Background and Purpose: Case series indicating cerebrovascular disorders in coronavirus disease 2019 (COVID-19) have been published. Comprehensive workups, including clinical characteristics, laboratory, electroencephalography, neuroimaging, and cerebrospinal fluid findings, are needed to understand the mechanisms. Methods: We evaluated 32 consecutive critically ill patients with COVID-19 treated at a tertiary care center from March 9 to April 3, 2020, for concomitant severe central nervous system involvement. Patients identified underwent computed tomography, magnetic resonance imaging, electroencephalography, cerebrospinal fluid analysis, and autopsy in case of death. Results: Of 32 critically ill patients with COVID-19, 8 (25%) had severe central nervous system involvement. Two presented with lacunar ischemic stroke in the early phase and 6 with prolonged impaired consciousness after termination of analgosedation. In all but one with delayed wake-up, neuroimaging or autopsy showed multiple cerebral microbleeds, in 3 with additional subarachnoid hemorrhage and in 2 with additional small ischemic lesions. In 3 patients, intracranial vessel wall sequence magnetic resonance imaging was performed for the first time to our knowledge. All showed contrast enhancement of vessel walls in large cerebral arteries, suggesting vascular wall pathologies with an inflammatory component. Reverse transcription-polymerase chain reactions for SARS-CoV-2 in cerebrospinal fluid were all negative. No intrathecal SARS-CoV-2-specific IgG synthesis was detectable. Conclusions: Different mechanisms of cerebrovascular disorders might be involved in COVID-19. Acute ischemic stroke might occur early. In a later phase, microinfarctions and vessel wall contrast enhancement occur, indicating small and large cerebral vessels involvement. Central nervous system disorders associated with COVID-19 may lead to long-term disabilities. Mechanisms should be urgently investigated to develop neuroprotective strategies.

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Objectives To evaluate optimal monoenergetic dual-energy computed tomography (DECT) settings for artefact reduction of posterior spinal fusion implants of various vendors and spine levels. Methods Posterior spinal fusion implants of five vendors for cervical, thoracic and lumbar spine were examined ex vivo with single-energy (SE) CT (120 kVp) and DECT (140/100 kVp). Extrapolated monoenergetic DECT images at 64, 69, 88, 105 keV and individually adjusted monoenergy for optimised image quality (OPTkeV) were generated. Two independent radiologists assessed quantitative and qualitative image parameters for each device and spine level. Results Inter-reader agreements of quantitative and qualitative parameters were high (ICC00.81-1.00, κ00.54-0.77). HU values of spinal fusion implants were significantly different among vendors (P<0.001), spine levels (P<0.01) and among SECT, monoenergetic DECT of 64, 69, 88, 105 keV and OPTkeV (P<0.01). Image quality was significantly (P<0.001) different between datasets and improved with higher monoenergies of DECT compared with SECT (V 00.58, P < 0.001). Artefacts decreased significantly (V00.51, P<0.001) at higher monoenergies. OPTkeV values ranged from 123-141 keV. OPTkeV according to vendor and spine level are presented herein. Conclusions Monoenergetic DECT provides significantly better image quality and less metallic artefacts from implants than SECT. Use of individual keV values for vendor and spine level is recommended. Key Points• Artefacts pose problems for CT following posterior spinal fusion implants.• CT images are interpreted better with monoenergetic extrapolation using dual-energy (DE) CT.• DECT extrapolation improves image quality and reduces metallic artefacts over SECT.• There were considerable differences in monoenergy values among vendors and spine levels.• Use of individualised monoenergy values is indicated for different metallic hardware devices.

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; on behalf of the European Organisation for Research and Treatment of Cancer (EORTC) Brain Tumor Group (BTG) Central Nervous System (CNS) Metastases Committee and the EORTC BTG Imaging Committee

The five most important radiological criteria for standard clinical reporting were selected. The five most important quantitative radiological parameters for research purposes were selected. These core criteria could help standardize the communication between health care providers.

Our systematic literature review identified 14 different semiquantitative or qualitative radiologic criteria that are used for the diagnosis of LSS; however, these criteria show remarkable variability in terms of their exact individual definitions and intra- and interrater reliability.

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