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In vivo measurement of the longitudinal relaxation time of arterial blood ( T 1a ) in the mouse using a pulsed arterial spin labeling approach
Author(s) -
Thomas David L.,
Lythgoe Mark F.,
Gadian David G.,
Ordidge Roger J.
Publication year - 2006
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.20823
Subject(s) - arterial spin labeling , nuclear magnetic resonance , in vivo , pulse (music) , time constant , perfusion , relaxation (psychology) , saturation (graph theory) , spin–lattice relaxation , biomedical engineering , nuclear medicine , materials science , chemistry , mathematics , physics , medicine , cardiology , optics , microbiology and biotechnology , electrical engineering , detector , biology , engineering , combinatorics , nuclear quadrupole resonance
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.