standOff. When we have changed our mind. Some entries in the table begin with a word in capitals and the reason for it. EVIDENCE CORRECTED — the finding still stands, but we had quoted the wrong sentence from the paper, and the quotation has been replaced with the right one. RETRACTED — the entry itself was wrong; it stays on the page, marked, with the reason, rather than being deleted. WITHDRAWN AND REPLACED — the entry was wrong, and a corrected version of it appears in the entries below. Each mark carries its own reason, in brackets, because the reasons differ from one entry to the next. An entry we have WITHDRAWN is removed from this page and kept in the record, with its reason. A line reading Audit and a date is a later re-reading of the entry against its whole sentence: DOUBTFUL means it was kept, and the reason says what is loose about it. Quotation marks inside the tagger's sentence. Where a tag is the tagger's own sentence, a phrase in quotation marks inside it is borrowed from the paper — the tagger's wording around it is not. The paper's own sentence is the evidence quote shown on the same row, so the borrowing can be checked against the thing borrowed from without leaving this page. Nothing inside quotation marks anywhere on this page is ours: if it is quoted, it is the paper's. Whose words a concept carries. A concept entry records a term the paper itself uses, so the term, the sense given for it, and its evidence are the paper's own words, quoted where the paper fixes them. This is the opposite of a sense entry in the tag table, which is the tagger's sentence about how the paper uses a term. Where a concept entry could not be grounded in the paper's words, the entry says so on its own row.| second reading | alternatives | an independent re-reading of a facet, recorded whether or not it agrees |
| relation to other work | claim_relations | how this paper stands to another: agrees, contradicts, extends, qualifies |
| claim type | claim_type | the shape of the claim: existence, mechanism, method, critique, prediction, null |
| concept edge | concept_edges | an asserted relation between two concepts, with the sentence asserting it |
| concept | concepts | an idea the paper works with, quoted where the paper uses it |
| content tag | content_tags | a finding, definition, quantity, statistic or variable named in the paper |
| contribution | contribution | what the paper claims to add |
| control | controls | an experiment run to eliminate a rival explanation |
| limitation | limitations | what the paper says its evidence cannot support |
| mechanism | mechanisms | how the reported effect is said to come about |
| method | method | how the paper produced its evidence |
| object of study | object_of_study | what the paper is about — the thing it investigates |
| phenomenon | phenomenon | the effect or regularity under study |
| research question | research_question | the question the paper sets itself |
| sense | senses | a distinct use of a term, quoted where the paper fixes it |
The reference list is not part of the text we hold for this paper. Our copy was extracted from the publisher's page and the bibliography did not survive that extraction, so the article below ends before its references. Nothing has been removed by us.
4009 radcardimg Radiology: Cardiothoracic Imaging Radiol Cardiothorac Imaging Radiological Society of North America PMC7233447 7233447 7977964 33778571 10.1148/ryct.2020200152 Radiological Society of North America Expert Consensus Document on Reporting Chest CT Findings Related to COVID-19: Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA Simpson Scott DO 1 Kay Fernando U MD, PhD 1 Abbara Suhny MD 1 Bhalla Sanjeev MD 1 Chung Jonathan H MD 1 Chung Michael MD 1 Henry Travis S MD 1 Kanne Jeffrey P MD 1 Kligerman Seth MD 1 Ko Jane P MD 1 Litt Harold MD, PhD 1 ✉ 1 From the Department of Radiology, Perelman School of Medicine of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104 (S.S., H.L.); Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Tex (F.U.K., S.A.); Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Mo (S.B.); Department of Radiology, University of Chicago Medicine, Chicago, Ill (J.H.C.); Department of Diagnostic, Molecular and Interventional Radiology, Icahn School of Medicine at Mount Sinai, New York, NY (M.C.); Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, Calif (T.S.H.); Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wis (J.P.K.); Department of Radiology, University of California San Diego, San Diego, Calif (S.K.); and Department of Radiology, New York University Langone Health, New York, NY (J.P.K.). ✉ Address correspondence to H.L. (e-mail: harold.litt@uphs.upenn.edu ).
✉ Corresponding author.
