Metabolic changes assessed by 1H MR spectroscopy in the corpus callosum of post-COVID patients

OBJECTIVE

Many patients with long COVID experience neurological and psychological symptoms. Signal abnormalities on MR images in the corpus callosum have been reported. Knowledge about the metabolic profile in the splenium of the corpus callosum (CCS) may contribute to a better understanding of the pathophysiology of long COVID.

MATERIALS AND METHODS

Eighty-one subjects underwent proton MR spectroscopy examination. The metabolic concentrations of total N-acetylaspartate (NAA), choline-containing compounds (Cho), total creatine (Cr), myo-inositol (mI), and NAA/Cho in the CCS were statistically compared in the group of patients containing 58 subjects with positive IgG COVID-19 antibodies or positive SARS-CoV-2 qPCR test at least two months before the MR and the group of healthy controls containing 23 subjects with negative IgG antibodies.

RESULTS

An age-dependent effect of SARS-CoV-2 on Cho concentrations in the CCS has been observed. Considering the subjective threshold of age = 40 years, older patients showed significantly increased Cho concentrations in the CCS than older healthy controls (p = 0.02). NAA, Cr, and mI were unchanged. All metabolite concentrations in the CCS of younger post-COVID-19 patients remained unaffected by SARS-CoV-2. Cho did not show any difference between symptomatic and asymptomatic patients (p = 0.91).

DISCUSSION

Our results suggest that SARS-CoV-2 disproportionately increases Cho concentration in the CCS among older post-COVID-19 patients compared to younger ones. The observed changes in Cho may be related to the microstructural reorganization in the CCS also reported in diffusion measurements rather than increased membrane turnover. These changes do not seem to be related to neuropsychological problems of the post-COVID-19 patients. Further metabolic studies are recommended to confirm these observations.

COVID-19-associated cerebral microbleeds in the general population

Cerebral microbleeds are frequent incidental findings on brain MRI and have previously been shown to occur in Coronavirus Disease 2019 (COVID-19) cohorts of critically ill patients. We aimed to determine the risk of having microbleeds on medically indicated brain MRI and compare non-hospitalized COVID-19-infected patients with non-infected controls. In this retrospective case-control study, we included patients over 18 years of age, having an MRI with a susceptibility-weighted sequence, between 1 January 2019 and 1 July 2021. Cases were identified based on a positive reverse transcriptase polymerase chain reaction test for SARS-CoV-2 and matched with three non-exposed controls, based on age, sex, body mass index and comorbidities. The number of cerebral microbleeds on each scan was determined using artificial intelligence. We included 73 cases and 219 matched non-exposed controls. COVID-19 was associated with significantly greater odds of having cerebral microbleeds on MRI [odds ratio 2.66 (1.23-5.76, 95% confidence interval)], increasingly so when patients with dementia and hospitalized patients were excluded. Our findings indicate that cerebral microbleeds may be associated with COVID-19 infections. This finding may add to the pathophysiological considerations of cerebral microbleeds and help explain cases of incidental cerebral microbleeds in patients with previous COVID-19.

High Frequency of Autoantibodies in COVID-19 Patients with Central Nervous System Complications: a Multicenter Observational Study

We present a panel of central nervous system (CNS) complications associated with coronavirus disease 2019 (COVID-19) and their clinical characteristics. We aim to investigate associations between neurological autoantibodies and COVID-19 patients with predominant CNS complications. In this retrospective multi-center study, we analyze neurologic complications associated with COVID-19 patients from Dec. 2022 to Feb. 2023 at four tertiary hospitals in China. CSF and/or serum in the enrolled patients were tested for autoantibodies using tissue-based assays (TBAs) and cell-based assays (CBAs). A total of 34 consecutive patients (median age was 40.5 years [range 15-83], 50% were female) were enrolled. CNS syndromes included encephalitis (n=15), encephalopathies (n=6), meningoencephalitis (n=3), ADEM (n=2), depression (n = 2), Alzheimer's disease (n=2), Parkinson disease (n=1), and central nervous system vasculitis (n=1). Twenty-eight specimens (of 44 tested; 11/27 [40.7%] CSF, 13/17 [76.5%] serums) were confirmed by TBAs to be autoantibodies positive. However, only a few autoantibodies (1 with MOG and 1 with NMDAR) were detected by CBAs assays. Twenty-four patients received immunotherapy. After a mean time of 7.26 months of follow-up, 75.8% (25/33) of patients had good outcome (mRS score ≤2). Although no significant difference was observed between the two groups, the proportion of positive CSF autoantibodies in the poor outcomes group was higher than that in the good outcomes group (57.1% vs 31.5%, P = 0.369). Autoantibodies were frequently observed in COVID-19-associated CNS complications. The identification of these autoantibody-positive COVID-19 cases is important as they respond favorably to immunotherapy.

COVID-19 Neuroimaging Update: Pathophysiology, Acute Findings, and Post-Acute Developments

COVID-19 has prominent effects on the nervous system with important manifestations on neuroimaging. In this review, we discuss the neuroimaging appearance of acute COVID-19 that became evident during the early stages of the pandemic. We highlight the underlying pathophysiology mediating nervous system effects and neuroimaging appearances including systemic inflammatory response such as cytokine storm, coagulopathy, and para/post-infections immune mediated phenomena. We also discuss the nervous system manifestations of COVID-19 and the role of imaging as the pandemic has evolved over time, including related to the development of vaccines and the emergence of post-acute sequalae such as long COVID.

On the merits and potential of advanced neuroimaging techniques in COVID-19: A scoping review

Many Coronavirus Disease 2019 (COVID-19) patients are suffering from long-term neuropsychological sequelae. These patients may benefit from a better understanding of the underlying neuropathophysiological mechanisms and identification of potential biomarkers and treatment targets. Structural clinical neuroimaging techniques have limited ability to visualize subtle cerebral abnormalities and to investigate brain function. This scoping review assesses the merits and potential of advanced neuroimaging techniques in COVID-19 using literature including advanced neuroimaging or postmortem analyses in adult COVID-19 patients published from the start of the pandemic until December 2023. Findings were summarized according to distinct categories of reported cerebral abnormalities revealed by different imaging techniques. Although no unified COVID-19-specific pattern could be subtracted, a broad range of cerebral abnormalities were revealed by advanced neuroimaging (likely attributable to hypoxic, vascular, and inflammatory pathology), even in absence of structural clinical imaging findings. These abnormalities are validated by postmortem examinations. This scoping review emphasizes the added value of advanced neuroimaging compared to structural clinical imaging and highlights implications for brain functioning and long-term consequences in COVID-19.

Neurologic Effects of SARS-CoV-2 Transmitted among Dogs

SARS-CoV-2 induces illness and death in humans by causing systemic infections. Evidence suggests that SARS-CoV-2 can induce brain pathology in humans and other hosts. In this study, we used a canine transmission model to examine histopathologic changes in the brains of dogs infected with SARS-CoV-2. We observed substantial brain pathology in SARS-CoV-2-infected dogs, particularly involving blood-brain barrier damage resembling small vessel disease, including changes in tight junction proteins, reduced laminin levels, and decreased pericyte coverage. Furthermore, we detected phosphorylated tau, a marker of neurodegenerative disease, indicating a potential link between SARS-CoV-2-associated small vessel disease and neurodegeneration. Our findings of degenerative changes in the dog brain during SARS-CoV-2 infection emphasize the potential for transmission to other hosts and induction of similar signs and symptoms. The dynamic brain changes in dogs highlight that even asymptomatic individuals infected with SARS-CoV-2 may develop neuropathologic changes in the brain.

