Primary	Primary outcome measure: Olfactory bulb volume (OBV) (on MRI scan)
Secondary	• Right orbital sulcus volume (MRI scan) • Blood-oxygen-level-dependant (BOLD)-signal in primary olfactory areas; amygdala, piriform, and insula (fMRI scan) • Cerebral blood flow (CBF) in primary olfactory areas; amygdala, piriform, and insula • Psychophysical smell test (TDI) score • Olfactory disorders questionnaire (ODQ) score • Brain-derived neurotrophic factor (BDNF) (pg/ml)