Respiratory Triggered Chemical Exchange Saturation Transfer MRI for pH Mapping in the Kidneys at 3T

Jochen Keupp¹, Edwin Heijman², Sander Langereis², Holger Grll², Dario L. Longo³, Enzo Terreno³, Silvio Aime³

A local MR pH measurement would be of high clinical interest, because several pathologies are associated with pH changes (i.e., tumors, renal diseases). CEST-MRI is promising, e.g. using Iopamidol as contrast agent, which exhibits two amide proton pools for a ratiometric pH measure independent of concentration. Existing CEST methodology was extended to anatomical regions affected by physiological motion by using a breathing triggered technique with continuous pulsed RF saturation during the wait time for the trigger event. Feasibility of motion compensated pH mapping in the kidneys of a rat could be demonstrated on a clinical 3T scanner.