biostudies-literatureSun PZNational Institute of Neurological Disorders and StrokeNational Institute of Arthritis and Musculoskeletal and Skin DiseasesEmory UniversityNINDS NIH HHSYerkes National Primate Research Center, Emory UniversityNational Institutes of HealthNIAMS NIH HHSNIH HHS107022https://www.ebi.ac.uk/biostudies/studies/S-EPMC8316384biostudies-literatureUnknown329Chemical exchange saturation transfer (CEST) MRI depends not only on the labile proton concentration and exchange rate but also on relaxation rates, particularly T<sub>1</sub> relaxation time. However, T<sub>1</sub> normalization has shown to be not straightforward under non-steady-state conditions and in the presence of radiofrequency spillover effect. Our study aimed to test if the combined use of the new quasi-steady-state (QUASS) analysis and inverse CEST calculation facilitates T<sub>1</sub> normalization for improved CEST quantification. The CEST signal was simulated with Bloch-McConnell equations, and the apparent CEST, QUASS CEST, and the inverse CEST effects were calculated. T<sub>1</sub>-normalized CEST effects were tested for their specificity to the underlying CEST system (i.e.Journal of magnetic resonance (San Diego, Calif. : 1997)Quasi-steady-state chemical exchange saturation transfer (QUASS CEST) MRI analysis enables T<sub>1</sub> normalized CEST quantification - Insight into T<sub>1</sub> contribution to CEST measurement.PMC8316384R21AR071529R21 AR071529P51 OD011132R01 NS0836542R01NS083654P51OD011132Sun PZfalseQuasi-steady-state chemical exchange saturation transfer (QUASS CEST) MRI analysis enables T<sub>1</sub> normalized CEST quantification - Insight into T<sub>1</sub> contribution to CEST measurement.Chemical exchange saturation transfer (CEST) MRI depends not only on the labile proton concentration and exchange rate but also on relaxation rates, particularly T<sub>1</sub> relaxation time. However, T<sub>1</sub> normalization has shown to be not straightforward under non-steady-state conditions and in the presence of radiofrequency spillover effect. Our study aimed to test if the combined use of the new quasi-steady-state (QUASS) analysis and inverse CEST calculation facilitates T<sub>1</sub> normalization for improved CEST quantification. The CEST signal was simulated with Bloch-McConnell equations, and the apparent CEST, QUASS CEST, and the inverse CEST effects were calculated. T<sub>1</sub>-normalized CEST effects were tested for their specificity to the underlying CEST system (i.e.2021-01-01T00:00:00Z2021 Aug2025-04-26T16:34:25.263Z2025-04-06T15:13:04.904ZS-EPMC83163843414436010.1016/j.jmr.2021.107022