Identification of hematomas in mild traumatic brain injury using an index of quantitative brain electrical activity

Abstract

Rapid identification of traumatic intracranial hematomas following closed head injury represents a significant health care need because of the potentially life-threatening risk they present. This study demonstrates the clinical utility of an index of brain electrical activity used to identify intracranial hematomas in traumatic brain injury (TBI) presenting to the emergency department (ED). Brain electrical activity was recorded from a limited montage located on the forehead of 394 closed head injured patients who were referred for CT scans as part of their standard ED assessment. A total of 116 of these patients were found to be CT positive (CT+), of which 46 patients with traumatic intracranial hematomas (CT+) were identified for study. A total of 278 patients were found to be CT negative (CT-) and were used as controls. CT scans were subjected to quantitative measurements of volume of blood and distance of bleed from recording electrodes by blinded independent experts, implementing a validated method for hematoma measurement. Using an algorithm based on brain electrical activity developed on a large independent cohort of TBI patients and controls (TBI-Index), patients were classified as either positive or negative for structural brain injury. Sensitivity to hematomas was found to be 95.7% (95% CI = 85.2, 99.5), specificity was 43.9% (95% CI = 38.0, 49.9). There was no significant relationship between the TBI-Index and distance of the bleed from recording sites (F = 0.044, p = 0.833), or volume of blood measured F = 0.179, p = 0.674). Results of this study are a validation and extension of previously published retrospective findings in an independent population, and provide evidence that a TBI-Index for structural brain injury is a highly sensitive measure for the detection of potentially life-threatening traumatic intracranial hematomas, and could contribute to the rapid, quantitative evaluation and treatment of such patients.

Keywords: classifier function; mild TBI (mTBI); neuroimaging; quantitative EEG (QEEG); traumatic hematomas.

FIG. 1.

Representation of the perimeter of a subdural (left panel, red) and an intracranial hematoma (right panel, pink). The volume was calculated by multiplying the area of each region of interest by the slice thickness.

FIG. 2.

Venn diagram of relative distribution of CT findings (location/etiology) in the hematoma population. Numbers shown are the percentage of the total hematoma population. The small gray circle represents the one epidural hematoma (EDH) in this population. ICH, intracerebral hematoma; SAH, subarachnoid hemorrhage; SDH, subdural hematoma.