Ventricles and sulci are within normal limits. Incidental note of a right frontal extra-axial CSF density lesion, with no contrast enhancement. It measures 49 x 12mm, is ovoid in morphology and scallops the inner table of the skull. Appearances are consistent with an arachnoid cyst but can be confirmed with MRI outside of the acute setting. No acute intracranial abnormality, including haemorrhage identified. No calvarial or skull base fracture. Bones, paranasal sinuses and orbits unremarkable.