High-dose glucocorticoids in COVID-19 patients with acute encephalopathy: clinical and imaging findings in a retrospective cohort study.

OBJECTIVES: Acute encephalopathy (AE) has been described as a severe complication of COVID-19. Inflammation has been suggested as a pathogenic mechanism, with high-dose glucocorticoids (GC) showing a beneficial effect. Here, we retrospectively analyzed the clinical and radiological features in a group of COVID-19 AE patients who received GC treatment (GT) and in a non-treated (NT) group. METHOD: Thirty-six patients with COVID-19 AE (mean age 72.6 ± 11 years; 86.11% men) were evaluated for GC treatment. Twelve patients (mean age 73.6 ± 4.5 years; 66.67% men) received GC, whereas 24 patients who showed signs of spontaneous remission were not treated with GC (mean age 70.1 ± 8.6 years; 95.83% men). Differences in clinical characteristics and correlations with imaging features were explored. RESULTS: The GT group showed signs of vulnerability, with a longer hospitalization (p = 0.009) and AE duration (p = 0.012) and a higher hypertensive arteriopathy (HTNA) score (p = 0.022), when compared to NT group. At hospital discharge, the two groups were comparable in terms of clinical outcome (modified Rankin scale; p = 0.666) or mortality (p = 0.607). In our whole group analyses, AE severity was positively correlated with periventricular white matter hyperintensities (p = 0.011), deep enlarged perivascular spaces (p = 0.039) and HTNA score (p = 0.014). CONCLUSION: This study suggests that, despite signs of radiological vulnerability and AE severity, patients treated by high-dose GC showed similar outcome at discharge, with respect to NT patients. Imaging features of cerebral small vessel disease correlated with AE severity, supporting the hypothesis that brain structural vulnerability can impact AE in COVID-19.

Insights into single-timepoint ASL hemodynamics: what visual assessment and spatial coefficient of variation can tell.

PURPOSE: Arterial spin labeling (ASL) represents a noninvasive perfusion biomarker, and, in the study of nonvascular disease, the use of the single-timepoint ASL technique is recommended. However, the obtained cerebral blood flow (CBF) maps may be highly influenced by delayed arterial transit time (ATT). Our aim was to assess the complexity of hemodynamic information of single-timepoint CBF maps using a new visual scale and comparing it with an ATT proxy, the "coefficient of spatial variation" (sCoV). MATERIAL AND METHODS: Individual CBF maps were estimated in a memory clinic population (mild cognitive impairment, dementia and cognitively unimpaired controls) and classified into four levels of delayed perfusion based on a visual rating scale. Calculated measures included global/regional sCoVs and common CBF statistics, as mean, median and standard deviation. One-way ANOVA was performed to compare these measures across the four groups of delayed perfusion. Spearman correlation was used to study the association of global sCoV with clinical data and CBF statistics. RESULTS: One hundred and forty-four participants (72 ± 7 years, 53% women) were included in the study. The proportion of maps with none, mild, moderate, and severe delayed perfusion was 15, 20, 37, and 28%, respectively. SCoV demonstrated a significant increase (p < 0.05) across the four groups, except when comparing none vs mild delayed perfusion groups (pBonf > 0.05). Global sCoV values, as an ATT proxy, ranged from 67 ± 4% (none) to 121 ± 24% (severe delayed) and were significantly associated with age and CBF statistics (p < 0.05). CONCLUSION: The impact of ATT delay in single-time CBF maps requires the use of a visual scale or sCoV in clinical or research settings.

MRI characterization of in vitro clots at 3T and 7T: A technical note.

In acute ischemic stroke, the composition of the occlusive clot can be associated with the underlying pathophysiology and the response to treatment. For these reasons, it is important to characterize the clot composition from clinical scans. We examine the ability of 3T and 7T MRI to distinguish the composition of in vitro clots, using quantitative T1 and T2*, alternatively R2*, mapping. When comparing the two field strengths, we found a tradeoff between sensitivity for clot composition and confidence in the clot depiction associated with spatial resolution. The loss of sensitivity at 7T can be mitigated by combining the T1 and T2* signals.

Obstructive sleep apnea: a major risk factor for COVID-19 encephalopathy?

