Imaging Pearls ❯ Chest ❯ COVID-19
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- Purpose: To conduct a prospective observational study across 12 U.S. hospitals to evaluate real-time performance of an interpretable artificial intelligence (AI) model to detect COVID-19 on chest radiographs.
Materials and Methods: A total of 95 363 chest radiographs were included in model training, external validation, and real-time validation. The model was deployed as a clinical decision support system, and performance was prospectively evaluated. There were 5335 total real-time predictions and a COVID-19 prevalence of 4.8% (258 of 5335). Model performance was assessed with use of receiver operating characteristic analysis, precision-recall curves, and F1 score. Logistic regression was used to evaluate the association of race and sex with AI model diagnostic accuracy. To compare model accuracy with the performance of board-certified radiologists, a third dataset of 1638 images was read independently by two radiologists.
Conclusion: AI-based tools have not yet reached full diagnostic potential for COVID-19 and underperform compared with radiologist prediction.
Performance of a Chest Radiograph AI Diagnostic Tool for COVID-19: A Prospective Observational Study
Ju Sun, et al.
Radiology: Artificial Intelligence 2022; 4(4):e210217 - Summary
This 12-site prospective study characterizes the real-time performance of an artificial intelligence–based diagnostic tool for COVID-19, which may serve as an adjunct to, but not as a replacement for, clinical decision-making in the diagnosis of COVID-19.
Key Points
• The COVID-19 artificial intelligence (AI) diagnostic tool achieved an area under the receiver operating characteristic curve of 0.70 on real-time validation.
• At equity and subgroup analysis, the AI tool demonstrated improved diagnostic capabilities in participants with more severe disease and in non-White participants, improved sensitivity in men, and improved specificity in women during real-time and external validations.
• The COVID-19 AI diagnostic system had significantly lower accuracy (63.5%) compared with radiologists (radiologist 1 = 67.8% correct, radiologist 2 = 68.6% correct; McNemar P , .001).
Performance of a Chest Radiograph AI Diagnostic Tool for COVID-19: A Prospective Observational Study
Ju Sun, et al.
Radiology: Artificial Intelligence 2022; 4(4):e210217 - “In conclusion, AI-based diagnostic tools may serve as an adjunct to, but not a replacement for, clinical decision-making concerning COVID-19 diagnosis, which largely hinges on exposure history, signs, and symptoms. Although AI-based tools have not yet reached full diagnostic potential in COVID-19, they may still offer valuable information to clinicians when taken into consideration along with clinical signs and symptoms.”
Performance of a Chest Radiograph AI Diagnostic Tool for COVID-19: A Prospective Observational Study
Ju Sun, et al.
Radiology: Artificial Intelligence 2022; 4(4):e210217
- “We present five cases of axillary lymphadenopathy which occurred after COVID-19 vaccination and that mimicked metastasis in oncologic patients. Initial radiologic diagnosis raised concerns for metastasis. However, further investigation revealed that patients received COVID-19 vaccinations in the ipsilateral arm prior to imaging. In two cases, lymph node biopsy confirmed vaccination related reactive lymphadenopathy. Ipsilateral axillary swelling / lymphadenopathy was reported based on symptoms and physical examination in COVID-19 vaccine trials. Knowledge of the potential for COVID-19 vaccine-related ipsilateral adenopathy is necessary to avoid unnecessary biopsy and change in therapy.”
Lymphadenopathy in COVID-19 Vaccine Recipients: Diagnostic Dilemma in Oncology Patients
Can Özütemiz et al.
Radiology (in press) - "In clinical studies, axillary lymphadenopathy was reported on the ipsilateral injection side. Ipsilateral axillary swelling/tenderness was the second most frequently reported local reaction to the Moderna COVID-19 vaccine, occurring in 11.6% and 16.0% of recipients following first and second dose respectively. In the Moderna cohort, clinically detected axillary and supraclavicular lymphadenopathy was reported in 1.1% of study participants within 2-4 days after vaccination, as an unsolicited adverse event. In the Pfizer-BioNTech COVID-19 vaccine trial, the rate of ipsilateral axillary and supraclavicular lymphadenopathy was reported to be 0.3% among vaccine recipients versus <0.1% among placebo group.”
Lymphadenopathy in COVID-19 Vaccine Recipients: Diagnostic Dilemma in Oncology Patients
Can Özütemiz et al.
Radiology (in press) - “Due to widescale vaccination of the majority of the U.S. population, axillary lymphadenopathy due to COVID-19 vaccination is likely to be encountered in oncologic patients. In addition, in this limited series, a triangle of intramuscular inflammation was demonstrated at the injection site on MRI and PET/CT, as also described by Eifer and Eshet , suggesting vaccine-related inflammation. Overall, our findings are important, particularly for cancer patients. Radiologists, oncologists, and internists should be aware of this secondary effect of vaccination to obviate unnecessary changes in management, unnecessary patient emotional stress or biopsy.”
Lymphadenopathy in COVID-19 Vaccine Recipients: Diagnostic Dilemma in Oncology Patients
Can Özütemiz et al.
Radiology (in press)
- • Several chest CT findings have been reported in more than 70% of RT-PCR test–proven COVID-19 cases, including ground-glass opacities, vascular enlargement, bilateral abnormalities, lower lobe involvement, and posterior predilection.
• Chest imaging is not indicated as a screening test for COVID-19 in asymptomatic patients or in patients with mild respiratory symptoms of COVID-19 (ie, absence of significant pulmonary dysfunction or damage).
• Chest imaging is indicated in patients with moderate to se- vere respiratory symptoms (ie, presence of significant pulmonary dysfunction or damage) and any pretest probability of COVID-19 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.
Chest CT in COVID-19: What the Radiologist Needs to Know
Kwee TC, Kwee RM
RadioGraphics 2020; 40:1848–1865 - • A negative chest CT examination result certainly does not exclude COVID-19. The proportion of false-positive chest CT examination results is substantial and due to overlapping im- aging features with numerous other diseases, including other viral pneumonias.
• It is important to realize that CT is not the standard for the diagnosis of COVID-19, but its findings help suggest the diagnosis in the appropriate setting. It is crucial to correlate chest CT findings with epidemiologic history, clinical presentation, and RT-PCR test results.
Chest CT in COVID-19: What the Radiologist Needs to Know
Kwee TC, Kwee RM
RadioGraphics 2020; 40:1848–1865 - “A wide spectrum of clinical manifestations can be seen with COVID-19. Fever (80.4%), cough (63.1%), fatigue (46%), and expectoration (41.8%) are the most common manifestations of COVID-19. Other common symptoms include anorexia (38.8%), chest tightness (35.7%), shortness of breath (35%), dyspnea (33.9%), and muscle soreness (33%) (14). Olfactory dysfunction (41.0%) and gustatory dysfunction (38.2%) also appear to be relatively frequent symptoms. Other less frequently reported symp- toms include headache (15.4%), pharyngalgia (13.1%), diarrhea (12.9%), shivering (10.9%), nausea and vomiting (10.2%), and abdominal pain (4.4%).”
Chest CT in COVID-19: What the Radiologist Needs to Know
Kwee TC, Kwee RM
RadioGraphics 2020; 40:1848–1865 - “Patients referred for CT should undergo non– contrast material–enhanced chest CT unless CT pulmonary angiography is required to detect pulmonary embolism (PE). Patients of all ages can become infected with SARS- CoV-2 and may need to undergo chest imaging. In addition, although chest radiography is most frequently used for follow-up imaging, some patients with COVID-19 may need to undergo follow-up chest CT. Therefore, nonenhanced chest CT should preferably be performed by using a low-radiation-dose protocol to minimize radiation burden.”
