TY  - GEN
N2  - Phosphorus (31P) magnetic resonance spectroscopic imaging (MRSI) enables non-invasive imaging of pH value and magnesium ion concentration, [Mg2+], in living tissue. Typically, the chemical shifts of 31P metabolites are translated to pH and [Mg2+] via calibration equations, which, however, are well-defined only for physiological conditions, thus limiting their reliability in pathologies.

In this thesis, a novel approach for the in vivo determination of pH and [Mg2+] applicable for various chemical conditions, utilizing multiple 31P spectral properties in form of a look-up table, is proposed. To this end, the variability of spectral properties in vivo was investigated in high-quality human 31P MRSI data acquired at B0 = 7T, and reproduced in measurements of 114 model solutions prepared with physiologically relevant pH, [Mg2+] and ionic strengths, at B0 = 9.4T. The identified chemical shift changes of the adenosine-5?-triphosphate (ATP) resonances were translated into a multi-dimensional model, which was used for the implementation of a look-up algorithm, accounting also for measurement uncertainties. Application to in vivo data resulted in successful assignments of plausible pH and [Mg2+] values in healthy and tumorous tissue. The proposed approach is extendable by including further spectral properties, potentially allowing for more profound tissue characterizations, being particularly important for the application in pathologies.
A1  - Franke, Vanessa Lydia
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/32909/
KW  - Magnetic Resonance Spectroscopic Imaging
ID  - heidok32909
CY  - Heidelberg
AV  - public
Y1  - 2023///
TI  - In vivo determination of pH and magnesium ion concentration by means of 31P MRSI: A multi-parametric look-up approach
ER  -