Variability of radiological grading of blunt cerebrovascular injuries in trauma patients

Blunt cerebrovascular injury (BCVI) occurs in 1%-2% of all blunt trauma patients. Computed tomographic angiography of the neck (CTAn) is commonly used for the diagnosis and grading of BCVIs. Grade of injury dictates treatment, and there remains a lack in understanding the inter-reader reliability of these interpretations.

The aim of this study is to determine the extent of variability in BCVIs among specialized neuroradiologist interpretation of CTAn.

Retrospective review of trauma patients admitted to a level one trauma center with a BCVI from January 2012 to December 2017. Patients were randomly assigned for CTAn re-evaluation by two of three blinded, neuroradiologists.

The variability in BCVI grades was measured using the coefficient of unalikeability (u), and inter-reader reliability was calculated using weighted Cohen's kappa (k).

Two hundred and twenty-eight BCVIs were analyzed with initial grades of 71 (31%) grade one, 74 (32%) grade two, 26 (11%) grade three, 57 (25%) grade four, and 0 grade five. Variability was present in 93 (41%) of all BCVIs. Grade one injuries had the lowest occurrence of total agreement (31%) followed by grade three (61%), grade two (63%), and grade four (92%). Total variability of grade interpretations (u = 100) occurred most frequently with grade three BCVIs (21%). Weighted Cohen's k calculations had a mean of 0.07, indicating poor reader agreement.

This novel study demonstrated the BCVI variability of radiological grade interpretation occurs in more than a third of patients. The reliability of CTAn interpretation of BCVI grades is not uniform, potentially leading to undertreatment and overtreatment.