Purpose or Case Report: Differentiation of sutural variants from fractures can be a challenging topic for radiology trainees. Genetic disorders and vascular channels can create the appearance of traumatic injury and potentially suggest the diagnosis of abusive head trauma to the untrained radiologist. Likewise, expert witnesses may use alternate diagnoses to explain findings in which the current evidence basis favors a traumatic mechanism. This exhibit describes the pediatric skull with attention to the differentiation between fractures and mimics as an aid to the trainee.
Methods & Materials: Normal ossification patterns and variations of normal including Wormian/Inca bones, enlarged parietal foramina, bathrocephaly, craniotabes, and convolutional markings are described with emphasis on age-expected findings. Skull fractures and the evidence basis for coexisting intracranial and extracalvarial manifestations of abusive head trauma are included with specific reference to non-evidence-based theories suggested in an actual criminal trial. Strategies to elucidate fractures from sutures and calvarial variations are discussed.
Results: Molding and overriding of sutures is normal in the newborn, as are subdural hematomas following both complicated and normal vaginal deliveries. Prominent vascular channels may mimic fracture lines on 3D reformats. Wormian bones are often normal but may merit a work-up for an underlying genetic disorder if extensive. Subsequent MRA can demonstrate tortuosity of the internal carotid arteries to suggest a diagnosis of Menkes Disease, a known mimic of abusive head trauma. Fractures that contact 2 or more sutures have been shown to have a greater association with non-accidental trauma compared to accidental trauma. Craniotabes and convolutional markings can be normal findings used by fringe belief supporters to suggest a diagnosis of rickets when defending an alleged child abuser. Depressed fractures that exhibit a ping pong ball appearance and linear fractures are not specific for child abuse in the absence of additional supporting findings. Injury from a fall off of a surface may still be due to neglect in which consultation with a child abuse pediatrician may be instructive for the caregiver. The ordering provider should always be contacted whenever child abuse is suspected.
Conclusions: Differentiating fractures from normal calvarial variants can be challenging, but understanding common and uncommon atraumatic findings can aid the radiologist in his or her crucial role in the protection of children.