Jiadi Xu1, Nirbhay N. Yadav1, Amnon Bar-Shir2, Craig Jones1, 2, Kannie W.Y. Chan1, Jingyang Zhang2, Piotr Walczak2, Michael T. McMahon1, Peter C.M. van Zijl1
1F. M. Kirby Center, Kennedy Krieger Institute, Baltimore, MD, United States; 2Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States
We propose a new technique, variable delay pulsed CEST (VDP CEST), which eliminates the need for performing asymmetry analysis in CEST imaging. The scheme involves acquiring images with variable delay times between RF saturation pulses in pulsed CEST, producing a series of CEST images sensitive to the speed of saturation transfer. Subtracting two images or fitting a time series produces CEST and NOE-relayed CEST maps without effects of direct saturation and strongly reduced influence of semi-solid magnetization transfer. This technique, which can provide very short scan times when using a single RF frequency, is demonstrated in vivo on rat brain.