Current status quo on COVID-19 including chest imaging

Table 1 A summary on the consensus statements/recommendations from various international organizations on the use of chest radiographs and computed tomography in coronavirus disease 2019 suspected patients

Fleischner Society Consensus Statement
Mild respiratory diseases are those with no evidence of pulmonary dysfunction or damage (e.g., no or minimal dyspnea, no hypoxemia, etc.)
Moderate-severe respiratory disease: Evidence of significant pulmonary dysfunction or damage (e.g., moderate-severe dyspnea, hypoxemia, etc.)
Main Recommendations:
Asymptomatic COVID-19 patients: Imaging is not routinely indicated for screening
Mild respiratory features of COVID-19: Imaging is not indicated unless they at risk for disease progression, i.e., the patient has underlying risk factors (refer text)
Moderate-severe respiratory features of COVID-19 regardless of COVID-19 test result: Imaging is indicated
Patients with COVID-19 and with evidence of worsening respiratory symptoms/signs: Imaging is indicated
Healthcare facility with limited resources including limited access to CT: CXR may be done in this category of patients. However, CT may be warranted in those cases where there is evidence of respiratory worsening
Additional recommendations:No role for daily CXRs in stable intubated patients with COVID-19
CT is indicated in those patients that have recovered from COVID-19 but show functional impairment and/or hypoxemia
Patients found to have incidental finding on CT suggestive of COVID-19 should undergo a COVID-19 testing
American College of Radiology (ACR) Recommendations
Viral testing (RT-PCR) remains the only accepted method for diagnosing COVID-19 disease. Confirmation with viral testing is required even if the CXR or CT findings are suggestive of the disease
CXR or CT is not currently recommended to diagnose COVID-19
The findings on chest imaging in COVID-19 patients are not specific and can overlap with other diseases such as influence, H1N1, SARS and MERS; thereby limiting the specificity of chest CT
British Society of Thoracic Imaging (BSTI) Guidelines
No role for chest CT in the diagnosis of COVID-19 unless, the patient is seriously ill or if PCR testing is unavailable
The current position is that there is no recommended use of CT, beyond “routine clinical care”
Imaging (CXR or CT) may be useful in guiding patient management decisions, complications or when looking for alternate diagnosis
Canadian Association of Thoracic Radiology/Canadian Association of Radiologists Consensus Statement
RT-PCR assay remains the gold standard for diagnosis
Chest radiograph: Should not be used to exclude COVID-19 infection. CXR is often normal early in the disease, and even when present the imaging features are non-specific for COVID-19. CXRs are most useful when an alternate diagnosis is suspected e.g., pneumothorax, pulmonary edema, large pleural effusions, lung mass or lung collapse. The study needs to be limited to those in whom the findings are expected to change the management in order to reduce the risk of transmission of the virus to healthcare workers
Chest CT: Similar to CXR, CT should only be performed if the results are expected to influence patient management. CT should not be used to routinely screen patients for possible COVID-19. Although not limited to, potential indications for CT chest in COVID-19 include detection of intrathoracic complications (e.g., pulmonary embolism), immunosuppressed or high-risk patients with suspected respiratory infection and a negative chest radiograph, initial negative RT-PCR result and normal CXR but high clinical suspicion for COVID-19 infection or clinical deterioration. In patients requiring urgent intervention or procedure, it is impractical to wait 24 h for a swab result to decide on the level of PPE required. In such situations CT chest may be used as additional tool to guide the use of PPE. Although a negative CT does not completely rule out COVID-19 infection, it can help stratify the patients into low or high-risk category

COVID-19: Coronavirus disease 2019; CT: Computed tomography; CXR: Chest radiograph; RT-PCR: Reverse transcription polymerase chain reaction; H1N1: Influenza A; SARS: Severe acute respiratory syndrome; MERS: Middle East respiratory syndrome; PPE: Personal protective equipment.

