Case 1
A 42-year-old man confirmed with nCovid 19 by RT-PCR with no comorbidities, day 7 after the onset of initial symptoms, was admitted. He has no cough, dyspnea, or fever. His vital signs are normal, SpO2 is 98% in room air, and chest X-ray is normal. Inflammatory markers were not raised. Is chest CT required now in this patient?
Answer
No. He has only mild disease. He has no risk factors to develop any complications. Hence, he just needs observation for up to 15 days for any complications.
Learning point
Chest imaging is not indicated in asymptomatic patients or in patients with mild respiratory symptoms of nCOVID-19 with a low risk to develop complications [4].
After the initial evaluation, this patient was discharged as the disease was mild. He was monitored for 15 days with home quarantine. He made an uneventful complete recovery.
Case 2
An 18-year-old female was admitted with fever, diarrhea, and lower abdominal pain since 3 days. She was diagnosed to have acute appendicitis by classical clinical signs and ultrasound abdomen. She required emergency surgery under general anesthesia. She had no respiratory symptoms. Vitals were normal. Respiratory system examination was normal, SpO2 −98% while breathing room air, no comorbidities, and no history of exposure or contact to nCovid19. Chest X-ray was normal. C-reactive protein was raised. Other inflammatory markers were normal. The rapid antigen test was negative. RT-PCR report will take 2 days as the sample load was heavy.
Question
Is CT scan thorax required before surgery?
Answer
Yes. Some patients with nCovid19 may present with GI symptoms and may not have any respiratory symptoms. CT may show early lung involvement if any, within 3–4 days. If CT is normal, the risk for postoperative complications will be less. If RT-PCR is readily available before surgery and is negative, a CT scan may not be essential in these types of cases.
Learning point
CT scan thorax may be done in pre-operative cases where emergency surgery is required, nCovid19 is suspected, or confirmatory report takes time [4]. This will help in risk stratification. The same applies to confirmed nCovid19 cases requiring emergency surgery since a CT scan will help find out early lung lesions if any.
CT thorax was normal in this patient. She underwent appendectomy and recovery without any complications.
Case 3
A 67-year-old man, confirmed with nCovid19, has diabetes mellitus, systemic hypertension, and ischemic heart disease and has no history of any lung diseases, day 6 from initial symptoms. He has a cough and progressive dyspnea for the last 2 days, SpO2 is 88% on room air, and cardiac and renal functions are normal. Has a 3-fold rise in D-dimer and a 4-fold rise in serum ferritin. Chest X-ray shows bilateral lower zone peripheral opacities (Fig. 1).
Question
Is a CT scan required in this patient?
Answer
No. Diagnosis of nCovid19 pneumonia is already confirmed by symptoms and chest X-ray. No other comorbid or premorbid lung disease is suspected.
Learning point
CT scan is not required if no additional pathology is suspected in confirmed nCovid19 bronchopneumonia where chest X-ray shows the lesions [4].
Case 4 continued
He progressively deteriorates despite the standard treatment. He was in the Intensive Care Unit for 15 days and has persistently high inflammatory markers and D-dimer. He is dependent on oxygen 10 li by a high concentration mask. No other contributing factors for hypoxia.
Question
Is chest CT required now?
Answer
Yes. CT thorax with CT pulmonary angiogram is needed to see for the extent of the parenchymal lesion and pulmonary embolism if any as patient has persistent hypoxia. Most of the patients recover from hypoxia within 15 days. Persistent hypoxia beyond 15 days needs evaluation.
Learning point
Chest CT is valuable to evaluate patients with clinical deterioration for nCOVID-19 progression or secondary cardiopulmonary complications such as acute respiratory distress syndrome, pulmonary embolism, superimposed pneumonia, or heart failure [4]. Contrast CT is required if pulmonary embolism or other conditions which require contrast is suspected. CT is also helpful in predicting long-term prognosis and outcome. Fibrosis and honeycombing indicate permanent changes and may indicate the need for long-term oxygen therapy in patients with persistent hypoxia.
