Multiresolution data acquisition and detection in functional MRI.

In an investigation of a multiresolution and multistaged approach in functional MRI, the relationship between spatial resolution and detection of functional activation is examined. The difference between functional detection and mapping is defined, and a multiresolution approach to functional detection is analyzed by constructing simple theoretical and experimental models simulating variations of in-plane resolution. Experimentally measured blood oxygenation level-dependent (BOLD) signal changes as well as BOLD contrast-to-noise ratio (CNR) with respect to different spatial resolutions are compared with results from theoretical predictions and simulation. From both an experimental and a theoretical perspective, it is shown that BOLD CNR and, thus, the concomitant detection of the functional activation are maximized when the resolution matches the size of activation.