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Abstract:
Learning Objectives: Chemical exchange saturation transfer (CEST) MRI is a non-invasive method that enables to indirectly detect metabolites, peptides and proteins via protons in functional groups that are in exchange with the abundant water proton pool (1–2). Principles of the CEST phenomena and efficient sequences will be introduced for endogenous protein CEST, and glucoCEST or dynamic glucose enhancement that utilizes the change in CEST signal after glucose injection. Applications in tumor imaging for these techniques are shown; similarities and differences to Gadolinium enhanced images are discussed. Body: To generate a CEST contrast a fast MRI readout is used with an RF presaturation module that saturation proton groups nearby the water protons (Fig. 1). Exchanging protons then transport the saturation state to the water pool and generate the CEST effect directly as an image contrast. For endogenous protein and peptide CEST signal the most similar patterns to Gadolinium uptake were achieved using the downfield-NOE suppressed APT signal (3), see Fig. 2. injection were tested in humans (4, 5, 6). Here a partial overlap with gadolinium could be observed (6), see Fig. 3. Early CEST results shows a great potential of the non-invasive CEST contrast to yield similar information as DCE. If this will translate to all applications of DCE and all types and grades of pathology has still to be investigated.
