Is COVID Evolution Due to Occurrence of Pulmonary Vascular Thrombosis?

The radiological findings of COVID-19

Background/aim

Available information on the radiological findings of the 2019 novel coronavirus disease (COVID-19) is constantly updated. Ground glass opacities (GGOs) and consolidation with bilateral and peripheral distribution have been reported as the most common CT findings, but less typical features can also be identified. According to the reported studies, SARS-CoV-2 infection is not limited to the respiratory system, and it can also affect other organs. Renal dysfunction, gastrointestinal complications, liver dysfunction, cardiac manifestations, and neurological abnormalities are among the reported extrapulmonary features. This review aims to provide updated information for radiologists and all clinicians to better understand the radiological manifestations of COVID-19.

Materials and methods

Radiological findings observed in SARS-CoV-2 virus infections were explored in detail in PubMed and Google Scholar databases.

Results

The typical pulmonary manifestations of COVID-19 pneumonia were determined as GGOs and accompanying consolidations that primarily involve the periphery of the bilateral lower lobes. The most common extrapulmonary findings were increased resistance to flow in the kidneys, thickening of vascular walls, fatty liver, pancreas, and heart inflammation findings. However, these findings were not specific and significantly overlapped those caused by other viral diseases, and therefore alternative diagnoses should be considered in patients with negative diagnostic tests.

Conclusion

Radiological imaging plays a supportive role in the care of patients with COVID-19. Both clinicians and radiologists need to know associated pulmonary and extrapulmonary findings and imaging features to help diagnose and manage the possible complications of the disease at an early stage. They should also be familiar with CT findings in patients with COVID-19 since the disease can be incidentally detected during imaging performed with other indications.

Automated Quantitative Lung CT Improves Prognostication in Non-ICU COVID-19 Patients beyond Conventional Biomarkers of Disease

(1) Background: COVID-19 continues to represent a worrying pandemic. Despite the high percentage of non-severe illness, a wide clinical variability is often reported in real-world practice. Accurate predictors of disease aggressiveness, however, are still lacking. The purpose of our study was to evaluate the impact of quantitative analysis of lung computed tomography (CT) on non-intensive care unit (ICU) COVID-19 patients' prognostication; (2) Methods: Our historical prospective study included fifty-five COVID-19 patients consecutively submitted to unenhanced lung CT. Primary outcomes were recorded during hospitalization, including composite ICU admission for the need of mechanical ventilation and/or death occurrence. CT examinations were retrospectively evaluated to automatically calculate differently aerated lung tissues (i.e., overinflated, well-aerated, poorly aerated, and non-aerated tissue). Scores based on the percentage of lung weight and volume were also calculated; (3) Results: Patients who reported disease progression showed lower total lung volume. Inflammatory indices correlated with indices of respiratory failure and high-density areas. Moreover, non-aerated and poorly aerated lung tissue resulted significantly higher in patients with disease progression. Notably, non-aerated lung tissue was independently associated with disease progression (HR: 1.02; p-value: 0.046). When different predictive models including clinical, laboratoristic, and CT findings were analyzed, the best predictive validity was reached by the model that included non-aerated tissue (C-index: 0.97; p-value: 0.0001); (4) Conclusions: Quantitative lung CT offers wide advantages in COVID-19 disease stratification. Non-aerated lung tissue is more likely to occur with severe inflammation status, turning out to be a strong predictor for disease aggressiveness; therefore, it should be included in the predictive model of COVID-19 patients.

Retinal capillary involvement in early post-COVID-19 patients: a healthy controlled study

BACKGROUND

Systemic vascular involvement in COVID-19 has been identified in several patients: not only endothelial derangement and increased permeability are reported to be early hallmarks of organ damage in patients with COVID-19 but are also the most important cause of worsening of clinical conditions in severe cases of SARS-CoV-2 infection. There are several reasons to hypothesize that the eye, and the retina in particular, could be a target of organ damage in SARS-CoV-2 infection.

METHODS

This cohort observational study analyzes OCT angiography and structural OCT of 70 post-COVID-19 patients evaluated at 1-month hospital discharge and 22 healthy control subjects. Primary outcomes were macular vessel density (VD) and vessel perfusion (VP); structural OCT features were evaluated as secondary outcomes. In addition, patients and healthy volunteers were evaluated for best corrected visual acuity, slit lamp photograph, and fundus photo image.

