Comparison of Ultrasound and Computed Tomography Optic Nerve Sheath Diameter for Intracranial Pressure Assessment in Pediatric Neurocritical Care.

BACKGROUND

Noninvasive intracranial pressure (ICP) assessment remains challenging in pediatric neurocritical care. Optic nerve sheath diameter (ONSD) measured by ultrasound (ONSD-US) and computed tomography (ONSD-CT) has been proposed as a surrogate marker of ICP, although comparative pediatric data remain limited.

METHODS

Prospective observational study conducted in a tertiary pediatric intensive care unit. Patients requiring invasive ICP monitoring were consecutively included. ONSD-US measurements were obtained simultaneously with invasive ICP measurements and, for patients undergoing CT, within 5 minutes before or after transfer for imaging. Pearson correlation and linear mixed-effects models accounting for repeated measurements were used. Bland-Altman analysis assessed intermodality agreement.

RESULTS

Eighteen patients contributed 139 measurement occasions. ONSD-US measurements were available in 116 occasions and ONSD-CT measurements in 37; 14 paired measurements from 11 patients included both modalities. One additional CT-derived measurement was excluded because of inadequate image quality, while the corresponding ONSD-US measurement was retained. ONSD-US showed a positive correlation with ICP (r = 0.32, P < 0.001), whereas ONSD-CT did not demonstrate a significant correlation (r = 0.23, P = 0.17). In mixed-effects analysis, each 1-mm increase in ONSD-US was associated with an estimated 3.24-mmHg increase in ICP (standard error 1.10; 95% confidence interval 1.09-5.39). Correlation between modalities was weak and not statistically significant (r = 0.31, P = 0.29).

CONCLUSIONS

ONSD-US demonstrated an association with invasively measured ICP after accounting for repeated measurements, whereas ONSD-CT did not show a clear association. Weak intermodality correlation suggests that ONSD-US and ONSD-CT should not be considered interchangeable methods for noninvasive ICP assessment in pediatric neurocritical care.