Dependency of R and R * relaxation on Gd-DTPA concentration in arterial blood: Influence of hematocrit and magnetic field strength.

Dynamic susceptibility contrast (DSC) MRI is clinically used to measure brain perfusion by monitoring the dynamic passage of a bolus of contrast agent through the brain. For quantitative analysis of the DSC images, the arterial input function is required. It is known that the original assumption of a linear relation between the R relaxation and the arterial contrast agent concentration is invalid, although the exact relation is as of yet unknown.

Interpulse phase corrections for unbalanced pseudo-continuous arterial spin labeling at high magnetic field.

Purpose: To evaluate a prescan-based radiofrequency phase-correction strategy for unbalanced pseudo-continuous arterial spin labeling (pCASL) at 9.4 T in vivo and to test its robustness toward suboptimal shim conditions.

Methods: Label and control interpulse phases were optimized separately by means of two prescans in rats.

Impact of tissue T on perfusion measurement with arterial spin labeling.

Purpose: Arterial spin labeling (ASL) may provide quantitative maps of cerebral blood flow (CBF). Because labeled water exchanges with tissue water, this study evaluates the influence of tissue T on CBF quantification using ASL.

Methods: To locally modify T , a low dose of manganese (Mn) was intracerebrally injected in one hemisphere of 19 rats (cortex or striatum).

A simulation tool for dynamic contrast enhanced MRI.

The quantification of bolus-tracking MRI techniques remains challenging. The acquisition usually relies on one contrast and the analysis on a simplified model of the various phenomena that arise within a voxel, leading to inaccurate perfusion estimates. To evaluate how simplifications in the interstitial model impact perfusion estimates, we propose a numerical tool to simulate the MR signal provided by a dynamic contrast enhanced (DCE) MRI experiment.