BACKGROUND: This study evaluates the impact of high risk of obstructive sleep apnea (OSA) on coronavirus disease 2019 (COVID-19) acute encephalopathy (AE). METHODS: Between 3/1/2020 and 11/1/2021, 97 consecutive patients were evaluated at the Geneva University Hospitals with a neurological diagnosis of COVID-19 AE. They were divided in two groups depending on the presence or absence of high risk for OSA based on the modified NOSAS score (mNOSAS, respectively ≥ 8 and < 8). We compared patients' characteristics (clinical, biological, brain MRI, EEG, pulmonary CT). The severity of COVID-19 AE relied on the RASS and CAM scores. RESULTS: Most COVID-19 AE patients presented with a high mNOSAS, suggesting high risk of OSA (> 80%). Patients with a high mNOSAS had a more severe form of COVID-19 AE (84.8% versus 27.8%), longer mean duration of COVID-19 AE (27.9 versus 16.9 days), higher mRS at discharge (≥ 3 in 58.2% versus 16.7%), and increased prevalence of brain vessels enhancement (98.1% versus 20.0%). High risk of OSA was associated with a 14 fold increased risk of developing a severe COVID-19 AE (OR = 14.52). DISCUSSION: These observations suggest an association between high risk of OSA and COVID-19 AE severity. High risk of OSA could be a predisposing factor leading to severe COVID-19 AE and consecutive long-term sequalae.

Experimental evaluation of the performance of large bore aspiration catheters.

BACKGROUND AND PURPOSE: Mechanical thrombectomy using an aspiration catheter (AC) is widely performed in patients with acute ischemic stroke due to large vessel occlusion. AC diameter directly impacts aspiration performance, which has led device companies to develop large bore ACs. The purpose of this study was to evaluate the in vitro performance of several commercially available large bore ACs. MATERIALS AND METHODS: We conceived an experimental set up to assess tracking force, aspiration flow rate, and distal end tensile force pre- and post-thrombectomy of ACs including Sofia 6 (Microvention Inc., California, USA), React 71 (Medtronic Neurovascular, Irvine, California, USA), Jet 7 (Penumbra Inc, Alameda, California, USA), Catalyst 7 (Stryker Neurovascular, Kalamazoo, Michigan, USA) and Embovac 071 (Johnson & Johnson Medical Ltd, UK). RESULTS: React 71 and Sofia 6 had significantly lower trackability force compared to the other ACs tested. Distal AC segment tensile force was highest for React 71 and lowest for Jet 7. Jet 7 had the highest internal diameter and the highest aspiration flow rate. CONCLUSION: The data from this comparative analysis may assist clinicians in selecting the appropriate AC and highlights the need for key performance criteria during the development of next-generation large-bore ACs for optimal AC performance.

Spatial heterogeneity of occlusive thrombus in acute ischemic stroke: A systematic review.

Following the advent of mechanical thrombectomy, occlusive clots in ischemic stroke have been amply characterized using conventional histopathology. Many studies have investigated the compositional variability of thrombi and the consequences of thrombus composition on treatment response. More recent evidence has emerged about the spatial heterogeneity of the clot or the preferential distribution of its components and compact nature. Here we review this emerging body of evidence, discuss its potential clinical implications, and propose the development of adequate characterization techniques.

COVID-19 encephalopathy: Clinical and neurobiological features.

Severe acute respiratory coronavirus 2 (SARS-CoV-2) has been associated with neurological complications, including acute encephalopathy. To better understand the neuropathogenesis of this acute encephalopathy, we describe a series of patients with coronavirus disease 2019 (COVID-19) encephalopathy, highlighting its phenomenology and its neurobiological features. On May 10, 2020, 707 patients infected by SARS-CoV-2 were hospitalized at the Geneva University Hospitals; 31 (4.4%) consecutive patients with an acute encephalopathy (64.6 ± 12.1 years; 6.5% female) were included in this series, after exclusion of comorbid neurological conditions, such as stroke or meningitis. The severity of the COVID-19 encephalopathy was divided into severe and mild based on the Richmond Agitation Sedation Scale (RASS): severe cases (n = 14, 45.2%) were defined on a RASS < -3 at worst presentation. The severe form of this so-called COVID-19 encephalopathy presented more often a headache. The severity of the pneumonia was not associated with the severity of the COVID-19 encephalopathy: 28 of 31 (90%) patients did develop an acute respiratory distress syndrome, without any difference between groups (p = .665). Magnetic resonance imaging abnormalities were found in 92.0% (23 of 25 patients) with an intracranial vessel gadolinium enhancement in 85.0% (17 of 20 patients), while an increased cerebrospinal fluid/serum quotient of albumin suggestive of blood-brain barrier disruption was reported in 85.7% (6 of 7 patients). Reverse transcription-polymerase chain reaction for SARS-CoV-2 was negative for all patients in the cerebrospinal fluid. Although different pathophysiological mechanisms may contribute to this acute encephalopathy, our findings suggest the hypothesis of disturbed brain homeostasis and vascular dysfunction consistent with a SARS-CoV-2-induced endotheliitis.

