Optimizing Saturation Time for Maximum CEST Contrast
- 1Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15203, USA
Abstract
Purpose To determine the optimal saturation time (T sat ) that maximizes the CEST contrast between a reference and a target signal, such as normal versus pathological tissues or pre- versus post-contrast conditions. Methods The optimal T sat (T sat, opt ) was determined from T 1 and a single measurement of the normalized saturated signal (S sat /S 0 ). We evaluated the analytically derived T sat, opt using simulation, phantom, and in vivo experiments. Results Theoretical analysis showed that the S sat /S 0 measured at T sat, opt is always higher than 0.37. When the repetition time (TR) is fixed or is very long (i.e., >5 T 1 ), the T sat, opt is independent of TR and can be derived from T 1 and S sat /S 0 measured at any T sat . When the steady state S sat /S 0 is 0.5 or 1/3, the T sat, opt equals to T 1 or T 1 /2, respectively. The analytically derived T sat, opt were validated by simulation, phantom and in vivo experiment results, and can be extended to include multiple CEST and non-CEST effects (excluding changes in T 1 ). The relative error of the T sat,opt is <10–15% for typical CEST contrasts of <5%. For very large contrast (e.g., >10% of S 0 ), more accurate estimation of T sat, opt can be obtained from the averaged S sat /S 0 of the reference and target signals. Conclusion T sat, opt can be determined from T 1 and a single measurement of the saturated signal. This approach simplifies optimization of T sat in CEST experiments, especially when using relatively high saturation powers or resonance frequencies close to water.
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BibTeX
@article{zhao2026optimizing,
title = {{Optimizing Saturation Time for Maximum CEST Contrast}},
author = {Yifan Zhao and Julius Juhyun Chung and Tao Jin},
journal = {Magnetic resonance imaging},
year = {2026},
month = jul,
doi = {10.1016/j.mri.2026.110747},
url = {https://doi.org/10.1016/j.mri.2026.110747},
note = {CC BY},
}
RIS
TY - JOUR
TI - Optimizing Saturation Time for Maximum CEST Contrast
AU - Yifan Zhao
AU - Julius Juhyun Chung
AU - Tao Jin
PY - 2026
DA - 2026/07/13
JO - Magnetic resonance imaging
DO - 10.1016/j.mri.2026.110747
UR - https://doi.org/10.1016/j.mri.2026.110747
AB - Purpose To determine the optimal saturation time (T sat ) that maximizes the CEST contrast between a reference and a target signal, such as normal versus pathological tissues or pre- versus post-contrast conditions. Methods The optimal T sat (T sat, opt ) was determined from T 1 and a single measurement of the normalized saturated signal (S sat /S 0 ). We evaluated the analytically derived T sat, opt using simulation, phantom, and in vivo experiments. Results Theoretical analysis showed that the S sat /S 0 measured at T sat, opt is always higher than 0.37. When the repetition time (TR) is fixed or is very long (i.e., >5 T 1 ), the T sat, opt is independent of TR and can be derived from T 1 and S sat /S 0 measured at any T sat . When the steady state S sat /S 0 is 0.5 or 1/3, the T sat, opt equals to T 1 or T 1 /2, respectively. The analytically derived T sat, opt were validated by simulation, phantom and in vivo experiment results, and can be extended to include multiple CEST and non-CEST effects (excluding changes in T 1 ). The relative error of the T sat,opt is <10–15% for typical CEST contrasts of <5%. For very large contrast (e.g., >10% of S 0 ), more accurate estimation of T sat, opt can be obtained from the averaged S sat /S 0 of the reference and target signals. Conclusion T sat, opt can be determined from T 1 and a single measurement of the saturated signal. This approach simplifies optimization of T sat in CEST experiments, especially when using relatively high saturation powers or resonance frequencies close to water.
SN - 0730-725X
SN - 1873-5894
ER -