Olfactory function evaluated by SPECT

Few articles on neuroimaging techniques in the study of central and peripheral olfactory pathways are present in the literature. By Single Photon Emission Computed Tomography (SPECT), cortical perfusion increment after sensorial stimulation can be evaluated objectively. In the present research, 10 healthy adults underwent SPECT by CER.TO.96 cerebral tomograph, before and after olfactory stimulation with lavender-water. A variable degree of cortical activation was detected in all patients. Gyrus rectus (+24.5%), orbito-frontal cortex (right +26.6%, left +25.6%), and superior temporal (right +9.9%, left +5.5%) cortical areas were always activated. A slight perfusion increase was present in middle temporal (right +3.2%, left +2.1%) and parieto-occipital (right +0.4%, left +2%) regions. Five patients affected by posttraumatic anosmia were also investigated: they showed a perfusion increment markedly inferior to 0.5% in every olfactory area. SPECT is a rather diffused, easily performed technique which yields objective semi-quantitative information on brain perfusion. Hence, it can be regarded as a promising contribution in the fields of smell neurophysiology, clinical olfactometry, and medicolegal queries.