Felipe Tancredi1,2, Claudine Gauthier1,2,
Ccile Madjar2, Joseph Fisher3, Danny J. J. Wang4,
Richard Hoge1,2
1Universit de Montral,
Montreal, Quebec, Canada; 2Centre de recherche de l'institut
universitaire de griatrie de Montral, Montreal, Quebec, Canada; 3University
of Toronto, Toronto, Ontario, Canada; 4Neurology, UCLA, Los
Angeles, CA, United States
Hypercapnia is known to induce a global increase in cerebral blood flow and is an important component in MRI-based techniques measuring brains metabolic and vascular reactivity. While ASL methods have shown promise in these applications, there has been concern about possible underestimation of flow changes during global manipulations. We sought to compare pulsed and continuous labeling methods for detection and quantification of CBF changes induced by mild hypercapnia. Our results show that, although both offer comparable sensitivity to visually evoked CBF responses, continuous labeling yields higher flow change values for a given global manipulation and at higher SNR.