Objective: To investigate the differences of olfactory bulb (OB) volumes between younger and older, male and female, left-side and right-side in healthy middle and old-aged persons by MRI.
Methods: Ninety five healthy middle and old-aged volunteers (male:female = 45:50) were divided into 2 groups, group one included persons aged from 50 to 69, group two included persons elder than 70. The left-side, right-side and both-side volumes of OB, the volumes of brain and the ratio of OB/brain were measured by MRI.
Results: (1) The left-side and both-side volumes of OB (x(-) +/- s), the volumes of brain [(39.89 +/- 8.7) mm(3), (81.70 +/- 16.8) mm(3) and (1281.86 +/- 140.2) cm(3)] in 50 - 69 years old group were respectively larger than those in >/= 70 years old group [(34.45 +/- 10.4) mm(3), (72.10 +/- 19.3) mm(3) and (1165.77 +/- 165.3) cm(3)], and the differences reached statistical significance (t were respectively 2.649, 2.449, 3.516, all P < 0.05). There were no significant differences of right-side OB volumes and the ratio of OB/brain between 50 - 69 years old group and >/= 70 years old group (t were respectively 1.904, 0.616, each P > 0.05). (2) The male's OB volumes of left-side, right-side and both-side, the brain volumes and the ratio of OB/brain were respectively larger than females', and the differences reached statistical significance (t were respectively 4.461, 3.630, 4.399, 3.800, 2.400, all P < 0.05). (3) The right-side OB volumes were larger than left-side's and significant differences were found in female group, 50 - 60 years old group and >/= 70 years old group (t were respectively 2.732, 2.117, 3.516, all P < 0.05). There were no significant differences of OB volumes between left-side and right-side in female (t = 2.649, P = 0.110). The ratio of right-side OB/brain were larger than the ratio of left-side's and the differences reached statistical significance (t = 3.183, P = 0.002).
Conclusions: MRI could be used to measure the volume of OB. The older the people, the smaller the OB volumes. There was no influence of age on the ratio OB/brain. The OB volumes of right-side were larger than those of left-side. The OB volumes of male were larger than those of female.