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.