Skull Imaging

Excerpt

The skull is a compact structure that covers and protects the brain and facial organs. It is in a complex anatomical relationship with many craniofacial organs and associated tissues, each of which has a different embryological origin and performs different functions. Therefore, skull lesions may be of the bone origin or may have originated from the adjacent brain, scalp, or craniofacial organs. Although the definitive diagnosis of a skull lesion usually requires histopathologic evaluation, radiologic imaging plays an important role in limiting the diagnosis list and establishing the management plan. Radiologic evaluation should be based upon clinical factors such as the patient's age, gender, trauma history, and medical history, which play a decisive role in the differential diagnosis. The main radiological features guiding the diagnostic approach include the location, number, type of margin, vascular configuration, and radiolucency of the lesion, as well as the attenuation/signal characteristics, presence or absence of remodeling/destruction, and presence or absence of accompanying soft tissue involvement.

While radiography has been the principal imaging modality of skull lesions until recent years, today it is largely replaced by computed tomography (CT) and magnetic resonance imaging (MRI). Thanks to its high spatial resolution, CT is excellent at precisely localizing the skull lesion and defining its extensions. And owing to its high contrast resolution, MRI is the preferred method for the assessment of diploic involvement and lesion texture. Bone scintigraphy has a considerably high sensitivity in detecting bone lesions. However, its low specificity usually necessitates further evaluation using other radiologic or nuclear medicine imaging techniques. In this review, after a brief anatomical description of the skull, the imaging methods used in the diagnosis of skull pathologies and the main strengths and drawbacks of these methods will be discussed.