Quantitative elastography of renal transplants using supersonic shear imaging: a pilot study

Eur Radiol. 2012 Oct;22(10):2138-46. doi: 10.1007/s00330-012-2471-9. Epub 2012 May 17.

Abstract

Purpose: To evaluate the reliability of quantitative ultrasonic measurement of renal allograft elasticity using supersonic shear imaging (SSI) and its relationship with parenchymal pathological changes.

Materials and methods: Forty-three kidney transplant recipients (22 women, 21 men) (mean age, 51 years; age range, 18-70 years) underwent SSI elastography, followed by biopsy. The quantitative measurements of cortical elasticity were performed by two radiologists and expressed in terms of Young's modulus (kPa). Intra- and inter-observer reproducibility was assessed (Kruskal-Wallis test and Bland-Altman analysis), as well as the correlation between elasticity values and clinical, biological and pathological data (semi-quantitative Banff scoring). Interstitial fibrosis was evaluated semi-quantitatively by the Banff score and measured by quantitative image analysis.

Results: Intra- and inter-observer variation coefficients of cortical elasticity were 20 % and 12 %, respectively. Renal cortical stiffness did not correlate with any clinical parameters, any single semi-quantitative Banff score or the level of interstitial fibrosis; however, a significant correlation was observed between cortical stiffness and the total Banff scores of chronic lesions and of all elementary lesions (R = 0.34, P = 0.05 and R = 0.41, P = 0.03,respectively).

Conclusion: Quantitative measurement of renal cortical stiffness using SSI is a promising non-invasive tool to evaluate global histological deterioration.

Key points: • Supersonic shear imaging elastography can measure cortical stiffness in renal transplants • The level of cortical stiffness is correlated with the global degree of tissue lesions • The global histological deterioration of transplanted kidneys can be quantified using elastography.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Elasticity Imaging Techniques / methods*
  • Elasticity Imaging Techniques / statistics & numerical data
  • Female
  • Humans
  • Kidney Transplantation / diagnostic imaging*
  • Kidney Transplantation / pathology
  • Male
  • Middle Aged
  • Observer Variation
  • Pilot Projects
  • Prospective Studies
  • Reproducibility of Results
  • Young Adult