RESULTS

VD and VP in 3 × 3 and 6 × 6 mm scans for SCP and DCP showed no significant differences between the groups. Similarly, CMT and GCL did not reveal significant differences between post-COVID-19 and healthy patients. Nine patients (12.9%) featured retinal cotton wool spots and 10 patients had vitreous fibrillary degeneration. The prevalence of epiretinal membrane and macular hole was similar in the two groups. One case of extra papillary focal retinal hemorrhage was reported in the post-COVID-19 group.

CONCLUSIONS

Macula and perimacular vessel density and perfusion resulted unaltered in mild post-COVID-19 patients at 1-month hospital discharge, suggesting no or minimal retinal vascular involvement by SARS-CoV-2.

Severe COVID-19 pneumonia: Perfusion analysis in correlation with pulmonary embolism and vessel enlargement using dual-energy CT data

BACKGROUND

Gas exchange in COVID-19 pneumonia is impaired and vessel obstruction has been suspected to cause ventilation-perfusion mismatch. Dual-energy CT (DECT) can depict pulmonary perfusion by regional assessment of iodine uptake.

OBJECTIVE

The purpose of this study was the analysis of pulmonary perfusion using dual-energy CT in a cohort of 27 consecutive patients with severe COVID-19 pneumonia.

METHOD

We retrospectively analyzed pulmonary perfusion with DECT in 27 consecutive patients (mean age 57 years, range 21-73; 19 men and 8 women) with severe COVID-19 pneumonia. Iodine uptake (IU) in regions-of-interest placed into normally aerated lung, ground-glass opacifications (GGO) and consolidations was measured using a dedicated postprocessing software. Vessel enlargement (VE) within opacifications and presence of pulmonary embolism (PE) was assessed by subjective analysis. Linear mixed models were used for statistical analyses.

RESULTS

Compared to normally aerated lung 106/151 (70.2%) opacifications without upstream PE demonstrated an increased IU, 9/151 (6.0%) an equal IU and 36/151 (23.8%) a decreased IU. The estimated mean iodine uptake (EMIU) in opacifications without upstream PE (GGO 1.77 mg/mL; 95%-CI: 1.52-2.02; p = 0.011, consolidations 1.82 mg/mL; 95%-CI: 1.56-2.08, p = 0.006) was significantly higher compared to normal lung (1.22 mg/mL; 95%-CI: 0.95-1.49). In case of upstream PE, EMIU of opacifications (combined GGO and consolidations) was significantly decreased compared to normal lung (0.52 mg/mL; 95%-CI: -0.07-1.12; p = 0.043). The presence of VE in opacifications correlated significantly with iodine uptake (p<0.001).

CONCLUSIONS

DECT revealed the opacifications in a subset of patients with severe COVID-19 pneumonia to be perfused non-uniformly with some being hypo- and others being hyperperfused. Mean iodine uptake in opacifications (both ground-glass and consolidation) was higher compared to normally aerated lung except for areas with upstream pulmonary embolism. Vessel enlargement correlated with iodine uptake: In summary, in a cohort of 27 consecutive patients with severe COVID-19 pneumonia, dual-energy CT demonstrated a wide range of iodine uptake in pulmonary ground-glass opacifications and consolidations as a surrogate marker for hypo- and hyperperfusion compared to normally aerated lung. Applying DECT to determine which pathophysiology is predominant might help to tailor therapy to the individual patient´s needs.

Machine Learning to Predict In-Hospital Mortality in COVID-19 Patients Using Computed Tomography-Derived Pulmonary and Vascular Features

Pulmonary parenchymal and vascular damage are frequently reported in COVID-19 patients and can be assessed with unenhanced chest computed tomography (CT), widely used as a triaging exam. Integrating clinical data, chest CT features, and CT-derived vascular metrics, we aimed to build a predictive model of in-hospital mortality using univariate analysis (Mann-Whitney U test) and machine learning models (support vectors machines (SVM) and multilayer perceptrons (MLP)). Patients with RT-PCR-confirmed SARS-CoV-2 infection and unenhanced chest CT performed on emergency department admission were included after retrieving their outcome (discharge or death), with an 85/15% training/test dataset split. Out of 897 patients, the 229 (26%) patients who died during hospitalization had higher median pulmonary artery diameter (29.0 mm) than patients who survived (27.0 mm, p < 0.001) and higher median ascending aortic diameter (36.6 mm versus 34.0 mm, p < 0.001). SVM and MLP best models considered the same ten input features, yielding a 0.747 (precision 0.522, recall 0.800) and 0.844 (precision 0.680, recall 0.567) area under the curve, respectively. In this model integrating clinical and radiological data, pulmonary artery diameter was the third most important predictor after age and parenchymal involvement extent, contributing to reliable in-hospital mortality prediction, highlighting the value of vascular metrics in improving patient stratification.

