Computed tomography utilization patterns and diagnostic imaging performance in children undergoing appendectomy for suspected appendicitis: a real-world cohort study

Current guidelines recommend an ultrasound-first approach in children with suspected acute appendicitis, reserving computed tomography (CT) for equivocal cases. This study evaluated diagnostic imaging performance, inflammatory markers, and documented imaging utilization in children undergoing appendectomy, with histopathology as the reference standard. This single-center retrospective cohort included 675 patients younger than 18 years undergoing appendectomy during 2019–2024. Analyses included ultrasonography (US; n = 526), CT ( n = 333), and an exploratory either-positive US–CT rule in the dual-imaging subgroup ( n = 198). Diagnostic performance (sensitivity, specificity, accuracy, PPV, NPV), categorical agreement (Cohen’s kappa, Gwet’s AC1), and diameter agreement (ICC) were assessed. Inflammatory markers were compared across histopathological groups. Histopathology confirmed appendicitis in 571 patients (84.6%). US showed 79.9% sensitivity and 51.1% specificity, whereas CT showed 76.8% sensitivity and 71.7% specificity. In the dual-imaging subgroup, the either-positive rule yielded higher sensitivity (89.2%) and accuracy (84.8%) than either modality alone but lower specificity (67.5%), demonstrating a sensitivity–specificity trade-off. CT results were available for 333 patients (49.3%); however, imaging timing, sequence, and indications were not consistently retrievable. Both US and CT underestimated appendiceal diameter relative to histopathology. CRP, white blood cell count, neutrophil count, and neutrophil-to-lymphocyte ratio were associated with diagnosis and severity (all P < 0.001). In this appendectomy cohort, US supports first-line imaging, with selective CT for unresolved cases. The combined result was exploratory and does not establish overall superiority. Exclusion of non-operated patients introduces verification bias, while missing patient-level imaging indications prevent assessment of CT overuse or appropriateness. Not applicable.