COVID-protected pathways for image-guided lung cancer intervention during the COVID-19 pandemic: A cohort study.

OBJECTIVES: To compare the experience of COVID-protected and mixed cohort pathways in COVID-19 transmission at a tertiary referral hospital for elective CT-guided lung biopsy and ablation during the COVID-19 pandemic. METHODS: From September 2020 to August 2021, patients admitted for elective thoracic intervention were treated at a tertiary hospital (Site 1). Site 1 received patients for extracorporeal membrane oxygenation (ECMO) and invasive ventilation in the treatment of COVID-19. Shared imaging, theater, and hallway facilities were used.From April 2020 to August 2020, patients admitted for elective thoracic intervention were treated at a COVID-protected hospital (Site 2). No patients with suspected or confirmed COVID-19 were treated at Site 2.Patients were surveyed for clinical and laboratory signs of COVID-19 infection up to 30 days post-procedure. RESULTS: At Sites 1 and 2, patients (2.4%) were tested positive for COVID-19 at 10 and 14 days post-procedure.At Site 2, there were no COVID-19 positive cases within 30 days of undergoing elective thoracic intervention. CONCLUSION: A mixed-site method for infection control could represent a pragmatic approach to the management of elective procedures during the COVID-19 pandemic or for similar illnesses. ADVANCES IN KNOWLEDGE: Mixed-cohort infection control is possible in the prevention of nosocomial COVID-19 infection.

Pulmonary hypertension: the hallmark of acute COVID-19 microvascular angiopathy?

In situ pulmonary arterial thrombosis in COVID-19 is not visible on CTPA. However, the presence of CT-measured right heart and pulmonary artery dilatation in COVID-19 is likely attributable to this process and may be a possible surrogate for its detection. https://bit.ly/3g7z5TV.

Pulmonary Hypertension: The Hallmark of Acute COVID-19 Microvascular Angiopathy?

There have been over 481 million cases of Coronavirus Disease-19 (COVID-19), caused by the SARS-CoV-2 virus worldwide since December 2019 [1]. One of the hallmark features of acute COVID-19 pneumonia is pulmonary vascular involvement, most commonly manifesting as pulmonary artery thrombosis (PAT) [2, 3]. Post-mortem data in ten patients with COVID-19 pneumonia shows their central pulmonary arteries were free of thrombosis but all patients had small, firm thrombi in the peripheral parenchyma [4]. These findings raise the possibility that the CT finding of isolated subsegmental PAT may reflect "the tip of the iceberg”;that small segmental thrombi may reflect downstream in situ thrombosis in the microvasculature. In patients with severe COVID-19 pneumonitis, Dual-Energy CTPA (DECTPA) has been used to demonstrate reduced pulmonary perfusion in the absence of any visible central thromboembolism [5, 6], further supporting the view that microscopic PAT is prevalent [6].

Persistent isolated impairment of gas transfer following COVID-19 pneumonitis relates to perfusion defects on dual-energy computed tomography.

A novel iodine perfusion score correlates with breathlessness and D LCO in patients post-#COVID19 without obvious interstitial disease on CT, suggesting that lung perfusion assessment may be useful in patients without another cause of dyspnoea https://bit.ly/3U6E2f5.

Dual-Energy CT Pulmonary Angiography (DECTPA) Quantifies Vasculopathy in Severe COVID-19 Pneumonia.