Chest CT in COVID-19: What the Radiologist Needs to Know
Kwee TC, Kwee RM
RadioGraphics 2020; 40:1848–1865 - “The incidence of normal chest CT findings in asymptomatic patients with COVID-19 is considerably high (an estimated 46% of patients). Low viral loads and confinement to the upper respiratory tract are plausible explanations for false-negative chest CT findings for COVID-19 on a patient level. In addition, there are likely host factors that lead to false-negative chest CT findings. Many patients simply do not elicit the pulmonary inflammatory response needed to produce the chest CT findings of lung injury.”
Chest CT in COVID-19: What the Radiologist Needs to Know
Kwee TC, Kwee RM
RadioGraphics 2020; 40:1848–1865 - "Several chest CT findings have been reported in more than 70% of RT-PCR test–proven CO- VID-19 cases, including ground-glass opaci- ties, vascular enlargement, bilateral abnormalities, lower lobe involvement, and posterior predilection. In COVID-19– endemic regions, the observation of these chest CT findings should raise the suspicion of possible COVID-19 diagnosis.”
Chest CT in COVID-19: What the Radiologist Needs to Know
Kwee TC, Kwee RM
RadioGraphics 2020; 40:1848–1865 - "Several chest CT findings have been reported in 10%–70% of RT-PCR test–proven COVID-19 cases, including consolidation (51.5%), linear opacity (40.7%), septal thickening and/ or reticulation (49.6%), crazy-paving pattern (34.9%), air bronchogram (40.2%), pleural thickening (34.7%), halo sign (34.5%) , bronchiectasis (24.2%), nodules (19.8%), bronchial wall thickening (14.3%), and reversed halo sign (11.1%).The following lesion distributions have been reported: unilateral (15.0%), multifocal (63.2%), diffuse (26.4%), single and/or focal (10.5%), middle or upper lobe involvement (49.3%–55.4%), peripheral location (59.0%), and central and peripheral location (36.2%).”
Chest CT in COVID-19: What the Radiologist Needs to Know
Kwee TC, Kwee RM
RadioGraphics 2020; 40:1848–1865 - "Roughly four stages of COVID-19 at chest CT have been described: (a) early stage (0–5 days after symptom onset), which is characterized by either normal findings or mainly ground-glass opacities; (b) progressive stage (5–8 days after symptom onset), which is characterized by increased ground- glass opacities and crazy-paving appearance; (c) peak stage (9–13 days after symptom onset), which is characterized by progressive consolidation; and (d) late stage (≥14 days after symptom onset), which is characterized by a gradual decrease of consolidation and ground-glass opacities, while signs of fibrosis (including parenchymal bands, architectural distortion, and traction bronchiectasis) may manifest.”
Chest CT in COVID-19: What the Radiologist Needs to Know
Kwee TC, Kwee RM
RadioGraphics 2020; 40:1848–1865 - "COVID-19 may rapidly progress to ARDS, with older patients being at higher risk. ARDS seen with COVID-19 is a cytokine release syndrome, in which immune and nonimmune cells release large amounts of proinflammatory cytokines that cause damage to the host. ARDS is characterized by an acute onset of non- cardiogenic pulmonary edema, hypoxemia, and the need for mechanical ventilation. Diffuse alveolar damage is the pathognomonic histologic finding. ARDS is the most common reason for patient admission to the intensive care unit and the main cause of mortality in patients with COVID-19.”
Chest CT in COVID-19: What the Radiologist Needs to Know
Kwee TC, Kwee RM
RadioGraphics 2020; 40:1848–1865 - “Cardiac injury occurs in 12.5%–19.7% of hospitalized patients with COVID-19 and is an independent risk factor for in-hospital mortality . Pericardial effusion manifests in an estimated 5.2% of patients with COVID-19, with a higher incidence in those with severe or critical illness. Pericardial effusion may also be a sign of cardiac injury in COVID-19. Although pericardial effusion is a nonspecific finding , radiologists should suggest the possibility of COVID-19–related cardiac injury when pericardial effusion is depicted on chest CT images.”
Chest CT in COVID-19: What the Radiologist Needs to Know
Kwee TC, Kwee RM
RadioGraphics 2020; 40:1848–1865 - “The clinical presentation, course, and outcome of COVID-19 are heterogeneous, and this also applies to the degree of pulmonary involvement. Performing CT in patients with suspected or proven COVID-19 requires comprehensive pre- cautionary safety measures. Low-radiation-dose chest CT is recommended unless CT pulmonary angiography is required to evaluate for PE. Several chest CT features are commonly seen in COVID-19 (including ground-glass opacities, vascular enlargement, bilateral abnormalities, lower lobe involvement, and posterior predilection), whereas others are not, and this may help in diagnostic decision making.”
Chest CT in COVID-19: What the Radiologist Needs to Know
Kwee TC, Kwee RM
RadioGraphics 2020; 40:1848–1865 - "The appearance of COVID-19 on chest CT images follows a somewhat predictable pattern over time. Notably, asymptomatic patients with SARS-CoV-2 infection frequently have normal chest CT examination results, and the proportion of symptomatic patients with COVID-19 and a normal chest CT examination is nonnegligible. Furthermore, lung abnormalities on chest CT images are nonspecific for COVID-19. Owing to these limitations, chest CT should not be used as an independent diagnostic tool to exclude or confirm COVID-19. RT-PCR test results are the standard for diagnosis and key component in clinical decision making.”
Chest CT in COVID-19: What the Radiologist Needs to Know
Kwee TC, Kwee RM
RadioGraphics 2020; 40:1848–1865
- “COVID-19 primarily targets the lung, with patients presenting with pneumonia that can result in acute respiratory distress syndrome (ARDS). However, COVID-19 can result in multiorgan systemic disease, affecting the brain, gastrointestinal system, heart, and kidneys, either directly or indirectly through the host’s inflammatory response and a hypercoagulable state.”
Pulmonary COVID-19: Multimodality Imaging Examples
Ko JP et al.
RadioGraphics 2020; 40:1893–1894
- “In this study, we used artificial intelligence (AI) algorithms to integrate chest CT findings with clinical symp- toms, exposure history and laboratory testing to rapidly diagnose patients who are positive for COVID-19. Among a total of 905 patients tested by real-time RT–PCR assay and next-generation sequencing RT–PCR, 419 (46.3%) tested positive for SARS-CoV-2. In a test set of 279 patients, the AI system achieved an area under the curve of 0.92 and had equal sensitivity as compared to a senior thoracic radiologist. The AI system also improved the detection of patients who were positive for COVID-19 via RT–PCR who presented with normal CT scans, correctly identifying 17 of 25 (68%) patients, whereas radiologists classified all of these patients as COVID-19 negative. When CT scans and associated clinical history are available, the proposed AI system can help to rapidly diagnose COVID-19 patients.”
Artificial intelligence–enabled rapid diagnosis of patients with COVID-19
Xueyan Mei et al.