COVID-19 Imaging: What We Know Now and What Remains Unknown

Infection with SARS-CoV-2 ranges from an asymptomatic condition to a severe and sometimes fatal disease, with mortality most frequently being the result of acute lung injury. The role of imaging has evolved during the pandemic, with CT initially being an alternative and possibly superior testing method compared with reverse transcriptase-polymerase chain reaction (RT-PCR) testing and evolving to having a more limited role based on specific indications. Several classification and reporting schemes were developed for chest imaging early during the pandemic for patients suspected of having COVID-19 to aid in triage when the availability of RT-PCR testing was limited and its level of performance was unclear. Interobserver agreement for categories with findings typical of COVID-19 and those suggesting an alternative diagnosis is high across multiple studies. Furthermore, some studies looking at the extent of lung involvement on chest radiographs and CT images showed correlations with critical illness and a need for mechanical ventilation. In addition to pulmonary manifestations, cardiovascular complications such as thromboembolism and myocarditis have been ascribed to COVID-19, sometimes contributing to neurologic and abdominal manifestations. Finally, artificial intelligence has shown promise for use in determining both the diagnosis and prognosis of COVID-19 pneumonia with respect to both radiography and CT.

Complications in COVID-19 patients: Characteristics of pulmonary embolism

Objective

The purpose of this study is to evaluate chest CT imaging features, clinical characteristics, laboratory values of COVID-19 patients who underwent CTA for suspected pulmonary embolism. We also examined whether clinical, laboratory or radiological characteristics could be associated with a higher rate of PE.

Materials and methods

This retrospective study included 84 consecutive patients with laboratory-confirmed SARS-CoV-2 who underwent CTA for suspected PE. The presence and localization of PE as well as the type and extent of pulmonary opacities on chest CT exams were examined and correlated with the information on comorbidities and laboratory values for all patients.

Results

Of the 84 patients, pulmonary embolism was discovered in 24 patients. We observed that 87% of PE was found to be in lung parenchyma affected by COVID-19 pneumonia. Compared with no-PE patients, PE patients showed an overall greater lung involvement by consolidation (p = 0.02) and GGO (p < 0.01) and a higher level of D-Dimer (p < 0,01). Moreover, the PE group showed a lower level of saturation (p = 0,01) and required more hospitalization (p < 0,01).

Conclusion

Our study showed a high incidence of PE in COVID-19 pneumonia. In 87% of patients, PE was found in lung parenchyma affected by COVID-19 pneumonia with a worse CT severity score and a greater number of lung lobar involvement compared with non-PE patients. CT severity, lower level of saturation, and a rise in D-dimer levels could be an indication for a CTPA.

Advances in knowledge

Certain findings of non-contrast chest CT could be an indication for a CTPA.

[COVID-19: Coagulopathy and thrombosis]

Le virus SARS-CoV-2 a provoqué une pandémie mondiale en quelques semaines, causant l’infection de plus de 20 millions de sujets. Près du 15 % des patients atteints de la maladie à coronavirus 2019 (COVID-19) et plus de 70 % des formes graves présentent des anomalies de coagulation. Cet état « d’hypercoagulabilité » incluant essentiellement une élévation marquée des D-Dimères est associé à un risque accru de décès. En outre, une proportion substantielle de patients atteints de COVID-19 sévère développent des complications thromboemboliques veineuses, incidence d’autant plus élevée que les patients sont admis en unités de soins intensifs ou en réanimation. Une meilleure compréhension de la physiopathologie de la COVID-19, en particulier des troubles de l’hémostase, permettra d’adapter des stratégies thérapeutiques, notamment anti-thrombotiques. La mise en évidence de ces anomalies doit être associée à une évaluation rigoureuse du risque thrombotique permettant la mise en place d’une stratégie anti-thrombotique adaptée. Nous passons en revue les caractéristiques des données biologiques de la « coagulopathie » associée à la COVID-19, l’incidence des événements thromboemboliques et leurs spécificités ainsi que les interventions thérapeutiques potentielles.

