Fig. 7
a Anatomical axial T2-weighted image of mice kidney encircled with white ROIs. For shim improvements, the mouse, as well as a [1-13C]lactate-phantom for B1 calibration are covered with carbomer gel. b Segmentation mask for a 14 × 12 CSI data sets acquired on the anatomy in a. White areas indicate voxels corresponding to spectra with three pH compartments, black areas indicate voxels of which spectra contain two or less compartments. c Top row: Individual pH compartment maps for the cortex or a physiological pH compartment (compartment 1), a slightly acidified compartment, mainly the medulla (compartment 2) and a strongly acidified compartment of the ureter (compartment 3) as derived from supervised line fitting. The mean pH map represents the un-weighted average of all three pH compartment maps. Bottom row: Compartment maps derived from line fitting where white areas in the segmentation mask have been replaced by voxel-wise predicted pH values from CNNmix. The mean pH map displays the average pH value of the respective number of pH compartments