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Simultaneous in vivo pH and temperature mapping using a PARACEST‐MRI contrast agent
Author(s) -
McVicar Nevin,
Li Alex X.,
Suchý Mojmír,
Hudson Robert H. E.,
Me Ravi S.,
Bartha Robert
Publication year - 2013
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.24539
Subject(s) - chemistry , in vivo , nuclear magnetic resonance , analytical chemistry (journal) , saturation (graph theory) , chromatography , physics , microbiology and biotechnology , mathematics , combinatorics , biology
Altered tissue temperature and/or pH is a common feature in pathological conditions, where metabolic demand exceeds oxygen supply such as in tumors and following stroke. Therefore, in vivo tissue temperature and pH may become valuable biomarkers for disease detection and the monitoring of disease progression or treatment response in conditions with altered metabolic demand. In this study, pH is measured using the amide protons of a thulium (Tm 3+ ) complex with a DOTAM‐Glycine‐Lysine (ligand: Tm 3+ ‐DOTAM‐Gly‐Lys). The pH was uniquely determined from the linewidth of the asymmetry curve of the chemical exchange saturation transfer spectrum, independent of contrast agent concentration, or temperature for a given saturation pulse. pH maps with an inter‐pixel standard deviation of less than 0.1 pH units were obtained in 10 mM Tm 3+ ‐DOTAM‐Gly‐Lys solutions with pH ranging from 6.0 to 8.0 pH units at 37°C. Temperature maps were simultaneously obtained using the chemical shift of the chemical exchange saturation transfer peak. Temperature and pH maps are demonstrated in the mouse leg ( N = 3), where the mean and standard deviation for pH was 7.2 ± 0.2 pH unit and temperature was 37.4 ± 0.5°C. Magn Reson Med, 70:1016–1025, 2013. © 2012 Wiley Periodicals, Inc.