Imaging fibrosis in pediatric kidney transplantation: A pilot study

Pediatr Transplant. 2023 Aug;27(5):e14540. doi: 10.1111/petr.14540. Epub 2023 May 11.


Background: Noninvasive alternatives to biopsy for assessment of interstitial fibrosis and tubular atrophy (IFTA), the major determinant of kidney transplant failure, remain profoundly limited. Elastography is a noninvasive technique that propagates shear waves across tissues to measure their stiffness. We aimed to test utility of elastography for early detection of IFTA in pediatric kidney allografts.

Methods: We compared ultrasound (USE) and MR elastography (MRE) stiffness measurements, performed on pediatric transplant recipients referred for clinically indicated biopsies, and healthy controls.

Results: Ten transplant recipients (median age 16 years) and eight controls (median age 16.5 years) were enrolled. Three transplant recipients had "stable" allografts and seven had Banff Grade 1 IFTA. Median time from transplantation to biopsy was 12 months. Mean estimated glomerular filtration rate was 61.5 mL/min/1.73m2 by creatinine-cystatin-C CKiD equation at time of biopsy. Mean stiffness, calculated through one-way ANOVA, was higher for IFTA allografts (23.4 kPa USE/5.6 kPa MRE) than stable allografts (13.7 kPa USE/4.4 kPa MRE) and controls (9.1 kPa USE/3.6 kPa MRE). Pearson's coefficient between USE and MRE stiffness values was strong (r = .97). AUC for fibrosis prediction in transplanted kidneys was high for both modalities (0.91 USE and 0.89 MRE), although statistically nonsignificant (p > .05). Stiffness cut-off values for USE and MRE were 13.8 kPa and 4.6 kPa, respectively. Both values yielded a sensitivity of 100% but USE specificity (72%) was slightly higher than MRE (67%).

Conclusion: Elastography shows potential for detection of low-grade IFTA in allografts although a larger sample is imperative for clinical validation.

Keywords: children; elastography; healthy controls; kidney; magnetic resonance; transplant; ultrasound.

MeSH terms

  • Adolescent
  • Child
  • Elasticity Imaging Techniques* / methods
  • Fibrosis
  • Humans
  • Kidney / diagnostic imaging
  • Kidney / pathology
  • Kidney Diseases*
  • Kidney Transplantation*
  • Liver Cirrhosis / pathology
  • Lung Diseases, Interstitial*
  • Magnetic Resonance Imaging / methods
  • Pilot Projects