Molecular MRI using chemical exchange saturation tranfer at 9.4 T and 3 T
Molecular MRI using chemical exchange saturation transfer at 9.4T and 3T CEST MRI is regarded as an exciting topic in the field of biomedical imaging. Its major advantage is imaging of physiological and molecular information with spatial resolution comparable to that of conventional MRI. Correlations of CEST signals with protein content and protein structure, metabolite concentration (especially glucose), as well as pH have made CEST an interesting imaging modality for studies of cancer: Metabolic changes indicate tumor activity, Protein content is a measure of increased cellularity during tumor infiltration; furthermore, there is a correlation between gradients in pH and tumor migration.
Find previous publications on pubmed http://www.ncbi.nlm.nih.gov/pubmed/?term=moritz+zaiss
Find resources for CEST-MRI on the project page www.cest-sources.org
QUESP and QUEST revisited - fast and accurate quantitative CEST experiments. DOI: 10.1002/mrm.26813
T1ρ-weighted Dynamic Glucose-enhanced MR Imaging in the Human Brain DOI: doi.org/10.1148/radiol.2017162351
Fast magentization-prepared imaging readouts
For all CEST experiments the magnetization must be prepared by saturation which takes several seconds to build up. Subsequently this magentization state must be read out as quickly as possible before it is lost again. Thus, one major project that forms the basis of all subprojects is the development of fast imaging readouts. Hand in hand with sequence development , evaluation must be refined; evaluation software is shared on our project webiste www.cest-sources.org.
We are part of the EU Project GLINT
The promise of the technique is to give a subject a drink of soda with high sugar and see if tumors light up due to their enhanced metabolism. First applications in vivo showed glucoCEST signal enhancmenet in tumor areas, see our recent article.
CEST allows MRI imaging of protein content, conformation and denaturation. All of these might be interesting markers in brain tumors as well as other pathologies, especially in tumors it might overcome the need for contrast agents (see Figure 1). In addition, protein signals have a correlation with pH that is investitgated for use of a pH-weighted imaging.
Figure 1: Comparison of Gadolinium enhanced (left column) and 'Downfield NOE-suppressd amide-CEST effect' in human glioblastoma patients revealed that amide-CEST contrast forms a unique contrast that delineates tumor regions and show remarkable overlap with the gadolinium contrast enhancement.