Abstract #4528

In Vivo Acquisition of CEST MRI using Length & Offset VARiation of Saturation CEST (LOVARS-CEST) for Artifact Reduction

Xiaolei Song^1,2, Guanshu Liu^1,3, Amnon Bar-Shir^1,2, Michael Gorelik^1,2, Assaf A. Gilad^1,2, Peter C. M. Van Zijl^1,3, Jeff W. M. Bulte,,², Michael T. McMahon^1,3

¹Division of MR Research, the Russell H. Morgan Department of Radiology & Radiological Science, the Johns Hopkins University, Baltimore, MD, United States; ²Cellular Imaging Section, Institute for Cell Engineering, Johns Hopkins University, Baltimore, MD, United States; ³F.M. Kirby Research Center, Kennedy Krieger Institute, Baltimore, MD, United States

Chemical Exchange Saturation Transfer (CEST) MRI has been shown to provide additional information for assessing the grade of brain tumors. Most existing CEST acquisitions rely on acquisition of many saturation frequency offsets to correct for B0 inhomogeneities, which is time-consuming and inefficient. We developed a scheme termed Length and Offset VARiation of Saturation (LOVARS-CEST) using saturation pulse length variation combined with FFT post-processing to identify CEST contrast and compensate for field inhomogeneity artifacts. This was tested on mice with 9L brain tumors. The results show that LOVARS-CEST imaging can reduce B0 inhomogeneity artifacts and improve CNR.