arXiv subjects

Caixia Fu

Publications and source records attributed to Caixia Fu.

2 recordsLinked to original sources

arXiv2025

A framework for rapid, reproducible, and high-fidelity whole-brain multi-pool CEST imaging at 3T

Purpose: To develop and validate a framework for rapid, accurate, and reproducible whole-brain, multi-pool chemical exchange saturation transfer (CEST) imaging at 3T, addressing challenges of long acquisition times and confounding factors. Methods: A single-shot 3D true fast imaging with steady-state precession (True FISP) sequence was optimized for whole-brain multi-pool CEST. Rapid B0, B1, and T1 mapping was performed using a dual-echo modified four-angle method. A feed-forward neural network was developed for rapid B1 correction, trained against the conventional multi-power method. The apparent exchange-dependent relaxation (AREX) metric was used to correct for T1 and magnetization transfer (MT) effects. The framework was validated in phantoms and healthy human subjects (N=8), including a test-retest reproducibility assessment. Results: The True FISP sequence yielded high-quality, whole-brain images with minimal artifacts and distortion in a clinically feasible scan time (~9 minutes). Phantom studies confirmed the effectiveness of B1 correction (coefficient of variation [CV] for MT_MTRLD decreased from 22.49% to 4.61%) and AREX-based confounder correction (CV for APT_AREX reduced from 33.6% to 6.9%). The neural network B1 correction showed excellent agreement with the conventional multi-power method in vivo (ICC > 0.97). High test-retest reproducibility was demonstrated across 96 brain regions, with the average CV for APT_AREX under 10% for over 95% of regions. Conclusion: A rapid and robust framework for whole-brain quantitative multi-pool CEST imaging was successfully developed and validated. By integrating an efficient acquisition sequence with a streamlined correction pipeline, this approach overcomes key barriers to clinical translation, enabling reliable metabolic imaging for widespread brain pathologies.

physics.med-ph↗

arXiv2025

3D Single-shot CEST imaging at 3T Based on True FISP Readout

To simultaneously fit multiple-pool effects, spectrally selective 3D CEST imaging typically requires single-shot readouts to save time. However, to date, FLASH and EPI have been the primary pulse sequences used for this purpose. They suffer from low SNR or image distortion related to B0 field inhomogeneity. In this work, we developed a 3D single-shot CEST sequence using true fast imaging with steady-state precession (True FISP) readout, also known as bSSFP, and optimized the scanning parameters through simulations. The performance of the CEST sequence was validated using an egg white phantom, ten healthy volunteers, and a patient with a brain tumor on a 3T human scanner. Subsequently, the proposed CEST sequence using True FISP was compared with the commonly used FLASH-based CEST sequence, focusing on SNR and image contrast, while maintaining identical pre-saturation modes, repetition time, echo time and scan time. In the simulation experiments, the maximum CEST signal obtained from the True FISP was significantly greater than that obtained from the FLASH sequence. In the egg white phantom, the SNRs of amide proton transfer (APT) and nuclear Overhauser enhancement (NOE) effect images obtained from the True FISP were 68.3% and 57.0% higher than those obtained from the FLASH sequence, respectively. In healthy volunteers, saturated images collected with the True FISP sequence at 3.5 ppm showed an approximate 84% increase in mean temporal SNR compared to those collected with the FLASH sequence. Compared to the FLASH sequence, the CEST images obtained from the True FISP sequence could display more detailed brain tissue structures of both normal individuals and the patient with a brain tumor. Therefore, due to the high SNR inherent in the sequence, True FISP has the potential to be used for fast and high-quality 3D image readout of CEST contrasts in clinical applications.

physics.med-ph↗