CT features can identify patients at risk for unfavorable outcomes after mild TBI

Pathological CT features indicated different prognostic implications at 1 year after mild traumatic brain injury, with some injury patterns indicating worse outcomes, according to a study published in JAMA Neurology.

“The study population was enriched for so-called complicated [mild TBI]: 37% of participants demonstrated intracranial hemorrhage on head CT, while the mean positive head CT rate in US emergency departments is approximately 9%,” Esther L. Yuh, MD, PhD, from the department of radiology and biomedical imaging at University of California, South Francisco, and colleagues wrote. “This enrichment provided sufficient power to determine the prognostic importance of CT abnormalities at a more granular level than simply positive vs. negative categories. These more granular CT findings can immediately aid in the triage to TBI-specific education and systematic follow-up of the nearly 5 million patients with [mild TBI] evaluated annually in U.S. emergency departments. We also demonstrate, to our knowledge for the first time, the existence of common CT patterns or phenotypes of intracranial injury in mTBI and show that these different phenotypes have varying implications for outcomes up to 1-year postinjury.”

Yuh and colleagues identified 1,935 patients in the Transforming Research and Clinical Knowledge in Traumatic Brain Injury (TRACK-TBI) study with mild acute TBI. Patients were aged 17 years and older with Glasgow Coma Scale scores of 13 to 15 who presented to 18 U.S. level 1 trauma center EDs between February 26, 2014, and August 8, 2018. Patients underwent head CT imaging within 24 hours of TBI.

At 2 weeks and 3, 6 and 12 months post injury, Yuh and colleagues evaluated the Glasgow Outcome Scale-Extended scores. Primary outcomes included frequency, co-occurrence and clustering of CT features, incomplete recovery (Glasgow Outcome Scale-Extended scores less than 8 vs. 8); and an unfavorable outcome (Glasgow Outcome Scale-Extended scores less than 5 vs. equal to or greater than 5) at 2 weeks and 3, 6, and 12 months. The researchers also used the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) study to externally validate the results in 2,594 CENTER-TBI patients with mild TBI.

Yuh and colleagues identified three clusters of CT features, including contusion, subarachnoid hemorrhage and/or subdural hematoma; intraventricular and/or petechial hemorrhage; and epidural hematoma.

“Contusion, subarachnoid hemorrhage and/or subdural hematoma features were associated with incomplete recovery (ORs for Glasgow Outcome Scale-Extended scores <8 at 1 year: TRACK-TBI, 1.8 [95% CI, 1.39-2.33]; CENTER-TBI, 2.73 [95% CI, 2.18-3.41]) and greater degrees of unfavorable outcomes (ORs for Glasgow Outcome Scale-Extended scores <5 at 1 year: TRACK-TBI, 3.23 [95% CI, 1.59-6.58]; CENTER-TBI, 1.68 [95% CI, 1.13-2.49]) out to 12 months after injury, but epidural hematoma was not,” Yuh and colleagues wrote.

According to researchers, up to 12 months after injury, intraventricular and/or petechial hemorrhage correlated with greater degrees of unfavorable outcomes. Certain CT features were linked more significantly with outcomes compared with previously validated variables, such as neuropsychiatric history vs. contusion, subarachnoid hemorrhage or subdural hematoma.

“These routinely obtained imaging findings can be used to identify patients at risk for unfavorable outcomes and improve clinical trial design,” Yuh and colleagues wrote. “Patients with [mild TBI] and these CT features should be considered for TBI-specific education and systematic follow-up.”