Magnetic Resonance Spectroscopy Findings of Brain Olfactory Areas in Patients with COVID-19 Related Anosmia: a Preliminary Comparative Study

Abstract

Objectives: COVID-19 infection is commonly associated with olfactory dysfunctions, but the basic pathogenesis of these complications remains controversial. This study seeks to evaluate the value of magnetic resonance spectroscopy (MRS) in determining the molecular neurometabolite alterations within the main brain olfactory areas in patients with COVID-19 related anosmia. Methods: In a cross-sectional study, seven patients with persistent COVID19 related anosmia (mean age: 29.57 years) and seven healthy volunteers (mean age: 27.28 years) underwent MRS in which N-acetyl-aspartate (NAA), choline (Cho), creatine (Cr) and their ratios were measured in the anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC), orbitofrontal cortex (OFC), insular cortex (IC) and ventromedial prefrontal cortex (VMPFC). Data were analyzed using TARQUIN software (version 4.3.10), and the results were compared with an independent sample T test and non-parametric Mann-Whitney test based on the normality of the MRS data distribution. Results: The mean duration of anosmia before imaging was 8.5 months. MRS analysis elucidated a significant association between MRS findings within OFC and COVID-19 related anosmia (Pdisease<0.01), and NAA was among the most important neurometabolites (Pinteraction=0.006). Reduced levels of NAA (P<0.001), Cr (P<0.001) and NAA/Cho ratio (p=0.007) within OFC characterize COVID-19 related anosmia. Conclusions: This study emphasizes that MRS can be illuminating in COVID-19 related anosmia and indicates a possible association between central nervous system impairment and persistent COVID-19 related anosmia.