Nanoparticle-Based Contrast Agents for ¹²⁹Xe HyperCEST NMR and MRI Applications

Figure 2

Concept of Xe HyperCEST detection. (a) Direct Xe NMR spectrum illustrating the abundant detected pool (in red) and the pool of reversibly bound Xe in a nanohost system (in green). (b) Applying the RF saturation pulse at different frequency offsets enables selective detection of different host structures in a CEST spectrum. The more efficient the Xe exchange is, the more pronounced will be the CEST response (as long as the exchange is not too fast to eliminate a separate chemical shift for bound Xe).