Background Cerebral microbleeds are increasingly reported in critical ill patients with respiratory failure in need of mechanical ventilation and/or extracorporeal membrane oxygenation (ECMO). Typically, these critical illness-associated microbleeds involve the juxtacortical white matter and corpus callosum. Recently, this pattern was reported in patients with respiratory failure, suffering from COVID-19. Materials and methods In this retrospective single-center study, we listed patients from March 11, 2020 to September 2, 2020, with laboratory-confirmed COVID-19, critical illness and cerebral microbleeds. Literature research was conducted through a methodical search on Pubmed databases on critical illness-associated microbleeds and cerebral microbleeds described in patients with COVID-19. Results and discussion On 279 COVID-19 admissions, two cases of cerebral microbleeds were detected in critical ill patients with respiratory failure due to COVID-19. Based on review of existing literature critical illness-associated microbleeds tend to predominate in subcortical white matter and corpus callosum. Cerebral microbleeds in patients with COVID-19 tend to follow similar patterns as reported in critical illness-associated microbleeds. Hence, one patient with typical critical illness-associated microbleeds and COVID-19 is reported. However, a new pattern of widespread cortico-juxtacortical microbleeds, predominantly in the anterior vascular territory with relative sparing of deep gray matter, corpus callosum and infratentorial structures is documented in a second case. The possible etiologies of these microbleeds include hypoxia, hemorrhagic diathesis, brain endothelial erythrophagocytosis and/or cytokinopathies. An association with COVID-19 remains to be determined. Conclusion Further systematic investigation of microbleed patterns in patients with neurological impairment and COVID-19 is necessary.

Impact of a code stroke protocol on the door-to-needle time for IV thrombolysis: a feasibility study

Objectives: Bedside radiographs are usually obtained gridless, without a physical scatter correction grid because of several limitations. Therefore, multiple manufacturers of mobile radiography systems provide the possibility to apply scatter correction software (SC SW) on those images. The purpose of this study was to characterize different series of radiographs-gridless, SC SW, and physical grid-with an image quality assessment algorithm (IQAA). Furthermore, we investigated the potential dose reduction and the correlation between the output of the IQAA and the human observers. Materials and Methods: We obtained different series of radiographs with an anthropomorphic phantom (multipurpose chest phantom N1 "Lungman," Kyoto Kagaku, Kyoto, Japan). All radiographs were obtained with flat-panel detectors of 5 different manufacturers in a wall bucky system. An IQAA to analyze the radiographs was implemented in our department but was originally developed by the research group of the Duke University Medical Center. Seven physical quantities were calculated by the IQAA: rib-lung contrast (RL contrast ), subdiaphragmlung contrast (SL contrast ), lung detail (L detail ), mediastinum detail (M detail ), lung noise (L noise ), mediastinum noise (M noise ), and rib-lung sharpness (RL sharpness ). In a proof of concept, the results of the IQAA were validated by 3 experienced radiologists. Results: Regression coefficients (b) of the linear regression model indicate that the human observer results correlate well with the IQAA (b ≥ 0.89, R 2 ≥ 0.83). All manufacturers have SC SW that increases the 7 physical quantities of the gridless images. However, several manufacturers have SC SW that increases the physical metrics to the same level as the physical grid images. The SC SW radiographs obtained with a reduced tube load have an increased level of contrast, detail, sharpness, and noise compared with the gridless images obtained with the higher tube load. Conclusions: We have proven in a proof of concept that the originally developed IQAA can be used to characterize different series of images of different manufacturers. Based on the physical quantities, SC SW increases the contrast, detail, sharpness, and noise. The experimental results in this study assume a patient dose reduction could be possible when SC SW is applied.

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