Nat Med (2020). https://doi.org/10.1038/s41591-020-0931-3 - “In a test set of 279 patients, the AI system achieved an area under the curve of 0.92 and had equal sensitivity as compared to a senior thoracic radiologist. The AI system also improved the detection of patients who were positive for COVID-19 via RT–PCR who presented with normal CT scans, correctly identifying 17 of 25 (68%) patients, whereas radiologists classified all of these patients as COVID-19 negative. When CT scans and associated clinical history are available, the proposed AI system can help to rapidly diagnose COVID-19 patients.”
Artificial intelligence–enabled rapid diagnosis of patients with COVID-19
Xueyan Mei et al.
Nat Med (2020). https://doi.org/10.1038/s41591-020-0931-3 - "We believe implementation of the joint algorithm discussed above could aid in both issues. First, the AI algorithm could evaluate the CT immediately after completion. Second, the algorithm outperformed radiologists in identifying patients positive for COVID-19, demonstrating normal CT results in the early stage. Third, the algorithm performed equally well in sensitivity (P = 0.05) in the diagnosis of COVID-19 as compared to a senior thoracic radiologist. Specifically, the joint algorithm achieved a statistically significant 6% (P = 0.00146) and 12% (P < 1 × 10−4) improvement in AUC as compared to the CNN model using only CT images and the MLP model using only clinical information respectively.”
Artificial intelligence–enabled rapid diagnosis of patients with COVID-19
Xueyan Mei et al.
Nat Med (2020). https://doi.org/10.1038/s41591-020-0931-3 - "In conclusion, these results illustrate the potential role for a highly accurate AI algorithm for the rapid identification of COVID-19 patients, which could be helpful in combating the current disease outbreak. We believe the AI model proposed, which combines CT imaging and clinical information and shows equivalent accuracy to a senior chest radiologist, could be a useful screening tool to quickly diagnose infectious diseases such as COVID-19 that does not require radiologist input or physical tests.”
Artificial intelligence–enabled rapid diagnosis of patients with COVID-19
Xueyan Mei et al.
Nat Med (2020). https://doi.org/10.1038/s41591-020-0931-3
- “Patients with confirmed COVID-19 pneumonia have typical imaging features that can be helpful in early screening of highly suspected cases and in evaluation of the severity and extent of disease. Most patients with COVID-19 pneumonia have GGO or mixed GGO and consolidation and vascular enlargement in the lesion. Lesions are more likely to have peripheral distribution and bilateral involvement and be lower lung predomi- nant and multifocal. CT involvement score can help in evaluation of the severity and extent of the disease.”
Relation Between Chest CT Findings and Clinical Conditions of Coronavirus Disease (COVID-19) Pneumonia: A Multicenter Study
Zhao W et al.
AJR 2020; 214:1072–1077 - “Patients with confirmed COVID-19 pneumonia have typical imaging features that may be helpful in early screening of highly suspected cases and in evaluating the severity and extent of the disease.”
Relation Between Chest CT Findings and Clinical Conditions of Coronavirus Disease (COVID-19) Pneumonia: A Multicenter Study
Zhao W et al.
AJR 2020; 214:1072–1077 
Relation Between Chest CT Findings and Clinical Conditions of Coronavirus Disease (COVID-19) Pneumonia: A Multicenter Study
Zhao W et al.
AJR 2020; 214:1072–1077
Relation Between Chest CT Findings and Clinical Conditions of Coronavirus Disease (COVID-19) Pneumonia: A Multicenter Study
Zhao W et al.
AJR 2020; 214:1072–1077- "CT is considered the routine imaging modality for diagnosis and for monitoring the care of patients with COVID-19 pneumonia. It may help in early detection of lung abnormalities for screening out patients with highly suspected disease, especially patients with an initial negative RT-PCR screening result. In our study, typical imaging features, such as GGO (86.1%), mixed GGO and consolidation (64.4%), and reticulation (48.5%) were present.”
Relation Between Chest CT Findings and Clinical Conditions of Coronavirus Disease (COVID-19) Pneumonia: A Multicenter Study
Zhao W et al.
AJR 2020; 214:1072–1077 - “The differences between the nonemergency and emergency groups regarding basic clinical and radiographic features were also analyzed. The patients in the emergency group were older than the patients in the nonemergency group. However, the rate of underlying disease was not significantly different in the two groups, indicating that other factors (e.g., viral load) may be more of a reflection of the severity and extent of COVID-19 pneumonia.”
Relation Between Chest CT Findings and Clinical Conditions of Coronavirus Disease (COVID-19) Pneumonia: A Multicenter Study
Zhao W et al.
AJR 2020; 214:1072–1077 - “Clinicians worldwide face this new severe infectious lung disease with no proven therapies. Based on recent reports that demonstrated a strong association between elevated D-dimer levels and poor prognosis, concerns have risen about thrombotic complications in patients with COVID-19.”
Diagnosis, Prevention, and Treatment of Thromboembolic Complicationsin COVID-19: Report of the National Institute for Public Health of the Netherlands
Oudkerk M et al.
Radiology (in press) - "Recent observations suggest that respiratory failure in COVID-19 is not driven by the development of the acute respiratory distress syndrome (ARDS) alone, but that (microvascular) thrombotic processes may play a role as well. This may have important consequences for the diagnostic and therapeutic management of these patients. There is a strong association between D-dimer levels, disease progression and chest CT features suggesting venous thrombosis.”
Diagnosis, Prevention, and Treatment of Thromboembolic Complicationsin COVID-19: Report of the National Institute for Public Health of the Netherlands
Oudkerk M et al.
Radiology (in press) - "Diffuse alveolar damage (DAD) is common autopsy finding in COVID-19 patients (18, 19). One series (19) describes the pulmonary histopathology in SARS1 (N=44) and SARS2 (COVID-19) (N=4) patients with both infections showing DAD, pulmonary microvascular thrombosis and necrosis in mediastinal lymph nodes and the spleen. However, only COVID-19 patients showed small vessel thrombosis in multiple organs.”
Diagnosis, Prevention, and Treatment of Thromboembolic Complicationsin COVID-19: Report of the National Institute for Public Health of the Netherlands
Oudkerk M et al.
Radiology (in press) - 1. Prophylactic-dose low-molecular-weight heparin should be initiated in all patients with (suspected) COVID-19 admitted to the hospital, irrespective of risk scores (e.g. Padua score).
2. A baseline (non-contrast) chest CT should be considered in all patients with suspected COVID-19 who have an indication for hospital admission (Dutch Healthcare).
3. In patients with suspected COVID-19 as well as a high clinical suspicion for PE (e.g. based on hemoptysis, unexplained tachycardia, or signs/symptoms of DVT, acute deterioration upon moving patient), CT pulmonary angiography should be considered if the D-dimer level is elevated. The D-dimer threshold used should follow locally used algorithms, i.e. ≥500 mg/L, age-adjusted threshold, or ≥1,000 mg/L when no YEARS criteria are present. If PE is confirmed, therapeutic anticoagulation is indicated.
Diagnosis, Prevention, and Treatment of Thromboembolic Complicationsin COVID-19: Report of the National Institute for Public Health of the Netherlands
Oudkerk M et al.
Radiology (in press) - “Using multiple sources of data, machine learning models would be trained to measure an ndividuals clinical risk of suffering severe outcomes (if infected with Covid): what is the probability they will need intensive care, for which there are limited resources. How likely is it they will die. The data could include individuals basic medical histories (for COVID-19 the severity of symptoms seems to increase with age and with the presence of co-morbidities such as diabetes and hypertension) as well as other data such as household composition.”
