Imaging proton exchange generates contrast for many biomedical applications. Chemical Exchange Saturation Transfer (CEST) MRI is one of those contrast mechanisms that enables us to sensitively reveal unique molecular information in vivo. This talk will discuss the recent developments in CEST contrast characterizations and its applications. It will be divided into two parts, first part is the endogenous and exogenous molecules that can be detected via CEST, and second part is the preclinical CEST applications in diagnosis and therapy.
Target audience
Researchers/clinicians who are interested in studying proton exchange in vivo using CEST.Syllabus
CEST is characterized by z-spectrum, which contains signals from both positive and negative offset frequencies from water (1-4). It provides ample information about the exchangeable protons, such as Amide Proton Transfer (APT) (4-7), Nuclear Overhauser Enhancement (NOE) (8-10), Magnetization Transfer (MT) (11,12) and metabolites (13-31). Endogenous CEST contrast has been applied to study brain tumor in both preclinical and clinical settings. It has also been investigated to highlight tumor in other parts of the body and pathology in neurodegenerative diseases. Exogenous CEST contrast includes the applications of biomaterials, such as natural glucose, drugs and polymers to indicate abnormalities, guide treatments and monitor therapeutic outcomes.
APT has shown promises in differentiating tumor recurrence from radiation necrosis (4-7,32). Imaging pH and metabolites could indicate disease status, e.g. using glucoCEST, gluCEST, and CrCEST (13-25,28-31). In addition to the CEST map, dynamic imaging approach has been applied to study glucose uptake and perfusion-related parameters in brain tumors (13,16,17,33). Moreover, new analysis approaches have been developed in an attempt to specify the actual signal contributions, with reference to the conventional analysis of the Z-spectrum using MTRasym. This talk will present recent developments in CEST contrast characterization, and applications of endogenous and exogenous CEST contrast in diagnosis and therapy.