title: In vivo quantification of regional myocardial blood flow: validity of the fast-exchange approximation for intravascular T1 contrast agent and long inversion time.
abstract: In the present study we investigated the effects of water exchange between intra- and extravascular compartments on absolute quantification of regional myocardial blood flow (rMBF) using a saturation-recovery sequence with a rather long inversion time (TI, 176 ms) and a T1-shortening intravascular contrast agent (CMD-A2-Gd-DOTA). Data were acquired in normal and ischemically injured pigs, with radiolabeled microsphere flow measurements used as the gold standard. Five water exchange rates (fast, 6 Hz, 3 Hz, 1 Hz, and no exchange) were tested. The results demonstrate that the fast-exchange approximation may be appropriate for rMBF quantification using the described experimental setting. Relaxation rate change (DeltaR1) analysis improved the accuracy of the analysis of rMBF compared to the MR signal. In conclusion, the current protocol could provide sufficient accuracy for estimating rMBF assuming fast exchange and a linear relationship between signal and tissue concentration when quantification of precontrast T1 is not an option.
authors.affiliation: Creatis UMR CNRS 5515 U630 INSERM, Lyon, France.
authors.forename: Marlene
authors.initials: M
authors.lastname: Wiart
authors.forename: Sabin
authors.initials: S
authors.lastname: Carme
authors.forename: Wilfried
authors.initials: W
authors.lastname: Maï
authors.forename: Henrik B W
authors.initials: HB
authors.lastname: Larsson
authors.forename: Bruno
authors.initials: B
authors.lastname: Neyran
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Canet-Soulas
mesh_terms: D000818:Animals; D003287:Contrast Media; D003326:Coronary Circulation / Q000502:physiology; D023921:Coronary Stenosis / Q000503:physiopathology*; D007091:Image Processing, Computer-Assisted; D008863:Microspheres; D009942:Organometallic Compounds; D012039:Regional Blood Flow / Q000502:physiology; D013552:Swine
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C107329:carboxymethyl-dextran-A2-gadolinium-DOTA