Nuclear imaging with radiolabeled odor molecules in patients with olfactory disorder.

Smell loss originates from peripheral disorders, like intranasal obstruction and olfactory cell injury, as well as central pathway diseases. Information derived from electrophysiological and psychophysical tests are useful for identifying loss of smell, but not for discriminating between central and peripheral deficits. This is because conventional imaging modalities are unable to deliver information about functional olfactory performance. Although functional imaging is able to show abnormal changes in central olfactory pathways, it seems that it is only possible to observe such abnormalities in olfactory cell dysfunction. We hypothesize that the scanning of peripheral olfactory systems by radiolabeled odor molecules may specifically reveal olfactory dysfunction and may be useful for differentiating peripheral from central olfactory disorders.