Abusive head trauma in children: radiographs of the skull do not provide additional information in the diagnosis of skull fracture when multiplanar computed tomography with three-dimensional reconstructions is available.

Background: Some data suggest that CT is more accurate than skull radiographs in diagnosing skull fractures in abusive head trauma.

Objectives: We investigated whether multiplanar CT with three-dimensional (3-D) reconstructions alone is non-inferior to combination CT/skull radiography for the diagnosis of skull fracture in suspected physical abuse.

Materials And Methods: We identified children who had skull radiographs and concurrent multiplanar CT with 3-D reconstructions obtained during suspected physical abuse imaging between 2010 and 2019, and a fracture diagnosis in the formal report. We included all fracture cases and an equal number of randomly selected non-fracture controls in an anonymised dataset. This dataset was independently reviewed for skull fracture by two paediatric radiologists and one less-experienced trainee using either radiography alone, CT alone or CT/skull radiography. The primary outcome was discordance in diagnosis of skull fracture between CT alone and CT/skull radiography, with a result > 0.03 deemed to indicate inferiority of CT alone. The Fleiss kappa was used to assess interobserver agreement.

Results: We included 106 children, 53 with and 53 without skull fracture. A single case was discordant between CT alone and CT/skull radiography, resulting in discordance of 0.009, consistent with non-inferiority of CT alone. The sensitivity and specificity of CT alone and CT/skull radiography were 98% and 96-98%, respectively, whereas radiography alone was more inaccurate (81% sensitivity and 96% specificity). Interobserver agreement for all modalities was very high (kappa 0.86-0.95).

Conclusion: Multiplanar CT with 3-D reconstructions alone is not inferior (and clinically equivalent) to CT/skull radiography for diagnosing skull fracture in suspected physical abuse imaging and was as accurate when reported by a less-experienced trainee. This suggests that skull radiography can be removed from suspected physical abuse imaging guidelines.