Methods for an improved detection of the MRI-CEST effect.
CEST imaging is a recently introduced MRI contrast modality based on the use of endogenous or exogenous molecules whose exchangeable proton pools transfer saturated magnetization to bulk water, thus creating negative contrast. One of the critical issues for further development of these agents is represented by their limited sensitivity in vivo. The aim of this work is to improve the detection of CEST agents by exploring new approaches through which the saturation transfer (ST) effect can be enhanced. The performance of the proposed methods has been tested in vitro and in vivo using highly sensitive and highly shifted lipoCEST agents, and the results were compared with the standard ST evaluation mode. The acquired Z-spectra were interpolated locally and voxel-by-voxel by smoothing splines. Besides expressing the ST in the standard mode, we explore two methods, enhanced and integral ST, which better exploit all the information contained in the Z-spectrum. By combining different modes for ST assessment a significant improvement in the detection of the lipoCEST agents, both in vitro and in vivo, has been found. The results obtained from the application of the proposed methods outline the importance of post-processing analysis for highlighting the CEST-MRI contrast.
Terreno
Enzo
E
Dipartimento di Chimica IFM and Molecular Imaging Center, University of Torino, Via P. Giuria 7, 10125 Torino, Italy.
Stancanello
Joseph
J
Longo
Dario
D
Castelli
Daniela Delli
DD
Milone
Luciano
L
Sanders
Honorius M H F
HM
Kok
Maarten B
MB
Uggeri
Fulvio
F
Aime
Silvio
S
D000818:Animals; D002417:Cattle; D045744:Cell Line, Tumor; D003198:Computer Simulation; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D019047:Phantoms, Imaging; D014867:Water / Q000737:chemistry
D014867:Water