title: TSI ultrasound elastography for the diagnosis of chronic allograft nephropathy in kidney transplanted patients.
abstract: OBJECTIVE
  To answer the question whether the TSI (tissue strain imaging) sonoelastography technique can contribute to the diagnosis of chronic renal allograft damage.
  
  
  METHODS
  A prospective study of 112 patients between June 2010 and April 2011 was conducted to compare elastography data with biopsy results and laboratory parameters in order to determine whether any correlations exist. Elastography parameters were acquired with a high-end ultrasound system and analyzed using the semiquantitative strain ratio. For comparison, patients were divided into three groups based on biopsy findings (Banff classification): group A: biopsy not necessary; group B: Banff grade I; group C: Banff grades II and III. Correlations were assessed by means of correlation (Pearson) and regression analysis. Differences between ordinal groups were tested for statistical significance by the Mann-Whitney U test.
  
  
  RESULTS
  Mean patient age was 54.2 ± 15.01 years. Fifty-nine percent of the patients were male. The calculated TSI strain ratio of groups A and C differed significantly (p = 0.024). Groups B and C (p = 0.056) and groups A and B (p = 0.88) showed no significant difference. The TSI strain ratio did not correlate with glomerular filtration rate (r = 0.105) or creatinine (r = 0.092).
  
  
  CONCLUSIONS
  The TSI sonoelastography technique can contribute to the differentiation of different stages of renal graft damage (according to Banff classification). However, significant results were not observed for all investigated features. The TSI technique should be further evaluated in future studies including larger numbers of patients.
authors.affiliation: Department of Radiology, Charité, Berlin, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Kahn
authors.affiliation: Department of Nephrology, Charité, Berlin, Germany.
authors.forename: Torsten
authors.initials: T
authors.lastname: Slowinski
authors.affiliation: Department of Obstetrics, Charité, Berlin, Germany.
authors.forename: Anke
authors.initials: A
authors.lastname: Thomas
authors.affiliation: Department of Radiology, Charité, Berlin, Germany.
authors.forename: Sergej
authors.initials: S
authors.lastname: Filimonow
authors.affiliation: Department of Radiology, Charité, Berlin, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Fischer
keywords: allograft; elastography; kidney; tissue strain imaging; ultrasound