Mohammad Haris1, Anup Singh1, Kejia Cai1, Ravi Prakash Reddy Nanga1, Catherine Debrosse1, Hari Hariharan1, Ravinder Reddy1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States
Exchange rate (kex) and logarithmic dissociation constant (pKa) of amine protons of creatine (Cr), phosphocreatine (PCr) and adenosine-triphosphate (ATP) were calculated with an objective to explore the chemical-exchange-saturation-transfer-effects (CEST) of these metabolites. The kex of amine protons in Cr was found to be 7-8 times higher than PCr and ATP. Higher kex in Cr is associated with the low pKa value suggesting the faster dissociation of its amine protons compared to PCr and ATP. CEST imaging of these metabolites showed predominant CEST contrast from Cr. These results provide a new method to perform high resolution proton imaging of Cr without any contamination from PCr.