Brain Metabolic Correlates of Persistent Olfactory Dysfunction after SARS-Cov2 Infection

Maria Isabella Donegani; Alberto Miceli; Matteo Pardini; Matteo Bauckneht; Silvia Chiola; Michele Pennone; Cecilia Marini; Federico Massa; Stefano Raffa; Giulia Ferrarazzo; Dario Arnaldi; Gianmario Sambuceti; Flavio Nobili; Silvia Morbelli

doi:10.3390/biomedicines9030287

Brain Metabolic Correlates of Persistent Olfactory Dysfunction after SARS-Cov2 Infection

Biomedicines. 2021 Mar 12;9(3):287. doi: 10.3390/biomedicines9030287.

Authors

Maria Isabella Donegani^{1

2}, Alberto Miceli^{1

2}, Matteo Pardini^{1

3}, Matteo Bauckneht^{1

2}, Silvia Chiola^{4

5}, Michele Pennone^{1

2}, Cecilia Marini^{1

6}, Federico Massa^{1

3}, Stefano Raffa^{1

4}, Giulia Ferrarazzo^{1

4}, Dario Arnaldi^{1

4}, Gianmario Sambuceti^{1

4}, Flavio Nobili^{1

3}, Silvia Morbelli^{1

2}

Affiliations

¹ IRCCS Ospedale Policlinico San Martino, 16131 Genova, Italy.
² Nuclear Medicine Unit, Department of Health Sciences, University of Genoa, 516126 Genoa, Italy.
³ Department of Neuroscience (DINOGMI), University of Genoa, 516126 Genoa, Italy.
⁴ Humanitas Clinical and Research Center-IRCCS, Via Manzoni 56, Rozzano, 20089 Milan, Italy.
⁵ Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20090 Milan, Italy.
⁶ CNR Institute of Molecular Bioimaging and Physiology (IBFM), 20090 Milano, Italy.

Abstract

We aimed to evaluate the brain hypometabolic signature of persistent isolated olfactory dysfunction after SARS-CoV-2 infection. Twenty-two patients underwent whole-body [¹⁸F]-FDG PET, including a dedicated brain acquisition at our institution between May and December 2020 following their recovery after SARS-Cov2 infection. Fourteen of these patients presented isolated persistent hyposmia (smell diskettes olfaction test was used). A voxel-wise analysis (using Statistical Parametric Mapping software version 8 (SPM8)) was performed to identify brain regions of relative hypometabolism in patients with hyposmia with respect to controls. Structural connectivity of these regions was assessed (BCB toolkit). Relative hypometabolism was demonstrated in bilateral parahippocampal and fusiform gyri and in left insula in patients with respect to controls. Structural connectivity maps highlighted the involvement of bilateral longitudinal fasciculi. This study provides evidence of cortical hypometabolism in patients with isolated persistent hyposmia after SARS-Cov2 infection. [¹⁸F]-FDG PET may play a role in the identification of long-term brain functional sequelae of COVID-19.

Keywords: 18F-FDG PET; COVID-19; SARS-CoV-2; anosmia; olfactory dysfunction.