Neuroimmunological Effect of Vitamin D on Neuropsychiatric Long COVID Syndrome: A Review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the coronavirus disease 2019 (COVID-19). COVID-19 is now recognized as a multiorgan disease with a broad spectrum of manifestations. A substantial proportion of individuals who have recovered from COVID-19 are experiencing persistent, prolonged, and often incapacitating sequelae, collectively referred to as long COVID. To date, definitive diagnostic criteria for long COVID diagnosis remain elusive. An emerging public health threat is neuropsychiatric long COVID, encompassing a broad range of manifestations, such as sleep disturbance, anxiety, depression, brain fog, and fatigue. Although the precise mechanisms underlying the neuropsychiatric complications of long COVID are presently not fully elucidated, neural cytolytic effects, neuroinflammation, cerebral microvascular compromise, breakdown of the blood-brain barrier (BBB), thrombosis, hypoxia, neurotransmitter dysregulation, and provoked neurodegeneration are pathophysiologically linked to long-term neuropsychiatric consequences, in addition to systemic hyperinflammation and maladaptation of the renin-angiotensin-aldosterone system. Vitamin D, a fat-soluble secosteroid, is a potent immunomodulatory hormone with potential beneficial effects on anti-inflammatory responses, neuroprotection, monoamine neurotransmission, BBB integrity, vasculometabolic functions, gut microbiota, and telomere stability in different phases of SARS-CoV-2 infection, acting through both genomic and nongenomic pathways. Here, we provide an up-to-date review of the potential mechanisms and pathophysiology of neuropsychiatric long COVID syndrome and the plausible neurological contributions of vitamin D in mitigating the effects of long COVID.

Radiologic-Pathologic Correlation of COVID-19-Associated Acute Disseminated Encephalomyelitis

A 42-year-old woman presented with drooling, slurred speech, inability to walk and talk, and a recent positive COVID-19 test. She had two prior hospital admissions within the past week for similar symptoms with inconclusive evaluation. MRI of the brain demonstrated multifocal white matter hyperintense lesions on fluid-attenuated inversion recovery (FLAIR)/diffusion with variable enhancement. These imaging findings have been described in recent literature and are associated with inflammatory demyelinating disease, such as acute disseminated encephalomyelitis. The patient subsequently underwent a brain biopsy with a final diagnosis of inflammatory demyelinating lesion. To our knowledge, this is the first radiologic-pathologic correlation of COVID-19-associated acute disseminated encephalomyelitis.

Neuroimaging Spectrum in COVID-19 Infection: A Single-Center Experience

Background and Purpose  The ongoing coronavirus disease 2019 (COVID-19) pandemic is a multisystemic disease and involvement of the nervous system is well established. The neurological and neuroimaging features of the disease have been extensively evaluated. Our study aimed to elucidate the neuroradiological findings in COVID-19 infected patients admitted to our institute during the first and second waves of the pandemic in India. Methods  This was a single-center retrospective study of all COVID-19 positive patients who underwent neuroimaging between March 2020 and May 2021. The presenting neurological complaints, the imaging findings in computed tomography (CT) imaging, and/or magnetic resonance imaging (MRI) were recorded. They recorded the findings in the subheadings of ischemic stroke, hemorrhagic stroke, parainfectious demyelination, acute encephalitis syndrome, and changes of global hypoxic changes. Patients with age-related, chronic, and incidental findings were excluded. Results  The study comprised of 180 COVID-19 positive patients who underwent neuroimaging. CT scan was performed for 169 patients, MRI for 28, and a combination of both CT and MRI was performed for 17 patients. Seventy percent of patients were males, and median age was 61.5 years (interquartile range: 48.25-70.75). Out of the 180 patients, 66 patients had nonspecific findings that could not be attributed to COVID-19 infection. In the remaining 114 patients, 77 (42.7%) had ischemic findings, while 22 (12.2%) had hemorrhagic stroke. Hypoxic ischemic changes were noted in five patients. The rest of the patients had a spectrum of changes including, cerebellitis (3), tumefactive demyelination (1), COVID-19-associated encephalitis (1), hemorrhagic acute demyelinating encephalomyelitis (1), transverse myelitis (1), cytotoxic lesions of corpus callosum (1), Guillain-Barre syndrome (1), and COVID-19-associated microhemorrhages (1). Conclusion  Neurological manifestations of COVID-19 infection are not uncommon, and our understanding of this topic is expanding. A complex interplay of neurotropism and direct central nervous system invasion, immune activation and cytokine storm, vasculitis, and parainfectious processes are implicated in the pathophysiology. While the most common imaging finding was ischemic stroke, followed by hemorrhagic stroke, a diverse range of parainfectious findings was also noted in our study.

[Neurological forms of long COVID in adults: Critical approach]

Now recognized by health authorities, long COVID is identified as a frequent condition complicating the evolution of SARS-CoV-2 infection. Its polymorphic and sometimes disconcerting clinical expression raises questions about its mechanism. Patterns of clinical expression suggest extensive involvement of the nervous system through an almost ubiquitous cognitive complaint. This article reviews the neurological symptoms and forms of these patients, and the neuropsychological explorations aimed at objectifying a cognitive deficit. The studies published until now confronted with the clinical mode of expression, did not make it possible to define a deficit neuropsychological profile at the level of the groups, and evoked more a functional impairment than a lesion. However, each series mentions a small number of patients in whom a cognitive deficit is objectified. The uncertainties about the causes of the prolonged forms of COVID, the heterogeneity of the published studies, and the virtual absence of temporal evolution data should make one cautious about the interpretation of these data but should in no way delay or prevent taking into account care of these patients.

Neuroimaging of COVID-19

We review the wide variety of common neuroimaging manifestations related to coronavirus disease 2019 (COVID-19) and COVID therapies, grouping the entities by likely pathophysiology, recognizing that the etiology of many entities remains uncertain. Direct viral invasion likely contributes to olfactory bulb abnormalities. COVID meningoencephalitis may represent direct viral infection and/or autoimmune inflammation. Para-infectious inflammation and inflammatory demyelination at the time of infection are likely primary contributors to acute necrotizing encephalopathy, cytotoxic lesion of the corpus callosum, and diffuse white matter abnormality. Later postinfectious inflammation and demyelination may manifest as acute demyelinating encephalomyelitis, Guillain-Barré syndrome, or transverse myelitis. The hallmark vascular inflammation and coagulopathy of COVID-19 may produce acute ischemic infarction, microinfarction contributing to white matter abnormality, space-occupying hemorrhage or microhemorrhage, venous thrombosis, and posterior reversible encephalopathy syndrome. Adverse effects of therapies including zinc, chloroquine/hydroxychloroquine, antivirals, and vaccines, and current evidence regarding "long COVID" is briefly reviewed. Finally, we present a case of bacterial and fungal superinfection related to immune dysregulation from COVID.