Pulmonary thromboembolism in coronavirus disease 2019 patients undergoing thromboprophylaxis

We aimed to investigate the prevalence of pulmonary thromboembolism (PTE) and its association with clinical variables in a cohort of hospitalized coronavirus disease 2019 (COVID-19) patients receiving low-molecular-weight heparin (LMWH) at prophylactic dosage.In this retrospective observational study we included COVID-19 patients receiving prophylactic LMWH from admission but still referred for lower-limbs venous Doppler ultrasound (LL-US) and computed tomography pulmonary angiography (CTPA) for clinical PTE suspicion. A dedicated radiologist reviewed CTPA images to assess PTE presence/extension.From March 1 to April 30, 2020, 45 patients were included (34 men, median age 67 years, interquartile range [IQR] 60-76). Twenty-seven (60%) had PTE signs at CTPA, 17/27 (63%) with bilateral involvement, none with main branch PTE. In 33/45 patients (73%) patients LL-US was performed before CTPA, with 3 patients having superficial vein thrombosis (9%, none with CTPA-confirmed PTE) and 1 patient having deep vein thrombosis (3%, with CTPA-confirmed PTE). Thirty-three patients (73%) had at least one comorbidity, mainly hypertension (23/45, 51%) and cardiovascular disease (15/45, 33%). Before CTPA, 5 patients had high D-dimer (11.21 μg/mL, IQR 9.10-13.02), 19 high fibrinogen (550 mg/dL, IQR 476-590), 26 high interleukin-6 (79 pg/mL, IQR 31-282), and 11 high C-reactive protein (9.60 mg/dL, IQR 6.75-10.65), C-reactive protein being the only laboratory parameter significantly differing between patients with and without PTE (P = .002)High PTE incidence (60%) in COVID-19 hospitalized patients under prophylactic LMWH could substantiate further tailoring of anticoagulation therapy.

Adult cardiovascular surgery and the coronavirus disease 2019 (COVID-19) pandemic: the Italian experience

The coronavirus disease 2019 (COVID-19) pandemic has profoundly affected all health care professionals. The outbreak required a thorough reorganization of the Italian regional local health care system to preserve resources such as ventilators, beds in intensive care units and surgical and anaesthesiological staff. Levels of priority were created, together with a rigorous triage procedure for patients with COVID-19, which led to postponement of all elective procedures. Urgent cases were discussed with the local heart team and percutaneous approaches were selected as the first treatment option to reduce hospital stay. COVID-19 and COVID-19-free pathways were created, including adequate preparation of the operating room, management of anaesthesiological procedures, transportation of patients and disinfection. It was determined that patients with chronic diseases were at increased risk of adverse outcomes. Systemic inflammation, cytokine storm and hypercoagulability associated with COVID-19 increased the risk of heart failure and cardiac death. In this regard, the early use of extracorporeal membrane oxygenation could be life-saving in patients with severe forms of acute respiratory distress syndrome or refractory heart failure. The goal of this paper was to report the Italian experience during the COVID-19 pandemic in the setting of cardiovascular surgery.

Endothelial dysfunction in Coronavirus disease 2019 (COVID-19): Gender and age influences

Several risk factors are associated with a worse outcome for COVID-19 patients; the most recognized are demographic characteristics such as older age and male gender, and pre-existing cardiovascular conditions. About the latter, hypertension and coronary heart disease are among the most common comorbidities recorded in infected patients, together with type 2 diabetes mellitus (T2DM). Data from Istituto Superiore di Sanità (ISS, Italy) show that more than 68.3% of patients had hypertension, 28.2% ischemic heart disease, 22.5% atrial fibrillation, while 30.1% T2DM. Several authors suggested that cardiovascular diseases and diabetes mellitus are linked to endothelial dysfunction, and all of them are strictly related to aging. Considering the impact of the gender on the COVID-19 epidemic, even if confirmed cases from each nation are changing every day, epidemiological data clearly evidence that in men the infection causes worse outcomes compared to women. In Italy, up to 21 May, in the age range of 60-89 years, male deaths were 63.9% of total cases. The reason behind this difference between genders appears not clear; however, the diversity in sex-hormones and styles of life are believed to play a role in the patient's susceptibility to severe SARS-CoV-2 outcomes. It is known that the activation of endothelial estrogen receptors increases NO and decreases ROS, protecting the vascular system from angiotensin II-mediated vasoconstriction, inflammation, and ROS production. During the pandemic, joining forces is vital; thus, as people help doctors by limiting their displacements out of their houses avoiding hence the spread of the infection, doctors help patients to overcome severe SARS-CoV-2 infections by using multiple pharmacological approaches. In this context, the preservation of endothelial function and the mitigation of vascular inflammation are prominent targets, essential to reduce severe outcomes also in male older patients.

