Multimodal Point-of-Care Ultrasound Measurements for Noninvasive Intracranial Pressure Assessment

Point-of-care ocular ultrasound (POCoUS) measurement of optic nerve sheath diameter (ONSD) is commonly used to screen for elevated intracranial pressure (eICP), but diagnostic accuracy is limited by operator and technology dependence, and no clear ONSD cutoff is published. We sought to determine whether adjunctive sonographic parameters, including ONSD-to-eyeball diameter ratio (ONSD/EBD), optic disc elevation (ODE), and posterior globe angle (PGA), improve specificity for detecting eICP compared with ONSD alone.

We conducted a pilot retrospective diagnostic accuracy study using a stratified random sampling design from an academic emergency department POCoUS database (2022–2025). Discrete time periods were randomly selected, and consecutive eligible subjects within each time stratum were enrolled. Trained reviewers measured ONSD, EBD, ODE, and PGA on still images, with duplicate measurements for each parameter. Clinical data were abstracted from the electronic health record. Confirmed eICP was defined by invasive ICP monitoring and/or neuroimaging with compatible clinical findings. Diagnostic performance of individual and combined sonographic parameters was assessed using sensitivity, specificity, and receiver operating characteristic (ROC) curve analysis with 95% confidence intervals.

We enrolled 102 subjects (mean age 55.3±19.6 years; 61% female), of whom 12 (12%) had confirmed eICP. Using ONSD specificity alone increased with higher ONSD cutoffs: 48% at >5.0 mm, 74% at >5.5 mm, and 81% at >5.8 mm. ONSD/EBD >0.19 was poorly specific (17%), while >0.22 improved specificity to 54%. Combining ONSD/EBD with ONSD further improved specificity: 95% for ONSD/EBD >0.19 with ONSD >5.8 mm and 98% for ONSD/EBD >0.22 with ONSD >5.8 mm. ODE >0.6 mm alone was 98% specific and reached 100% specificity when combined with ONSD >5.0 mm. PGA ≥118.5° demonstrated limited sensitivity, with only 2/12 eICP patients meeting this threshold, but a specificity of 87%.

Despite the limited number of eICP cases, including adjunctive POCoUS parameters demonstrated higher specificity and consistent directional performance across thresholds, particularly ONSD/EBD and ODE combined with ONSD. A multimodal POCoUS protocol may enhance clinical decision-making for eICP diagnosis in emergency settings.