Leveraging AI to Battle This Pandemic and The Next One
Evgeniou T, Hardoon DR, Ovchinnikov A
Harvard Business Review April 20, 2020 - Purpose: To report CT features of coronavirus disease-2019 (COVID-19) in patients with various disease severity.
Results: Six patients (8%) were diagnosed as mild type pneumonia; these patients had no obvious abnormal CT findings or manifested mild changes of lung infection. All 43 patients (59 %) with common type presented unique or multiple ground-glass opacities (GGO) in the periphery of the lungs, with or without interlobular septal thickening. In the 21 patients (29 %) with severe type, extensive GGO and pulmonary consolidation were found in 16 cases (16/21, 76 %) and 5 cases (24 %), respectively. An extensive "white lung", with atelectasis and pleural effusion were found in critical type patients (3, 4%). On the resolutive phase of the disease, CT abnormalities showed complete resolution, or demonstrated residual linear opacities.
Conclusions: Different CT features are seen according to disease severity, which can help COVID-19 stratification.
CT manifestations of coronavirus disease-2019: A retrospective analysis of T 73 cases by disease severity
Kai-Cai Liu et al.
European Journal of Radiology 126 (2020) 108941 
- “In conclusion, CT imaging can play an important role in the early diagnosis and disease stratification of COVID-19.Patchy ground-glass opacities and large consolidation located in the peripheral part of both lungs are the typical CT manifestations. The size and type of CT ab- normalities are related to disease severity.”
CT manifestations of coronavirus disease-2019: A retrospective analysis of T 73 cases by disease severity
Kai-Cai Liu et al.
European Journal of Radiology 126 (2020) 108941 - OBJECTIVE. Coronavirus disease (COVID-19) is a global pandemic. Studies in the radiology literature have suggested that CT might be sufficiently sensitive and specific in diagnosing COVID-19 when used in lieu of a reverse transcription–polymerase chain reaction test; however, this suggestion runs counter to current society guidelines. The purpose of this article is to critically review some of the most frequently cited studies on the use of CT for detecting COVID-19.
CONCLUSION. To date, the radiology literature on COVID-19 has consisted of limited retrospective studies that do not substantiate the use of CT as a diagnostic test for COVID-19.
Chest CT and Coronavirus Disease (COVID-19): A Critical Review of the Literature to Date
Raptis CA et al.
AJR 2020;215:1-4 - “The role of CT as an adjunct to or replacement for reverse transcription– polymerase chain reaction (RT-PCR) in the screening or diagnosis of COVID-19 pneumonia has been the subject of much debate. The potential value of CT is that it is widely available and fast. RT-PCR, on the other hand, still is not readily available because of a lack of testing kits and reagents, and its turnaround times are variable, ranging from hours to days.”
Chest CT and Coronavirus Disease (COVID-19): A Critical Review of the Literature to Date
Raptis CA et al.
AJR 2020;215:1-4 - “The radiology literature has reported the characteristic CT findings of COVID-19 pneumonia, which most commonly include bilateral, peripheral, often-rounded ground-glass opacities that are predominantly located in the lower lobes and that may be accompanied by consolidation. These reported findings of COVID-19 pneumonia are not unique or surprising; instead, they represent common but nonspecific imaging manifestations of acute lung injury with subsequent organization and are associated with numerous infectious and noninfectious inflammatory conditions.”
Chest CT and Coronavirus Disease (COVID-19): A Critical Review of the Literature to Date
Raptis CA et al.
AJR 2020;215:1-4 - “At present, CT should be reserved for evaluation of complications of COVID-19 pneumonia or for assessment if alternative diagnoses are suspected. As the medical community gains experience in treating patients with COVID-19 pneumonia, high quality data hopefully will emerge and will support a more expanded role for CT. We (and the radiology community at large) will welcome any such data to improve the care of patients with this disease.”
Chest CT and Coronavirus Disease (COVID-19): A Critical Review of the Literature to Date
Raptis CA et al.
AJR 2020;215:1-4 - “Coronavirus disease is an emerging infection caused by a novel coronavirus that is moving rapidly. High resolution computed tomography (CT) allows objective evaluation of the lung lesions, thus enabling us to better understand the pathogenesis of the disease. With serial CT examinations, the occurrence, development, and prognosis of the disease can be better understood. The imaging can be sorted into four phases: early phase, progressive phase, severe phase, and dissipative phase. The CT appearance of each phase and temporal progression of the imaging findings are demonstrated.”
Coronavirus Disease (COVID-19): Spectrum of CT Findings and Temporal Progression of the Disease
Mingzhi Li et al.
Acad Radiol 2020; 27:603–608 - “CT plays an important role in the diagnosis, staging, and monitoring of patients with COVID-19 pneumonia. In the early phase, multiple small patchy shadows and interstitial changes emerge, and show a distribution starting near the pleura or bronchi rather than pulmonary parenchyma. In the progressive phase, the lesions increase and enlarge, developing into multiple GGOs as well as infiltrating consolidation in both lungs. In the severe phase, massive pulmonary consolidations and “white lungs” are seen, but pleural effusion is rare. In the dissipative phase, the GGOs and pulmonary consolidations were completely absorbed, and the lesions began to change into fibrosis.”
Coronavirus Disease (COVID-19): Spectrum of CT Findings and Temporal Progression of the Disease
Mingzhi Li et al.
Acad Radiol 2020; 27:603–608 
Coronavirus Disease (COVID-19): Spectrum of CT Findings and Temporal Progression of the Disease
Mingzhi Li et al.
Acad Radiol 2020; 27:603–608- ■ Imaging is not indicated in patients with suspected 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.
■ In a resource-constrained environment, imaging is indicated for medical triage of patients with suspected COVID-19 who present with moderate-severe clinical features and a high pre-test probability of disease.
The Role of Chest Imaging in Patient Management during the COVID-19 Pandemic: A Multinational Consensus Statement from the Fleischner Society
Rubin GD et al.
Radiology (in press April 2020) - “We aim to provide guidance to radiologists in reporting CT findings potentially attributable to COVID-19 pneumonia, including standardized language to reduce reporting variability when addressing the possibility of COVID-19. When typical or indeterminate features of COVID-19 pneumonia are present in endemic areas as an incidental finding, we recommend contacting the referring providers to discuss the likelihood of viral infection. These incidental findings do not necessarily need to be reported as COVID-19 pneumonia. In this setting, using the term “viral pneumonia” can be a reasonable and inclusive alternative. However, if one opts to use the term "COVID-19" in the incidental setting, consider the provided standardized reporting language. In addition, practice patterns may vary, and this document is meant to serve as a guide.”
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Radiology (in press April 2020) - "At this time, CT screening for the detection of COVID-19 is not recommended by most radiological societies. However, we anticipate that the use of CT in clinical management as well as incidental findings potentially attributable to COVID-19 will evolve. We believe it important to provide radiologists and referring providers guidance and confidence in reporting these findings and a more consistent framework to improve clarity. Clear and frequent communication among health care providers, including radiologists, is imperative to improving patient care during this pandemic.”
