Brain Imaging Changes in Patients Recovered From COVID-19: A Narrative Review

Abstract

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has caused several outbreaks of highly contagious respiratory diseases worldwide. The respiratory symptoms of Coronavirus Disease-19 (COVID-19) have been closely monitored and studied, while the central nervous system (CNS) and peripheral system (PNS) lesions induced by COVID-19 have not received much attention. Currently, patients with COVID-19-associated encephalopathy present with dizziness, headache, anxiety and depression, stroke, epileptic seizures, the Guillain-Barre syndrome (GBS), and demyelinating disease. The exact pathologic basis for these neurological symptoms is currently not known. Rapid mutation of the SARS-CoV-2 genome leads to the appearance of SARS-CoV-2 variants of concern (VOCs), which have higher infectivity and virulence. Therefore, this narrative review will focus on the imaging assessment of COVID-19 and its VOC. There has been an increase in technologies, such as [¹⁸F]fluorodeoxyglucose positron emission tomography (¹⁸F-FDG-PET) and functional magnetic resonance imaging (fMRI), that have been used to observe changes in brain microstructure over time in patients with COVID-19 recovery. Medical imaging and pathological approaches aimed at exploring the associations between COVID-19 and its VOC, with cranial nerve and abnormal nerve discharge will shed light on the rehabilitation process of brain microstructural changes related to SARS-CoV-2, and aid future research in our understanding of the treatment and prognosis of COVID-19 encephalopathy.

Keywords: COVID-19; COVID-19 variants of concern; SARS-CoV-2; brain imaging; magnetic resonance imaging.

FIGURE 1

Graph’s x-axis (dates from December 2019 to December 2021) shows the clinical timeline and dynamics of microstructural changes in Coronavirus Disease-19 (COVID-19) encephalopathy in China. Novel Coronavirus cases of meningitis were first detected in February 2020. By September 2020, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) had developed several variants of concern (VOC), such as B.1.1.7 (Alpha), B.1.351 (Beta), B.1.617/B.1.617.2 (Delta), and P.1 (Gamma). Three months after discharge, 55% of patients had persistent mood changes, fatigue, central nervous system symptoms. Six months after discharge, 25% of patients had cognitive impairment and motor impairment, and only 2% had tension-type headache. At the same time, 66% of patients fully recovered their olfactory and taste functions after 6 months. A year after discharge from the hospital, 2,433 patients who were discharged from Wuhan hospital were followed up and observed. It was reported that severe patients still had fatigue, sweating, anxiety, and joint pain after review.