Neurological Manifestations of Non-Severe COVID-19-A Multidirectional Approach

COVID-19 remains a significant clinical issue worldwide, with frequent neurological manifestations. In this study, the authors combine data obtained from the patient's medical history, physical examinations, and additional test results in the pursuit of any clinically relevant connections. Fifty-eight adult patients hospitalized in the Department of Neurology and Infectiology over a five-months period were retrospectively enrolled in this study. On admission, all patients included in this study were classified as mild or moderate COVID-19 cases, according to the World Health Organization (WHO) guidelines. Laboratory tests, Electroencephalography (EEG), and Magnetic Resonance Imaging (MRI) were performed. There was no statistically significant difference in the Neutrophil-Lymphocyte Ratio (NLR), C-reactive protein (CRP), and Interleukin 6 (IL-6) in patients who reported to the hospital within a week from the symptoms' onset and in those who reported later. In total, 49.06% of patients with eligible EEG recordings presented abnormal brain activity, while 27.59% of the study population had COVID-19-associated MRI findings. EEG and MRI abnormality occurrence did not correlate with the incidence of mild neurological symptoms (headache, olfactory, and gustatory disorders) of the SARS-CoV-2 infection. In three patients in this study population, unprovoked generalized epileptic seizures occurred for the first time in their life. Non-severe SARS-CoV-2 infection causes functional and structural abnormalities within the central nervous system. Brain microhemorrhages are frequently present in non-severe COVID-19 patients. There is no significant association between mild neurological symptoms of COVID-19 and additional test abnormalities. The time from SARS-CoV-2 infection's onset to hospital admission does not seem to influence the prognostic value of CRP, IL-6, and NLR in non-severe COVID-19. Mild-to-moderate SARS-CoV-2 infection can be a trigger factor for epilepsy and epileptic seizures.

Is a high chest CT severity score a risk factor for an increased incidence of long-term neuroimaging findings after COVID-19?

OBJECTIVES

We aimed to determine the incidences of neuroimaging findings (NIF) and investigate the relationship between the course of pneumonia severity and neuroimaging findings.

MATERIALS AND METHODS

Our study was a retrospective analysis of 272 (>18 years) COVID-19 patients who were admitted between "March 11, 2021, and September 26, 2022". All patients underwent both chest CT and neuroimaging. The patient's chest CTs were evaluated for pneumonia severity using a severity score system (CT-SS). The incidence of NIF was calculated. NIF were categorized into two groups; neuroimaging positive (NIP) and neuroimaging negative (NIN). Consecutive CT-SS changes in positive and negative NIF patients were analyzed.

RESULTS

The median age of total patients was 71; IQR, 57-80. Of all patients, 56/272 (20.6%) were NIP. There was no significant relationship between NIP and mortality (p = 0.815) and ICU admission (p = 0.187). The incidences of NIF in our patients were as follows: Acute-subacute ischemic stroke: 47/272 (17.3%); Acute spontaneous intracranial hemorrhage: 13/272 (4.8%); Cerebral microhemorrhages: 10/272 (3.7%) and Cerebral venous sinus thrombosis: 3/25 (10.7%). Temporal change of CT-SSs, there was a statistically significant increase in the second and third CT-SSs compared to the first CT-SS in both patients with NIP and NIN.

CONCLUSION

Our results showed that since neurological damage can be seen in the late period and neurological damage may develop regardless of pneumonia severity.

Coronavirus Disease: Subacute to Chronic Neuroimaging Findings

Several neurologic disorders are associated with coronavirus disease 2019 (COVID-19). In this article, clinical syndromes typically occurring in the subacute to chronic phase of illness and their neuroimaging findings are described with discussion of their COVID-19 specific features and prognosis. Proposed pathogenic mechanisms of these neuroimaging findings and challenges in determining etiology are reviewed.

Effects of COVID-19 on Synaptic and Neuronal Degeneration

Neurons are the basic building blocks of the human body's neurological system. Atrophy is defined by the disintegration of the connections between cells that enable them to communicate. Peripheral neuropathy and demyelinating disorders, as well as cerebrovascular illnesses and central nervous system (CNS) inflammatory diseases, have all been linked to brain damage, including Parkinson's disease (PD). It turns out that these diseases have a direct impact on brain atrophy. However, it may take some time after the onset of one of these diseases for this atrophy to be clearly diagnosed. With the emergence of the Coronavirus disease 2019 (COVID-19) pandemic, there were several clinical observations of COVID-19 patients. Among those observations is that the virus can cause any of the diseases that can lead to brain atrophy. Here we shed light on the research that tracked the relationship of these diseases to the COVID-19 virus. The importance of this review is that it is the first to link the relationship between the Coronavirus and diseases that cause brain atrophy. It also indicates the indirect role of the virus in dystrophy.

Brain diffusion alterations in patients with COVID-19 pathology and neurological manifestations

BACKGROUND AND OBJECTIVE

COVID-19 neurological manifestations have been progressively recognized. Among available MRI techniques, diffusion weighted imaging (DWI) shows promise to study microstructure, inflammation, and edema. Previous DWI studies reported alterations in brain diffusivity in COVID-19 patients, as assessed by morphologic evaluation of brain DWI scans only. The aim of this study was to assess and quantify brain diffusion alterations in COVID-19 patients with neurological manifestations.

METHODS

215 COVID-19 patients with neurological manifestations (olfactory and/or other neurological disorders) and 36 normal controls were compared and studied with DWI and T1-weighted MRI scans. MRI scans were processed by a semi-automatic processing procedure specifically developed for the purpose of this study, and the Apparent Diffusion Coefficient (ADC) was quantified in different brain tissues and individual white matter (WM) and gray matter (GM) regions. Differences in ADC values were assessed between COVID-19 patients and normal controls, as well as in the COVID-19 patient population grouped by hospitalization and neurological symptoms.

RESULTS

Among COVID-19 patients (median [IQR] = 52 [42 - 60] years of age, 58 % females), 91 were hospitalized and 26 needed intensive care. 84 patients had hyposmia/ageusia only, while 131 ones showed other neurological disorders. COVID-19 patients showed significantly increased ADC values in the WM and in several GM regions (p < 0.001). ADC values were significantly correlated with MRI time from disease onset (p < 0.05). Hospitalized patients showed significantly higher ADC alteration than non-hospitalized patients in all brain tissues; similarly, COVID-19 patients with neurological disorders showed significantly higher ADC values than those with olfactory loss only. ADC alteration was highest in patients with cognitive or memory disorder and in those with encephalitis or meningitis. ADC values were neither associated with the duration of hospitalization nor with the need for intensive care.

CONCLUSION

Current findings suggest DWI potential as a non-invasive marker of neuroinflammation in COVID-19, and the transient nature of the same. Future longitudinal studies are needed to confirm our findings.

Neuroimaging findings in hospitalized patients with COVID-19

Background

Variable neuroimaging findings have been reported in patients with coronavirus disease 2019 (COVID-19). In addition to respiratory symptoms, many neurologic manifestations of COVID-19 are increasingly reported and variable neuroimaging findings have been observed in patients with COVID-19. Our aim was to describe findings observed in hospitalized patients with COVID-19, presenting with acute neurologic manifestations and undergoing computed tomography (CT) or magnetic resonance imaging (MRI) of the brain.

Methods

We performed a retrospective study involving patients with laboratory-confirmed SARS-COV-2 infection, admitted to our hospital between July 1 and December 30, 2020. Patients who presented with acute neurologic symptoms and required neuroimaging were only included in the study. Neuroimaging examinations were evaluated for the presence of, infarction, hemorrhage and encephalopathy. The frequency of these findings was correlated with clinical variables, including presence of comorbidities, requirement for intensive care unit admission, and duration between admission and onset of neurologic signs and symptoms as documented in the hospital medical records.

