Olfactory bulbus volume and olfactory sulcus depth in migraine patients: an MRI evaluation

Objectives To compare the measurements of olfactory bulb volume and olfactory sulcus depth in patients with migraine and a control group. Methods The study included the cranial MRI (1.5 T) images of 200 adults diagnosed with migraine and a control group of 100 subjects without migraine. The control group mainly consisted of the patients with non-migraneous headache. The measurements were obtained from coronal T2-weighted images for standard olfactory bulb (OB) volume and olfactory sulcus (OS) depth. Results The OB volume and OS depth values were lower in the migraine group than in the control group. In the migraine group, left OB volume of the males was significantly lower than those of the females. In both the migraine and control groups separately, the left-side OB volume values and the right side OS depth values were significantly greater than those of the contralateral side. There were positive correlations between right and left OB volume, and right and left OS depth values. No change was seen in OB volume and OS depth values according to gender. In older patients, a decrease was determined in the right and left OB volume, and the left-side OS depth values. There was a negative correlation between osmophobia and OB volume values. In migraine patients with osmophobia, the OB volume values were significantly decreased. Conclusion OB volume values were lower in migraine patients. When osmophobia was present, the OB volume was lower than that of the non-osmophobia migraine patients. Olfactory function monitoring with olfactory tests and olfactory volume monitoring on MRI can be recommended for all migraine patients to diagnose olfactory dysfunction earlier, especially those with osmophobia. Because their OB volume values were detected as lower than those of the migraine patients without osmophobia, it may be thought that blood flow changes and osmophobia may affect the olfactory bulb volume shrinkage in migraine patients.