Quantitative magnetic resonance angiography for flow quantification of carotid and intracranial stenosis

Carotid and intracranial stenosis are responsible for stroke, which is the third leading cause of death globally. Carotid and intracranial stenting are used in management of stenosis. In-stent stenosis occurs in 25-35% of patients. Stent related artifacts and artificial lumen narrowing are problems during MRI scanning. A potential solution is estimate the flow profile across stenosis. The goal of this project is to optimize and implement quantitative magnetic resonance angiography (QMRA) for flow encoding and flow velocity estimation for better characterizing stenosis and assessing its degrees. We conducted multiple phantom measurements (mimicking normal carotid and middle cerebral anatomy) using phase contrast sequence with implementing different degrees of stenosis. Subsequent volunteer and patients measurements were conducted. In 8 mm tubes, flow was stable till 75 % stenosis while in 4 mm tubes, decline starts at 65% stenosis. In subject measurements, there is flow asymmetry between paired ICAs and MCAs that is not pathologic but within certain range. Patients had reduced flow in stenotic vessels compared to the other side and compared to mean flow in our volunteer subjects. QMRA results demonstrated reduced flow on the exact side detected with conventional MRA, with a strong correlation between QMRA and conventional MRA (R2 =0.7942). The percentage of flow difference between sides varied with the degree of stenosis. QMRA can be used for non-invasive diagnosis of suspected stenosis even if the stenosis itself cannot be visualized

The COVID-19 Pandemic: A Comprehensive Review of Taxonomy, Genetics, Epidemiology, Diagnosis, Treatment, and Control

A pneumonia outbreak with unknown etiology was reported in Wuhan, Hubei province, China, in December 2019, associated with the Huanan Seafood Wholesale Market. The causative agent of the outbreak was identified by the WHO as the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), producing the disease named coronavirus disease-2019 (COVID-19). The virus is closely related (96.3%) to bat coronavirus RaTG13, based on phylogenetic analysis. Human-to-human transmission has been confirmed even from asymptomatic carriers. The virus has spread to at least 200 countries, and more than 1,700,000 confirmed cases and 111,600 deaths have been recorded, with massive global increases in the number of cases daily. Therefore, the WHO has declared COVID-19 a pandemic. The disease is characterized by fever, dry cough, and chest pain with pneumonia in severe cases. In the beginning, the world public health authorities tried to eradicate the disease in China through quarantine but are now transitioning to prevention strategies worldwide to delay its spread. To date, there are no available vaccines or specific therapeutic drugs to treat the virus. There are many knowledge gaps about the newly emerged SARS-CoV-2, leading to misinformation. Therefore, in this review, we provide recent information about the COVID-19 pandemic. This review also provides insights for the control of pathogenic infections in humans such as SARS-CoV-2 infection and future spillovers