Results

A total of 135 patients underwent at least one cross-sectional imaging of the brain, the median age of these patients was 63 years, and 72% were men. Disturbed level of consciousness was the most common neurologic symptom (80.7%). Acute neuroimaging findings were found in 34 patients (25.2%) including; acute ischemic infarcts (16/135; 11.9%), intracranial hemorrhages (9/135, 6.7%), cerebral venous thrombosis (2/135; 1.5%), posterior reversible encephalopathy syndrome (1/135; 0.7%), and hypoxic-ischemic encephalopathy (6/135, 4.4%). There was no statistically significant difference in patient age (p = 0.062), sex (0.257), presence of comorbidities (p = 0.204), intensive care unit admission (p = 0.326) and duration between admission and onset of neurologic signs and symptoms (p = 0.755), in patients with positive versus negative neuroimaging studies.

Conclusions

Our study showed that cerebrovascular complications, ischemic and hemorrhagic were the most frequent imaging finding in hospitalized patients with COVID-19. Knowledge about these potentially serious complications can help optimize management for these patients.

How COVID-19 shaped mental health: from infection to pandemic effects

The Coronavirus Disease 2019 (COVID-19) pandemic has threatened global mental health, both indirectly via disruptive societal changes and directly via neuropsychiatric sequelae after SARS-CoV-2 infection. Despite a small increase in self-reported mental health problems, this has (so far) not translated into objectively measurable increased rates of mental disorders, self-harm or suicide rates at the population level. This could suggest effective resilience and adaptation, but there is substantial heterogeneity among subgroups, and time-lag effects may also exist. With regard to COVID-19 itself, both acute and post-acute neuropsychiatric sequelae have become apparent, with high prevalence of fatigue, cognitive impairments and anxiety and depressive symptoms, even months after infection. To understand how COVID-19 continues to shape mental health in the longer term, fine-grained, well-controlled longitudinal data at the (neuro)biological, individual and societal levels remain essential. For future pandemics, policymakers and clinicians should prioritize mental health from the outset to identify and protect those at risk and promote long-term resilience.

Role of Demyelination in the Persistence of Neurological and Mental Impairments after COVID-19

Long-term neurological and mental complications of COVID-19, the so-called post-COVID syndrome or long COVID, affect the quality of life. The most persistent manifestations of long COVID include fatigue, anosmia/hyposmia, insomnia, depression/anxiety, and memory/attention deficits. The physiological basis of neurological and psychiatric disorders is still poorly understood. This review summarizes the current knowledge of neurological sequelae in post-COVID patients and discusses brain demyelination as a possible mechanism of these complications with a focus on neuroimaging findings. Numerous reviews, experimental and theoretical studies consider brain demyelination as one of the mechanisms of the central neural system impairment. Several factors might cause demyelination, such as inflammation, direct effect of the virus on oligodendrocytes, and cerebrovascular disorders, inducing myelin damage. There is a contradiction between the solid fundamental basis underlying demyelination as the mechanism of the neurological injuries and relatively little published clinical evidence related to demyelination in COVID-19 patients. The reason for this probably lies in the fact that most clinical studies used conventional MRI techniques, which can detect only large, clearly visible demyelinating lesions. A very limited number of studies use specific methods for myelin quantification detected changes in the white matter tracts 3 and 10 months after the acute phase of COVID-19. Future research applying quantitative MRI assessment of myelin in combination with neurological and psychological studies will help in understanding the mechanisms of post-COVID complications associated with demyelination.

Ischemic and Hemorrhagic Cerebrovascular Events Related to COVID-19 Coagulopathy and Hypoxemia

Since the very beginning of the COVID-19 pandemic, numerous researchers have made an effort to determine the molecular composition of the SARS-CoV-2 virus, and the exact pathomechanism through which the virus exerts such a devastating effect on the host/infected organism. Recent scientific evidence highlights the affinity of the virus towards ACE2 receptors, which are widespread in multiple human systems, including the central nervous system (CNS) and cerebral vessels. Such an affinity may explain endothelial dysfunction and damage that is observed in COVID-positive patients in histopathological studies, with subsequent dysregulation of the cerebral circulation leading to transient or acute cerebrovascular accidents. In this paper, we aimed to evaluate the effects of COVID-related hypoxemia and direct viral invasion on the cerebral circulation, with special respect to the postulated pathomechanism, vulnerable groups of patients, clinical course and outcomes, as well as diagnostic imaging findings.

A Case Report: Splenium of the Corpus Callosum Infarct Associated With COVID-19

INTRODUCTION

Coronavirus disease 2019 (COVID-19) has been recently associated with infarction of the central splenium of the corpus callosum. These are described as cytotoxic lesions, and imaging rarely reveals enhancement. They have not been described in the body or head of the corpus callosum. Few diseases affect the corpus callosum, but the most common include multiple sclerosis, aquaporin-4 disease, and Susac syndrome. There is also emerging literature on Mild Encephalopathy with Reversible Splenial lesions associated with central and not basal lesions. The reason for the location of these lesions in acute COVID-19 infection is unknown.

CASE REPORT

A 22-year-old female presented to the ED for altered mental status after being found down. A brief history review indicated that the patient had been altered for 2-3 days before being found naked and covered in her own feces and urine by her family after they had not heard from her. As she lived alone, a clear history of the events preceding her admission remains unclear. On initial assessment, the patient was found to be somnolent and nonverbal, though she could follow simple commands. On admission, testing for SARS CoV-2 RNA PCR was positive. Patient was admitted to the hospital for further work up to determine the cause of the altered mental status.

CONCLUSION

We present a new case of a young woman who developed a central splenium lesion during acute COVID-19 infection and explain the predilection for the callosum in these patients, as well as literature to show that COVID-19 was most likely the cause.

Magnetic Resonance Imaging for Spine Emergencies

This article is devoted to the MR imaging evaluation of spine emergencies, defined as spinal pathologic conditions that pose an immediate risk of significant morbidity or mortality to the patient if not diagnosed and treated in a timely manner. MR imaging plays a central role in the timely diagnosis of spine emergencies. A summary of MR imaging indications and MR imaging protocols tailored for a variety of spinal emergencies will be presented followed by a review of key imaging findings for the most-encountered emergent spine pathologic conditions. Pathologic conditions will be broadly grouped into traumatic and atraumatic pathologic conditions. For traumatic injuries, a practical and algorithmic diagnostic approach based on the AO Spine injury classification system will be presented focused on subaxial spine trauma. Atraumatic spinal emergencies will be dichotomized into compressive and noncompressive subtypes. The location of external compressive disease with respect to the thecal sac is fundamental to establishing a differential diagnosis for compressive emergencies, whereas specific patterns of spinal cord involvement on MR imaging will guide the discussion of inflammatory and noninflammatory causes of noncompressive myelopathy.

DTI of the Olfactory Bulb in COVID-19-Related Anosmia: A Pilot Study

This study aimed to assess the utility of DTI in the detection of olfactory bulb dysfunction in COVID-19-related anosmia. It was performed in 62 patients with COVID-19-related anosmia and 23 controls. The mean diffusivity and fractional anisotropy were calculated by 2 readers. The difference between the fractional anisotropy and mean diffusivity values of anosmic and control olfactory bulbs was statistically significant (P = .001). The threshold of fractional anisotropy and mean diffusivity to differentiate a diseased from normal olfactory bulb were 0.22 and 1.5, with sensitivities of 84.4% and 96.8%, respectively, and a specificity of 100%.

