Teenager playing football who had a severe helmet to helmet collision with another player Pediatric Imaging Neurological September 10, 2019 Axial CT without contrast of the brain with normal (left) and sharpened (right) windows shows a left hemispheric high density cresenteric intracranial extra-axial fluid collection that extends anteriorly along the falx. The diagnosis was subdural hematoma. Related Published September 10, 2019