Table 2 Proposed standardized guidelines for reporting computed tomography findings related to coronavirus disease 2019[55]

COVID-19 pneumonia imaging classification	CT findings	Rationale
Typical appearance	Peripheral, bilateral, ground-glass opacities with or without consolidation or a “crazy-paving” pattern	CT imaging features most specifically associated with COVID-19
	Multifocal ground-glass opacities of rounded morphology with or without consolidation or visible intralobular lines (“crazy-paving” pattern)
	Reverse halo sign or other findings of organizing pneumonia
Indeterminate appearance	Absence of typical features + the presence of the following features: Multifocal, diffuse, perihilar, or unilateral ground-glass opacity with or without consolidation lacking a specific distribution and that are nonrounded or non-peripheral	Non-specific CT imaging features of COVID-19 pneumonia
	Few small ground-glass opacities, with a nonrounded and non-peripheral distribution
Atypical appearance	Absence of typical or indeterminate features + the presence of the following features: Isolated lobar or segmental consolidation without ground-glass opacities; discrete small nodules (centrilobular, “tree-in-bud” appearance); lung cavitation; smooth interlobular septal thickening with pleural effusion	Rarely associated with or not reported features of COVID-19
Negative for pneumonia	No features of pneumonia on chest CT	No features of pneumonia

COVID-19: Coronavirus disease 2019; CT: Computed tomography.

Table 3 Differentiating coronavirus disease 2019 from other infections based on the chest computed tomography pattern

COVID-19	Other viral pneumonias	Bacterial/mycoplasma and chlamydial pneumonias
Early stage: Peripheral pure GGO	Interstitial inflammation	Bronchial pneumonia, lobar pneumonia
Progressive stage: Peripheral multiple GGOs, consolidation, crazy-paving pattern, peripheral vascular “tree-in-bud” pattern	Hyperdense reticular patterns or multiple high-density fibrous streaks	Bronchial wall thickening
Advanced stage: Extensive exudative lesions, lung “whiteout”, fibrosis	Localized pulmonary edema and/or atelectasis	Centrilobular nodules
		Multiple consolidations
		Air bronchogram
		Tree-in-bud sign
		Pleural effusion

COVID-19: Coronavirus disease 2019; GGOs: Ground glass opacities.

Table 4 Precautions to be adopted by the radiologists, radiology staff, and trainees at the workplace and the various disinfection procedures that should be followed

