In vivo measurement of renal transplant viscoelasticity

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Common clinical practice is to follow-up a renal transplant with regular protocol biopsies of the transplanted organ to assess presence of inflammation or signs of rejection. The objective of this study was to investigate the viscoelastic mechanical properties of patients with renal transplants. Recent studies using shear wave-based techniques have shown that the elastic mechanical properties of the kidney increase in presence of inflammation and fibrosis. Under a protocol approved by the Mayo Clinic Institutional Review Board, we studied the transplanted kidneys of 14 patients and the native kidneys of six control subjects. We used ultrasound radiation force to generate shear waves in the renal cortex and measured the shear waves using compounded plane wave imaging. For this study we used a Verasonics system equipped with a linear array or curved array transducer. We measured the group velocity using a Radon transform algorithm on the displacement data for these subjects to calculate the elastic shear modulus. We also analyzed the motion using a two-dimensional fast Fourier transform (2D-FFT) method to examine the phase velocity dispersion and fit the data with a Voigt model, where μ1 is the elastic shear modulus and μ2 is the shear viscosity. Clinical parameters such as serum creatinine (SCr) and Banff scoring from histology of transplant biopsies were also recorded. We observed a positive trend with SCr and μ in patients with kidney transplants and found a Pearson correlation of R = 0.54. We measured the viscoelasticity of renal transplant kidneys. Quantitative shear modulus measurements correlated with clinically significant measurements such as serum tests and biopsy histology.

Original languageEnglish (US)
Title of host publication2013 IEEE International Ultrasonics Symposium, IUS 2013
Pages523-526
Number of pages4
DOIs
StatePublished - 2013
Event2013 IEEE International Ultrasonics Symposium, IUS 2013 - Prague, Czech Republic
Duration: Jul 21 2013Jul 25 2013

Publication series

NameIEEE International Ultrasonics Symposium, IUS
ISSN (Print)1948-5719
ISSN (Electronic)1948-5727

Other

Other2013 IEEE International Ultrasonics Symposium, IUS 2013
CountryCzech Republic
CityPrague
Period7/21/137/25/13

Keywords

  • Renal transplant
  • Shear wave
  • Viscoelastic

ASJC Scopus subject areas

  • Acoustics and Ultrasonics

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