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Detailing magnetic field strength dependence and segmental artifact distribution of myocardial effective transverse relaxation rate at 1.5, 3.0, and 7.0 T
Author(s) -
Meloni Antonella,
Hezel Fabian,
Positano Vincenzo,
Keilberg Petra,
Pepe Alessia,
Lombardi Massimo,
Niendorf Thoralf
Publication year - 2014
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.24856
Subject(s) - ventricle , artifact (error) , nuclear magnetic resonance , transverse plane , field strength , magnetic resonance imaging , relaxation (psychology) , physics , cardiology , materials science , magnetic field , medicine , anatomy , radiology , computer science , quantum mechanics , computer vision
Purpose Realizing the challenges and opportunities of effective transverse relaxation rate ( R 2 *) mapping at high and ultrahigh fields, this work examines magnetic field strength ( B 0 ) dependence and segmental artifact distribution of myocardial R 2 * at 1.5, 3.0, and 7.0 T. Methods Healthy subjects were considered. Three short‐axis views of the left ventricle were examined. R 2 * was calculated for 16 standard myocardial segments. Global and mid‐septum R 2 * were determined. For each segment, an artifactual factor was estimated as the deviation of segmental from global R 2 * value. Results The global artifactual factor was significantly enlarged at 7.0 T versus 1.5 T ( P = 0.010) but not versus 3.0 T. At 7.0 T, the most severe susceptibility artifacts were detected in the inferior lateral wall. The mid‐septum showed minor artifactual factors at 7.0 T, similar to those at 1.5 and 3.0 T. Mean R 2 * increased linearly with the field strength, with larger changes for global heart R 2 * values. Conclusion At 7.0 T, segmental heart R 2 * analysis is challenging due to macroscopic susceptibility artifacts induced by the heart–lung interface and the posterior vein. Myocardial R 2 * depends linearly on the magnetic field strength. The increased R 2 * sensitivity at 7.0 T might offer means for susceptibility‐weighted and oxygenation level‐dependent MR imaging of the myocardium. Magn Reson Med 71:2224–2230, 2014. © 2013 Wiley Periodicals, Inc .