BACKGROUND: The role of dual energy computed tomographic pulmonary angiography (DECTPA) in revealing vasculopathy in coronavirus disease 2019 (COVID-19) has not been fully explored. PURPOSE: To evaluate the relationship between DECTPA and disease duration, right ventricular dysfunction (RVD), lung compliance, D-dimer and obstruction index in COVID-19 pneumonia. MATERIALS AND METHODS: This institutional review board approved this retrospective study, and waived the informed consent requirement. Between March-May 2020, 27 consecutive ventilated patients with severe COVID-19 pneumonia underwent DECTPA to diagnose pulmonary thrombus (PT); 11 underwent surveillance DECTPA 14 ±11.6 days later. Qualitative and quantitative analysis of perfused blood volume (PBV) maps recorded: i) perfusion defect 'pattern' (wedge-shaped, mottled or amorphous), ii) presence of PT and CT obstruction index (CTOI) and iii) PBV relative to pulmonary artery enhancement (PBV/PAenh); PBV/PAenh was also compared with seven healthy volunteers and correlated with D-Dimer and CTOI. RESULTS: Amorphous (n=21), mottled (n=4), and wedge-shaped (n=2) perfusion defects were observed (M=20; mean age=56 ±8.7 years). Mean extent of perfusion defects=36.1%±17.2. Acute PT was present in 11/27(40.7%) patients. Only wedge-shaped defects corresponded with PT (2/27, 7.4%). Mean CTOI was 2.6±5.4 out of 40. PBV/PAenh (18.2 ±4.2%) was lower than in healthy volunteers (27 ±13.9%, p = 0.002). PBV/PAenh correlated with disease duration (ß = 0.13, p = 0.04), and inversely correlated with RVD (ß = -7.2, p = 0.001), persisting after controlling for confounders. There were no linkages between PBV/PAenh and D-dimer or CTOI. CONCLUSION: Perfusion defects and decreased PBV/PAenh are prevalent in severe COVID-19 pneumonia. PBV/PAenh correlates with disease duration and inversely correlates with RVD. PBV/PAenh may be an important marker of vasculopathy in severe COVID-19 pneumonia even in the absence of arterial thrombus.

Extracorporeal membrane oxygenation (ECMO): Radiographic appearances, complications and imaging artefacts for radiologists.

Extracorporeal membrane oxygenation (ECMO) is a form of cardiopulmonary support primarily used in cardiothoracic and intensive care unit (ICU) settings. The purpose of this review is to familiarise radiologists with the imaging features of ECMO devices, their associated complications and appropriate imaging protocols for contrast-enhanced CT imaging of ECMO patients. This paper will provide a brief introduction to ECMO and the imaging modalities utilised in ECMO patients, followed by a description of the types of ECMO available and cannula positioning. Indications and contraindications for ECMO will be outlined followed by a description of the complications associated with ECMO, which radiologists should recognise. Finally, the imaging protocol and interpretation of contrast-enhanced CT imaging in ECMO patients will be discussed. In the current clinical climate with millions of COVID-19 cases around the world and tens of thousands of critically ill patients, many requiring cardiopulmonary support in intensive care units, the use of ECMO in adults has increased, and thus so has the volume of imaging. Radiologists need to be familiar with the types of ECMO available, the correct positioning of the catheters depending on the type of ECMO being utilised, and the associated complications and imaging artefacts.

Prevalence of Thrombotic Complications in ICU-Treated Patients With Coronavirus Disease 2019 Detected With Systematic CT Scanning.

OBJECTIVES: Severe coronavirus disease 2019 is associated with an extensive pneumonitis and frequent coagulopathy. We sought the true prevalence of thrombotic complications in critically ill patients with severe coronavirus disease 2019 on the ICU, with or without extracorporeal membrane oxygenation. DESIGN: We undertook a single-center, retrospective analysis of 72 critically ill patients with coronavirus disease 2019-associated acute respiratory distress syndrome admitted to ICU. CT angiography of the thorax, abdomen, and pelvis were performed at admission as per routine institution protocols, with further imaging as clinically indicated. The prevalence of thrombotic complications and the relationship with coagulation parameters, other biomarkers, and survival were evaluated. SETTING: Coronavirus disease 2019 ICUs at a specialist cardiorespiratory center. PATIENTS: Seventy-two consecutive patients with coronavirus disease 2019 admitted to ICU during the study period (March 19, 2020, to June 23, 2020). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: All but one patient received thromboprophylaxis or therapeutic anticoagulation. Among 72 patients (male:female = 74%; mean age: 52 ± 10; 35 on extracorporeal membrane oxygenation), there were 54 thrombotic complications in 42 patients (58%), comprising 34 pulmonary arterial (47%), 15 peripheral venous (21%), and five (7%) systemic arterial thromboses/end-organ embolic complications. In those with pulmonary arterial thromboses, 93% were identified incidentally on first screening CT with only 7% suspected clinically. Biomarkers of coagulation (e.g., d-dimer, fibrinogen level, and activated partial thromboplastin time) or inflammation (WBC count, C-reactive protein) did not discriminate between patients with or without thrombotic complications. Fifty-one patients (76%) survived to discharge; 17 (24%) patients died. Mortality was significantly greater in patients with detectable thrombus (33% vs 10%; p = 0.022). CONCLUSIONS: There is a high prevalence of thrombotic complications, mainly pulmonary, among coronavirus disease 2019 patients admitted to ICU, despite anticoagulation. Detection of thrombus was usually incidental, not predicted by coagulation or inflammatory biomarkers, and associated with increased risk of death. Systematic CT imaging at admission should be considered in all coronavirus disease 2019 patients requiring ICU.