There was no evidence of pulmonary embolism in this patient. CT showed extensive disease with honeycombing (Figs. 2 and 3). He made a slow recovery and was required with long-term home oxygen for 3 months.
Case 5
A 55-year-old male, obese, and diabetic patient was confirmed with nCovid19 pneumonia, day 9 after initial symptoms. He was admitted to the hospital for 2 days due to uncontrolled diabetes mellitus with raised markers and developed sudden worsening of breathlessness with hypoxia and tachycardia on day 9. No obvious cause for sudden worsening. Electrocardiogram, echocardiography, chest X-ray, and renal and liver function were normal.
Question
Does chest CT has any role in this patient?
Answer
Yes. CT scan thorax with CT pulmonary angiogram is indicated as sudden worsening with no obvious cause may be due to pulmonary embolism. CT will also show extent of parenchymal lesion if any.
Learning point
CT may be required in unexplained worsening of symptoms. CT scan can detect small pneumothorax, pulmonary embolism, extent of lung involvement, and associated cardiopulmonary complications if any [4].
CT pulmonary angiogram showed bilateral small peripheral pulmonary emboli (Figs. 4 and 5). Despite all treatment, he progressively worsened requiring invasive ventilation. He finally succumbed on the 18th day.
Case 6
A 64-year-old male with anasarca, long standing diabetic with left foot infected gangrene, post-operative day 4 with fever, and cough was admitted. His SpO2 was 88% in room air. Chest X-ray showed right lower lobe infiltrates. No other obvious cause for respiratory symptoms. Rapid antigen test and RT-PCR for nCovid19 were negative. Cardiac evaluation was normal.
Question
Is there a role for CT in this patient?
Answer
Yes. High-resolution CT will show parenchymal lesions if any. CT will help to determine the cause for lung infiltrates.
Learning points
CT scan of the chest is helpful to detect alternative diagnosis and exclude nCovid19 pneumonia [4]. Normal chest CT excludes nCovid19 pneumonia. CT is helpful to differentiate cardiogenic pulmonary edema, volume overload pulmonary oedema, and other conditions which can mimic nCovid19.
CT scan showed bilateral small pleural effusion in this patient. No parenchymal lesions suggestive of nCovid19 were visualized in the CT scan (Fig. 6). He made uneventful recovery with correction of hypoprotinemia and nutritional status.
Case 7
A 62-year-old male was admitted 9 days after the initial symptoms with increasing cough and dyspnea, since last 2 days. He has no comorbidities. SpO2 was 90% in room air. Chest X-ray showed bilateral lower lobe opacities. Rapid antigen test and RT-PCR were negative. All inflammatory markers are raised.
Question
Does CT has any roles?
Answer
Yes. CT will show parenchymal lesions. This will help to determine the probable cause for lung infiltrates.
Learning point
Chest imaging is indicated in patients with moderate to severe respiratory symptoms and any pre-test probability of nCovid19 infection, when RT-PCR test results are negative, and in any patient for whom an RT-PCR test is not performed or not readily available [4].
CT scan showed typical features of nCovid19 bronchopneumonia (Fig. 7), and this patient was diagnosed as RT-PCR-negative nCovid19 bronchopneumonia. He made an uneventful recovery with treatment. RT-PCR may be negative in up to 20% of patients with nCovid19 pneumonia. These cases are diagnosed by symptoms, CT scan, and exclusion of other causes [5].
Case 8
A 55-year-old male was diagnosed with nCovid19, day 14 after initial symptoms. He had a severe dry cough for 1 week and was admitted with facial swelling. On examination, he has extensive surgical emphysema. Chest X-ray showed evidence of mediastinal and surgical emphysema, but did not show any evidence of pneumothorax (Fig. 8).
Question
Is CT required?
