Diagnostic value of renal scintigraphy in detecting early kidney allograft complications

Mykyta  Nechaiev

doi:10.31450/ukrjnd.1(89).2026.04

Mykyta Nechaiev State Non-Commercial Enterprise «National Children's Specialized Hospital «Okhmatdyt» Ministry of Health of Ukraine», Kyiv, Ukraine; Bogomolets National Medical University, Kyiv, Ukraine https://orcid.org/0000-0002-7345-5124

DOI: https://doi.org/10.31450/ukrjnd.1(89).2026.04

Keywords: kidney transplantation, renal scintigraphy, acute rejection, ureteral stenosis, vascular thrombosis, perfusion index, function index, , early post-transplant complications

Abstract

Early identification of kidney allograft complications is essential for preserving graft function. Serum creatinine is routinely used for post-transplant complications monitoring but has a lack of specificity in the early period. Imaging methods such as ultrasound (US) and renal scintigraphy (RS) provide complementary structural and functional information. The study aimed to assess temporal changes in scintigraphy perfusion index (PI), function index (FI), and glomerular filtration rate (GFR) in early kidney allograft complications and to compare these findings with ultrasonographic parameters.

Methods. This single-center observational study included 65 kidney transplant recipients examined within the first 7 days post-transplantation. Thirty-two patients with stable graft function served as controls, while 33 patients developed early allograft complications. All patients underwent dynamic ⁹⁹ᵐTc-DTPA renal scintigraphy with calculation of the PI, FI and GFR on postoperative days 1, 3, and 7, as well as Doppler ultrasonography. Quantitative data were compared using nonparametric tests; p<0.05 was considered statistically significant.

Results. Early complications included acute rejection (31%), ureteral stenosis (22%), urinary fistula (16%), infectious complications (12%), renal artery thrombosis (11%) and renal vein thrombosis (8%). In acute rejection, PI decreased from 0.76 on day 3 to 0.55 on day 7 (p<0.0001), accompanied by reductions in FI (from 0.78 to 0.50, p<0.0001) and GFR from 39.5 to 25.3 mL/min/1.73 m² (p<0.0001). Vascular thromboses showed the most pronounced decreases in all scintigraphy indices (p<0.0001). Ureteral stenosis demonstrated a progressive decline in PI, FI, and GFR between days 3 and 7 (p<0.0001), whereas urinary fistula and infectious complications showed no significant scintigraphic changes (p>0.05). Doppler-derived resistive index elevation was predominantly detected on day 7, later than scintigraphic abnormalities.

Conclusions. These results support the role of RS as an adjunct imaging modality for early post-transplant assessment and show early allograft complications much more effectively than ultrasound. Further prospective studies are needed to validate quantitative thresholds and diagnostic accuracy.