CEST Effect at 2ppm (CEST@2ppm): A Potential Biomarker for Grading Brain Tumor Malignancy

Kejia Cai¹, Mohammad Haris¹, Anup Singh¹, Ravi Prakash Reddy Nanga¹, Ranjit Ittyerah¹, Damodar Reddy¹, Harish Poptani¹, Hari Hariharan¹, Ravinder Reddy¹

The CEST effect at 2ppm (CEST@2ppm), quantified through fitting Z spectrum with Lorentzian functions, decreases in tumor compared to normal brain tissue and further reduces as tumor progresses, correlating to MRS quantification of creatine. Along with other justifications, we suggest creatine to be the major contribution to the CEST@2ppm. Our results show F98 tumors have significant lower CEST@2ppm effect compared to 9L tumors. Once validated, the high-resolution creatine mapping method could be used for grading brain tumors.