Key points are not available for this paper at this time.
Abstract Arterial spin labeling (ASL) permits quantification of tissue perfusion without the use of MR contrast agents. With standard ASL techniques such as flow‐sensitive alternating inversion recovery (FAIR) the signal from arterial blood is measured at a fixed inversion delay after magnetic labeling. As no image information is sampled during this delay, FAIR measurements are inefficient and time‐consuming. In this work the FAIR preparation was combined with a Look‐Locker acquisition to sample not one but a series of images after each labeling pulse. This new method allows monitoring of the temporal dynamics of blood inflow. To quantify perfusion, a theoretical model for the signal dynamics during the Look‐Locker readout was developed and applied. Also, the imaging parameters of the new ITS‐FAIR technique were optimized using an expression for the variance of the calculated perfusion. For the given scanner hardware the parameters were: temporal resolution 100 ms, 23 images, flip‐angle 25.4°. In a normal volunteer experiment with these parameters an average perfusion value of 48.2 ± 12.1 ml/100 g/min was measured in the brain. With the ability to obtain ITS‐FAIR time series with high temporal resolution arterial transit times in the range of −138 − 1054 ms were measured, where nonphysical negative values were found in voxels containing large vessels. Magn Reson Med 46:974–984, 2001. © 2001 Wiley‐Liss, Inc.
Günther et al. (Thu,) studied this question.