Molecular imaging as a tool for evaluation of COVID-19 sequelae – A review of literature

Coronavirus disease 2019 (COVID-19) is caused by the novel viral pathogen, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 primarily involves the lungs. Nucleic acid testing based on reverse-transcription polymerase chain reaction of respiratory samples is the current gold standard for the diagnosis of SARS-CoV-2 infection. Imaging modalities have an established role in triaging, diagnosis, evaluation of disease severity, monitoring disease progression, extra-pulmonary involvement, and complications. As our understanding of the disease improves, there has been substantial evidence to highlight its potential for multi-systemic involvement and development of long-term sequelae. Molecular imaging techniques are highly sensitive, allowing non-invasive visualization of physiological or pathological processes at a cellular or molecular level with potential for detection of functional changes earlier than conventional radiological imaging. The purpose of this review article is to highlight the evolving role of molecular imaging in evaluation of COVID-19 sequelae. Though not ideal for diagnosis, the various modalities of molecular imaging play an important role in assessing pulmonary and extra-pulmonary sequelae of COVID-19. Perfusion imaging using single photon emission computed tomography fused with computed tomography (CT) can be utilized as a first-line imaging modality for COVID-19 related pulmonary embolism. ¹⁸F-fluorodeoxyglucose positron emission tomography (PET)/CT is a sensitive tool to detect multi-systemic inflammation, including myocardial and vascular inflammation. PET in conjunction with magnetic resonance imaging helps in better characterization of neurological sequelae of COVID-19. Despite the fact that the majority of published literature is retrospective in nature with limited sample sizes, it is clear that molecular imaging provides additional valuable information (complimentary to anatomical imaging) with semi-quantitative or quantitative parameters to define inflammatory burden and can be used to guide therapeutic strategies and assess response. However, widespread clinical applicability remains a challenge owing to longer image acquisition times and the need for adoption of infection control protocols.

Sports Imaging of COVID-19: A Multi-Organ System Review of Indications and Imaging Findings

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first identified in December 2019 in Wuhan, China. Although coronavirus disease-19 (COVID-19) affects every population group, the sports community and athletes require special consideration of the effects on cardiovascular, musculoskeletal, neurologic, and respiratory systems. A comprehensive understanding of imaging indications, findings, and features of COVID-19 supports appropriate imaging utilization and effective patient management and treatment.

PURPOSE

To review the spectrum of sports imaging in COVID-19 infection, organ system manifestations, vaccine effects, and complications in recreational and competitive athletes.

STUDY DESIGN

Narrative review.

LEVEL OF EVIDENCE

Levels 4 and 5.

METHODS

Based on a PubMed database search, studies describing the imaging findings of COVID-19 infection, organ system manifestations, vaccine effects, and complications in recreational and competitive athletes were included.

RESULTS

On March 11, 2020, World Health Organization officially declared COVID-19 a global pandemic. As of May 9, 2022, more than 515 million confirmed cases of COVID-19 were reported globally. While the multisystem effects of COVID-19 are incompletely understood, the role of imaging in diagnosing, monitoring, and prognosticating active disease, long-term effects, and complications is evolving. In the respiratory system, imaging plays an important role in diagnosing, characterizing, and monitoring pulmonary COVID-19 infections, barotrauma, and COVID-19-associated chronic pulmonary opacities and fibrotic-like lung changes. Ultrasonography, computed tomography, and magnetic resonance imaging aid in the timely diagnosis of ischemic, embolic, and thrombotic peripheral and central cardiovascular events, including deep venous thrombosis, pulmonary embolism, myocarditis, and stroke. COVID-19-associated musculoskeletal and peripheral nervous system manifestations include rhabdomyolysis and myonecrosis, plexus and peripheral neuropathies, Guillain-Barré syndrome, and shoulder injury related to vaccine administration.

CONCLUSIONS

In athletes, COVID-19 infections and associated effects on cardiovascular, musculoskeletal, neurologic, and respiratory systems require special consideration. With the increasing understanding of the multisystem effects of COVID-19, the role of imaging in diagnosing, monitoring, and prognosticating active disease, long-term effects, and complications is evolving. A comprehensive understanding of imaging indications, COVID-19 imaging features, and organ system effects aids in appropriate imaging utilization and effective patient management and treatments.

Post-infectious cerebellar ataxia following COVID-19 in a patient with epilepsy

Background

Various neurological manifestations have been described in relation to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19). However, the development of cerebellar ataxia after recovery from COVID-19 is rare. We present a case of cerebellar ataxia 3 weeks after recovery from COVID-19.

Case Presentation

A 70-year-old male patient from an urban area of India presented with ataxia. He was hypertensive and had been receiving treatment for post-traumatic epilepsy for the previous 3 years. He had previously had laboratory-confirmed COVID-19 infection with mild symptoms that resolved within 2 weeks. However, 3 weeks after symptom improvement, he developed severe pan-cerebellar ataxia. Investigations were suggestive of post-infectious cerebellar ataxia. Other causes of ataxia were excluded. He responded well to pulse methylprednisolone therapy and was discharged with mild tremor and ataxia.

Conclusion

Post-infectious cerebellar ataxia is an unusual presentation after COVID-19. The clinician should be aware of such complications following COVID-19 infection as early diagnosis and proper management leads to better outcomes in many patients.

An Update on Sphingosine-1-Phosphate and Lysophosphatidic Acid Receptor Transcripts in Rodent Olfactory Mucosa

Olfactory neurons connect the external environment and the brain, allowing the translocation of materials from the nasal cavity into the brain. The olfactory system is involved in SARS-CoV-2 infections; early in the pandemic declared in 2020, a loss of the sense of smell was found in many infected patients. Attention has also been focused on the role that the olfactory epithelium appears to play in the entry of the SARS-CoV-2 virus into the brain. Specifically, SARS-CoV-2 enters cells via the angiotensin-converting enzyme 2 protein (ACE2), which is found on supporting cells in the olfactory epithelium. The intranasal administration of sphingosine has been proposed to prevent the binding of SARS-CoV-2 to ACE2. Further, sphingosine-1-phosphate (S1P) receptors appear to facilitate the entry of SARS-CoV-2 into the brain. The goal of these studies was to characterize S1P receptor expression status in rodent olfactory mucosa. The expression of receptors for a related sphingolipid, lysophosphatidic acid (LPA), was also assessed. The results confirm previous reports of S1P1 and S1P3 receptor expression, as well as LPA receptor 1, in mouse olfactory mucosa; moreover, they extend the previous findings to identify additional S1P and LPA receptor transcripts in rat and mouse olfactory mucosa, as well as in cultured olfactory neurons. These findings may enhance the utility of rodent models in identifying agonists and/or antagonists of S1P and LPA receptors that may block the entry of SARS-CoV-2 and other viruses into nasal epithelial cells, and prevent transmission from the nasal cavity into the brain.

Semi-automated Segmentation and Quantification of Perivascular Spaces at 7 Tesla in COVID-19

While COVID-19 is primarily considered a respiratory disease, it has been shown to affect the central nervous system. Mounting evidence shows that COVID-19 is associated with neurological complications as well as effects thought to be related to neuroinflammatory processes. Due to the novelty of COVID-19, there is a need to better understand the possible long-term effects it may have on patients, particularly linkage to neuroinflammatory processes. Perivascular spaces (PVS) are small fluid-filled spaces in the brain that appear on MRI scans near blood vessels and are believed to play a role in modulation of the immune response, leukocyte trafficking, and glymphatic drainage. Some studies have suggested that increased number or presence of PVS could be considered a marker of increased blood-brain barrier permeability or dysfunction and may be involved in or precede cascades leading to neuroinflammatory processes. Due to their size, PVS are better detected on MRI at ultrahigh magnetic field strengths such as 7 Tesla, with improved sensitivity and resolution to quantify both concentration and size. As such, the objective of this prospective study was to leverage a semi-automated detection tool to identify and quantify differences in perivascular spaces between a group of 10 COVID-19 patients and a similar subset of controls to determine whether PVS might be biomarkers of COVID-19-mediated neuroinflammation. Results demonstrate a detectable difference in neuroinflammatory measures in the patient group compared to controls. PVS count and white matter volume were significantly different in the patient group compared to controls, yet there was no significant association between PVS count and symptom measures. Our findings suggest that the PVS count may be a viable marker for neuroinflammation in COVID-19, and other diseases which may be linked to neuroinflammatory processes.

