Author/Authors :
Kikuchi, Kazufumi University of Texas Southwestern Medical Center - Dallas, USA , Ishimatsu, Keisuke University of Texas Southwestern Medical Center - Dallas, USA , Zhang, Shanrong University of Texas Southwestern Medical Center - Dallas, USA , Dimitrov, Ivan E University of Texas Southwestern Medical Center - Dallas, USA , Honda, Hiroshi Department of Clinical Radiology - Graduate School of Medical Sciences - Kyushu University - Fukuoka, Japan , Dean Sherry, A University of Texas Southwestern Medical Center - Dallas, USA , Takahashi, Masaya University of Texas Southwestern Medical Center - Dallas, USA
Abstract :
Chemical exchange saturation transfer (CEST) imaging has been demonstrated to discuss the concentration changes of amide
proton, glutamate, creatine, or glucose measured at 3.5, 3.0, 2.0, and 1.0–1.2 ppm. However, these peaks in z-spectra are quite
broad and overlap with each other, and thus, the independence of a CEST signal on any specific metabolite is still open to question.
Here, we described whether there was interference among the CEST signals and how these CEST signals behave when the power of
the presaturation pulse was changed. Based on these results, further experiments were designed to investigate a method to increase
the independence of the CEST signal in both phantoms and animals. e result illustrates a clear interference among CEST signals.
A presaturation power adjusted pulsed- (PPAP-) CESTmethod which was designed based on the exchange rates of the metabolites
can be used to remove contributions from other exchanging species in the same sample. Further, the method was shown to
improve the independence of the glutamate signal in vivo in the renal medulla in mice. e PPAP-CESTmethod has the potential
to increase the independence of any target CEST signals in vivo by choosing the appropriate combination of pulse amplitudes
and durations.
