CT-based abscess diameter as a predictor of true abscess in pediatric deep neck infections: a dual-threshold approach

Differentiating true abscess from phlegmon in pediatric deep neck infections is clinically challenging, particularly in patients with radiologically suspected abscess. Although computed tomography (CT) is widely used, its diagnostic accuracy is limited, and unnecessary surgical interventions remain a concern. This study aimed to evaluate the predictive value of laboratory parameters and to assess the diagnostic performance of CT-based abscess characteristics.

In this retrospective cohort study, 208 pediatric patients with radiologically suspected deep neck infection were included. Patients were classified as true abscess or phlegmon based on operative findings or clinical follow-up. Laboratory parameters and CT-based abscess diameter were analyzed. Univariable and multivariable logistic regression analyses were performed to identify independent predictors. Diagnostic performance was assessed using receiver operating characteristic (ROC) analysis.

Of 208 patients, 95 (45.7%) had true abscess. Although several laboratory parameters were significant in univariable analysis, none remained independently associated with abscess formation in multivariable analysis. CT-based abscess diameter was the only independent predictor (OR: 1.124, 95% CI: 1.089-1.161, p < 0.001). ROC analysis demonstrated excellent discrimination (AUC: 0.880). A cut-off of 17 mm yielded high sensitivity (88.4%), whereas a higher threshold of 19.5 mm improved specificity (86.7%) in radiologically suspected cases.

Laboratory markers have limited value in distinguishing true abscess from phlegmon. CT-based abscess diameter is the most reliable predictor, and a dual-threshold approach may improve clinical decision-making and reduce unnecessary surgical interventions.