C-reactive protein and white matter microstructural changes in COVID-19 patients with encephalopathy.

Encephalopathy is a neurological complication of COVID-19. The objective of this exploratory study is to investigate the link between systemic inflammation and brain microstructural changes (measured by diffusion-weighted imaging) in patients with COVID-19 encephalopathy. 20 patients with COVID-19 encephalopathy (age: 67.3 [Formula: see text] 10.0 years; 90% men) hospitalized in the Geneva University Hospitals for a SARS-CoV-2 infection between March and May 2020 were included in this retrospective cohort study. COVID-19 encephalopathy was diagnosed following a comprehensive neurobiological evaluation, excluding common causes of delirium, such as hypoxemic or metabolic encephalopathy. We investigated the correlation between systemic inflammation (measured by systemic C-reactive protein (CRP)) and brain microstructural changes in radiologically normal white matter (measured by apparent diffusion coefficient (ADC)) in nine spatially widespread regions of the white matter previously associated with delirium. Systemic inflammation (CRP = 60.8 ± 50.0 mg/L) was positively correlated with ADC values in the anterior corona radiata (p = 0.0089), genu of the corpus callosum (p = 0.0064) and external capsule (p = 0.0086) after adjusting for patients' age. No statistically significant association between CRP and ADC was found in the other six white matter regions. Our findings indicate high risk of white matter abnormalities in COVID-19 encephalopathy patients with high peripheral inflammatory markers, suggesting aggressive imaging monitoring may be warranted in these patients. Future studies should clarify a possible specificity of the spatial patterns of CRP-white matter microstructure association in COVID-19 encephalopathy patients and disentangle the role of individual cytokines on brain inflammatory mechanisms.

Tympanal bone fracture in forensic practice.

A tympanal bone fracture is an uncommon complication of head trauma and is mostly associated with a mandibular or petrous bone fracture. Upon reviewing the medicolegal literature, we could not find any publications on this topic. Tympanal bone fracture may lead to chronic complications (including external auditory canal stenosis and conductive hearing loss), with an important impact in both the medical and judiciary fields (e.g., chronic disabilities with loss of income). We decided to investigate the prevalence and mechanisms of tympanal bone fractures by means of a retrospective observational study on living victims who underwent head computed tomography after blunt head trauma and clinical forensic investigation at our center. We selected 159 cases of living victims with blunt head trauma (following an assault, traffic accident, or work accident) between January 2016 and December 2020. Re-examination of head imaging revealed 12 cases of tympanal bone fracture. Seven individuals showed cranial fractures involving the petrous bone (on the same side as the tympanal bone fracture). Three individuals had a temporomandibular fracture after a fall with chin impact. Only two victims exhibited an isolated tympanal bone fracture.

Hemorrhagic Plaques in Mild Carotid Stenosis: The Risk of Stroke.

OBJECTIVES: Embolic ischemic strokes cause significant mortality and morbidity worldwide. It has been proposed that some of these strokes are due to unstable carotid plaques with intraplaque hemorrhage (IPH) but a low overall degree of stenosis. Our aim was to test a fat-saturated T1-weighted (T1WI) black-blood sequence on MRI for the detection of IPH in symptomatic individuals and to quantify the relation between IPH, severity of stenoses, and ischemic brain lesions. MATERIALS AND METHODS: Sixty-two patients were examined by 3T MRI. Sequences included brain diffusion-weighted imaging (DWI) as well as 3D turbo spin echo (TSE) fat-saturated black-blood T1 of the carotid bifurcations, to detect IPH as a focal intraplaque hyperintensity. Both carotid arteries were analyzed in each patient. The North American Symptomatic Carotid Endarterectomy Trial scale was used for quantification of stenosis degree. RESULTS: Thirty-six out of 62 patients (mean age, 74) showed brain ischemia on DWI. Fifteen of these 36 patients (42%) had associated ipsilateral IPH at the carotid bifurcation or the proximal internal carotid artery. Mean degree of stenosis in this group was 50%. In 21 patients with ischemia without IPH, the mean degree of stenosis was 44%. CONCLUSIONS: MRI with 3D TSE fat-saturated black-blood T1 technique is a safe, reliable, and noninvasive tool for the detection of IPH. A high percentage (42%) of ischemic events in patients with low- to moderate-degree stenosis were associated with IPH, an easily detectable imaging biomarker of plaque vulnerability. The ability to confirm IPH by MRI may help stratify patients into different risk and treatment groups in the future.