Answer
Yes. CT will be helpful to determine the cause for surgical emphysema, small pneumothorax if any which may be missed in chest X-ray, and extent of lung lesion. CT is required if any complications are suspected during the course of the disease. In case of pneumothorax, an intercostal tube (ICT) is mandatory. If only surgical emphysema, ICT has no role.
Learning point
CT is required when complications/additional unexplained symptoms or X-ray lesions appear [4].
CT scan showed small right-sided pneumothorax, mediastinal, and surgical emphysema with typical parenchymal lesions suggestive of nCovid119 bronchopneumonia (Figs. 9 and 10). He eventually made an uneventful recovery with treatment.
Case 9
A 62-year-old man had a mitral valve replacement 3 years back; confirmed with nCovid19 disease, day 3 after initial symptoms; and has a cough and dyspnea for 1 day. SpPO2 was 91% in room air. Chest X-ray has no lung lesions (Fig. 11). The inflammatory markers were marginally raised, the cardiac evaluation did not reveal any new abnormality, the left ventricular ejection fraction was normal, and the mitral valve functions normally.
Question
Is there any role for chest CT?
Answer
Yes. He is at high risk to develop complications and has early symptoms of dyspnea. Early diagnosis of pneumonia and aggressive treatment will improve the outcome.
Learning point
In high-risk symptomatic cases, early CT may be required. CT may be useful in high-risk cases for early diagnosis of nCovid19 pneumonia, usually 3–4 days after the initial onset of symptoms [4].
Chest CT has been suggested to have potential value as a rapid triaging tool in patients with moderate to severe respiratory symptoms in a resource-constrained environment where nCovid-19 is highly prevalent [4].
His chest CT showed early ground-glass opacities (Figs. 12 and 13). He was initiated on early aggressive treatment, and he made an uneventful recovery.
CT for triaging of cases
When rapid antigen test is negative and RT-PCR test report takes time, CT can be used in sick, seriously ill symptomatic patients to differentiate between nCovid19 or non-Covid lung disease. Also, in case the patient requires emergency surgery and symptoms are equivocal, CT can be done. CT may be done to determine the duration of disease when history not clear as the duration from the onset of the disease is important for treatment [4].
Patients who are dependent on oxygen even after 2 weeks of CT may help to show the extent of lung involvement and predict long-term prognosis. CT may be repeated if there is unexplained worsening of hypoxia for any small pneumothorax, pulmonary embolism, or other conditions which can worsen symptoms.
Case 10
A 65-year-old patient was admitted for coronary artery bypass graft (CABG). This patient had no respiratory symptoms. He was treated as mild nCovid19 4 months back. Clinical examination of the respiratory system was normal on current admission. Resting SpO2 and 6-min walk test was normal. His chest CT showed few bilateral ground-glass opacities (Figs. 14, 15, and 16). Inflammatory markers were normal.
Question
Is the lung lesion needs to be treated and does the patient require any postponement of surgery?
Answer
Since the patient is asymptomatic and investigations are normal, lung lesion does not need any treatment. Post nCovid19 parenchymal opacities may take time to heal, and residual scarring may persist. Since it is already 4 months after the infection, surgery can be done.
Learning point
Lung lesions may take time to heal, and residual scarring may occur in some patients. If these patients are asymptomatic, markers are normal, 6-min walk test is normal (no hypoxia on exertion), and no further treatment or evaluation is required [4]. Since it is already 4 months after the infection, surgery can be done.
He underwent CABG. He had no complications after CABG.
Imaging modality
Till recently, a high-resolution CT scan was preferred. Recent studies showed that low-dose CT protocol is a reliable diagnostic tool to detect nCovid-19 pneumonia. Low-dose chest CT protocol results in a remarkable reduction (up to 89%) in the radiation dose compared to the standard-dose protocol without lowering diagnostic accuracy [6]. High-resolution CT is indicated only if any other diffuse parenchymal lung diseases are suspected. Contrast CT is required if any other additional pathologies requiring contrast are suspected. CT pulmonary angiogram is required if pulmonary embolism is suspected.