Pathogenesis of Olfactory Disorders in COVID-19

Since the outbreak of the SARS-CoV-2 pandemic, olfactory disorders have been reported as a frequent symptom of COVID-19; however, its pathogenesis is still debated. The aim of this review is to summarize the current understanding of the pathogenesis of smell impairment in the course of COVID-19 and to highlight potential avenues for future research on this issue. Several theories have been proposed to explain the pathogenesis of COVID-19-related anosmia, including nasal obstruction and rhinorrhea, oedema of the olfactory cleft mucosa, olfactory epithelial damage either within the olfactory receptor cells or the supporting non-neural cells (either direct or immune-mediated), damage to the olfactory bulb, and impairment of the central olfactory pathways. Although the pathogenesis of COVID-19-related anosmia is still not fully elucidated, it appears to be mainly due to sensorineural damage, with infection of the olfactory epithelium support cells via the ACE1 receptor and disruption of the OE caused by immense inflammatory reaction, and possibly with direct olfactory sensory neurons infection mediated by the NRP-1 receptor. Involvement of the higher olfactory pathways and a conductive component of olfactory disorders, as well as genetic factors, may also be considered.

Magnetic Resonance Imaging Confirmed Olfactory Bulb Reduction in Long COVID-19: Literature Review and Case Series

An altered sense of smell and taste was recognized as one of the most characteristic symptoms of coronavirus infection disease (COVID-19). Despite most patients experiencing a complete functional resolution, there is a 21.3% prevalence of persistent alteration at 12 months after infection. To date, magnetic resonance imaging (MRI) findings in these patients have been variable and not clearly defined. We aimed to clarify radiological alterations of olfactory pathways in patients with long COVID-19 characterized by olfactory dysfunction. A comprehensive review of the English literature was performed by analyzing relevant papers about this topic. A case series was presented: all patients underwent complete otorhinolaryngology evaluation including the Sniffin’ Sticks battery test. A previous diagnosis of SARS-CoV-2 infection was confirmed by positive swabs. The MRIs were acquired using a 3.0T MR scanner with a standardized protocol for olfactory tract analysis. Images were first analysed by a dedicated neuroradiologist and subsequently reviewed and compared with the previous available MRIs. The review of the literature retrieved 25 studies; most cases of olfactory dysfunction more than 3 months after SARS-CoV-2 infection showed olfactory bulb (OB) reduction. Patients in the personal case series had asymmetry and a reduction in the volume of the OB. This evidence was strengthened by the comparison with a previous MRI, where the OBs were normal. The results preliminarily confirmed OB reduction in cases of long COVID-19 with an altered sense of smell. Further studies are needed to clarify the epidemiology, pathophysiology and prognosis.

Neuroimaging in patients with COVID-19: a neuroradiology expert group consensus

Neurological and neuroradiological manifestations in patients with COVID-19 have been extensively reported. Available imaging data are, however, very heterogeneous. Hence, there is a growing need to standardise clinical indications for neuroimaging, MRI acquisition protocols, and necessity of follow-up examinations. A NeuroCovid working group with experts in the field of neuroimaging in COVID-19 has been constituted under the aegis of the Subspecialty Committee on Diagnostic Neuroradiology of the European Society of Neuroradiology (ESNR). The initial objectives of this NeuroCovid working group are to address the standardisation of the imaging in patients with neurological manifestations of COVID-19 and to give advice based on expert opinion with the aim of improving the quality of patient care and ensure high quality of any future clinical studies. KEY POINTS: • In patients with COVID-19 and neurological manifestations, neuroimaging should be performed in order to detect underlying causal pathology. • The basic MRI recommended protocol includes T2-weighted, FLAIR (preferably 3D), and diffusion-weighted images, as well as haemorrhage-sensitive sequence (preferably SWI), and at least for the initial investigation pre and post-contrast T1 weighted-images. • 3D FLAIR should be acquired after gadolinium administration in order to optimise the detection of leptomeningeal contrast enhancement.

Multisystem Inflammatory-like Syndrome in a Child Following COVID-19 mRNA Vaccination

A 12-year-old male was presented to the hospital with acute encephalopathy, headache, vomiting, diarrhea, and elevated troponin after recent COVID-19 vaccination. Two days prior to admission and before symptom onset, he received the second dose of the Pfizer-BioNTech COVID-19 vaccine. Symptoms developed within 24 h with worsening neurologic symptoms, necessitating admission to the pediatric intensive care unit. Brain magnetic resonance imaging within 16 h of admission revealed a cytotoxic splenial lesion of the corpus callosum (CLOCC). Nineteen days prior to admission, he developed erythema migrans, and completed an amoxicillin treatment course for clinical Lyme disease. However, Lyme antibody titers were negative on admission and nine days later, making active Lyme disease an unlikely explanation for his presentation to hospital. An extensive workup for other etiologies on cerebrospinal fluid and blood samples was negative, including infectious and autoimmune causes and known immune deficiencies. Three weeks after hospital discharge, all of his symptoms had dissipated, and he had a normal neurologic exam. Our report highlights a potential role of mRNA vaccine-induced immunity leading to MIS-C-like symptoms with cardiac involvement and a CLOCC in a recently vaccinated child and the complexity of establishing a causal association with vaccination. The child recovered without receipt of immune modulatory treatment.

Central Nervous System Effects of COVID-19 in People with HIV Infection

The convergence of the HIV and SARS-CoV-2 pandemics is an emerging field of interest. In this review, we outline the central nervous system (CNS) effects of COVID-19 in the general population and how these effects may manifest in people with HIV (PWH). We discuss the hypothetical mechanisms through which SARS-CoV-2 could impact the CNS during both the acute and recovery phases of infection and the potential selective vulnerability of PWH to these effects as a result of epidemiologic, clinical, and biologic factors. Finally, we define key research questions and considerations for the investigation of CNS sequelae of COVID-19 in PWH.

Neuroradiologic Imaging of Neurologic and Neuro-Ophthalmic Complications of Coronavirus-19 Infection

BACKGROUND

To review the literature and provide a summary of COVID-19-related neurologic and neuro-ophthalmic complications.

METHODS

The currently available literature was reviewed on PubMed and Google Scholar using the following keywords for searches: CNS, Neuro-Ophthalmology, COVID-19, SARS-CoV-2, coronavirus, optic neuritis, pseudotumor cerebri, Acute Disseminated Encephalomyelitis, posterior reversible encephalopathy syndrome (PRES), meningitis, encephalitis, acute necrotizing hemorrhagic encephalopathy, and Guillain-Barré and Miller Fisher syndromes.

