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.

MRI evidence of olfactory system alterations in patients with COVID-19 and neurological symptoms.

BACKGROUND AND OBJECTIVE: Despite olfactory disorders being among the most common neurological complications of coronavirus disease 2019 (COVID-19), their pathogenesis has not been fully elucidated yet. Brain MR imaging is a consolidated method for evaluating olfactory system's morphological modification, but a few quantitative studies have been published so far. The aim of the study was to provide MRI evidence of olfactory system alterations in patients with COVID-19 and neurological symptoms, including olfactory dysfunction. METHODS: 196 COVID-19 patients (median age: 53 years, 56% females) and 39 controls (median age 55 years, 49% females) were included in this cross-sectional observational study; 78 of the patients reported olfactory loss as the only neurological symptom. MRI processing was performed by ad-hoc semi-automatic processing procedures. Olfactory bulb (OB) volume was measured on T2-weighted MRI based on manual tracing and normalized to the brain volume. Olfactory tract (OT) median signal intensity was quantified on fluid attenuated inversion recovery (FLAIR) sequences, after preliminary intensity normalization. RESULTS: COVID-19 patients showed significantly lower left, right and total OB volumes than controls (p < 0.05). Age-related OB atrophy was found in the control but not in the patient population. No significant difference was found between patients with olfactory disorders and other neurological symptoms. Several outliers with abnormally high OT FLAIR signal intensity were found in the patient group. CONCLUSIONS: Brain MRI findings demonstrated OB damage in COVID-19 patients with neurological complications. Future longitudinal studies are needed to clarify the transient or permanent nature of OB atrophy in COVID-19 pathology.

Cerebral Microbleeds Assessment and Quantification in COVID-19 Patients With Neurological Manifestations.

It is increasingly acknowledged that Coronavirus Disease 2019 (COVID-19) can have neurological manifestations, and cerebral microbleeds (CMBs) have been observed in this setting. The aim of this study was to characterize CMBs patterns on susceptibility-weighted imaging (SWI) in hospitalized patients with COVID-19 with neurological manifestations. CMBs volume was quantified and correlated with clinical and laboratory parameters. The study included patients who were hospitalized due to COVID-19, exhibited neurological manifestations, and underwent a brain MRI between March and May 2020. Neurological, clinical, and biochemical variables were reported. The MRI was acquired using a 3T scanner, with a standardized protocol including SWI. Patients were divided based on radiological evidence of CMBs or their absence. The CMBs burden was also assessed with a semi-automatic SWI processing procedure specifically developed for the purpose of this study. Odds ratios (OR) for CMBs were calculated using age, sex, clinical, and laboratory data by logistic regression analysis. Of the 1,760 patients with COVID-19 admitted to the ASST Papa Giovanni XXIII Hospital between 1 March and 31 May 2020, 116 exhibited neurological symptoms requiring neuroimaging evaluation. Of these, 63 patients underwent brain MRI and were therefore included in the study. A total of 14 patients had radiological evidence of CMBs (CMBs+ group). CMBs+ patients had a higher prevalence of CSF inflammation (p = 0.020), a higher white blood cell count (p = 0.020), and lower lymphocytes (p = 0.010); the D-dimer (p = 0.026), LDH (p = 0.004), procalcitonin (p = 0.002), and CRP concentration (p < 0.001) were higher than in the CMBs- group. In multivariable logistic regression analysis, CRP (OR = 1.16, p = 0.011) indicated an association with CMBs. Estimated CMBs volume was higher in females than in males and decreased with age (Rho = -0.38; p = 0.18); it was positively associated with CRP (Rho = 0.36; p = 0.22), and negatively associated with lymphocytes (Rho = -0.52; p = 0.07). CMBs are a frequent imaging finding in hospitalized patients with COVID-19 with neurological manifestations and seem to be related to pro-inflammatory status.

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.

SARS-CoV-2 infection and acute ischemic stroke in Lombardy, Italy.

OBJECTIVE: To characterize patients with acute ischemic stroke related to SARS-CoV-2 infection and assess the classification performance of clinical and laboratory parameters in predicting in-hospital outcome of these patients. METHODS: In the setting of the STROKOVID study including patients with acute ischemic stroke consecutively admitted to the ten hub hospitals in Lombardy, Italy, between March 8 and April 30, 2020, we compared clinical features of patients with confirmed infection and non-infected patients by logistic regression models and survival analysis. Then, we trained and tested a random forest (RF) binary classifier for the prediction of in-hospital death among patients with COVID-19. RESULTS: Among 1013 patients, 160 (15.8%) had SARS-CoV-2 infection. Male sex (OR 1.53; 95% CI 1.06-2.27) and atrial fibrillation (OR 1.60; 95% CI 1.05-2.43) were independently associated with COVID-19 status. Patients with COVID-19 had increased stroke severity at admission [median NIHSS score, 9 (25th to75th percentile, 13) vs 6 (25th to75th percentile, 9)] and increased risk of in-hospital death (38.1% deaths vs 7.2%; HR 3.30; 95% CI 2.17-5.02). The RF model based on six clinical and laboratory parameters exhibited high cross-validated classification accuracy (0.86) and precision (0.87), good recall (0.72) and F1-score (0.79) in predicting in-hospital death. CONCLUSIONS: Ischemic strokes in COVID-19 patients have distinctive risk factor profile and etiology, increased clinical severity and higher in-hospital mortality rate compared to non-COVID-19 patients. A simple model based on clinical and routine laboratory parameters may be useful in identifying ischemic stroke patients with SARS-CoV-2 infection who are unlikely to survive the acute phase.

