Repeat CT of patients with head injury should be obtained if

there is sudden clinical deterioration, regardless of initial

imaging findings. Delayed development or enlargement of

both extra- and intraaxial hemorrhages typically occurs within

36 hours following the initial traumatic event.

Approach to Skull Base and Facial Trauma

Fractures involving the base of the skull (BOS) range from a

solitary linear fracture to complex injuries involving the

Brain: Pathology-Based Diagnoses: Malformations,

Trauma, and Stroke

32

Introduction to CNS Imaging, Trauma

craniofacial bones. BOS fractures are often associated with

intracranial injuries, such as cerebral contusion, intra- and

extraaxial hemorrhages, and vascular or cranial nerve injuries.

The objective of imaging patients with BOS &/or facial trauma

is to depict the location and extent of the fractures and

identify associated injuries to vital structures. Accurate

imaging interpretation also aids in surgical planning and in the

prevention of complications, such as cerebrospinal fluid leak.

Skull Base Trauma

Anterior skull base (ASB) fractures: ASB trauma is frequently

associated with sinonasal cavity &/or orbital injuries. The

majority of these patients have facial fractures. Imaging

should determine whether the fractures cross the cribriform

plate, traverse the frontal sinuses, and involve the orbital apex

or optic canals.

Central skull base (CSB) fractures: Imaging patients with CSB

trauma may involve the sphenoid bone, clivus, cavernous

sinuses, and carotid canal. Injury to the internal carotid artery

and CN 3, 4, 6, &/or the trigeminal nerve divisions can be

present.

Temporal bone (T-bone) fractures: T-bone fractures can be

oriented parallel (longitudinal) or perpendicular (transverse)

to the petrous ridge. Longitudinal fractures are more common

and traverse the mastoid and middle ear cavity, often

disrupting the ossicles and extending into the squamous

portion of the T-bone. Transverse fractures often cross the

inner ear and extend into the occipital bone.

Imaging evaluation should include the determination of

ossicular chain integrity, inner ear &/or facial nerve canal

involvement, and whether the T-bone tegmen (roof) is

transgressed.

Posterior skull base (PSB) fractures: Fractures of the

occipital bones may be isolated or associated with transverse

petrous T-bone fractures. PSB fractures may extend into the

transverse or sigmoid sinuses, jugular foramen, or hypoglossal

canal. Craniocervical junction injuries are also common in

patients with trauma to the PSB.