Emerging patterns of hypercoagulability associated with critical COVID-19: A review

While the COVID-19 pandemic sweeps the world, much evidence is being gathered regarding its novel pathological mechanisms. It is the authors' clinical experience that patients in the intensive care unit suffering from COVID-19 are extremely pro-coagulable, with venous and arterial thromboembolism frequently observed, and losses of vascular access lines and filtration circuits to thrombosis now commonplace. Here, we explore the evidence for hypercoagulability in this group, presenting evidence of both a localised pulmonary hypercoagulability, and a systemic hypercoagulability resulting in thrombosis distant to the pulmonary vasculature. Furthermore, we discuss the possible risk factors exacerbated by, or selected for in COVID-19. We review the available evidence for use of plasma D-dimer as a prognostic marker, exploring the possibility that it acts as a marker of a COVID-19-associated hypercoagulability. We review the evidence for a pro-coagulant subtype of disseminated intravascular coagulation, discussing its clinical significance. Finally, we discuss the current evidence surrounding treatment of COVID-19 hypercoagulability, including prophylactic and treatment-dose heparin, thrombolytic agents, antiplatelet agents, and direct thrombin inhibitors, among others. We suggest areas in which further investigation is urgently needed to reduce the startling incidence of thrombosis in this group, a complication no doubt contributing to morbidity and mortality.

Coagulation disorders in SARS-CoV-2 infection

A better understanding of the pathogenetic mechanisms triggered by SARS-CoV-2 infection may contribute to a more effective management of patients with COVID-19. Coagulation dysfunction is a key pathogenetic element of this disease as well as a challenge for practitioners. Marked inflammatory process found in severe forms of COVID-19, the complement activation, the cytokine storm, and disruption of the renin-angiotensin-aldosterone system are involved in the onset of thrombotic microangiopathy and large vessel coagulopathy. Virus-induced procoagulant activity occurs at the systemic level. Intravascular microthrombi disrupt vascularization in various tissues and organs, contributing to the occurrence of multiorgan failure and explain the higher morbidity and all-cause mortality of patients. It is estimated that almost 20% of patients with COVID-19 have significant coagulation disorders, and about a quarter of those hospitalized in intensive care units are prone to develop thrombosis events under prophylactic anticoagulant treatment. Some of patients who have been immunized after healing from the SARS-CoV-2 infection have a hypercoagulable state and are prone to develop thrombosis. Hypercoagulability is supported by thrombelastographic analysis: patients have an acceleration of the propagation phase of blood clot formation and higher clot strength. Markers of coagulation dysfunction in SARS-CoV2 are: decreased platelet count, increased INR, presence of fibrin degradation products, and especially higher plasma levels of D-dimers, which predict unfavorable outcome in these patients. Age, pre-existing diseases and associated risk factors, together with careful monitoring of clinical evolution and laboratory parameters allow the choice of the best personalized prophylactic or curative anticoagulant treatment.

COVID-19 versus HIT hypercoagulability

A striking feature of COVID-19 is the high frequency of thrombosis, particularly in patients who require admission to intensive care unit because of respiratory complications (pneumonia/adult respiratory distress syndrome). The spectrum of thrombotic events is wide, including in situ pulmonary thrombosis, deep-vein thrombosis and associated pulmonary embolism, as well as arterial thrombotic events (stroke, myocardial infarction, limb artery thrombosis). Unusual thrombotic events have also been reported, e.g., cerebral venous sinus thrombosis, mesenteric artery and vein thrombosis. Several hematology abnormalities have been observed in COVID-19 patients, including lymphopenia, neutrophilia, thrombocytopenia (usually mild), thrombocytosis, elevated prothrombin time and partial thromboplastin times (the latter abnormality often indicating lupus anticoagulant phenomenon), hyperfibrinogenemia, elevated von Willebrand factor levels, and elevated fibrin d-dimer. Many of these abnormal hematologic parameters—even as early as the time of initial hospital admission—indicate adverse prognosis, including greater frequency of progression to severe respiratory illness and death. Progression to overt disseminated intravascular coagulation in fatal COVID-19 has been reported in some studies, but not observed in others. We compare and contrast COVID-19 hypercoagulability, and associated increased risk of venous and arterial thrombosis, from the perspective of heparin-induced thrombocytopenia (HIT), including the dilemma of providing thromboprophylaxis and treatment recommendations when available data are limited to observational studies. The frequent use of heparin—both low-molecular-weight and unfractionated—in preventing and treating COVID-19 thrombosis, means that vigilance for HIT occurrence is required in this patient population.