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Radiology (in press April 2020) 
- “During the COVID-19 outbreak, the radiology staff, especially radiology technicians, have to be aware and trained to any incidental detection of appearances suggestive of SARS-CoV-2 infection. Such findings may be discovered not only on chest CT but, during any imaging performed for other clinical situations, also when the lungs are partially visible in non-pneumological studies. Therefore, while specific tracks for suspected or known COVID-19 patients have been established, the healthcare team should keep in mind that asymptomatic or paucisymptomatic carriers are potentially present in the non-COVID-19 pathway.”
Incidentally discovered COVID-19 pneumonia: the role of diagnostic imaging.
Pozzessere, C., Rotzinger, D.C., Ghaye, B. et al.
Eur Radiol (2020). https://doi.org/10.1007/s00330-020-06914-6 - “First, radiology technicians might be unexpectedly exposed and should be provided with adequate protective equipment. Second, we recommend reviewing all available chest images within any imaging examination as soon as possible before the patient leaves the radiology facility to identify suggestive abnormalities. Third, in case of suggestive findings, the CT suite needs to be appropriately cleaned before the next examination, while patients should be quickly directed to the COVID-19 pathway. Taken together, these actions are likely to slow down the clinical workflow, and prolonged waiting times for outpatients should be avoided.”
Incidentally discovered COVID-19 pneumonia: the role of diagnostic imaging.
Pozzessere, C., Rotzinger, D.C., Ghaye, B. et al.
Eur Radiol (2020). https://doi.org/10.1007/s00330-020-06914-6 - “Of note, once the outbreak will be under control and the number of cases declines, these emergency measures will be progressively discontinued. At the same time, the spread of SARS-CoV-2 will probably not end overnight, and some cases will still be diagnosed in the following months. Maintaining limited but adequate precautionary measures would be warranted to safeguard the health of the community, including healthcare actors and vulnerable persons. In particular, we suggest continuing to review chest images immediately after the acquisition to promptly detect suggestive features of COVID-19 pneumonia, even when the examination is performed for other clinical indications.”
Incidentally discovered COVID-19 pneumonia: the role of diagnostic imaging.
Pozzessere, C., Rotzinger, D.C., Ghaye, B. et al.
Eur Radiol (2020). https://doi.org/10.1007/s00330-020-06914-6 - “Interestingly, chest CT can be abnormal even if there are no clinical signs. Given the current prevalence of the disease, we can expect incidental detection of COVID-19 pneumonia on examinations not directly performed for this reason. This situation is of critical importance since radiologically visible COVID-19 pneumonia is associated with potential virus transmission.”
Incidentally discovered COVID-19 pneumonia: the role of diagnostic imaging.
Pozzessere, C., Rotzinger, D.C., Ghaye, B. et al.
Eur Radiol (2020). https://doi.org/10.1007/s00330-020-06914-6
The Role of Chest Imaging in Patient Management during the COVID-19 Pandemic: A Multinational Consensus Statement from the Fleischner Society.
Rubin GD et al. Radiology. 2020 Apr 7:201365. doi: 10.1148/radiol.2020201365. [Epub ahead of print]
The Role of Chest Imaging in Patient Management during the COVID-19 Pandemic: A Multinational Consensus Statement from the Fleischner Society.
Rubin GD et al. Radiology. 2020 Apr 7:201365. doi: 10.1148/radiol.2020201365. [Epub ahead of print]
The Role of Chest Imaging in Patient Management during the COVID-19 Pandemic: A Multinational Consensus Statement from the Fleischner Society.
Rubin GD et al. Radiology. 2020 Apr 7:201365. doi: 10.1148/radiol.2020201365. [Epub ahead of print]
The Role of Chest Imaging in Patient Management during the COVID-19 Pandemic: A Multinational Consensus Statement from the Fleischner Society.
Rubin GD et al. Radiology. 2020 Apr 7:201365. doi: 10.1148/radiol.2020201365. [Epub ahead of print]- “Thoracic imaging with chest radiography (CXR) and computed tomography (CT) are key tools for pulmonary disease diagnosis and management, but their role in the management of COVID-19 has not been considered within the multivariable context of the severity of respiratory disease, pre-test probability, risk factors for disease progression, and critical resource constraints. To address this deficit, a multidisciplinary panel comprised principally of radiologists and pulmonologists from 10 countries with experience managing COVID-19 patients across a spectrum of healthcare environments evaluated the utility of imaging within three scenarios representing varying risk factors, community conditions, and resource constraints. Fourteen key questions, corresponding to 11 decision points within the three scenarios and three additional clinical situations, were rated by the panel based upon the anticipated value of the information that thoracic imaging would be expected to provide. The results were aggregated, resulting in five main and three additional recommendations intended to guide medical practitioners in the use of CXR and CT in the management of COVID-19.”
The Role of Chest Imaging in Patient Management during the COVID-19 Pandemic: A Multinational Consensus Statement from the Fleischner Society.
Rubin GD et al.
Radiology. 2020 Apr 7:201365. doi: 10.1148/radiol.2020201365. [Epub ahead of print] - "Risk factors for poor outcomes in patients with COVID-19 infection are considered separately from pre-test probability, with common risk factors including age > 65 years, cardiovascular disease, diabetes, chronic respiratory disease, hypertension, and immune-compromised. Identifying a patient as being at high risk for COVID-19 progression is not necessarily a feature of any single risk factor, but is rather a clinical judgement based on the combination of underlying comorbidities and general health status that suggests a higher level of clinical concern. Where appropriate, management variations based upon risk factors for disease progression are called out explicitly, as in Scenario 1. All clinical scenarios begin by characterizing COVID-19 status based upon the availability of laboratory test results.”
The Role of Chest Imaging in Patient Management during the COVID-19 Pandemic: A Multinational Consensus Statement from the Fleischner Society.
Rubin GD et al.
Radiology. 2020 Apr 7:201365. doi: 10.1148/radiol.2020201365. [Epub ahead of print] - "For COVID-19 negative patients or any patient for whom testing is not performed, imaging may reveal an alternative diagnosis to explain the patient’s clinical features, which should direct patient care as per existing clinical guidelines or standard clinical practice. If an alternative diagnosis is not revealed or images demonstrate features of COVID-19 infection, then subsequent clinical evaluation would depend upon the pre-test probability of COVID-19 infection and COVID-19 test availability. Falsely negative COVID-19 testing is more prevalent in high pre-test probability circumstances and repeat COVID-19 testing is therefore advised if available. Depending upon the imaging findings, other clinical investigations may be pursued.”
The Role of Chest Imaging in Patient Management during the COVID-19 Pandemic: A Multinational Consensus Statement from the Fleischner Society.
Rubin GD et al.
Radiology. 2020 Apr 7:201365. doi: 10.1148/radiol.2020201365. [Epub ahead of print] - “Imaging is advised to support more rapid triage of patients in a resource-constrained setting when PoC COVID-19 testing is not available or negative . Imaging may reveal features of COVID-19, which within this scenario may be taken as a presumptive diagnosis of COVID-19 for medical triage and associated decisions regarding disposition, infection control, and clinical management. In this high pre-test probability environment, and as described for Scenario 2, the possibility of falsely negative COVID-19 testing creates a circumstance where a COVID-19 diagnosis may be presumed when imaging findings are strongly suggestive of COVID-19 despite negative COVID-19 testing. This guidance represents a variance from other published recommendations which advise against the use of imaging for the initial diagnosis of COVID-19 and was supported by direct experience amongst panelists providing care within the conditions described for this scenario. The relationship between disease severity and triage may need to be fluid depending upon resources and case load. When imaging reveals an alternative diagnosis to COVID-19, management is based upon established guidelines or standard clinical practice.”
