Volume 124, December 2025, 110506Author links open overlay panel, , AbstractSummary:

A novel steady-state CEST sequence design, based on the underlying physical model of longitudinal magnetization development during CEST saturation and data acquisition is presented and validated in-silico, in vitro and in vivo. This design ensures consistent data acquisition in the pure CEST steady-state, leading to high MTRasym scores and image quality, both in vitro and in vivo, when compared to contemporary sequential and steady-state CEST sequences.

Purpose:

The aim of this study was to enhance CEST sequences by utilizing the pure CEST steady-state in order to deliver higher CEST effects and better sensitivity.

Methods:

A novel CEST saturation/readout scheme was designed, tested in numerical simulations and subsequently validated in vitro and in vivo.

Results:

The novel Multi-2D Spiral pure steady-state CEST sequence showed to deliver advantageous sensitivity and efficacy.

Conclusion:

Constraining image acquisition to the pure CEST steady-state showed promising results in first in vitro and in vivo experiments.

Keywords

CEST

Steady-state

Spirals

Interleave

Data availabilityAll sequences were written in the vendor-agnostic, open-source pulse sequence development framework PyPulseq and are available on GitHub[27]. Moreover, the in-house built Python-based software used for image reconstruction and data analysis can also be found accompanying the sequence scripts, including example scripts to generate the figures in this work. The data that was used for the figures in this publication are available on Zenodo and are linked to in the example scripts, with exception of the in vivo data used for Fig. 6 and Fig. 7 due to protection of the volunteer’s data privacy.

© 2025 The Authors. Published by Elsevier Inc.