Utilization of computed tomography in pediatric temporal fractures: A dose reduction approach

METHODS: Retrospective chart review was performed of pediatric patients who underwent CT brain as part of a trauma pan-scan and dedicated temporal bone CT in the setting of head trauma. The original CT images were re-reviewed by two board certified Neuroradiologists in a blinded manner to determine the presence or absence of temporal bone fracture and if present, fracture line involvement of the 5 critical temporal bone anatomic structures. The dose length product (DLP), a measure of approximate total radiation dose delivered during CT scan (mGy-cm), was noted from the data available.

There were 24 temporal bone fractures in a total of 29 patients (4 with bilateral fractures). There were 21 of 24 fractures that were correctly identified on trauma pan-scan CT with dedicated temporal bone CT considered as the diagnostic gold standard. There was a combined sensitivity and specificity of 91 % and 100 % respectively. The sensitivity and specificity in identifying involvement of critical structures were as follows: carotid canal (100 % and 100 %); ossicular chain (75 % and 100 %); tegmen tympani (60 % and 97.9 %); facial nerve canal (25 % and 100 %); otic capsule (N/A and 98.5 %). The median DLP for trauma pan-scan CT and temporal bone CT were 627 mGy-cm and 267 mGy-cm respectively.

Dedicated TBCT is not required to accurately diagnose and characterize temporal bone fractures seen on trauma pan-scan CT. The radiation exposure of concurrent or subsequent dedicated temporal bone imaging is equal to approximately one half of the original trauma pan-scan CT.