Corona Virus Disease 2019 in situ arterial and venous thrombosis in critically ill patients: a case series.

BACKGROUND: Corona Virus Disease 2019 (COVID-19) pneumonitis associated with severe respiratory failure carries a high mortality. Coagulopathy has emerged as a significant contributor to thrombotic complications. CASE SUMMARY: We describe two cases of severe COVID-19 pneumonitis refractory to conventional mechanical ventilation and proning position, transferred to our specialist centre for cardiorespiratory failure. Cross-sectional imaging demonstrated concurrent venous and aortic thrombosis with end-organ ischaemic changes. One patient received thrombolysis with a partial response. This could not be offered to the other patient due to a recent haemorrhagic event. Both patients died of multi-organ failure in the hospital. DISCUSSION: Concurrent aortic and venous thromboses are rare. This finding in COVID-19 cases, who were both critically ill patients, likely reflects the strongly thrombogenic nature of this illness which ultimately contributed to poor outcomes. The absence of deep vein thrombosis or a potential systemic source of embolism suggests in situ thrombosis. Further, the management of anticoagulation and thrombolysis is challenging in patients where an attendant bleeding risk exists.

Pulmonary Angiopathy in Severe COVID-19: Physiologic, Imaging, and Hematologic Observations.

Rationale: Clinical and epidemiologic data in coronavirus disease (COVID-19) have accrued rapidly since the outbreak, but few address the underlying pathophysiology.Objectives: To ascertain the physiologic, hematologic, and imaging basis of lung injury in severe COVID-19 pneumonia.Methods: Clinical, physiologic, and laboratory data were collated. Radiologic (computed tomography (CT) pulmonary angiography [n = 39] and dual-energy CT [DECT, n = 20]) studies were evaluated: observers quantified CT patterns (including the extent of abnormal lung and the presence and extent of dilated peripheral vessels) and perfusion defects on DECT. Coagulation status was assessed using thromboelastography.Measurements and Results: In 39 consecutive patients (male:female, 32:7; mean age, 53 ± 10 yr [range, 29-79 yr]; Black and minority ethnic, n = 25 [64%]), there was a significant vascular perfusion abnormality and increased physiologic dead space (dynamic compliance, 33.7 ± 14.7 ml/cm H2O; Murray lung injury score, 3.14 ± 0.53; mean ventilatory ratios, 2.6 ± 0.8) with evidence of hypercoagulability and fibrinolytic "shutdown". The mean CT extent (±SD) of normally aerated lung, ground-glass opacification, and dense parenchymal opacification were 23.5 ± 16.7%, 36.3 ± 24.7%, and 42.7 ± 27.1%, respectively. Dilated peripheral vessels were present in 21/33 (63.6%) patients with at least two assessable lobes (including 10/21 [47.6%] with no evidence of acute pulmonary emboli). Perfusion defects on DECT (assessable in 18/20 [90%]) were present in all patients (wedge-shaped, n = 3; mottled, n = 9; mixed pattern, n = 6).Conclusions: Physiologic, hematologic, and imaging data show not only the presence of a hypercoagulable phenotype in severe COVID-19 pneumonia but also markedly impaired pulmonary perfusion likely caused by pulmonary angiopathy and thrombosis.