title: Magnetic resonance elastography of the kidneys: feasibility and reproducibility in young healthy adults.
abstract: OBJECTIVE
  To evaluate the feasibility and reproducibility of renal magnetic resonance elastography (MRE) in young healthy volunteers.
  
  
  METHODS
  Ten volunteers underwent renal MRE twice at a 4-5 week interval. The vibrations (45 and 76 Hz) were generated by a speaker positioned beneath the volunteers' back and centered on their left kidney. For each frequency, three sagittal slices were acquired (eight phase offsets per cycle, motion-encoding gradients successively positioned along the three directions of space). Shear velocity images were reconstructed using the curl operator combined with the local frequency estimation (LFE) algorithm.
  
  
  RESULTS
  The mean shear velocities measured in the renal parenchyma during the two examinations were not significantly different and exhibited a mean variation of 6% at 45 Hz and 76 Hz. The mean shear velocities in renal parenchyma were 2.21 ± 0.14 m/s at 45 Hz (shear modulus of 4.9 ± 0.5 kPa) and 3.07 ± 0.17 m/s at 76 Hz (9.4 ± 0.8 kPa, P < 0.01). The mean shear velocities in the renal cortex and medulla were respectively 2.19 ± 0.13 m/s and 2.32 ± 0.16 m/s at 45 Hz (P = 0.002) and 3.06 ± 0.16 m/s and 3.10 ± 0.22 m/s at 76 Hz (P = 0.13).
  
  
  CONCLUSIONS
  Renal MRE was feasible and reproducible. Two independent measurements of shear velocities in the renal parenchyma of the same subjects showed an average variability of 6%.
authors.affiliation: Hospices Civils de Lyon, Department of Urinary and Vascular Radiology, Hôpital Edouard Herriot, Lyon, France. olivier.rouviere@netcourrier.com
authors.forename: Olivier
authors.initials: O
authors.lastname: Rouvière
authors.forename: Rémi
authors.initials: R
authors.lastname: Souchon
authors.forename: Gaële
authors.initials: G
authors.lastname: Pagnoux
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Ménager
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Chapelon
mesh_terms: D000328:Adult; D015331:Cohort Studies; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007668:Kidney / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012016:Reference Values; D015203:Reproducibility of Results; D014732:Vibration; D055815:Young Adult