High-resolution diffusion tensor imaging of the human kidneys using a free-breathing, multi-slice, targeted field of view approach

• Published in: NMR in biomedicine 2014-11, Vol.27 (11), p.1300-1312
• Main Authors: Chan, Rachel W., Von Deuster, Constantin, Stoeck, Christian T., Harmer, Jack, Punwani, Shonit, Ramachandran, Navin, Kozerke, Sebastian, Atkinson, David
• Format: Article
• Language: English
• Subjects: Adult; Anisotropy; diffusion tensor imaging; Diffusion Tensor Imaging - methods; Female; free breathing; human kidney; Humans; Image Processing, Computer-Assisted; Kidney - anatomy & histology; Kidney Cortex - anatomy & histology; Kidney Medulla - anatomy & histology; Male; Motion; multi-slice imaging; Reference Values; Reproducibility of Results; Respiration; targeted field of view; Young Adult
• ISSN: 0952-3480; 1099-1492
• DOI: 10.1002/nbm.3190

Fractional anisotropy (FA) obtained by diffusion tensor imaging (DTI) can be used to image the kidneys without any contrast media. FA of the medulla has been shown to correlate with kidney function. It is expected that higher spatial resolution would improve the depiction of small structures within the kidney. However, the achievement of high spatial resolution in renal DTI remains challenging as a result of respiratory motion and susceptibility to diffusion imaging artefacts. In this study, a targeted field of view (TFOV) method was used to obtain high‐resolution FA maps and colour‐coded diffusion tensor orientations, together with measures of the medullary and cortical FA, in 12 healthy subjects. Subjects were scanned with two implementations (dual and single kidney) of a TFOV DTI method. DTI scans were performed during free breathing with a navigator‐triggered sequence. Results showed high consistency in the greyscale FA, colour‐coded FA and diffusion tensors across subjects and between dual‐ and single‐kidney scans, which have in‐plane voxel sizes of 2 × 2 mm2 and 1.2 × 1.2 mm2, respectively. The ability to acquire multiple contiguous slices allowed the medulla and cortical FA to be quantified over the entire kidney volume. The mean medulla and cortical FA values were 0.38 ± 0.017 and 0.21 ± 0.019, respectively, for the dual‐kidney scan, and 0.35 ± 0.032 and 0.20 ± 0.014, respectively, for the single‐kidney scan. The mean FA between the medulla and cortex was significantly different (p