[Using of ¹⁸F-FDG to evaluate the effect of traumatic olfactory nerve injury on drug delivery through the nasal-brain pathway: a PET-MRI pilot study].

Objective:This study evaluated the effect of traumatic olfactory nerve injury on drug delivery through the nasal-brain pathway via the instillation of ¹⁸F-FDG at the olfactory cleft. Method:Seven healthy volunteers and 5 patients with traumatic dysosmia were enrolled in the study. Subjects were all instilled with ¹⁸F-FDG on each side of the olfactory cleft under endoscopy. After 12 hours, a PET/MR scan was performed to track the metabolism pathway of ¹⁸F-FDG. Then, we compared the diameter of the olfactory bulb and the olfactory bulb intake between normal volunteers and patients with traumatic olfactory disorders. Result:In healthy volunteers, there was a significant difference in ¹⁸F-FDG uptake between the regions of interest in which ¹⁸F-FDG was or was not in contact with the cribriform plate（P=0.012 7）; this difference also existed in patients with traumatic olfactory disorders（P=0.038 1）. Patients with traumatic olfactory disorders did not exhibit significant differences in ¹⁸F-FDG uptake in the region of interest compared with healthy volunteers（P=0.937 2）. Conclusion:The olfactory bulb is obviously atrophied in patients with traumatic olfactory dysfunction, and the uptake of ¹⁸F-FDG in the olfactory bulb region of interest is also reduced. The administration of ¹⁸F-FDG via olfactory fissure area can enter olfactory bulb and parafrontal tissues through the nasal brain pathway,¹⁸F-FDG can enter the central nervous system through the nasal-brain pathway, which is not affected by olfactory nerve transection injury.