25 3 2020 2 2 e200152 e200152 2 6 2020 2020 by the Radiological Society of North America, Inc. Published under a http://creativecommons.org/licenses/by/4.0/ CC BY 4.0 license. Abstract
Routine screening CT for the identification of coronavirus disease 19 (COVID-19) pneumonia is currently not recommended by most radiology societies. However, the number of CT examinations performed in persons under investigation for COVID-19 has increased. We also anticipate that some patients will have incidentally detected findings that could be attributable to COVID-19 pneumonia, requiring radiologists to decide whether or not to mention COVID-19 specifically as a differential diagnostic possibility. alternativesWe 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 health care providers, assisting management of patients during this pandemic.
Published under a CC BY 4.0 license.
status released display-pdf yes is-olf no is-manuscript no is-preprint no is-journal-matter no is-scanned no is-retracted no Received 2020 Mar 23; Revision requested 2020 Mar 25; Accepted 2020 Mar 25; Collection date 2020 Apr.
Introduction
Coronavirus disease 2019 (COVID-19) ( 1 ), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ( 2 ), has become increasingly prevalent worldwide, reaching a pandemic stage in March 2020 ( 3 ). While most radiology professional organizations and societies have recommended against performing screening CT for the identification of COVID-19 ( 4 , 5 ), the number of CT examinations performed in persons under investigation (PUI) for COVID-19 may increase. We also anticipate that patients will have incidental lung findings on CT obtained for unrelated reasons that could be attributable to COVID-19.
Several recent publications have described CT imaging features of COVID-19, the evolution of these features over time, and the performance of radiologists in distinguishing COVID-19 from other viral infections ( 6 – 10 ). These studies have shown that COVID-19 often produces a CT pattern resembling organizing pneumonia, notably peripheral ground-glass opacities (GGOs) and nodular or masslike GGO that are often bilateral and multilobar ( 11 ). However, additional imaging findings have also been reported including linear, curvilinear, or perilobular opacities, consolidation, and diffuse GGO, which can mimic several disease processes including other infections, inhalational exposures, and drug toxicities ( 12 – 15 ).
COVID-19 pneumonia has a high mortality rate in some populations, including the elderly and those with diabetes, hypertension, and other comorbidities ( 16 – 18 ), and is spreading rapidly and sustainably in the community ( 19 ). research_questionphenomenonmechanismsconcepts↗concepts↗concept_edgescontent_tagsAs a result, including “COVID-19” in a radiology report could trigger a cascade of events including infection control measures and anxiety for both the managing provider and the patient. This potentially can complicate interpretations, as CT imaging features can overlap significantly with other causes of acute lung injury and organizing pneumonia ( 20 ). Standardized COVID-19 reporting language will improve communication with referring providers and has the potential to enhance efficiency and aid in management of patients during this pandemic.
This document aims to provide guidance to radiologists reporting CT findings potentially attributable to COVID-19 pneumonia in both PUI and when discovered incidentally. The potential role of CT in COVID-19; parameters for structured reporting; and the pros, cons, and limitations of adopting this strategy are discussed. In addition, practice patterns may vary by institution, and this document is meant to serve as a guide. If a radiologist, in accordance with one’s respective institutional procedures, chooses to mention COVID-19 specifically in CT reports, this standard framework can be adopted accordingly. Consultation with clinical colleagues at each institution is suggested to establish an agreed upon approach, which may evolve over time and be dependent upon the prevalence of the disease in the local population and other factors.
Chest CT in COVID-19 Infection
CT Imaging Features
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 ( 6 – 11 ). GGO has also been frequently reported to have round morphology or a “crazy paving” pattern ( 6 , 8 ). However, a significant portion of cases have opacities without a clear or specific distribution ( 8 ). 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 ( 8 ). Lymphadenopathy and pleural effusion have been rarely reported ( 6 , 21 ).
The frequency of imaging findings also depends on when infected patients are imaged. limitationscontent_tagsA slight majority of patients had a negative CT during the first 2 days after symptom onset with GGO usually developing between day 0 and 4 after symptom onset and peaking at 6–13 days ( 8 , 9 , 22 – 24 ). 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 ( 8 ). Available evidence regarding these CT findings is limited, and new patterns of pulmonary involvement may eventually be reported ( 25 ).
