Neuroimaging in patients with olfactory dysfunction.

This review summarizes neuroimaging findings in patients with olfactory dysfunction. Neuroimaging techniques offer a valuable means for evaluating and distinguishing disorders of olfaction. The new or refined techniques make it possible to pinpoint the anatomic and pathologic changes of many disorders of the sinonasal cavity and brain that cause olfactory deficits. From an anatomic point of view, the causes of olfactory deficits generally can be classified as peripheral or central (intracranial). In the assessment of the peripheral causes, CT and MR imaging reveal anatomic information and structural changes, enable a differential diagnosis, and provide a road map for surgical intervention. In the evaluation of the central causes, MR imaging, positron emission tomography, or single-photon emission computed tomography can provide the links between olfactory dysfunction and structural or functional changes in the brain.