The Role of Chest Imaging in Patient Management during the COVID-19 Pandemic: A Multinational Consensus Statement from the Fleischner Society.
Rubin GD et al.
Radiology. 2020 Apr 7:201365. doi: 10.1148/radiol.2020201365. [Epub ahead of print]
- “We propose four categories for reporting CT imaging findings potentially attributable to COVID19, each with suggested standardized language (Table 1). The reporting language does not offer an exact likelihood for COVID-19 pneumonia, which depends on several factors including prevalence in a community, exposure, risk factors, and clinical presentation. Rather, the reporting language focuses on CT findings reported in the literature and the typicality of these features in COVID-19 pneumonia rather than other diseases. Included in the reporting language are unique coding identifiers in brackets that can then be used for future data mining.”
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152 - “Typical features are those that are reported in the literature to be frequently and more specifically seen in COVID-19 pneumonia in the current pandemic. The principal differential diagnosis includes some viral pneumonias, especially influenza, and acute lung injury patterns, particularly organizing pneumonia, either secondary, such as from drug toxicity and connective tissue disease, or idiopathic.”
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152 
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152- “Indeterminate features are those that have been reported in COVID-19 pneumonia but are not specific enough to arrive at a relatively confident radiological diagnosis. An example would be diffuse GGO without a clear distribution. This finding is common in COVID-19 pneumonia but occurs in a wide variety of diseases such as acute hypersensitivity pneumonitis, Pneumocystis infection, and diffuse alveolar hemorrhage, which are difficult to distinguish by imaging alone. .”
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152 
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152- “Atypical features are those that are reported to be uncommon or not occurring in COVID-19 pneumonia and are more typical of other diseases such as lobar or segmental consolidation in the setting of a bacterial pneumonia, cavitation from necrotizing pneumonia, and tree-in-bud opacities with centrilobular nodules, as can occur with a variety of community acquired infections and aspiration.”
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152 
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152- “Negative for pneumonia implies that there are no parenchymal abnormalities that could be attributable to infection. Specifically, GGO and consolidation are absent. Importantly, there may be no findings on CT early in COVID-19. Conversely, CT has been reported to be more sensitive than RT-PCR earlier in the course of the disease, although this result may change with local RT-PCR test characteristics.”
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152 - “Imaging appearances in the standardized reporting language are based upon available literature at the time of writing in March 2020, noting the retrospective nature of many reports, including biases related to patient selection in cohort studies, examination timing, and other potential confounders. As radiologists’ experience with COVID-19 increases, our categorization of these findings as typical, indeterminate, or atypical may evolve.”
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152 - “We propose four categories for the suggested standardized CT reporting language of COVID-19 based on current literature and expert consensus. We acknowledge that for patients with unexpected findings that could be attributed to COVID-19, the matter is complex and that “viral pneumonia” is a reasonable alternative. As always, radiologists should follow the ACR Practice Parameters for Communication of Diagnostic Imaging Findings. If COVID-19 is a potential incidental diagnosis, staff at the site performing the exam should be notified to initiate SOP for potential exposure. We also acknowledge that practice patterns vary and this document is intended to provide guidance. If a radiologist chooses to mention COVID-19 in CT reports, this is a standard framework that can be adopted. Consensus between local imaging and clinical providers is essential to establish an agreed-upon approach.”
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152 
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020https://doi.org/10.1148/ryct.2020200152
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020https://doi.org/10.1148/ryct.2020200152
- “In this retrospective case series, chest CT scans of 21 symptomatic patients from China infected with the 2019 novel coronavirus (2019-nCoV) were reviewed, with emphasis on identifying and characterizing the most common findings. Typical CT findings included bilateral pulmonary parenchymal ground-glass and consolidative pulmonary opacities, sometimes with a rounded morphology and a peripheral lung distribution. Notably, lung cavitation, discrete pulmonary nodules, pleural effusions, and lymphadenopathy were absent. Follow-up imaging in a subset of patients during the study time window often demonstrated mild or moderate progression of disease, as manifested by increasing extent and density of lung opacities.”
CT Imaging Features of 2019 Novel Coronavirus (2019-nCoV)
Chung M et al.
Radiology 2020 (in press) - “This newly discovered virus has been temporarily named the 2019 novel coronavirus (2019-nCoV). Coronaviruses belong to the family Coronaviridae and the order Nidovarales, a family that includes viruses that cause diseases ranging from the common cold to severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS).”
CT Imaging Features of 2019 Novel Coronavirus (2019-nCoV)
Chung M et al.
Radiology 2020 (in press) - Key Results
• Of 21 patients with the 2019 novel coronavirus, 15 (71%) had involvement of more than two lobes at chest CT, 12 (57%) had ground-glass opacities, seven (33%) had opacities with a rounded morphology, seven (33%) had a peripheral distribution of disease, six (29%) had consolidation with ground-glass opacities, and four (19%) had crazy-paving pattern.
• Lung cavitation, discrete pulmonary nodules, pleural effusions, and lymphadenopathy were absent.
• Fourteen percent of patients (three of 21) presented with a normal CT scan.
CT Imaging Features of 2019 Novel Coronavirus (2019-nCoV)
Chung M et al.
Radiology 2020 (in press) - “Viruses are a common cause of respiratory infection. Imaging findings of viral pneumonias are varied, overlapping with other infectious and inflammatory lung diseases. Viruses in the same viral family share a similar pathogenesis; therefore, CT may help identify distinguishing patterns and features in immunocompetent patients. These preliminary data suggest that the CT findings for 2019-nCoV have many similar features to the other coronaviruses: SARS and MERS.”
CT Imaging Features of 2019 Novel Coronavirus (2019-nCoV)
Chung M et al.
Radiology 2020 (in press) - “Lung involvement with a peripheral predominance was also seen in SARS and MERS. Likewise, previous coronavirus pneumonias were also associated with a crazy-paving pattern (defined as thickened interlobular septa and intralobular lines with superimposed ground-glass opacification), which was also seen in some of our patients. The absence of pulmonary cavitation, pleural effusions, and lymphadenopathy noted in our data.”
CT Imaging Features of 2019 Novel Coronavirus (2019-nCoV)
Chung M et al.
Radiology 2020 (in press) - “There is value in recognizing that the CT appearance of 2019-nCoV shares some similarities with that of other diseases that cause viral pneumonia, particularly those within the same viral family (SARS and MERS). Presently, worldwide public health measures are updating and evolving on a daily basis to manage this current outbreak. As new cases are identified, other unique pulmonary CT imaging manifestations may emerge as potential points for discernment in this patient population.”
CT Imaging Features of 2019 Novel Coronavirus (2019-nCoV)
Chung M et al.
Radiology 2020 (in press) 
CT Imaging Features of 2019 Novel Coronavirus (2019-nCoV)
Chung M et al.
Radiology 2020 (in press)
- Key Points
• High-resolution CT (HRCT) of the chest is critical for early detection, evaluation of disease severity and follow-up of patients with the novel coronavirus pneumonia.
• The manifestations of the novel coronavirus pneumonia are diverse and change rapidly.
• Radiologists should be aware of the various features of the disease and temporal changes.
Initial CT findings and temporal changes in patients with the novel coronavirus pneumonia (2019-nCoV): a study of 63 patients in Wuhan, China.
