Semi-automated Computed Tomography Volumetry as a Proxy for Intracranial Pressure in Patients with Severe Traumatic Brain Injury: Clinical Feasibility Study

INTRODUCTION: Traumatic brain injury (TBI) is associated with high mortality due to intracranial pressure (ICP). Whether computed tomography (CT) scanning of the brain within the first 24 h is indicative of intracranial hypertension is largely unknown. We assessed the feasibility of semi-automated CT segmentation in comparison with invasive ICP measurements.

RELEVANCE: CT volumetry of the brain might provide ICP data when invasive monitoring is not possible or is undesirable.

METHODS: We identified 33 patients with TBI who received a CT scan at admission and ICP monitoring within 24 h. Semi-automated segmentation of CT images in Matlab yielded cerebrospinal fluid (CSF) and intracranial volume (ICV) data. The ratio CSF/ICV × 100 (expressed as a percentage) was used as a proxy for ICP. The association between invasive ICP and the CSF/ICV ratio was evaluated using a simple linear regression model and a mono-exponential function derived from previous research in animals.

RESULTS: ICP is moderately but significantly associated with the CSF/ICV ratio (r = -0.44, p = 0.01). The mono-exponential function provided a better fit of the relationship between ICP and the CSF/ICV ratio than the linear model.

CONCLUSION: Our feasibility TBI data show that cross-sectional volumetric CT measures are associated with ICP. This non-invasive method can be used in future studies to monitor patients who are not candidates for invasive monitoring or to evaluate therapy effects objectively.