Diffusion tensor MRI of the human kidney

Abstract

This study characterizes the diffusion anisotropy of the human kidney using a diffusion‐weighted, single‐shot echo planar imaging (EPI) sequence in order to access the full apparent diffusion tensor (ADT) within one breathhold. The fractional anisotropy (FA) of the cortex and the medulla were found to be 0.22 ± 0.12 and 0.39 ± 0.11, respectively (N = 10), which emphasizes the need for rotationally invariant diffusion measurements for clinical applications. Additional limitations for clinical diffusion imaging on the kidney are the strong susceptibility variations within the abdomen that restrict the use of imaging techniques employing long echo trains, and the severe motion sensitivity that limits the available imaging time to one breath‐hold. To overcome these problems an isotropic, diffusion‐weighted, segmented EPI protocol that facilitates the acquisition of high‐resolution diffusion‐weighted images within a single breath‐hold was implemented. Using this method, the apparent diffusion coefficient (ADC) of the cortex and medulla were found to be 2.89 ± 0.28 · 10⁻⁹ m²/s and 2.18 ± 0.36 · 10⁻⁹ m²/s (N = 10). J. Magn. Reson. Imaging 2001;14:42–49.