Diffusion tensor imaging of kidneys with respiratory triggering: optimization of parameters to demonstrate...

To demonstrate the feasibility of diffusion tensor imaging (DTI) of kidneys with respiratory triggering, and determine the optimal imaging parameters for fraction anisotropy (FA) maps.

DTI of kidneys from 16 healthy volunteers was performed using a 1.5T scanner. Five different sequences with different parameters including respiration-triggered acquisition or multiple breath-holding, slice thicknesses of 3 or 5 mm, and different numbers of signal averaging and b values were compared. FA and apparent diffusion coefficients (ADCs) of the cortex and medulla were measured. Measurement error within the same and repeated examination was examined using within-individual standard deviation (Sw).

FAs of the renal cortex were lower than the medulla (mean value of a sequence ranging 0.148-0.224, 0.433-0.476) and the ADCs of the cortex were higher than the medulla (2.26-2.69x10(-3) mm2/s, 1.77-2.19x10(-3) mm2/s) in all sequences (P<0.001). The renal cortex-medulla difference was the largest, with respiratory trigger- ing including a 3-mm slice thickness, three signal averages,and a b-value=0, 200, or 400 s/mm2 (P<0.001). Sw tended to be smaller in the sequence with a b-value of 400 s/mm2.

DTI of kidneys with respiratory triggering is feasible with excellent cortex-medulla differentiation.