Figure 8.

Basic principles of ASL perfusion imaging. (A) The two main labeling schemes (CASL/pCASL and PASL) are illustrated, in terms of the location and extent of the labeling region (left) and associated pulse sequences and their timings (right). (B) The magnetization difference between label and control images is illustrated by the difference images for five representative delays (top) and the underlying kinetic curve obtained based on the standard kinetic model (bottom). The ATT (arterial transit time) and label bolus duration (τ) are indicated. The red box and dot indicate a typical PLD/TI value for a single-delay acquisition.