The Role of Morphologic and Functional Imaging in Pretreatment Assessment

Anterior skull base (ASB) tumors can be classified into three groups according to their site of origin: (1) sinonasal neoplasms involving or extending through the anterior cranial base; (2) neoplasms which arise from the bony framework of the base itself; (3) neoplasms originating from adjacent intracranial structures. With few exceptions, most of these tumors have a non-specific appearance on CT and MRI, which limits the role of imaging in terms of characterization. However, treatment planning (transnasal endoscopic surgery in particular) mostly depends upon the tumor map, exploiting the potential of modern cross-sectional imaging. As a result, the radiologist who has to evaluate a neoplasm involving the ASB needs to be fully aware of all the technical solutions available and the specific strengths/weaknesses of the different imaging techniques. Knowledge of radiological anatomy (and its variants) is also essential, which includes the ability to translate the CT appearance of structures into the equivalent MR signal (and vice versa). These main prerequisites have to be combined with up-to-date knowledge of treatment options and surgical procedures in order to be able to create a reporting checklist covering all the aspects that are essential for clinical decision making.