CT of Normal Developmental and Variant Anatomy of the Pediatric Skull: Distinguishing Trauma from Normality

Abstract

The use of computed tomography (CT) in clinical practice has been increasing rapidly, with the number of CT examinations performed in adults and children rising by 10% per year in England. Because the radiology community strives to reduce the radiation dose associated with pediatric examinations, external factors, including guidelines for pediatric head injury, are raising expectations for use of cranial CT in the pediatric population. Thus, radiologists are increasingly likely to encounter pediatric head CT examinations in daily practice. The variable appearance of cranial sutures at different ages can be confusing for inexperienced readers of radiologic images. The evolution of multidetector CT with thin-section acquisition increases the clarity of some of these sutures, which may be misinterpreted as fractures. Familiarity with the normal anatomy of the pediatric skull, how it changes with age, and normal variants can assist in translating the increased resolution of multidetector CT into more accurate detection of fractures and confident determination of normality, thereby reducing prolonged hospitalization of children with normal developmental structures that have been misinterpreted as fractures. More important, the potential morbidity and mortality related to false-negative interpretation of fractures as normal sutures may be avoided. The authors describe the normal anatomy of all standard pediatric sutures, common variants, and sutural mimics, thereby providing an accurate and safe framework for CT evaluation of skull trauma in pediatric patients.

Pediatric Central Nervous System Imaging of Nonaccidental Trauma: Beyond Subdural Hematomas

“…Distinguishing skull fractures from accessory sutures remains a diagnostic challenge and is most difficult in the developing pediatric skull. Thin-section submillimeter CT in conjunction with 3D surface-shaded volume-rendered images of the skull provides the most optimal evaluation of skull fractures (17). While skull radiographs are obtained as part of skeletal surveys in suspected AHT cases, they are often unreliable for diagnosing small fractures and differentiating accessory sutures from fractures.…”

“…sutures, while accessory sutures join the major sutures without crossing them. Sutures also have a zigzag or interdigitating pattern with sclerotic borders (17)(18)(19).…”

Computed Tomography of the Petrous Bone: Particularities in Children

“…The distinction between normal sutural anatomy and fractures is critical, not only when known traumatic events alert the radiologist to potential injury, but also in cases of nonaccidental head injury, which carries a significant overall mortality rate of 20% and leaves 34% of survivors with severe disability. In these patients, in whom trauma may not be suspected initially, delayed diagnosis further worsens prognosis [2].…”

“…It is continuous posteriorly with the short and nearly horizontal parietomastoid suture, which unites the mastoid process of the temporal bone with the region of the mastoid angle of the parietal bone. The sphenosquamosal suture, which courses inferiorly from the pterion and separates the sphenoid bone from the squama of the temporal bone, is often mistaken for a skull base fracture because of its location [2].…”

“…Not infrequently, the occipitomastoid suture may be mistaken for a skull base fracture, particularly if axial images demonstrate obliquity to the true axial plane so that symmetric visualization of the contralateral suture is hampered. Knowledge of the superior continuation of the occipitomastoid suture, along with the presence of a second symmetric occipitomastoid suture at the base of the skull, are helpful in differentiating this developmental suture from a fracture [2].…”