Susceptibility Etching on MRI in Patients with Microangiopathy

D-Dimer Is Associated With Coronary Microvascular Dysfunction in Patients With Non-obstructive Coronary Artery Disease and Preserved Ejection Fraction

BACKGROUND

Coronary microvascular dysfunction (CMVD), an important etiology of ischemic heart disease, has been widely studied. D-dimer is a simple indicator of microthrombosis and inflammation. However, whether an increase in D-dimer is related to CMVD is still unclear.

MATERIALS AND METHODS

This retrospective study consecutively enrolled patients with myocardial ischemia and excluded those with obstructive coronary artery. D-dimer was measured at admission and the TIMI myocardial perfusion grade (TMPG) was used to distinguish CMVD. Patients were divided into the two groups according to whether the D-dimer was elevated (>500 ng/ml). Logistic models and restricted cubic splines were used to explore the relationship between elevated D-dimer and CMVD.

RESULTS

A total of 377 patients were eventually enrolled in this study. Of these, 94 (24.9%) patients with CMVD had older age and higher D-dimer levels than those without CMVD. After full adjustment for other potential clinical risk factors, patients with high D-dimer levels (>500 ng/ml) had a 1.89-times (95% CI: 1.09-3.27) higher risk of CMVD than patients with low D-dimer levels. A non-linear relationship was found between concentrations of D-dimer and CMVD. With increased D-dimer level, the incidence of CMVD increased and then remained at a high level. Stratified analysis was performed and showed similar results.

CONCLUSION

Elevated D-dimer level is associated with the incidence of CMVD and potentially serves as a simple biomarker to facilitate the diagnosis of CMVD for patients with angina.

Nervous System Involvement in Coronavirus Disease 2019: Results from a Retrospective Consecutive Neuroimaging Cohort

Background Neurologic complications in coronavirus disease 2019 (COVID-19) have been described, but the understanding of their pathophysiologic causes and neuroanatomical correlates remains limited. Purpose To report on the frequency and type of neuroradiological findings in COVID-19. Materials and Methods In this retrospective study, all consecutive adult hospitalized patients with polymerase chain reaction positivity for severe acute respiratory syndrome coronavirus 2 and who underwent neuroimaging at Karolinska University Hospital between March 2 and May 24, 2020, were included. All examinations were systematically re-evaluated by 12 readers. Summary descriptive statistics were calculated. Results A total of 185 patients with COVID-19 (62 years ± 14 [standard deviation]; 138 men) underwent neuroimaging. In total, 222 brain CT, 47 brain MRI, and seven spinal MRI examinations were performed. Intra-axial susceptibility abnormalities were the most common finding (29 of 39; 74%, 95% CI: 58, 87) in patients who underwent brain MRI, often with an ovoid shape suggestive of microvascular pathology and with a predilection for the corpus callosum (23 of 39; 59%; 95% CI: 42, 74) and juxtacortical areas (14 of 39; 36%; 95% CI: 21, 53). Ischemic and macrohemorrhagic manifestations were also observed, but vascular imaging did not demonstrate overt abnormalities. Dynamic susceptibility contrast perfusion MRI in 19 patients did not reveal consistent asymmetries between hemispheres or regions. Many patients (18 of 41; 44%; 95% CI: 28, 60) had leukoencephalopathy and one patient had a cytotoxic lesion of the corpus callosum. Other findings included olfactory bulb signal abnormalities (seven of 37; 19%), prominent optic nerve subarachnoid spaces (20 of 36; 56%), and enhancement of the parenchyma (three of 20; 15%), leptomeninges (three of 20; 15%), cranial nerves (two of 20; 10%), and spinal nerves (two of four; 50%). At MRI follow-up, regression of leukoencephalopathy and progressive leptomeningeal enhancement was observed in one patient each, respectively, which is suggestive of dynamic processes. Conclusion Patients with coronavirus disease 2019 had a wide spectrum of vascular and inflammatory involvement of both the central and peripheral nervous system. © RSNA, 2020 Online supplemental material is available for this article.

Cerebral microhaemorrhage in COVID-19: a critical illness related phenomenon?

BACKGROUND

Cerebral microhaemorrhages are increasingly being recognised as a complication of COVID-19. This observational retrospective study aims to further investigate the potential pathophysiology through assessing the pattern of microhaemorrhage and clinical characteristics of patients with COVID-19 and microhaemorrhage. By comparing with similar patterns of microhaemorrhage in other non-COVID-19 disease, this study aims to propose possible common pathogenic mechanisms.

METHODS

A retrospective observational case series was performed identifying all patients with COVID-19 complicated by cerebral microhaemorrhage on MRI. The distribution and number of microhaemorrhages were recorded using the microbleed anatomical scale, and patients' baseline characteristics and salient test results were also recorded.

RESULTS

Cerebral microhaemorrhages were noted to have a predilection for the corpus callosum, the juxtacortical white matter and brainstem. All patients had a preceding period of critical illness with respiratory failure and severe hypoxia necessitating intubation and mechanical ventilation.

DISCUSSION

This study demonstrates a pattern of cerebral microhaemorrhage that is similar to the pattern reported in patients with non-COVID-19 related critical illness and other causes of severe hypoxia. This raises questions regarding whether microhaemorrhage occurs from endothelial dysfunction due the direct effect of SARS-CoV-2 infection or from the secondary effects of critical illness and hypoxia.