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HIT and COVID-19 are associated with a high risk of thrombosis (venous > arterial).

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HIT and COVID-19 both feature coagulation and “pancellular” activation.

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Therapeutic anticoagulation is indicated for HIT, but dosing unknown for COVID-19.

Did we turn a blind eye? The answer is simply there. Peripheral pulmonary vascular thrombosis in COVID-19 patients explains sudden worsening of clinical conditions

COVID-19 patients suffering sudden worsening of clinical conditions have an atypical peripheral pulmonary arterial obstruction at computed tomography pulmonary angiogram (CTPA), poorly associated to deep venous thrombosis (DVT), suspicious for thrombotic in situ nature rather than embolic.

Postulated Adjuvant Therapeutic Strategies for COVID-19

The number of COVID-19 patients is still growing exponentially worldwide due to the high transmissibility of the SARS-CoV-2 virus. Therapeutic agents currently under investigation are antiviral drugs, vaccines, and other adjuvants that could relieve symptoms or improve the healing process. In this review, twelve therapeutic agents that could play a role in prophylaxis or improvement of the COVID-19-associated symptoms (as add-on substances) are discussed. Agents were identified based on their known pharmacologic mechanism of action in viral and/or nonviral fields and are postulated to interact with one or more of the seven known mechanisms associated with the SARS-CoV-2 virus: (i) regulation of the immune system; (ii) virus entrance in the cell; (iii) virus replication; (iv) hyperinflammation; (v) oxidative stress; (vi) thrombosis; and (vii) endotheliitis. Selected agents were immune transfer factor (oligo- and polypeptides from porcine spleen, ultrafiltered at <10 kDa; Imuno TF®), anti-inflammatory natural blend (Uncaria tomentosa, Endopleura uchi and Haematoccocus pluvialis; Miodesin®), zinc, selenium, ascorbic acid, cholecalciferol, ferulic acid, spirulina, N-acetylcysteine, glucosamine sulfate potassium hydrochloride, trans-resveratrol, and maltodextrin-stabilized orthosilicic acid (SiliciuMax®). This review gives the scientific background on the hypothesis that these therapeutic agents can act in synergy in the prevention and improvement of COVID-19-associated symptoms.

Chest CT features of coronavirus disease 2019 (COVID-19) pneumonia: key points for radiologists

COVID-19 is an emerging infection caused by a novel coronavirus that is moving so rapidly that on 30 January 2020 the World Health Organization declared the outbreak a Public Health Emergency of International Concern and on 11 March 2020 as a pandemic. An early diagnosis of COVID-19 is crucial for disease treatment and control of the disease spread. Real-time reverse-transcription polymerase chain reaction (RT-PCR) demonstrated a low sensibility; therefore chest computed tomography (CT) plays a pivotal role not only in the early detection and diagnosis, especially for false negative RT-PCR tests, but also in monitoring the clinical course and in evaluating the disease severity. This paper reports the CT findings with some hints on the temporal changes over the course of the disease: the CT hallmarks of COVID-19 are bilateral distribution of ground glass opacities with or without consolidation in the posterior and peripheral lung, but the predominant findings in later phases include consolidations, linear opacities, “crazy-paving” pattern, “reversed halo” sign and vascular enlargement. The CT findings of COVID-19 overlap with the CT findings of other diseases, in particular the viral pneumonia including influenza viruses, parainfluenza virus, adenovirus, respiratory syncytial virus, rhinovirus, human metapneumovirus, etc. There are differences as well as similarities in the CT features of COVID-19 compared with those of the severe acute respiratory syndrome. The aim of this article is to review the typical and atypical CT findings in COVID-19 patients in order to help radiologists and clinicians to become more familiar with the disease.

COVID-19 Associated Coagulopathy and Thrombotic Complications

The SARS-CoV-2 virus caused a global pandemic within weeks, causing hundreds of thousands of people infected. Many patients with severe COVID-19 present with coagulation abnormalities, including increase D-dimers and fibrinogen. This coagulopathy is associated with an increased risk of death. Furthermore, a substantial proportion of patients with severe COVID-19 develop sometimes unrecognized, venous, and arterial thromboembolic complications. A better understanding of COVID-19 pathophysiology, in particular hemostatic disorders, will help to choose appropriate treatment strategies. A rigorous thrombotic risk assessment and the implementation of a suitable anticoagulation strategy are required. We review here the characteristics of COVID-19 coagulation laboratory findings in affected patients, the incidence of thromboembolic events and their specificities, and potential therapeutic interventions.