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In vivo quantification of regional myocardial blood flow: Validity of the fast‐exchange approximation for intravascular T 1 contrast agent and long inversion time
Author(s) -
Wiart Marlene,
Carme Sabin,
Maï Wilfried,
Larsson Henrik B.W.,
Neyran Bruno,
CanetSoulas Emmanuelle
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.20969
Subject(s) - blood flow , saturation (graph theory) , chemistry , nuclear magnetic resonance , biomedical engineering , nuclear medicine , mathematics , physics , medicine , cardiology , combinatorics
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 T 1 ‐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 (Δ R 1 ) 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 T 1 is not an option. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.