Diagnostic CT Performance and Screening
Chest CT findings can precede positivity on reverse-transcription polymerase chain reaction testing (RT-PCR). limitationscontrolscontent_tagsEarly reports of RT-PCR sensitivity vary considerably, ranging from 42% to 71% ( 26 , 27 ), and an initially negative RT-PCR may take up to 4 days to convert in a patient with COVID-19 ( 26 ). mechanismscontent_tagscontent_tagscontent_tagsThe reported sensitivities and specificities of CT for COVID-19 vary widely (60%–98% and 25%–53%, respectively) ( 26 – 29 ), 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 (eg, 85% prevalence by RT-PCR) ( 27 ). 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.
Literature comparing individual CT features of COVID-19 or radiologists’ performance in correctly choosing COVID-19 as a first-choice diagnosis on imaging is limited. In one study, six of seven radiologists demonstrated 93%–100% specificity in correctly distinguishing CT features of COVID-19 from other viral infections ( 10 ). A peripheral distribution of GGO was found to correctly distinguish COVID-19 from other viral causes 63%–80% of the time. However, the authors did not include high numbers of influenza-A or any noninfectious causes such as drug reaction, which could degrade radiologists’ performance.
Viral Testing—Implications for CT
In reviewing CT publications on COVID-19, it is important to consider the accuracy of the laboratory viral testing used. This applies both to the collection method and the laboratory testing method ( 30 ), as many articles published on chest CT do not specify the sample collection or RT-PCR method used ( 31 ). With respect to collection method, bronchoalveolar lavage fluid (BALF) testing is the most sensitive, but not for general use given the invasive nature of fluid collection, and because it is an aerosol-generating procedure that could place health care workers at greater risk. Sputum and nasopharyngeal swab collection are considered equivalent in sensitivity, while throat swab testing is less sensitive. As viral pneumonias typically do not result in production of purulent sputum, nasopharyngeal swab is the preferred method for sample collection ( 31 ). limitationscontent_tagsAs an example, in a recently published series of 1070 patients, the majority of samples collected were throat swabs, and throat swabs detected only approximately half of the positive cases that were detected by nasal swabs ( 32 ).
Rapid antigen tests are fast but have poor sensitivity. While RT-PCR is the most accurate, not all tests are equivalent. content_tagsEleven different RT-PCR tests were approved for use in China between January 26 and March 12, 2020, with varying levels of sensitivity. In a report of CT findings in 1014 patients ( 26 ), with 59% having a positive RT-PCR and 88% having a positive chest CT, the method of swab collection was not described. Two different RT-PCR tests were used, one of which does not appear on the list of approved tests, and the other approved for use in nasal, throat and sputum collection. The sensitivity of tests approved for use in the United States is high, with emergency use authorizations available on the website of the U.S. Food and Drug Administration ( 33 ).
Structured Reporting
Rationale and use.— The goal of structured reporting in the setting of COVID-19 pneumonia is to help radiologists recognize the findings seen, decrease reporting variability, reduce uncertainty in reporting findings potentially attributable to this infection, and enhance the referring provider’s understanding of those radiologic findings, thereby allowing better integration into clinical decision making. While we do not currently recommend the use of CT screening for COVID-19 pneumonia, we suggest using a standardized language when specifically asked to address whether or not findings of COVID-19 pneumonia may be present on CT and propose language that could be placed in the impression of the report.
How to report incidentally discovered features potentially attributable to COVID-19 pneumonia is more complex. When typical features of COVID-19 pneumonia are present in an endemic area as an incidental finding, we recommend direct communication with the referring provider to discuss the likelihood of viral infection and to try to reach consensus. As always, radiologists should follow the ACR Practice Parameter for Communication of Diagnostic Imaging Findings ( 34 ). mechanismsclaim_relationsconcept_edgesThese incidental findings do not necessarily need to be reported as COVID-19 pneumonia, with “viral pneumonia” as a reasonable and inclusive alternative. However, if consensus is reached, and COVID-19 is mentioned as a potential diagnosis in the radiology report, we suggest using the provided standardized reporting language. Additionally, staff at the site performing the examination should be notified to initiate standard operating procedures (SOP) for potential exposure.
mechanismsconcepts↗concepts↗sensescontent_tagscontent_tags↗It should be noted that viral pneumonias have a wide variety of imaging manifestations, some of which are atypical or less common in COVID-19 such as tree-in-bud opacities and other small nodules, bronchial wall thickening, and bronchial mucus plugs ( 12 ). Thus, the term viral pneumonia encompasses a range of imaging findings some of which are not typical for COVID-19. It is also important to describe other lung abnormalities that may be associated with increased morbidity in the setting of COVID-19, such as emphysema and diffuse parenchymal lung disease.
