Diagnostic Accuracy of Ultrasonography in the Detection of Undescended Testes in Children: A Comparative Study Using MRI as the Gold Standard

Abstract

Background: Cryptorchidism occurs in 1–4% of male infants, and a delay in diagnosis increases risks for infertility and testicular cancer. Ultrasonography (USG) is the imaging modality of choice, but its specificity versus magnetic resonance imaging (MRI)—the diagnostic standard of care—is debated. This study evaluates USG’s diagnostic performance while exploring socioeconomic and geographic influences often overlooked in clinical guidelines. Objective: To evaluate the diagnostic accuracy of ultrasonography in detecting undescended testes in children using MRI as the gold standard, while examining the influence of socioeconomic and geographic factors. Methods: In this study, 87 male children (1 month–5 years) evaluated at Combined Military Hospital Abbottabad for cryptorchidism. Participants underwent scrotal USG followed by confirmatory MRI. Diagnostic accuracy metrics (sensitivity, specificity, PPV, NPV) were calculated using MRI as the reference. Subgroup analyses assessed variations by socioeconomic status and residence (rural/urban). Results: USG exhibited excellent overall performance: sensitivity 96.1%, specificity 80%, and accuracy 94.3%. Geographic inequalities appeared, with rural groups showing greater specificity (100% vs. 66.7%) and accuracy (95.6% vs. 92.9%) than urban groups. Socioeconomic stratification disclosed perfect diagnostic concordance in middle-income participants (100% sensitivity, specificity, accuracy), as opposed to lower specificity in high-income (66.7%) and low-income (75%) groups. Weight negatively correlated with cryptorchidism diagnosis (p=0.049), whereas age, height, and BMI were not significantly correlated. Conclusion: USG is still a useful first-line diagnostic instrument for detecting cryptorchidism, especially in resource-constrained environments, given its sensitivity and affordability. Nonetheless, MRI accuracy for non-palpable conditions justifies its application in the case of persistent clinical suspicion despite normal ultrasound results. Rural-urban gaps in performance likely represent variability in operator training and access to care, necessitating uniform ultrasound training programs. Socioeconomic differences imply systemic disparities in quality of diagnosis, prompting policymakers to intervene against imaging infrastructure disparities. As a means to maximizing outcomes, protocols must set aside MRI for referral cases and take advantage of USG's efficacy as a first-screening tool. These results emphasize the imperative for context-specific diagnostic pathways to guarantee equality of care among diverse populations.