MR Imaging-Based Evaluations of Olfactory Bulb Atrophy in Patients with Olfactory Dysfunction

Area of Science:

• Neurology
• Radiology
• Otolaryngology

Background:

• Olfactory bulb volume on MRI correlates with olfactory function.
• Olfactory bulb size is not routinely assessed in clinical evaluations of olfactory dysfunction.
• Visual assessment of olfactory bulb atrophy may offer diagnostic utility.

Purpose of the Study:

• To evaluate the effectiveness of visual olfactory bulb atrophy and neuropathy analysis using MRI.
• To determine the diagnostic value of MRI findings in patients with subjective olfactory loss.

Main Methods:

• 34 patients with subjective olfactory loss underwent nasal endoscopy, olfactory testing (Korean Version of the Sniffin' Sticks), and MRI.
• Olfactory bulb atrophy and neuropathy were assessed on MRI by two radiologists.
• Validated questionnaires (Sino-Nasal Outcome Test, Questionnaire of Olfactory Disorders) were administered.

Main Results:

• Chronic rhinosinusitis was the most common cause of olfactory loss (44.1%).
• Olfactory bulb atrophy was detected more frequently in patients with hyposmia/anosmia compared to normosmic patients (P = .002).
• No significant difference in olfactory bulb neuropathy was found between normosmic and hyposmic/anosmic groups (P = .395).

Conclusions:

• MRI-based visual evaluation of olfactory bulb atrophy can objectively diagnose olfactory dysfunction.
• This imaging technique is valuable for patients experiencing subjective smell loss.