Categories.— object_of_studycontributionclaim_typemechanismscontrolscontrolsalternativesclaim_relationscontent_tagsWe propose four categories for reporting CT imaging findings potentially attributable to COVID-19, 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.
Table 1: Proposed Reporting Language for CT Findings Related to COVID-19, including Rationale, CT Findings, and Suggested Reporting Language for each Category
sensescontent_tags↗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 ( 10 , 11 ). ( Figs 1 – 4 ). 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.
Figure 1: Typical CT imaging features for COVID-19. Unenhanced thin-section axial images of the lungs in a 52-year-old man with a positive RT-PCR ( A–D ) show bilateral, multifocal rounded (asterisks) and peripheral GGO (arrows) with superimposed interlobular septal thickening and visible intralobular lines (“crazy-paving”). Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.
Typical CT imaging features for COVID-19. Unenhanced thin-section axial images of the lungs in a 52-year-old man with a positive RT-PCR (A–D) show bilateral, multifocal rounded (asterisks) and peripheral GGO (arrows) with superimposed interlobular septal thickening and visible intralobular lines (“crazy-paving”). Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention. Figure 4: Typical CT imaging features for COVID-19 and other diseases with similar findings. Posterior, peripheral, and rounded GGO and consolidation in axial images of four patients; COVID-19 ( A, B ), organizing pneumonia secondary to dermatomyositis ( C ), and influenza A pneumonia ( D ). Organizing pneumonia and influenza pneumonia can be indistinguishable from COVID-19 by CT. Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.
Typical CT imaging features for COVID-19 and other diseases with similar findings. Posterior, peripheral, and rounded GGO and consolidation in axial images of four patients; COVID-19 (A, B), organizing pneumonia secondary to dermatomyositis (C), and influenza A pneumonia (D). Organizing pneumonia and influenza pneumonia can be indistinguishable from COVID-19 by CT. Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention. Figure 2: Typical CT imaging features for COVID-19. Unenhanced thin-section axial ( A–C ) and coronal multiplanar reformatted images ( D ) of the lungs in a 77-year-old man with a positive RT-PCR show bilateral, multifocal rounded and peripheral GGO. Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.
Typical CT imaging features for COVID-19. Unenhanced thin-section axial (A–C) and coronal multiplanar reformatted images (D) of the lungs in a 77-year-old man with a positive RT-PCR show bilateral, multifocal rounded and peripheral GGO. Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention. Figure 3: Typical CT imaging features for COVID-19. Unenhanced axial ( A–C ) and sagittal multiplanar reformatted ( D ) images of the lungs in a 29-year-old man with a positive RT-PCR show multiple bilateral, rounded consolidations with surrounding GGO. Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.
Typical CT imaging features for COVID-19. Unenhanced axial (A–C) and sagittal multiplanar reformatted (D) images of the lungs in a 29-year-old man with a positive RT-PCR show multiple bilateral, rounded consolidations with surrounding GGO. Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention. sensescontent_tags↗Indeterminate features are those that have been reported in COVID-19 pneumonia but are not specific enough to arrive at a relatively confident radiologic diagnosis. An example would be diffuse GGO without a clear distribution ( Figs 5 , 6 ). 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.
Figure 5: Indeterminate CT imaging features for COVID-19. Unenhanced axial images in two patients showing patchy GGO with nonrounded morphology and no specific distribution, in a case of COVID-19 pneumonia ( A, B ) and acute lung injury from presumed drug toxicity ( C, D ). Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.
Indeterminate CT imaging features for COVID-19. Unenhanced axial images in two patients showing patchy GGO with nonrounded morphology and no specific distribution, in a case of COVID-19 pneumonia (A, B) and acute lung injury from presumed drug toxicity (C, D). Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention. Figure 6: Indeterminate CT imaging features for COVID-19. Widespread GGO with nonrounded morphology and no specific distribution in unenhanced axial images from two different patients secondary to acute lung injury from presumed drug toxicity ( A ) and Pneumocystis pneumonia ( B ). Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.
Indeterminate CT imaging features for COVID-19. Widespread GGO with nonrounded morphology and no specific distribution in unenhanced axial images from two different patients secondary to acute lung injury from presumed drug toxicity (A) and Pneumocystis pneumonia (B). Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention. sensescontent_tags↗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 ( Figs 7 – 9 ).
