced changes in cerebral blood volume (CBV) have been demonstrated using VAscular Space Occupancy (VASO) techniques (noninvasive and newly developed) and a contrast agent-based (Gd- DTPA) method (invasive but well-established) with functional magnetic resonance imaging (fMRI). We compared the two methods in determining CBV changes during multi-frequency visual stimulation (4 and 8 Hz). Specifically, we aimed to assess the impact of repetition time (TR) on CBV changes determination using VASO. With additional measurements of cerebral blood flow (CBF), the flow-volume coupling relationship (α value) and cerebral metabolic rate of oxygen were further determined. The results showed that i) using VASO, short TR (2s) caused overestimation of CBV changes, while long TR (6s) generated consistent CBV results, by comparison to the GD-DTPA method; ii) overestimation of CBV changes caused underestimated CMRO(2) changes, but did not alter the frequency-related pattern, i.e., CMRO(2) changes at 4 Hz were greater than those at 8 Hz regardless of the TR; and iii) the tasked-induced CBF-CBV coupling was stimulus frequency-dependent, i.e., α = 0.35-0.38 at 4 Hz and α = 0.51-0.53 at 8 Hz. Our data demonstrated that, with carefully chosen TRs, CBV measurements can be achieved non-invasively with VASO techniques.
期刊介绍:
The Open Neuroimaging Journal is an Open Access online journal, which publishes research articles, reviews/mini-reviews, and letters in all important areas of brain function, structure and organization including neuroimaging, neuroradiology, analysis methods, functional MRI acquisition and physics, brain mapping, macroscopic level of brain organization, computational modeling and analysis, structure-function and brain-behavior relationships, anatomy and physiology, psychiatric diseases and disorders of the nervous system, use of imaging to the understanding of brain pathology and brain abnormalities, cognition and aging, social neuroscience, sensorimotor processing, communication and learning.