B1 Inhomogeneity Correction of In-Vivo CEST Contrast

Anup Singh¹, Kejia Cai¹, Mohammad Haris¹, Hari Hariharan¹, Ravinder Reddy¹

In current study effect of B1 in-homogeneities on in vivo chemical-exchange-saturation-transfer(CEST) asymmetry contrast from human brain at 7T is studied and a procedure for correction of these in-homogeneities is presented. The z-spectral and CEST data (at 3ppm) at multiple saturation powers and fixed duration(1s) were obtained from brain of healthy human volunteers at 7T research scanner. These data were corrected for B0 in-homogeneities before generating z-spectral and CEST asymmetry contrast. B1 map from human brains were highly in-homogeneous (~50% variation) and CESTasy map without these corrections were difficult to interpret. Proposed calibration based approach resulted in B1-inhomogeneities corrected CESTasy map.