Purpose: 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.
Materials and Methods: 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).
Results: 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 (2.26-2.69 x 10(-3) mm(2)/s, 1.77-2.19 d 10(-3) mm(2)/s) in all sequences (P < 0.001). The renal cortex-medulla difference was the largest, with respiratory triggering including a 3-mm slice thickness, three signal averages,and a b-value = 0, 200, or 400 s/mm(2) (p < 0.001). SW tended to be smaller in the sequence with a b-value of 400 s/mm(2).
Conclusion: DTI of kidneys with respiratory triggering is feasible with excellent cortex-medulla differentiation.