Diagnostic efficacy and safety of ultrasound-guided kidney transplant biopsy using cortex-only view: a retrospective single-center study

Purpose: Cortical biopsy is the cornerstone to reveal a cause of unexplained dysfunction of the kidney transplant. Nevertheless, only a few studies have reported the biopsy technique with its performance. We described a novel technique of ultrasound (US)-guided kidney transplant biopsy using cortex-only view and analyzed its diagnostic efficacy and safety. Materials and methods: Between January 2014 and December 2016, a consecutive series of 188 patients who underwent US-guided kidney transplant biopsy using cortex-only view by an experienced radiologist were evaluated (mean age, 46.1 ± 12.5 years; range, 21–79 years). Biopsy time, biopsy distance, biopsy core number, and glomerular number per patient were recorded. Successful biopsy (e.g., adequate, 10 or more glomeruli; marginal, 7–9 glomeruli) and complication rates were investigated, using Banff criteria and Clavien-Dindo classification, respectively. Results: Mean biopsy time, distance, and core number were 20.6 ± 6.7 min (range, 10–44 min), 3.2 ± 0.7 cm (range, 2.1–5.4 cm), and 1.9 ± 0.3 (range, 1.0–3.0), respectively. Mean glomerular number per patient was 20.4 ± 10.0 (range, 0–54). Adequate and marginal biopsy rates were 87.2% (164/188) and 95.2% (179/188), respectively. There was no major complication requiring treatment (no patient with Clavien-Dindo grade 2 or greater complication), while there were self-limiting minor complications in 5 patients (overall complication rate, 2.7%). Conclusion: US-guided biopsy using cortex-only view is feasible and safe in sampling cortical tissues of kidney transplant. Key Points: • Ultrasound (US)-guided kidney transplant biopsy using cortex-only view is feasible and safe. • Adequate and marginal biopsy rates were 87.2% and 95.2%, respectively. • No major complication requiring treatment occurred after biopsy.