Impact of SARS-CoV-2 on reperfusion therapies for acute ischemic stroke in Lombardy, Italy: the STROKOVID network.

Whether and how SARS-CoV-2 outbreak affected in-hospital acute stroke care system is still matter of debate. In the setting of the STROKOVID network, a collaborative project between the ten centers designed as hubs for the treatment of acute stroke during SARS-CoV-2 outbreak in Lombardy, Italy, we retrospectively compared clinical features and process measures of patients with confirmed infection (COVID-19) and non-infected patients (non-COVID-19) who underwent reperfusion therapies for acute ischemic stroke. Between March 8 and April 30, 2020, 296 consecutive patients [median age, 74 years (interquartile range (IQR), 62-80.75); males, 154 (52.0%); 34 (11.5%) COVID-19] qualified for the analysis. Time from symptoms onset to treatment was longer in the COVID-19 group [230 (IQR 200.5-270) minutes vs. 190 (IQR 150-245) minutes; p = 0.007], especially in the first half of the study period. Patients with COVID-19 who underwent endovascular thrombectomy had more frequently absent collaterals or collaterals filling ≤ 50% of the occluded territory (50.0% vs. 16.6%; OR 5.05; 95% CI 1.82-13.80) and a lower rate of good/complete recanalization of the primary arterial occlusive lesion (55.6% vs. 81.0%; OR 0.29; 95% CI 0.10-0.80). Post-procedural intracranial hemorrhages were more frequent (35.3% vs. 19.5%; OR 2.24; 95% CI 1.04-4.83) and outcome was worse among COVID-19 patients (in-hospital death, 38.2% vs. 8.8%; OR 6.43; 95% CI 2.85-14.50). Our findings showed longer delays in the intra-hospital management of acute ischemic stroke in COVID-19 patients, especially in the early phase of the outbreak, that likely impacted patients outcome and should be the target of future interventions.

Brain microvascular occlusive disorder in COVID-19: a case report.

We describe the case of a COVID-19 patient with severely impaired consciousness after sedation hold, showing magnetic resonance imaging (MRI) findings of (i) acute bilateral supratentorial ischemic lesions involving the fronto-parietal white matter and the corpus callosum and (ii) multiple diffuse susceptibility weighted imaging (SWI) hypointense foci, infra and supratentorial, predominantly bithalamic, suggestive of microhemorrhage or alternatively microthrombi. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) RNA was detected in the cerebrospinal fluid. Our findings suggest the occurrence of vascular damage, predominantly involving microvessels. The underlying mechanisms, which include direct and indirect penetration of the virus to the central nervous system and systemic cardiorespiratory complications, are yet to be elucidated, and a direct correlation with SARS-CoV-2 infection remains uncertain.

Neurologic manifestations in 1760 COVID-19 patients admitted to Papa Giovanni XXIII Hospital, Bergamo, Italy.

OBJECTIVES: Evidences from either small series or spontaneous reporting are accumulating that SARS-CoV-2 involves the Nervous Systems. The aim of this study is to provide an extensive overview on the major neurological complications in a large cohort of COVID-19 patients. METHODS: Retrospective, observational analysis on all COVID-19 patients admitted from February 23rd to April 30th, 2020 to ASST Papa Giovanni XXIII, Bergamo, Italy for whom a neurological consultation/neurophysiological assessment/neuroradiologic investigation was requested. Each identified neurologic complication was then classified into main neurologic categories. RESULTS: Of 1760 COVID-19 patients, 137 presented neurologic manifestations that manifested after COVID-19 symptoms in 98 pts and was the presenting symptom in 39. Neurological manifestations were classified as: (a) cerebrovascular disease [53 pts (38.7%)] including 37 ischemic and 11 haemorrhagic strokes, 4 transient ischemic attacks, 1 cerebral venous thrombosis; (b) peripheral nervous system diseases [31 (22.6%)] including 17 Guillain-Barrè syndromes; (c) altered mental status [49 (35.8%)] including one necrotizing encephalitis and 2 cases with RT-PCR detection of SARS-Cov-2 RNA in CSF; (d) miscellaneous disorders, among whom 2 patients with myelopathy associated with Ab anti-SARS-CoV-2 in CSF. Patients with peripheral nervous system involvement had more frequently severe ARDS compared to patients with cerebrovascular disease (87.1% vs 42%; difference = 45.1% 95% CI 42.0-48.2; χ2= 14.306; p < 0.0002) and with altered mental status (87.1% vs 55.6%; difference = 31.5% 95% CI 27.5-37.5%; χ2= 7.055; p < 0.01). CONCLUSION: This study confirms that involvement of nervous system is common in SARS-CoV-2 infection and offers clinicians useful information for prevention and prompt identification in order to set the adequate therapeutic strategies.