Integration of S100B and GFAP with the PECARN Rule for CT Decision-Making in Pediatric Mild Traumatic Brain Injury: A Preliminary Study.

Abstract

Objective: Many mild traumatic brain injury (TBI) cases may not exhibit overt clinical symptoms; however, they still carry a risk of significant intracranial injury and even mortality. While brain computed tomography (CT) is the gold standard for diagnosis, minimizing radiation exposure in children is critical. This study aimed to evaluate whether integrating the PECARN rule with serum biomarkers S100B and glial fibrillary acidic protein (GFAP) could reduce unnecessary CT scans and improve the prediction of TBI in pediatric patients.

Methods: This prospective study included 88 patients with isolated mild head trauma (presenting within three hours) and 88 healthy controls. Patients were evaluated using the PECARN rule, and serum S100B and GFAP levels were measured via ELISA. Receiver operating characteristic (ROC) curve analysis was used to determine diagnostic performance, reporting sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) with 95% confidence intervals (CIs).

Results: The PECARN algorithm demonstrated 100.0% sensitivity but only 17.9% specificity for predicting abnormal CT findings. The median serum S100B protein level in the patient group was 407.6 ng/L (range: 109.5-12668.3), while the median GFAP level was 18.5 pg/mL (range: 5.2-112.0). Notably, patients with positive CT findings had significantly elevated median S100B (7261.6 ng/L vs. 383.4 ng/L; p<0.001) and GFAP levels (86.0 pg/mL vs. 17.5 pg/mL; p<0.001) compared to those with negative scans. Median S100B and GFAP levels were significantly higher in the patient group [407.6 ng/L (109.5-12668.3) and 18.5 pg/mL (5.2-112.0), respectively] compared to healthy controls [324.7 ng/L (148.5-1733.7) and 13.0 pg/mL (4.4-32.8)] (p=0.006 and p<0.001, respectively). Using optimized cutoff values (2667.14 ng/L for S100B and 61.1 pg/mL for GFAP), both biomarkers achieved high diagnostic accuracy.

Conclusions: Our preliminary findings suggest that the addition of S100B and GFAP to the PECARN algorithm could refine CT decision-making in pediatric mild TBI. Within the PECARN intermediate-to-high risk subgroup, serum S100B levels below 2667.14 ng/L and GFAP levels below 61.1 pg/mL may identify patients in whom CT could potentially be deferred. However, larger cohort studies are required to validate these high cutoff thresholds and mitigate potential overfitting.