RESULTS

Neuroradiologic findings of neurologic and neuro-ophthalmologic complications in relationship to COVID-19 infection were reviewed. Afferent visual pathway-related disorders with relevant imaging manifestations included fundus nodules on MRI, papilledema and pseudotumor cerebri syndrome, optic neuritis, Acute Disseminated Encephalomyelitis, vascular injury with thromboembolism and infarct, leukoencephalopathy, gray matter hypoxic injury, hemorrhage, infectious meningitis/encephalitis, acute necrotizing hemorrhagic encephalopathy, and PRES. Efferent visual pathway-related complications with relevant imaging manifestations were also reviewed, including orbital abnormalities, cranial neuropathy, Guillain-Barré and Miller Fisher syndromes, and nystagmus and other eye movement abnormalities related to rhombencephalitis.

CONCLUSION

COVID-19 can cause central and peripheral nervous system disease, including along both the afferent and efferent components of visual axis. Manifestations of disease and long-term sequela continue to be studied and described. Familiarity with the wide variety of neurologic, ophthalmic, and neuroradiologic presentations can promote prompt and appropriate treatment and continue building a framework to understand the underlying mechanism of disease.

Long-term neuroimaging follow-up of COVID-19-related leukoencephalopathy

More than a year after the start of the COVID-19 pandemic, long-term neurological manifestations of COVID-19 are increasingly being reported. The long-term sequelae of COVID-19-related leukoencephalopathy, however, remain unclear. Here, we present long-term neuroimaging follow-up in two cases of COVID-19-related leukoencephalopathy. The two cases demonstrate the utility of brain MRI for evaluating neurologic symptoms in critically ill patients with COVID-19, for diagnosis of underlying neural injury and prognostication of future recovery. The presence of leukoencephalopathy may result in chronic neurologic manifestations and may represent a poor prognosticator of neurologic recovery. The presence of leukoencephalomalacia on follow-up neuroimaging is potentially an indicator of irreversible white matter damage, which may be associated with more severe chronic deficits.

What can the neurological manifestations of COVID-19 tell us: a meta-analysis

Background

Covid-19 became a global pandemic in 2019. Studies have shown that coronavirus can cause neurological symptoms, but clinical studies on its neurological symptoms are limited. In this meta-analysis, we aimed to summarize the various neurological manifestations that occurred in COVID-19 patients and calculate the incidence of various neurological manifestations. At the same time, we further explored the mechanism of nervous system injury and prognosis in COVID-19 patients in combination with their nervous system manifestations. This study provides a reference for early clinical identification of COVID-19 nervous system injury in the future, so as to achieve early treatment and reduce neurological sequelae.

Methods

We systematically searched all published English literature related to the neurological manifestations of COVID-19 from January 1, 2020, to April 30, 2021, in Pubmed, Embase, and Cochrane Library. The keywords used were COVID-19 and terminology related to the nervous system performance. All included studies were selected by two independent reviewers using EndNote and NoteExpress software, any disagreement was resolved by consensus or by a third reviewer, and the selected data were then collected for meta-analysis using a random-effects model.

Results

A total of 168 articles (n = 292,693) were included in the study, and the meta-analysis showed that the most common neurological manifestations of COVID-19 were myalgia(33%; 95%CI 0.30–0.37; I² = 99.17%), smell impairment(33%; 95%CI 0.28–0.38; I² = 99.40%), taste dysfunction(33%; 95%CI 0.27–0.39; I² = 99.09%), altered mental status(32%; 95%CI 0.22–0.43; I² = 99.06%), headache(29%; 95%CI 0.25–0.33; I² = 99.42%), encephalopathy(26%; 95%CI 0.16–0.38; I² = 99.31%), alteration of consciousness(13%; 95%CI 0.08–0.19; I² = 98.10%), stroke(12%; 95%CI 0.08–0.16; I² = 98.95%), dizziness(10%; 95%CI 0.08–0.13; I² = 96.45%), vision impairment(6%; 95%CI 0.03–0.09; I² = 86.82%), intracerebral haemorrhage(5%; 95%CI 0.03–0.09; I² = 95.60%), seizure(4%; 95%CI 0.02 -0.05; I² = 98.15%), encephalitis(2%; 95%CI 0.01–0.03; I² = 90.36%), Guillan-Barré Syndrome (GBS) (1%; 95%CI 0.00–0.03; I² = 89.48%).

Conclusions

Neurological symptoms are common and varied in Covid-19 infections, and a growing number of reports suggest that the prevalence of neurological symptoms may be increasing. In the future, the role of COVID-19 neurological symptoms in the progression of COVID-19 should be further studied, and its pathogenesis and assessment methods should be explored, to detect and treat early neurological complications of COVID-19 and reduce mortality.

Review of COVID-19, part 2: Musculoskeletal and neuroimaging manifestations including vascular involvement of the aorta and extremities

The coronavirus disease 2019 (COVID-19) pandemic caused by the novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) has affected almost every country in the world resulting in severe morbidity, mortality and economic hardship, altering the landscape of healthcare forever. Its devastating and most frequent thoracic and cardiac manifestations have been well reported since the start of the pandemic. Its extra-thoracic manifestations are myriad and understanding them is critical in diagnosis and disease management. The role of radiology is growing in the second wave and second year of the pandemic as the multiorgan manifestations of COVID-19 continue to unfold. Musculoskeletal, neurologic and vascular disease processes account for a significant number of COVID-19 complications and understanding their frequency, clinical sequelae and imaging manifestations is vital in guiding management and improving overall survival. The authors aim to provide a comprehensive overview of the pathophysiology of the virus along with a detailed and systematic imaging review of the extra-thoracic manifestation of COVID-19. In Part I, abdominal manifestations of COVID-19 in adults and multisystem inflammatory syndrome in children will be reviewed. In Part II, manifestations of COVID-19 in the musculoskeletal, central nervous and vascular systems will be reviewed.

Abnormal MRI findings of the orbital or visual pathways in patients with severe COVID-19: Observations from the French multicenter COVID-19 cohort

Objectives

COVID-19 is a multisystemic disease. Ophthalmological abnormalities are relatively rare among COVID-19-infected patients. The aim of our study was to report orbital and visual pathways MRI findings in a nationwide multicenter cohort of patients with severe COVID-19.

Methods

This IRB-approved retrospective multi-center study included participants presenting with severe COVID-19, who underwent brain MRI from March 4th to May 1st 2020. Two neuroradiologists (“blinded”), blinded to all data, individually analyzed morphological MRIs focusing on the orbits and the visual pathways. A second consensus reading session was performed in the case of disagreement between both readers. Clinical and ophthalmological data were compared to MRI findings. Descriptive statistical analysis and interobserver agreement for MRI reading using non-weighted Cohen kappa statistics were performed.

Results

129 participants (43 [33%] women and 86 [67%] men, mean age 63 ± 14 years) were included in the study. 17/129 (13%) patients had abnormal MRI findings of the orbit or visual pathways. 11/17 (65%) patients had a FLAIR-WI hyperintense optic disc. 6/17 (35%) patients had abnormal signal of at least one of the visual pathway structures: 6/6 (100%) of the optic nerve, 1/6 (17%) of the optic chiasm, 2/6 (33%) of the optic tract and 1/6 (17%) of the optic radiations.

Conclusions

Our study showed that a substantial number of patients with severe COVID-19 presented with abnormal MRI findings of the orbit or visual pathways, which might lead to potentially severe visual impairment.

Brain imaging in patients with COVID-19: A systematic review

Background

There is increasing evidence that SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) not only affects the respiratory tract but also influence the central nervous system (CNS), resulting in neurological symptoms such as loss of smell and taste. Growing literature indicates largely distributed brain alterations encompassing subcortical micro- and macro-bleeds, cerebral swelling and haemorrhage in gray and white matter tissue. A systematic review was performed to synthesise the potential evidence of the brain correlates of SARS-CoV-2.

