Flow-weighted arterial transit time mapping of the human brain

Introduction The knowledge of the arterial transit time, δa, from the labeling plane into the brain is essential for blood-flow quantification. In previous work, the MATISSE (Mapping of Arterial Transit times by Intravascular Signal Selection) approach for the mapping of δa was introduced (1). It relies on the use of short repetition times, TR, and the application of an amplitude-modulated shape of the labeling function. The results were found to agree well with the vascular territories of the brain-feeding arteries (1). Under these conditions, flow-through signals, i. e. the signals of arterial vessels permeating the voxel of interest, are a major source of the MATISSE signal. For CBF quantification, however, δa is defined as the time the label needs to travel from the labeling plane to the voxel assuming the endpoint of the arterial vascular tree in the same voxel (2). In the current work, it is shown that a mild flow-weighting (FW) is suitable for an almost complete removal of flow-through signals in MATISSE. The goal was to closer meet the demands for CBF quantification by the corresponding δa maps.