Medical imaging differential diagnosis of ureterocele and ectopic ureter in deplex kidney

LI Yuan; MA Rui

doi:10.20258/j.cnki.1006-9011.2025.07.019

Abstract：Objective To investigate the imaging characteristics and underlying causes of misdiagnosis in cases of uretero-cele and ectopic ureter in duplex kidney,with the aim of enhancing diagnostic accuracy.Methods This study retrospectively analyzed the clinical and imaging data of 129 patients with renal ureterocele or ectopic ureteral orifice in duplex kidney,con-firmed by clinical follow-up or surgical intervention at our institution.Among the cases,40 were diagnosed with ureterocele and 89 with ectopic ureteral orifice.All patients initially underwent abdominal ultrasound screening followed by CT urography(CTU),with 3 patients additionally undergoing magnetic resonance urography(MRU).Two experienced radiologists indepen-dently reviewed the imaging studies to summarize the CT/MR imaging features of ureterocele and ectopic ureteral orifice.Results No statistically significant differences in age of onset or gender distribution were observed between ureteral ureterocele and ectopic ureteral orifice in duplex kidney.However,distinct imaging features were identified between the two groups.In the ureterocele group(n=40),cross-sectional CT/MR imaging revealed ureteral terminal circumference ratios>60%(appeared as triple-surface bladder contact sign)in 27 cases(67.5%).In contrast,the ectopic ureteral orifice group(n=89)demonstrated cir-cumference ratios<60%(appeared as single-surface bladder contact)in 69 cases(77.5%).Furthermore,68 cases(76.4%)in ectopic ureteral orifice group exhibited orifice locations distal to the bladder neck,significantly higher than the 13 cases(32.5%)observed in the ureterocele group.As the clinical and surgical correlation were evaluated,the diagnostic accuracy rates for ureterocele and ectopic ureteral orifice were 82.6%and 97.6%,respectively,with corresponding misdiagnosis rates of 17.4%and 2.4%,respectively.Conclusion The incidence of ectopic ureteral orifice is higher compared to ureterocele in duplex kid-ney.Ectopic ureter associated with distal dilation is often misdiagnosed as ureterocele.Key imaging features for differential diag-nosis include the contact shape and circumference ratio between the dilated segment and the bladder,which can enhance diag-nostic accuracy and better support clinical management.