Noninvasive Intracranial Pressure Monitoring in Pediatric Traumatic Brain Injury: Systematic Review of Transcranial Doppler and Optic Nerve Sheath Diameter With Identification of an Evidence Gap in Pupillometry.

BACKGROUND

To systematically review the diagnostic performance and feasibility of transcranial Doppler (TCD) and optic nerve sheath diameter (ONSD) as noninvasive intracranial pressure (ICP) assessment tools in pediatric traumatic brain injury (TBI).

DATA SOURCES: Ovid MEDLINE, EMBASE, Cochrane CENTRAL, and the Cochrane Database of Systematic Reviews were searched from inception through February 2025.

STUDY SELECTION: Prospective and retrospective studies evaluating TCD, ONSD, or both against invasive ICP monitoring in children with TBI.

DATA EXTRACTION: Two reviewers independently screened studies, extracted data, and assessed risk of bias using Quality Assessment of Diagnostic Accuracy Studies, version 2. Outcomes included ICP correlations and diagnostic accuracy measures (area under the curve [AUC], sensitivity, specificity, and diagnostic thresholds).

DATA SYNTHESIS: Six studies met inclusion criteria: three evaluated TCD, two evaluated ONSD, and one evaluated both. TCD findings were variable; pulsatility index (PI) demonstrated the strongest performance, with PI ≥ 1.3 yielding 100% sensitivity and 82% specificity for ICP >20 mmHg in one study, and PI ≥ 1.065 yielding AUC 0.95 and r = 0.68 in another. End-diastolic velocity showed weaker diagnostic performance. ONSD studies were more consistent, with correlations of r = 0.71-0.74, AUC 0.85-0.93, and optimal thresholds of 5.5-6.1 mm. The single combined-modality study reported r = 0.97 and AUC = 0.99 for ONSD plus PI.

CONCLUSIONS

TCD and ONSD are feasible adjunctive tools for noninvasive ICP assessment in pediatric TBI, though diagnostic performance varied substantially across studies. Evidence supporting combined modality models remains preliminary. Larger multicenter studies are needed to standardize acquisition protocols, establish age-appropriate thresholds, and define clinical utility.