Clinical and Radiological Profiles of COVID-19 Patients with Neurological Symptomatology: A Comparative Study

Abstract

Patients with COVID-19 can require radiological examination, with chest CT being more frequent than neuro-imaging. The objective is to identify epidemiological, clinical and radiological factors considered as predictors of neurological involvement in patients with COVID-19 assessed by neuroimaging and to describe the neuroimaging findings. This retrospective study was performed with 232 consecutive confirmed COVID-19 patients, from two radiological units, which were divided into two groups: (1) those who underwent a brain CT/MRI scan (n = 35) versus (2) those who did not undergo the brain CT/MRI scan, but underwent only chest CT (n = 197). There was a statistically significant difference with associations regarding the COVID-19 brain scan group for: admission to ICU, greater severity of lung injuries, the use of a mechanical ventilator and sepsis. Statistical tendency was found for chronic renal failure and systemic arterial hypertension. Forty-percent of COVID-19 patients from the brain scan group were abnormal on brain CT and/or brain MRI (22.9% of the cases with bleeding or microbleeding, 8.6% with restricted diffusion lesions). One ischemic stroke case was associated with irregularity at the M1 segment of the right middle cerebral artery. There was a case of left facial nerve palsy with enhancement of the left geniculate ganglia. An analysis of the olfactory bulbs was possible in 12 brain MRIs and 100% had enhancement and/or microbleeding. In conclusion, a more severe COVID-19 disease from ICU, a more severe form of lung disease, the use of mechanical ventilator and sepsis were associated to the COVID-19 patients with neurological involvement who had undergone brain scans. Microvascular phenomenon was a frequent finding in the brain and olfactory bulbs evaluated by neuroimaging.

A Systematic Review of Imaging Studies in Olfactory Dysfunction Secondary to COVID-19

“…Other findings on MRI included OB enhancement following gadolinium injection in 18/218 (8.25%) ( 5 , 7 , 8 , 28 ) and T2 hyperintensity in the OB/tract in 29/218 (13.30%) ( 4 , 10 , 12 , 17 , 18 , 19 , 20 , 21 , 26 ) ( Figure 3 A), while hypointense focus, consistent with microhemorrhage/methemoglobin deposition ( Figure 3 B), was identified in 17/218 (7.8%) ( 5 , 10 , 28 ). T2 hyperintensity in OB was detected in 11/80 (13.75%) and 18/85 (21.17%) during the early and late imaging, respectively.…”

“…Prolonged inflammation of the olfactory tract can be detected as thickening and clumped appearance of the olfactory nerve filia on MRI ( 5 , 7 , 8 ). Additionally, microbleeding secondary to microvascular injury and microthrombosis by SARS-Cov-2 may appear as foci of hyposignal intensity within the OB ( 5 , 10 , 28 ).…”

“…The exact pathophysiology of COVID-19-induced anosmia is not fully understood ( 1 , 2 , 3 ). Various imaging modalities have been used to assess the olfactory dysfunction in COVID-19, mainly by imaging OB and OC, such as with magnetic resonance imaging (MRI) ( 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ), computed tomography (CT) of paranasal sinuses ( 29 , 30 , 31 , 32 ), or with functional modalities such as positron emission tomography (PET) of brain ( 15 , 22 , 33 ). These studies have reported a variety of findings, which are at times divergent.…”

Reply:

“…

F irst, we would like to the thank authors of the new commentary, 1 which gave us the chance to reply to critics of our first publication 2 entitled "Anosmia in COVID-19 Associated with Injury to the Olfactory Bulbs Evident on MRI" written before the existence of anatomopathologic studies.Our research group had the opportunity to study and publish 3 other recent articles 3-5 about the same subject. In these articles, [3][4][5] we explained why we have interpreted 2 the alterations on brain imaging of patients with coronavirus disease 2019 (COVID-19) detected on thin slices of the coronal fat-suppressed T1WI, pre-and/or postcontrast, as olfactory bulb injuries (bloodbrain barrier and/or methemoglobin) and not artifacts. However, we will present these explanations again and also comment about some aspects of your Letter, 1 as follows:

…”

“…Our research group had the opportunity to study and publish 3 other recent articles 3-5 about the same subject. In these articles, [3][4][5] we explained why we have interpreted 2 the alterations on brain imaging of patients with coronavirus disease 2019 (COVID-19) detected on thin slices of the coronal fat-suppressed T1WI, pre-and/or postcontrast, as olfactory bulb injuries (bloodbrain barrier and/or methemoglobin) and not artifacts. However, we will present these explanations again and also comment about some aspects of your Letter, 1 as follows:…”