Abstract #4493

Simulation & Optimization of Pulsed RF Irradiation Scheme for Chemical Exchange Saturation Transfer (CEST) MRI Demonstration of PH-Weighted Pulsed-CEST MRI in Acute Ischemic Stroke Animal Model

Phillip Zhe Sun¹, Enfeng Wang¹, Jerry S. Cheung¹, Thomas Benner¹, A. Gregory Sorensen¹

¹Radiology, Athinoula. A. Martinos Center for Biomedical Imaging, MGH & Harvard Medical School, Charlestown, MA, United States

Chemical exchange saturation transfer (CEST) imaging remains promising for clinical translation. However, CEST contrast also depends on experimental parameters, particularly, RF irradiation power and scheme. Moreover, continuous wave (CW) RF irradiation is not available on most clinical systems due to hardware limitations, for which, the pulsed RF irradiation scheme must be applied instead. Our study quantitatively analyzed and showed that pulsed-CEST provides similar CEST contrast as CW-CEST MRI for slow chemical exchange, while it become less efficient for higher exchange rates. In addition, we confirmed the simulation with pH-weighted pulsed-CEST MRI, both in phantom and in vivo.