Methods

A literature search was conducted using electronic databases for studies reporting neuroimaging abnormalities in SARS-CoV-2 infected individuals. Identified case series, cohort studies, and case control studies on SARS-CoV-2 effects on the brain were critically appraised for methodological quality. A narrative synthesis of the findings from the included studies is presented.

Results

Twenty-seven studies were included in the review, including 5 case series, 8 cohort studies and 14 case control studies. The findings revealed predominant involvement of the olfactory system with disruptions across four olfactory structures. Abnormalities also extended to the corpus callosum, cingulate cortex, and insula, jointly implicating the olfactory brain network.

Conclusion

Alterations in olfactory areas, along with neighbouring brain regions, including prefrontal and limbic regions were associated to contraction of SARS-CoV-2. Viral infection could either trigger systemic reactions, or use the olfactory's unique anatomical organisation as an environmental entry zone to directly impact on the CNS.

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A spectrum of brain changes particularly at advanced stage relates to SARS-CoV-2

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Across severity phases SARS-CoV-2 affects olfactory structures

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Emerging abnormalities in COVID-19 is associated with the olfactory brain network

Neurologic Involvement in Children and Adolescents Hospitalized in the United States for COVID-19 or Multisystem Inflammatory Syndrome

Importance

Coronavirus disease 2019 (COVID-19) affects the nervous system in adult patients. The spectrum of neurologic involvement in children and adolescents is unclear.

Objective

To understand the range and severity of neurologic involvement among children and adolescents associated with COVID-19.

Setting, Design, and Participants

Case series of patients (age <21 years) hospitalized between March 15, 2020, and December 15, 2020, with positive severe acute respiratory syndrome coronavirus 2 test result (reverse transcriptase-polymerase chain reaction and/or antibody) at 61 US hospitals in the Overcoming COVID-19 public health registry, including 616 (36%) meeting criteria for multisystem inflammatory syndrome in children. Patients with neurologic involvement had acute neurologic signs, symptoms, or diseases on presentation or during hospitalization. Life-threatening involvement was adjudicated by experts based on clinical and/or neuroradiologic features.

Exposures

Severe acute respiratory syndrome coronavirus 2.

Main Outcomes and Measures

Type and severity of neurologic involvement, laboratory and imaging data, and outcomes (death or survival with new neurologic deficits) at hospital discharge.

Results

Of 1695 patients (909 [54%] male; median [interquartile range] age, 9.1 [2.4-15.3] years), 365 (22%) from 52 sites had documented neurologic involvement. Patients with neurologic involvement were more likely to have underlying neurologic disorders (81 of 365 [22%]) compared with those without (113 of 1330 [8%]), but a similar number were previously healthy (195 [53%] vs 723 [54%]) and met criteria for multisystem inflammatory syndrome in children (126 [35%] vs 490 [37%]). Among those with neurologic involvement, 322 (88%) had transient symptoms and survived, and 43 (12%) developed life-threatening conditions clinically adjudicated to be associated with COVID-19, including severe encephalopathy (n = 15; 5 with splenial lesions), stroke (n = 12), central nervous system infection/demyelination (n = 8), Guillain-Barré syndrome/variants (n = 4), and acute fulminant cerebral edema (n = 4). Compared with those without life-threatening conditions (n = 322), those with life-threatening neurologic conditions had higher neutrophil-to-lymphocyte ratios (median, 12.2 vs 4.4) and higher reported frequency of D-dimer greater than 3 μg/mL fibrinogen equivalent units (21 [49%] vs 72 [22%]). Of 43 patients who developed COVID-19-related life-threatening neurologic involvement, 17 survivors (40%) had new neurologic deficits at hospital discharge, and 11 patients (26%) died.

Conclusions and Relevance

In this study, many children and adolescents hospitalized for COVID-19 or multisystem inflammatory syndrome in children had neurologic involvement, mostly transient symptoms. A range of life-threatening and fatal neurologic conditions associated with COVID-19 infrequently occurred. Effects on long-term neurodevelopmental outcomes are unknown.

Current perspectives on neuroimaging techniques used to identify stroke mimics in clinical practice

INTRODUCTION

Urgent clinical assessment and brain imaging are essential for differentiating stroke mimics from stroke and to avoid unnecessary initiation of reperfusion and other therapies in stroke mimic patients.

AREAS COVERED

In this article, the authors will review acute stroke imaging and then the imaging patterns of the most common stroke mimics. The authors have focused our review on brain CT scan, and more specifically CT perfusion, as this is the most commonly available and emerging tool in emergency settings. The authors also provide information on acute brain MRI and MR perfusion.

EXPERT OPINION

Imaging can contribute to the detection and diagnosis of acute stroke mimics. Knowledge of imaging findings in different stroke mimics can help distinguish these from patients with stroke who require timely reperfusion therapy. CT and MRI perfusion and diffusion-weighted imaging (DWI) MRI are useful imaging modalities for the assessment of acute stroke patients as they provide more accurate information than plain CT scan. Some of these modalities should be available in the emergency setting. The authors recommended CT perfusion as a useful tool for stroke management and differentiation with stroke mimics.

Subacute cerebellar ataxia following respiratory symptoms of COVID-19: a case report

Background

Severe acute respiratory syndrome virus 2 (SARS-CoV-2) is spreading globally and causes most frequently fever and respiratory symptoms, i.e. Coronavirus disease 2019 (COVID-19), however, distinct neurological syndromes associated with SARS-CoV-2 infection have been described. Among SARS-CoV-2-infections-associated neurological symptoms fatigue, headache, dizziness, impaired consciousness and anosmia/ageusia are most frequent, but less frequent neurological deficits such as seizures, Guillain-Barré syndrome or ataxia may also occur.

Case presentation

Herein we present a case of a 62-year-old man who developed a subacute cerebellar syndrome with limb-, truncal- and gait ataxia and scanning speech 1 day after clinical resolution of symptomatic SARS-CoV-2 infection of the upper airways. Apart from ataxia, there were no signs indicative of opsoclonus myoclonus ataxia syndrome or Miller Fisher syndrome. Cerebral magnetic resonance imaging showed mild cerebellar atrophy. SARS-CoV-2 infection of the cerebellum was excluded by normal cerebrospinal fluid cell counts and, most importantly, absence of SARS-CoV-2 RNA or intrathecal SARS-CoV-2-specific antibody production. Other causes of ataxia such as other viral infections, other autoimmune and/or paraneoplastic diseases or intoxication were ruled out. The neurological deficits improved rapidly after high-dose methylprednisolone therapy.

Conclusions

The laboratory and clinical findings as well as the marked improvement after high-dose methylprednisolone therapy suggest a post-infectious, immune-mediated cause of ataxia. This report should make clinicians aware to consider SARS-CoV-2 infection as a potential cause of post-infectious neurological deficits with an atypical clinical presentation and to consider high-dose corticosteroid treatment in case that a post-infectious immune-mediated mechanism is assumed.

Acute spontaneous hematoma of the corpus callosum in a COVID-19 patient: a case report

Neurovascular involvement is a frequent occurring reported in COVID-19 patients. However, spontaneous hematomas of the corpus callosum are exceptionally seen. The authors of this article aim to report an unusual case of corpus callosum hematoma in a COVID-19 patient and discuss potential etiologies and mechanisms responsible for intracranial hemorrhage.