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On the confounding effect of temperature on chemical shift‐encoded fat quantification
Author(s) -
Hernando Diego,
Sharma Samir D.,
Kramer Harald,
Reeder Scott B.
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.24951
Subject(s) - imaging phantom , nuclear magnetic resonance , echo time , signal (programming language) , confounding , chemistry , magnetic resonance imaging , analytical chemistry (journal) , materials science , nuclear medicine , mathematics , physics , statistics , computer science , chromatography , radiology , medicine , programming language
Purpose To characterize the confounding effect of temperature on chemical shift‐encoded (CSE) fat quantification. Methods The proton resonance frequency of water, unlike triglycerides, depends on temperature. This leads to a temperature dependence of the spectral models of fat (relative to water) that are commonly used by CSE‐MRI methods. Simulation analysis was performed for 1.5 Tesla CSE fat–water signals at various temperatures and echo time combinations. Oil–water phantoms were constructed and scanned at temperatures between 0 and 40°C using spectroscopy and CSE imaging at three echo time combinations. An explanted human liver, rejected for transplantation due to steatosis, was scanned using spectroscopy and CSE imaging. Fat–water reconstructions were performed using four different techniques: magnitude and complex fitting, with standard or temperature‐corrected signal modeling. Results In all experiments, magnitude fitting with standard signal modeling resulted in large fat quantification errors. Errors were largest for echo time combinations near TE init ≈ 1.3 ms, ΔTE ≈ 2.2 ms. Errors in fat quantification caused by temperature‐related frequency shifts were smaller with complex fitting, and were avoided using a temperature‐corrected signal model. Conclusion Temperature is a confounding factor for fat quantification. If not accounted for, it can result in large errors in fat quantifications in phantom and ex vivo acquisitions. Magn Reson Med 72:464–470, 2014. © 2013 Wiley Periodicals, Inc.