Role of ct chest in covid management

Regarding use of CT scan in Diagnosis and Disease monitoring of Pneumonia in COVID 19 patients

1. ROLE OF CT CHEST IN COVID-19 MANAGEMENT MODERATOR- Dr. VISHVANAYAK SIR PROFESSOR, DEPT. OF MEDICINE PRESENTER- Dr. VEERESH KUMAR DHANNI PG RESIDENT 2 ND YEAR, DEPT. OF MEDICINE 1

2. What is COVID-19? Coronavirus disease 2019 (COVID-19) is a contagious respiratory and vascular disease. It is caused by becoming infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is a specific type of coronavirus. SARS-CoV-2 is closely related to the original SARS- CoV . It is thought to have an animal (zoonotic) origin. Genetic analysis has revealed that the coronavirus genetically clusters with the genus Betacoronavirus , in subgenus Sarbecovirus (lineage B) together with two bat-derived strains. It is 96% identical at the whole genome level to other bat coronavirus samples ( BatCov RaTG13). The structural proteins of SARS-CoV-2 include membrane glycoprotein (M), envelope protein (E), nucleocapsid protein (N), and the spike protein (S ). 2

3. Usual onset: 2–14 days (typically 5) from day of infection. Duration: 5 days to 28 days as known. Diagnostic method: RT-PCR testing, rapid antigen test, antibody titre, markers & CT scan. Prevention: Hand washing, face coverings, quarantine, social distancing. Treatment: Symptomatic and supportive. 3

4. Strains Identified Till Date The harmless strains of coronavirus ( t hese cause symptoms of common cold and rarely cause severe pneumonia) are: Serotype 229E Serotype OC43 Serotype NL63 Serotype HUK1 The more dangerous strains are: Sars-CoV which causes Severe Acute Respiratory Syndrome or SARS Mers-CoV which causes Middle East Respiratory Syndrome or MERS Sars-CoV2 that causes the coronavirus disease COVID-19. 4

5. Mortality Overal mortality rate is 2.3% in some series of patients who had a positive test for COVID-19. Since we do not know the number of people who were infected but not tested for the virus, the actual mortality rate of all the people that are infected is probably much lower . 5

6. Clinical Features Symptoms to look for in detail: 6

7. Extra Pulmonary Manifestations 7

8. Series of Pathologic Changes in Pneumonia 8

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10. Immunopathology Acute Respiratory Distress Syndrome (ARDS) elevated C-reactive protein (CRP), lactate dehydrogenase (LDH), D-dimer, and ferritin. Cytokine Release Syndrome (CRS) Elevated IL-2, IL-7, IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon-γ inducible protein 10 (IP-10), monocyte chemoattractant protein 1 (MCP-1), Macrophage inflammatory protein 1-α (MIP-1α), and tumour necrosis factor-α (TNF-α). Systemic Inflammatory Response Syndrome (SIRS) GM-CSF-secreting T-cells responsible for recruitment of inflammatory IL-6-secreting monocytes into lungs, which further enters systemic circulation. 10

11. Severity Categorization Mild: mild coughing and fever. (oxygen saturation > 94%) Moderate: fever, cough and shortness of breath. (oxygen saturation > 90% but < 94%) Severe: dyspnea , hypoxia or > 50% lung involvement on imaging. (oxygen saturation < 90%) Critical: respiratory failure, shock, multi-organ failure. 11

12. Diagnostic Testing Common laboratory findings in COVID-19 are a decreased lymphocyte count and an increased CRP level & D-Dimer. Diagnostic test is reverse-transcriptase polymerase chain reaction (RT-PCR) assay. Rapid antigen test ( point-of-care test ) Antibody tests CT-scan of chest (thorax). 12

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14. Typical Imaging Features Of Pulmonary Involvement In COVID 19 14

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17. Ground Glass Opacities 17

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19. Reverse Halo Sign 19

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21. Crazy Paving 21

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23. Consolidation 23

24. Vascular Dilatation 24

25. Traction Bronchiectasis 25

26. Subpleural Bands & Architectural Distortion 26

27. Post COVID 19 Pumonary Fibrosis 27

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31. Case 1 31

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34. COVID 19 Pneumonia Imaging Classification 34

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36. Radiological Evidence of Covid 19 COVID-19 Reporting and Data System (CO-RADS) for use in the standardized assessment of pulmonary involvement of COVID-19 on unenhanced chest CT images and to report its initial interobserver agreement and performance . 36

37. Chest CT Severity Score Assessment 37

38.  M Chung et al. (Radiology 2020 ) &   F Pan et al. (Radiology 2020) described the CT findings of COVID-19 and total severity score 38

