In vivo measurement of the longitudinal relaxation time of arterial blood (T1a) in the mouse using a pulsed arterial spin labeling approach

✍ Scribed by David L. Thomas; Mark F. Lythgoe; David G. Gadian; Roger J. Ordidge

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 261 KB
• Volume: 55
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.20823

✦ Synopsis

Abstract

A novel method for measuring the longitudinal relaxation time of arterial blood (T~1a~) is presented. Knowledge of T~1a~ is essential for accurately quantifying cerebral perfusion using arterial spin labeling (ASL) techniques. The method is based on the flow‐sensitive alternating inversion recovery (FAIR) pulsed ASL (PASL) approach. We modified the standard FAIR acquisition scheme by incorporating a global saturation pulse at the beginning of the recovery period. With this approach the FAIR tissue signal difference has a simple monoexponential dependence on the recovery time, with T~1a~ as the time constant. Therefore, FAIR measurements performed over a range of recovery times can be fitted to a monoexponential recovery curve and T~1a~ can be calculated directly. This eliminates many of the difficulties associated with the measurement of T~1a~. Experiments performed in vivo in the mouse at 2.35T produced a mean value of 1.51 s for T~1a~, consistent with previously published values. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.