The diffusion tensor is currently the accepted model of diffusion in biological tissues. The measured diffusion behavior may be more complex when two or more distinct tissues with different diffusion tensors occupy the same voxel. In this study, a partial volume model of MRI signal behavior for two diffusion-tensor compartments is presented. Simulations using this model demonstrate that the con...

An improved method for correction of partial volume effects (PVE) in brain SPECT is proposed. It is fully three-dimensional, does not require particular patient positioning, and works with scans only partially covering the brain. The location of functionally inactive brain regions (primarily cerebrospinal fluid) is extracted from high-resolution MRI. An automatic 3D registration algorithm then ...

Introduction: The longitudinal relaxation time (T1) of tissues plays an important role both as a contrast mechanism for anatomical imaging and as a disease marker. To date, several techniques have been proposed for measuring it (e.g. [1,2]). Most of them are based on modeling monoexponential behavior for individual voxels. Even though brain tissue is considered to exhibit monoexponential T1 beh...

Figure 4: Comparison of activation data averaged across subjects with and without PVE correction. Baseline CBF is shown in blue and the amount of CBF change due to activation is shown in red. 3.5 10.4 0 150 Figure 3: Activation Z maps (hot colour scale) superimposed on CBF map (grey scale in ml / 100g / min) from one representative subject. Correction of partial volume effects in PASL perfusion...

High non-specific uptake of [11C]Pittsburgh compound B ([11C]PiB) in white matter and signal spillover from white matter, due to partial volume effects, confound radioactivity measured in positron emission tomography (PET) with [11C]PiB. We aimed to reveal the partial volume effect in absolute values of kinetic parameters for [11C]PiB, in terms of spillover from white matter. Dynamic data acqui...

Quantification of -aminobutyric acid (GABA) concentration using localized MRS suffers from partial volume effects related to differences in the intrinsic concentration of GABA in grey matter (GM) and white matter (WM). These differences can be represented as a ratio between intrinsic GABA in GM and WM, rM. Individual differences in GM tissue volume can therefore potentially drive apparent conce...