Pan, Y., Guan, H., Zhou, S. et al. Eur Radiol (2020). https://doi.org/10.1007/s00330-020-06731-x - “The mean number of affected lobes was 3.3 ± 1.8. Nineteen (30.2%) patients had one affected lobe, five (7.9%) patients had two affected lobes, four (6.3%) patients had three affected lobes, seven (11.1%) patients had four affected lobes while 28 (44.4%) patients had 5 affected lobes. Fifty-four (85.7%) patients had patchy/punctate ground glass opacities, 14 (22.2%) patients had GGO, 12 (19.0%) patients had patchy consolidation, 11 (17.5%) patients had fibrous stripes and 8 (12.7%) patients had irregular solid nodules. Fifty-four (85.7%) patients progressed, including single GGO increased, enlarged and consolidated; fibrous stripe enlarged, while solid nodules increased and enlarged.”
Initial CT findings and temporal changes in patients with the novel coronavirus pneumonia (2019-nCoV): a study of 63 patients in Wuhan, China.
Pan, Y., Guan, H., Zhou, S. et al. Eur Radiol (2020). https://doi.org/10.1007/s00330-020-06731-x - "Coronavirus is a large RNA virus family. Six subtypes have been identified in the past, including SARS and MERS. 2019-nCoV is a new subtype whose genetic structure is 82% similar to SARS-CoV [2]. The source of infection is wild animals, which may be Chinese chrysanthemum head bats or snakes. 2019-nCoV can be transmitted through droplets or contact, and may also be transmitted through the fecal-oral route, with a high incidence and rapid infection, posing a huge threat to global public health [3]. Therefore, detecting the disease accurately and quickly is of great significance. Chest HRCT is an important screening tool for 2019-nCoV due to its high sensitivity and convenience. This study collected 63 confirmed new coronavirus pneumonia patients’ chest CT to analyze their imaging manifestations.”
Initial CT findings and temporal changes in patients with the novel coronavirus pneumonia (2019-nCoV): a study of 63 patients in Wuhan, China.
Pan, Y., Guan, H., Zhou, S. et al. Eur Radiol (2020). https://doi.org/10.1007/s00330-020-06731-x - “This study shows that the most common manifestations of new coronavirus pneumonia are patchy/punctate ground glass opacities (85.7%), patchy consolidation (19.0%), and mainly distributed in a sub-pleural area; chest CT of the patients for re-examination after 3–14 days were also observed. It was found that, as the disease progressed, the range of ground glass density patches and consolidation increased, which were mainly distributed in the middle and outer zones of the lung. When patients' condition would improve, a little fibrous stripe may appear. Conversely, when patients' condition worsened, the lungs showed diffuse lesions, and the density of both lungs increased widely, showing a "white lung" appearance, which seriously affects the patient's lung function.”
Initial CT findings and temporal changes in patients with the novel coronavirus pneumonia (2019-nCoV): a study of 63 patients in Wuhan, China.
Pan, Y., Guan, H., Zhou, S. et al. Eur Radiol (2020). https://doi.org/10.1007/s00330-020-06731-x 
Initial CT findings and temporal changes in patients with the novel coronavirus pneumonia (2019-nCoV): a study of 63 patients in Wuhan, China.
Pan, Y., Guan, H., Zhou, S. et al.
Eur Radiol (2020). https://doi.org/10.1007/s00330-020-06731-x
Initial CT findings and temporal changes in patients with the novel coronavirus pneumonia (2019-nCoV): a study of 63 patients in Wuhan, China.
Pan, Y., Guan, H., Zhou, S. et al.
Eur Radiol (2020). https://doi.org/10.1007/s00330-020-06731-x- Purpose: We aimed to compare chest HRCT lung signs identified in scans of differently aged patients with COVID-19 infections.
Methods: Case data of patients diagnosed with COVID-19 infection in Hangzhou City, Zhejiang Province in China were collected, and chest HRCT signs of infected patients in four age groups (<18 years, 18-44 years, 45-59 years, ≥60 years) were compared.
Results: Small patchy, ground-glass opacity (GGO), and consolidations were the main HRCT signs in 98 patients with confirmed COVID-19 infections. Patients aged 45–59 years and aged ≥60 years had more bilateral lung, lung lobe, and lung field involvement, and greater lesion numbers than patients <18 years. GGO accompanied with the interlobular septa thickening or a crazy-paving pattern, consolidation, and air bronchogram sign were more common in patients aged 45-59 years, and ≥60 years, than in those aged <18 years, and aged 18-44 years.
Conclusions: Chest HRCT manifestations in patients with COVID-19 are related to patient’s age, and HRCT signs may be milder in younger patients.
High-resolution computed tomography manifestations of COVID-19 infections in patients of different ages
Chen Z, Fan H, Cai J et al.
European Journal of Radiology(2020) ,doi:https://doi.org/10.1016/j.ejrad.2020.108972 - Results: Small patchy, ground-glass opacity (GGO), and consolidations were the main HRCT signs in 98 patients with confirmed COVID-19 infections. Patients aged 45–59 years and aged ≥60 years had more bilateral lung, lung lobe, and lung field involvement, and greater lesion numbers than patients <18 years. GGO accompanied with the interlobular septa thickening or a crazy-paving pattern, consolidation, and air bronchogram sign were more common in patients aged 45-59 years, and ≥60 years, than in those aged <18 years, and aged 18-44 years.
Conclusions: Chest HRCT manifestations in patients with COVID-19 are related to patient’s age, and HRCT signs may be milder in younger patients.
High-resolution computed tomography manifestations of COVID-19 infections in patients of different ages
Chen Z, Fan H, Cai J et al.
European Journal of Radiology(2020) ,doi:https://doi.org/10.1016/j.ejrad.2020.108972 - “In this study, the lesions of patients were mainly located in the lower lobe of the right lung. This finding may be related to the thick and short physiological structure of the right lower lobe bronchus, which may have allowed the virus to enter this area more easily. In addition, whether the air bronchogram is associated with the central representation needs further study. The lesions of patients were mostly distributed in peripheral zone of the lung (80.7%), probably because the virus mainly affects the terminal bronchioles and lung parenchyma around the respiratory bronchioles in the early stage.”
High-resolution computed tomography manifestations of COVID-19 infections in patients of different ages
Chen Z, Fan H, Cai J et al.
European Journal of Radiology(2020) ,doi:https://doi.org/10.1016/j.ejrad.2020.108972 - “In patients, GGO with a crazy paving pattern or interlobular septum thickening was the most common sign (48.8%), with PGGO (33.2%) second-most common. The lesions were mostly 1–3 cm patchy or nodular opacity (49.4%), and 56.2% of the lesions were accompanied with signs of air bronchogram.”
High-resolution computed tomography manifestations of COVID-19 infections in patients of different ages
Chen Z, Fan H, Cai J et al.
European Journal of Radiology(2020) ,doi:https://doi.org/10.1016/j.ejrad.2020.108972
(GGO, ground-glass opacity; PGGO, pure ground-glass opacity) - “Possible reasons for these findings are as follows: 1) adolescent cases are mostly third-generation infection cases, which may involve mainly family cluster cases. Furthermore, COVID-19 has weak virulence, resulting in lighter imaging signs in these patients ; 2) minors have immature lung structure development, resulting in atypical HRCT signs, and; 3) a COVID-19 attack on the immune system is more likely to cause diffuse alveolar damage and a large number of inflammatory exudations in middle-aged and older patients with more baseline diseases.”
