Normative Parameters of Olfactory Bulbs Based on Magnetic Resonance Imaging and Olfactory Function

Area of Science:

• Neuroimaging
• Olfactory Neuroscience
• Geriatric Medicine

Background:

• Olfactory dysfunction is common in aging populations.
• Quantitative MRI reference values for olfactory structures are lacking.
• Aging impacts sensory perception and associated brain anatomy.

Purpose of the Study:

• To establish reference quantitative values for olfactory bulbs (OBs) and olfactory sulcus (OS) in Korean adults.
• To assess the relationship between OB/OS parameters, age, and olfactory function.
• To provide normative data for MRI-based evaluation of olfactory dysfunction.

Main Methods:

• Retrospective analysis of 217 Korean adults undergoing sellar MRI and olfactory function tests.
• Quantitative evaluation of OB and OS size and morphology using T2-weighted MRI.
• Correlation analysis between MRI parameters, age, and Korean version of the Sniffin' Sticks (KVSS) test II scores.

Main Results:

• Mean OB volume was 45.6 ± 15.3 mm³; mean KVSS II score was 26.8 ± 4.1.
• OB volume, height, and anteroposterior diameter (APD) significantly decreased with age (P < 0.001).
• Reduced OB volume correlated significantly with older age (r = -0.58) and lower olfactory function scores (r = 0.34).

Conclusions:

• Reference MRI values for OB and OS in Korean adults across age groups were established.
• Aging is associated with reduced OB volume, height, and APD, correlating with olfactory decline.
• These quantitative MRI values aid in assessing olfactory dysfunction in adults.