Figure 7: Atypical CT imaging features for COVID-19. Contrast-enhanced axial CT image ( A ) and frontal chest radiograph ( B ) showing segmental consolidation without significant GGO. Although this patient tested positive for COVID-19, the imaging features are not typical and could represent pneumonia related to COVID-19 or a secondary infectious process. Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.
Atypical CT imaging features for COVID-19. Contrast-enhanced axial CT image (A) and frontal chest radiograph (B) showing segmental consolidation without significant GGO. Although this patient tested positive for COVID-19, the imaging features are not typical and could represent pneumonia related to COVID-19 or a secondary infectious process. Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention. Figure 9: Atypical CT imaging features for COVID-19. Axial CT images from two different patients showing tree-in-bud opacities and centrilobular nodules, caused by respiratory syncytial virus ( A ) and active tuberculosis ( B ). A small cavity (arrow) is also present in ( B ) Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.
Atypical CT imaging features for COVID-19. Axial CT images from two different patients showing tree-in-bud opacities and centrilobular nodules, caused by respiratory syncytial virus (A) and active tuberculosis (B). A small cavity (arrow) is also present in (B) Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention. Figure 8: Atypical CT imaging features for COVID-19. Axial images of the lungs of two patients showing cavitation (arrow) in Klebsiella pneumonia ( A ) and tree-and-bud opacities (circle) and a cavity (arrow) in nontuberculous mycobacterial infection ( B ). Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.
Atypical CT imaging features for COVID-19. Axial images of the lungs of two patients showing cavitation (arrow) in Klebsiella pneumonia (A) and tree-and-bud opacities (circle) and a cavity (arrow) in nontuberculous mycobacterial infection (B). Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention. sensescontent_tags↗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 ( 29 ), although this result may change with local RT-PCR test characteristics.
Pros, Cons, and Limitations of Standardized Reporting
There are compelling arguments both for and against the use of standardized reporting language in describing CT findings potentially attributable to COVID-19 ( Table 2 ). This project largely stemmed from the expectation that despite most current professional guidelines recommending against the routine use of screening CT for COVID-19, CT may be requested for potential assistance in diagnosis and management, particularly if RT-PCR is not readily available.
Table 2: Pros and Cons of Standardized Reporting for Chest CT Findings Related to COVID-19
Pros.— Without expert consensus, radiologists may be left with uncertainty as to how to convey the presence, absence, or likelihood of COVID-19 when confronted with this as a specific indication or as an incidental finding. Standardized reporting can provide guidance and confidence to radiologists as well as increased clarity to providers through reduced reporting variability. Providing unique identifiers for each category facilitates mining data for future educational, research, and quality improvement. In addition, standardized radiology reports combined with clinical assessment may enable future care pathways to determine which patients may preferentially undergo RT-PCR should testing capacity be exceeded. Initial RT-PCR testing may also be negative, and typical imaging findings may encourage repeat testing.
Cons.— The true sensitivity and specificity of CT for COVID-19 remains relatively unknown. One study showed that radiologists identified COVID-19 versus other viral pneumonias correctly 60%–83% of the time based on typical CT imaging features ( 10 ). However, the results of this study must be evaluated cautiously as all of the COVID-19 cases came from one country (China) and most of the control cases from a single institution in another country (United States). Additionally, this moderate level of distinction may be reduced in clinical practice as the control cases included a low proportion of influenza-A, which is the major viral pneumonia that must be differentiated from COVID-19 during the winter and spring months across the northern hemisphere. limitationsconcepts↗concepts↗concept_edgescontent_tagsReporting “atypical features” may result in false-negative cases, and the risk of missing COVID-19 can have broad implications. Ordering providers may also feel that having “COVID-19” or “coronavirus” documented in a radiology report constrains their clinical decision making and treatment options. This concern is less relevant in PUIs, as clinical suspicion already exists. However, difficulties may arise in patients with findings suggestive of COVID-19 that are incidentally detected. Direct communication with the referring provider about the likelihood of COVID-19 is recommended to avoid surprising providers and patients. We again emphasize that as an incidental finding, particularly with indeterminate or atypical features, “viral pneumonia” may be preferable to “COVID-19” or “coronavirus.”