High-resolution computed tomography manifestations of COVID-19 infections in patients of different ages
Chen Z, Fan H, Cai J et al.
European Journal of Radiology(2020) ,doi:https://doi.org/10.1016/j.ejrad.2020.108972 - “Finally, it's worth noting that the HRCT is depicting one second within the entire development of COVID-19, therefore different patterns might be expected in patients that undergo follow up. According to previous studies, , the lesions are related to the evolution time: they mainly manifests as GGO in the early stage (0-4 days),an increased crazy-paving pattern in the progressive stage (5-8 days) , consolidation in the peak stage (9-13 days), gradient resolution of consolidation in the dissipative stage (≥14 days).”
High-resolution computed tomography manifestations of COVID-19 infections in patients of different ages
Chen Z, Fan H, Cai J et al.
European Journal of Radiology(2020) ,doi:https://doi.org/10.1016/j.ejrad.2020.108972 - “CT is a useful tool for the surveillance of pneumonic lesions and is more likely to detect early and/or mild lesions in the virus lifecycle. Therefore, CT examinations play an important role in detecting or monitoring pulmonary parenchyma in patients suspected with COVID-19 pneumonia. Secondly, not all patients with COVID-19 have abnormal CT features. The real-time reverse transcriptase-polymerase chain reaction amplification of the viral DNA is considered the “gold standard”. Therefore, a CT examination and nuclear acid test should be used together for detecting COVID-19. Thirdly, fever and cough have been the most frequent initial symptoms, and radiologists should pay attention to these chief symptoms. Lastly, the history of exposure to other patients with COVID-19 or the epidemic area is critical to know. In conclusion, radiologists should make a comprehensive analysis when diagnosing COVID-19 infection that is beyond just assessing the radiological features.”
Key Considerations for Radiologists When Diagnosing the Novel Coronavirus Disease (COVID-19).
Lei P, Mao J, Huang Z, Liu G, Wang P, Song W.
Korean J Radiol. 2020 Jan;21:e44. https://doi.org/10.3348/kjr.2020.0190 - “In conclusion, the patients with COVID-19 pneumonia had a typical transition from early stage to advanced stage and advanced stage to dissipating stage. The manifestations of single or multiple ground-glass opacities were observed and distributed along the bronchovascular or subpleural in the pulmonary parenchyma in the early stage, higher density consolidations were presented in the advanced stage, and ground-glass opacities and consolidations were absorbed in dissipating stage. However, the patients with fibrosis in follow CT were older, with longer LOS, higher rate of ICU admission than that of those who without fibrosis.”
The Progression of Computed Tomographic (CT) Images in Patients with Coronavirus Disease (COVID-19) Pneumonia
Lei, Dr. Pinggui
Journal of Infection 2020 (in press) 
Artificial Intelligence and COVID-19- Key Results:
• A deep learning method was able to identify COVID-19 on chest CT exams (area under the receiver operating characteristic curve, 0.96).
• A deep learning method to identify community acquired pneumonia on chest CT exams (area under the receiver operating characteristic curve, 0.95).
• There is overlap in the chest CT imaging findings of all viral pneumonias with other chest diseases that encourages a multidisciplinary approach to the final diagnosis used for patient treatment.
Artificial Intelligence Distinguishes COVID-19 from Community Acquired Pneumonia on Chest CT
Lin Li t al.
Radiology 2020 (in press) - “In this study, we designed and evaluated a three-dimensional deep learning model for detecting coronavirus disease 2019 (COVID-19) from chest CT images. On an independent testing data set, we showed that this model achieved high sensitivity (90% [95% CI: 83%, 94%] and high specificity of 96% [95% CI: 93%, 98%] in detecting COVID-19. The AUC values for COVID-19 and community acquired pneumonia (CAP) were 0.96 [95% CI: 0.94, 0.99] and 0.95 [95% CI: 0.93, 0.97], respectively.”
Artificial Intelligence Distinguishes COVID-19 from Community Acquired Pneumonia on Chest CT
Lin Li t al.
Radiology 2020 (in press) 
- Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson*, Fernando U. Kay*, Suhny Abbara, Sanjeev Bhalla, Jonathan H. Chung, Michael Chung, Travis S. Henry, Jeffrey P. Kanne, Seth Kligerman, Jane P. Ko, Harold Litt
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152 - “We aim to provide guidance to radiologists in reporting CT findings potentially attributable to COVID-19 pneumonia, including standardized language to reduce reporting variability when addressing the possibility of COVID-19. When typical or indeterminate features of COVID-19 pneumonia are present in endemic areas as an incidental finding, we recommend contacting the referring providers to discuss the likelihood of viral infection. These incidental findings do not necessarily need to be reported as COVID-19 pneumonia. In this setting, using the term “viral pneumonia” can be a reasonable and inclusive alternative. However, if one opts to use the term "COVID-19" in the incidental setting, consider the provided standardized reporting language. In addition, practice patterns may vary, and this document is meant to serve as a guide. Consultation with clinical colleagues at each institution is suggested to establish a consensus reporting approach. The goal of this expert consensus is to help radiologists recognize findings of COVID-19 pneumonia and aid their communication with other healthcare providers, assisting management of patients during this pandemic.”
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152 - “Several papers have found that COVID-19 typically presents with GGO with or without consolidation in a peripheral, posterior, and diffuse or lower lung zone distribution. GGO has also been frequently reported to have round morphology or a “crazy paving” pattern. However, a significant portion of cases have opacities without a clear or specific distribution. A predominant perihilar pattern was not reported (8). Bronchial wall thickening, mucoid impactions, and nodules (“tree-in-bud” and centrilobular) seen commonly in infections, are not typically observed. Lymphadenopathy and pleural effusion have been rarely reported.”
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152 - “The frequency of imaging findings also depends on when infected patients are imaged. A slight majority of patients had a negative CT during the first two days after symptom onset with GGO usually developing between day 0 and 4 after symptom onset and peaking at 6-13 days. Therefore, a negative CT should not be used to exclude the possibility of COVID-19, particularly early in the disease. Later in the course of the disease, the frequency of consolidation increases as does the likelihood of seeing a reverse halo or atoll sign, typically absent near the time of symptom onset.”
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152 - “Chest CT findings can precede positivity on reverse transcriptase polymerase chain reaction testing (RT-PCR). Early reports of RT-PCR sensitivity vary considerably, ranging from 42% to 71%, and an initially negative RT-PCR may take up to 4 days to convert in a patient with COVID-19 (26). The reported sensitivities and specificities of CT for COVID-19 vary widely (60 to 98% and 25% to 53%, respectively), likely due to the retrospective nature of the currently published studies, including lack of strict diagnostic criteria for imaging and procedural differences for confirming infection. The positive and negative predictive value of chest CT for COVID-19 are estimated at 92% and 42%, respectively, in a population with high pretest probability for the disease (e.g., 85% prevalence by RT-PCR). The relatively low negative predictive value suggests that CT may not be valuable as a screening test for COVID-19 at least in earlier stages of the disease.”
Radiological Society of North America Expert Consensus Statement on Reporting Chest CT Findings Related to COVID-19. Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA.
Scott Simpson et al.
Published Online:Mar 25 2020 https://doi.org/10.1148/ryct.2020200152