Precautions to be adopted by the radiologists, radiology staff, and trainees at the workplace and the various disinfection procedures that should be followed
As a standard practice with any major public health emergencies from infectious diseases, any patient or personnel entering the health care facility should be screened by infrared temperature detector which measures the individual’s head temperature and displayed on the device
Mandatory wearing of surgical masks by all patients and staff prior to entering the hospital and at all times within the hospital premises
Isolating of symptomatic workers and social distancing to the risk of transmission from asymptomatic careers
Separating workstations by at least 6 feet
Reducing one-on-one consultations and conferences
Rotating the radiologists and staffs within the department in to 2-3 teams, off and on service together to limit the chance of spread of infection within small teams e.g., instituting a 1-week-on, 1-week-off work schedule so an adequate reserve capacity is maintained in case one group has to be quarantined
While continuing to provide emergency and oncology services, non-urgent outpatient visits, imaging studies and interventional procedures should be rescheduled or postponed after discussing with the patient’s referring physician/surgeon. These steps not only allow to free limited resources for the COVID-19 patients, but also allows to maintain safe distance among patients in the waiting, thereby, reducing the risk of transmission of the disease
Enabling teleradiology services, so that radiologists can interpret images remotely from home
Access to PPE especially to those directly dealing with confirmed and suspected COVID-19 cases (including nurses, trainees, technicians and radiologists). It is imperative to practise sterile donning and doffing of PPE in advance, and training should be provided including for safe disposal. A PPE equipment comprises of-medical protective clothing (non-sterile waterproof gown and sterile surgical gown), surgical cap, N95 mask or Ffp2/3 mask, double sterile gloves, face shields and goggles or adhering mask which also provides eye protection
Wide implementation of supportive protection: By using disposable medical caps, medical protective face masks (antifog type or N95 respirators, disposable latex gloves (double layered) and strictly implementing good hand hygiene with alcohol-based rub containing at least 60%-95% alcohol or by washing hands with soap and water for at least 20 s
Mandatory wearing of surgical masks by all patients prior to undergoing imaging
When transporting the patient for any imaging or to IR section, identify the lowest traffic/risk path, including avoiding areas with critically ill patients, if possible
Maintain spatial distance of at least 1 meter whenever possible between patient and staff during transfer
If possible, divide the radiology department into 4 zones: (1) Contaminated zone: Connected to the fever clinic, fever access way, the CT and DR examination rooms; (2) Semi-contaminated: Includes the fever-CT and fever DR control rooms and other patient examination access areas; (3) Buffer zone: Access areas for medical personnel ad a dressing area for technologists; and (4) Clean zones: Includes administrative office and the diagnostic room (rooms containing the work stations and storage rooms for medical supplies). Patients are strictly forbidden from entering the clean zones
No observers, students or unauthorized personnel should be allowed to enter the radiology department
Warning signs should be hung on the doors to the entrance of his hospital as well as the radiology department reminding the mandatory use of face masks as well as maintaining a safe distance
In hospital with more than one CT and one DR systems, one CT scanner and one DR system closest to the emergency department can be exclusively designated for confirmed and suspected COVID-19 patients
Disposable sheets should be used for every CT examination, which should be changed after each study
For ultrasound studies or USG guided procedures: Use single-use sterile gel, and the USG machine and transducer should have an extra-long cord and covered in a double bag
Equipment and environment sterilization procedures: (1) Object surface sterilization: Object surface is cleaned with 1000 mg/L chlorine containing disinfectant, wiped twice with 75% ethanol for non-corrosion resistance, once every 4 h; (2) Equipment sterilization: Cleaned with 2000 mg/L chlorine containing disinfectant. The DR detector and CT gantry in the affected area should be disinfected after each examination, using solutions suggested by the manufacturer/ vendor or wiped with 75% alcohol solution; (3) Equipment located in the buffer zone: Are wiped with 500-1000 mg/L chlorinated disinfectant or alcohol-containing disposable disinfectant wipes twice a day; (4) Sterilization of the air: All central air conditioners should be turned off to prevent air contamination with each other. In the contaminated area: The door is opened for ventilation, each time more than 30 min, once every 4 h. The air sterilizer is continuously sterilized or the ultraviolet ray is continuously used in the unmanned state for 1 h, four times a day. During disinfection the inner shielding should be closed. Other ambient air is sprayed with 1000 mg/L chlorinated disinfectant and ventilated twice a day; (5) Floor disinfection: The floors are wiped with 1000 mg/L chlorinated disinfectant; and (6) Disinfection of the bed: Both the bed and floors are wiped with 2000 mg/L chlorine-containing disinfectant. Visible contamination: Disposable absorbents should be used initially, to completely remove the pollutants, following which a cloth soaked with 2000 mg/L chlorine-containing disinfectant should be used for 30 min before wiping
Additional guidelines for IR staff & procedures: (1) If possible, perform IR procedures at the patient’s bedside to minimize transfer, at the discretion of the interventional radiologist; (2) Identify a procedure room with adequate ventilation/air-exchange (ideally a negative pressure room), with a minimum of 6 air changes per hour; (3) Minimize the number of healthcare professionals/support staff involved in the care of the COVID-19 patients whenever possible; (4) Ensure proper disinfection of re-usable eye protection (e.g., leaded glasses) and lead aprons, and for proper cleaning of the room and equipment; (5) Place appropriate signs indicating the presence of a COVID-19 patient (e.g., “COVID-19 patient: DO NOT ENTER”) on the room entrance; and (6) For AGP, such as gastrostomy/gastrojejunostomy/jejunostomy feeding tube insertion, chest tube insertion, lung/mediastinal biopsy, bronchial artery embolization, etc.; the staff and physicians should wear the following PPE: Gowns, gloves, N95 or equivalent respirator and eye protection (goggles or face shield)

COVID-19: Coronavirus disease 2019; CT: Computed tomography; PPE: Personal protective equipment; IR: Interventional radiology; AGP: Aerosol generating procedures; DR: Digital radiography; USG: Ultrasonography.