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T 2 preparation method for measuring hyperemic myocardial O 2 consumption: in vivo validation by positron emission tomography
Author(s) -
McCommis Kyle S.,
O'Connor Robert,
Abendschein Dana R.,
Muccigrosso David,
Gropler Robert J.,
Zheng Jie
Publication year - 2011
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.22322
Subject(s) - positron emission tomography , nuclear medicine , in vivo , tomography , medicine , biomedical engineering , radiology , microbiology and biotechnology , biology
Purpose To validate a new T 2 ‐prepared method for the quantification of regional myocardial O 2 consumption during pharmacologic stress with positron emission tomography (PET). Materials and Methods A T 2 prepared gradient‐echo sequence was modified to measure myocardial T 2 within a single breath‐hold. Six beagle dogs were randomly selected for the induction of coronary artery stenosis. Magnetic resonance imaging (MRI) experiments were performed with the T 2 imaging and first‐pass perfusion imaging at rest and during either dobutamine‐ or dipyridamole‐induced hyperemia. Myocardial blood flow (MBF) was quantified using a previously developed model‐free algorithm. Hyperemic myocardial O 2 extraction fraction (OEF) and consumption (MVO 2 ) were calculated using a two‐compartment model developed previously. PET imaging using 11 C‐acetate and 15 O‐water was performed in the same day to validate OEF, MBF, and MVO 2 measurements. Results The T 2 ‐prepared mapping sequence measured regional myocardial T 2 with a repeatability of 2.3%. By myocardial segment‐basis analysis, MBF measured by MRI is closely correlated with that measured by PET (R 2 = 0.85, n = 22). Similar correlation coefficients were observed for hyperemic OEF (R 2 = 0.90, n = 9, mean difference of PET – MRI = −2.4%) and MVO 2 (R 2 = 0.83, n = 7, mean difference = 4.2%). Conclusion The T 2 ‐prepared imaging method may allow quantitative estimation of regional myocardial oxygenation with relatively good accuracy. The precision of the method remains to be improved. J. Magn. Reson. Imaging 2011;33:320–327. © 2011 Wiley‐Liss, Inc.