Project Details
Projekt
Comprehensive chemical exchange saturation transfer (CEST) MRI
Applicant
Professor Dr. Moritz Zaiss
Subject Area
Medical Physics, Biomedical Technology
Radiology
Radiology
Term
since 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 500888779
This project is part of the research unit “Fast Mapping of Quantitative MR biosignatures at Ultra-high Magnetic Field”. It focuses on extending, accelerating, and improving chemical exchange saturation transfer (CEST) MRI at 7 T. CEST MRI is an imaging method with spectroscopic information that greatly benefits from increased SNR and increased spectral resolution at 7 T. 7 T CEST is rich in information on several chemically relevant contributions such as pH, creatine, glutamate, phosphocreatine, glycosaminoglycans (GAG), protein/peptide content, protein structure, as well as lipid content. CEST has already shown promising diagnostic results in imaging of tumors, stroke, and neurodegeneration. However, CEST MRI is actually not one single method, but rather a variety of different options can be chosen for different CEST labeling. Depending on the exchange rate and frequency shift of the respective proton group the optimal CEST labeling is different, opening a whole space of parameters given by the triple (saturation offset, saturation amplitude, and the saturation time). Most often until now due to scan time limitations, only one point in this parameter space is investigated in clinical studies. The goal of this project is to cover this CEST parameter space in a comprehensive manner, so that most CEST-weightings are available within one single scan. This will be possible due to recent advancements in fast acquisition (snapshot CEST), feature reduction, and possible reduction of saturation times. In combination with methods developed in collaboration with other projects of the research unit 5534, such as undersampled acquisition, homogeneous pTx saturation, motion stable acquisition, and deep learning techniques, a comprehensive CEST method is aimed at that covers most CEST labelings and - as part of the MR biosignature scan - provides maximum tissue information in minimal scan time. Thus, we both extend and accelerate CEST MRI at 7 T to reach a clinically feasible, but comprehensive CEST scan. Hypotheses that comprehensive CEST will yield benefits for the clinical research questions of the RU are evident, e.g. for breast tissue cancer risk stratification, the detected age correlation of amide CEST, as well as correlations with GAG content indicates a potential for more detailed characterization of fibroglandular tissue microstructure. In muscle tissue, pH and urea induced CEST changes upon dialysis are expected. For neurodegeneration, a key indicator are lipids, which were shown to contribute to the rNOE CEST signal, but also protein aggregation and denaturation processes where shown to lead to detectable CEST changes. The envisioned comprehensive CEST scan includes all these labelings and explores yet unknown labeling regimes to generate further hypotheses.
DFG Programme
Research Units
