Reduced Field of View APT Imaging of Rectum (RAPTOR) at 3T MRI Scanner / 生物化学与生物物理进展

ABSTRACT

ObjectiveThe chemical exchange saturation transfer (CEST) technique has become a valuable tool in diagnosing metabolic changes associated with cerebral and systemic diseases, leveraging the calculation of compounds with exchangeable protons in proximity to water molecules. Specifically, the amide proton transfer (APT) CEST technique has shown promise in diagnosing cerebral strokes and tumors by comparing altered endogenous proteins or peptides with normal tissues. Reduced field of view (rFOV) imaging technology has been widely used in the diagnosis of small organ lesions in the body. In this study, we aim to apply the rFOV imaging to identify CEST signals in the rectum, investigating the potential utility of rFOV technique in clinical diagnosis of rectal diseases and providing metabolic insights for chemoradiotherapy. MethodsMRI images of eleven healthy volunteers were acquired using transverse Full_FOV and rFOV CEST imaging on a 3T scanner. The resolution was set at 2.5×2.5×6 mm³ and 1.5×1.5×6 mm³ for Full_FOV or the rFOV method. Saturation powers of 0.7 μT and 2 μT were applied. For the 2 μT saturation, MTRasym at ±3.5 ppm was employed, while for 0.7 μT saturation, Lorentzian difference was used for CEST quantification of the contrast maps and curves. ResultsThe rFOV method has the advantage of halving the scan time while maintaining the same contrast as the Full_FOV method. When compared to Full_FOV methods, rFOV methods exhibited nearly identical Z_spec and very similar MTRasym curves. Additionally, rFOV with a 1.5 mm×1.5 mm in-plane resolution could be achieved in approximately 3 min. rFOV method displayed better structural details for the entire rectum, including CEST contrast maps and quantitative curves. ConclusionCEST MRI proves valuable in diagnosing rectal diseases, and employing the rFOV technique could provide higher spatial and temporal resolution. CEST MRI should be the preferred choice for offering improved diagnostic capabilities with its potential for rectal disease diagnosis.