39. According to Yang et al. (Radiology 2020 ) , the 18 segments of both lungs were divided into 20 regions, in which the posterior apical segment of the left upper lobe was subdivided into apical and posterior segmental regions, while the anteromedial basal segment of the left lower lobe was subdivided into anterior and basal segmental regions. The lung opacities in all of the 20 lung regions were subjectively evaluated on chest CT using a system attributing scores of 0, 1, and 2 if parenchymal opacification involved 0%, less than 50%, or equal or more than 50% of each region. The CT-SS was defined as the sum of the individual scored in the 20 lung segment regions, which may range from 0 to 40 points, patients scored more than 19.5 out of 40, are categorized as severe. 39

40. 40 CT-SS 35 CT-SS 07

41. Diagnostic Challenges While laboratory based performance evaluations of RT-PCR tests show high analytical sensitivity and near-perfect specificity with no misidentification of other coronaviruses or common respiratory pathogens , test sensitivity in clinical practice may be adversely affected by a number of variables, including adequacy of specimen, specimen type, specimen handling, and stage of infection when the specimen is acquired, as stated by Centers of Disease Control guidelines for in-vitro diagnostics. False-negative RT-PCR tests have been reported in patients with CT findings of COVID-19 who eventually tested positive with serial sampling. 41

42. Limited testing capacity due to insufficient specimen collection kits, laboratory test supplies, and testing equipment precluded early widespread testing and is believed to have contributed to rapid and unchecked transmission of infection within communities by undetected individuals with milder, limited, or no symptoms. The RT-PCR test is very specific, but has a lower sensitivity of 65-95%, which means that the test can be negative even when the patient is infected. Another problem is, that you have to wait for the test results, which can take more than 24 hours, while CT-scan results are available right away. For example, CT screening of 82 asymptomatic individuals with confirmed COVID-19 from the cruise ship “Diamond Princess” showed findings of pneumonia in 54 %. 42

43. Imaging Logistics During Pandemic Provision of diagnostic imaging services to large numbers of patients suspected of having or confirmed to have COVID-19 during an outbreak can be challenging, as each study is lengthened and complicated by the need for strict adherence to infection control protocols designed to minimize risk of transmission and protect health care personnel. Droplet transmission followed by contaminated surfaces are believed to be the main modes of spread for SARS-CoV2 in radiology suites ; all patients undergoing imaging should be masked and imaged by using dedicated equipment that is cleaned and disinfected after each patient encounter. 43

44. Role of Chest Imaging in COVID-19 According to a study “The Role of Chest Imaging in Patient Management during the COVID-19 Pandemic: A Multinational Consensus Statement from the Fleischner Society” by Rubin et al, three scenarios/situations were identified which included 11 distinct nodes where imaging potentially provides clinically actionable information. Imaging is not indicated in patients suspected of having coronavirus disease 2019 (COVID-19) and mild clinical features unless they are at risk for disease progression. Imaging is indicated in a patient with COVID-19 and worsening respiratory status. 44

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52. Use of Imaging in COVID-19 The value of an imaging test relates to the generation of results that are clinically actionable either for establishing a diagnosis or for guiding management, triage or therapy. That value is diminished by costs that include the risk of radiation exposure to the patient , risk of COVID-19 transmission to uninfected health care workers and other patients, consumption of PPE, and need for cleaning and downtime of radiology rooms in resource-constrained environments. Chest radiography is insensitive in mild or early COVID-19 infection. 52

53. When patients are encouraged to present early in the course of their disease, as was the case in Wuhan, China, chest radiography has little value. The greater sensitivity of CT for early pneumonic changes is more relevant in the setting of a public health approach that required isolation of all infected patients within an environment where the reliability of COVID-19 testing was limited and turn around times were long. Alternatively , in New York City, where patients were instructed to stay at home until they experienced advanced symptoms, chest radiographs were often abnormal at the time of presentation . 53

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58. Additional Key Features Avoidance of non-value added imaging is particularly important in the COVID-19 patient population to minimize exposure risk of radiology technologists and to conserve PPE. CT Is Indicated in a Patient with Functional Impairment and/or Hypoxemia after Recovery from COVID-19. Patients with functional impairment after recovery from COVID-19 should undergo imaging to differentiate between expected morphologic abnormalities as sequelae of infection, mechanical ventilation, or both versus a different and potentially treatable process. 58

59. COVID-19 Testing is indicated in a patient who is found incidentally to have typical findings of COVID-19 at CT. Although CT findings of COVID-19 infection are nonspecific, their presence in an asymptomatic patient with no or mild respiratory symptoms is concerning in a setting of known community transmission, particularly if there is no better alternative diagnosis . In highly prevalent areas, an additional uncertainty is whether CT should be used as a screening tool either as a stand-alone or as an adjunct to RT-PCR to exclude occult infection before surgery or intensive immunosuppressive therapies. Daily Chest Radiographs Are Not Indicated in Stable Intubated Patients with COVID-19 . 59

60. THANK YOU 60