Diffuse Intracranial Injury Patterns Are Associated with Impaired Cerebrovascular Reactivity in Adult Traumatic Brain Injury: A CENTER-TBI Validation Study

Abstract

Recent single-center retrospective analysis displayed the association between admission computed tomography (CT) markers of diffuse intracranial injury and worse cerebrovascular reactivity. The goal of this study was to further explore these associations using the prospective multi-center Collaborative European Neurotrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) high-resolution intensive care unit (HR ICU) data set. Using the CENTER-TBI HR ICU sub-study cohort, we evaluated those patients with both archived high-frequency digital physiology (100 Hz or higher) and the presence of a digital admission CT scan. Physiological signals were processed for pressure reactivity index (PRx) and both the percent (%) time above defined PRx thresholds and mean hourly dose above threshold. Admission CT injury scores were obtained from the database. Quantitative contusion, edema, intraventricular hemorrhage (IVH), and extra-axial lesion volumes were obtained via semi-automated segmentation. Comparison between admission CT characteristics and PRx metrics was conducted using Mann-U, Jonckheere-Terpstra testing, with a combination of univariate linear and logistic regression techniques. A total of 165 patients were included. Cisternal compression and high admission Rotterdam and Helsinki CT scores, and Marshall CT diffuse injury sub-scores were associated with increased percent (%) time and hourly dose above PRx threshold of 0, +0.25, and +0.35 (p < 0.02 for all). Logistic regression analysis displayed an association between deep peri-contusional edema and mean PRx above a threshold of +0.25. These results suggest that diffuse injury patterns, consistent with acceleration/deceleration forces, are associated with impaired cerebrovascular reactivity. Diffuse admission intracranial injury patterns appear to be consistently associated with impaired cerebrovascular reactivity, as measured through PRx. This is in keeping with the previous single-center retrospective literature on the topic. This study provides multi-center validation for those results, and provides preliminary data to support potential risk stratification for impaired cerebrovascular reactivity based on injury pattern.

Keywords: CT; PRx; autoregulation; computed tomography; image segmentation; injury patterns.

FIG. 1.

Box plots of % time and hourly dose above PRx +0.25 in relation to CT scoring systems. (A) Box plot of mean hourly dose above PRx +0.25 and Marshall CT grade. (B) Box plot of mean hourly dose above PRx +0.25 and Rotterdam CT score. (C) Box plot of mean hourly dose above PRx +0.25 and Helsinki CT score. (D) Box plot of % time above PRx +0.25 and Marshall CT grade. (E) Box plot of % time above PRx +0.25 and Rotterdam CT score. (F) Box plot of % time above PRx +0.25 and Helsinki CT score. P-values for Marshall CT grade reflect Kruskal-Wallis testing, whereas those for Rotterdam and Helsinki CT scores represent Jonckheere-Terpstra testing. CT, computed tomography; P, p-value; PRx, pressure reactivity index (correlation between slow waves in intracranial pressure and mean arterial pressure); %, percent.