Evaluation of anterior olfactory nucleus changes on magnetic resonance imaging: could it be a game changer in smell disorders?

Abstract

Objectives This study aimed to investigate morphological and signal changes of the anterior olfactory nucleus (AON) on high-resolution magnetic resonance imaging (MRI) in patients with olfactory dysfunction (OD) of varying aetiologies.Methods A retrospective analysis of 135 patients with post-coronavirus disease 2019 (COVID-19), post-viral, or post-traumatic OD was conducted. High-resolution MRI was used to assess AON signal intensity and area, as well as olfactory bulb (OB) morphology. Clinical evaluation included Threshold (T), Discrimination (D), and Identification (I) scores and the presence of parosmia.Results AON signal abnormalities were present in 55.5 % of cases. Post-COVID-19 patients had significantly lower TDI scores than other groups. While AON signal and morphological differences were observed across aetiologies, a consistent correlation with TDI scores was not found, except in limited subgroup analyses.Conclusion Abnormalities of the AON are common in OD, but do not reliably indicate severity or aetiology. Further research is needed to determine their clinical relevance.