Limitations.— limitationscontrolscontent_tagscontent_tagsWe anticipate cases with mixed imaging findings, that is, those that have both typical and atypical imaging features for COVID-19. Recent analysis suggests that over 20% of patients with COVID-19 may have coexistent infections complicating the categorization of imaging observations ( 35 ). The radiologist will have to determine whether or not these findings are part of the same process or are unrelated. For example, a hospitalized patient undergoing chest CT for fever could have lower lobe tree-in-bud opacities as well as peripheral GGO, which could reflect aspiration superimposed on viral pneumonia. It is also possible that atypical features such as lobar consolidation may reflect a secondary bacterial pneumonia even in patients who test positive for COVID-19. Available evidence is still limited concerning the appearance of COVID-19 in the presence of secondary disease processes such as coexistent infections and aspiration. In scenarios such as these, discussion with the treating team would be prudent.
method↗limitationscontent_tagsImaging 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.
alternativesConclusions
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 examination 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.
At this time, CT screening for the detection of COVID-19 is not recommended by most radiologic 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.
Acknowledgments
Acknowledgments
We gratefully acknowledge colleagues who contributed to the development of these guidelines. University of Pennsylvania: Ana Kolansky, MD, Maya Galperin-Aizenberg, MD, Eduardo Barbosa, MD. University of Texas Southwestern Medical Center: Neil M. Rofsky, MD, Cecelia Brewington, MD, Travis Browning, MD, Eric Zeikus, MD. Washington University: Constantine Raptis, MD, Andrew Bierhals, MD. University of Chicago: Steven M. Montner, MD. Mount Sinai: Corey Eber, MD, Bradley N. Delman, MD, Adam Bernheim, MD, Adam Jacobi, MD. University of California San Francisco: Brett Elicker, MD, Michael Hope, MD, Kimberly Kallianos, MD, Karen Ordovas, MD, Brian Haas, MD, Thienkhai Vu, MD. University of Wisconsin School of Medicine and Public Health: M. Daniela Martin, MD. NYU Langone Health: William Moore, MD. University of Michigan: Ella Kazerooni, MD.
Footnotes
* S.S. and F.U.K. contributed equally to this work.
Disclosures of Conflicts of Interest: S.S. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: employed by University of Pennsylvania. Other relationships: disclosed no relevant relationships. F.U.K. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: employed by University of Texas Southwestern Medical Center. Other relationships: disclosed no relevant relationships. S.A. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: institution receives grants from NIH; author receives royalties from Elsevier for authoring of textbooks; Editor of RCTI (RSNA). Other relationships: disclosed no relevant relationships. S.B. disclosed no relevant relationships. J.H.C. disclosed no relevant relationships. M.C. disclosed no relevant relationships. T.S.H. disclosed no relevant relationships. J.P. Kanne Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: author is consultant for Parexel Informatics (clinical trial support, not related to topic at hand). Other relationships: disclosed no relevant relationships. S.K. disclosed no relevant relationships. J.P. Ko Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: institution receives money for consulting for Siemens Healthineers (research collaboration); author’s spouse is employed by Allovir (biotechnology company developing cell therapies for treatment of viral diseases). Other relationships: disclosed no relevant relationships. H.L. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: institution receives grant from Siemens Healthineers; author receives travel/accommodations/meeting expenses from GE Healthcare and Edwards LifeSciences. Other relationships: editorial board member, RCTI .
Relations on this page carry a quotation for the claim. Where a relation was separately evidenced — and so tested against the vocabulary for its type — the row says so; none of 3 relations here carry that mark. The rest are the tagger’s reading of the sentence quoted beside them.
| facet | tag | field | conf. | whose words |
|---|---|---|---|---|
| object_of_study | A REPORTING VOCABULARY WRITTEN IN TWO DAYS BECAUSE THE WORDS DID NOT AGREE - four named categories standing between a chest CT and a diagnosis, with the consequences of each word stated in the same document | object_of_study | the paper's words | |
| research_question | what language radiologists should use when a chest CT shows findings that could be COVID-19, given that naming the disease sets off a cascade and not naming it may miss it | research_question | the paper's words | |
| contribution | four reporting categories - typical, indeterminate, atypical, negative - each with standardized language and a unique coding identifier, plus an explicit pros/cons/limitations account of adopting them | contribution | the paper's words | |
| claim_type | method | claim_type | the paper's words | |
| phenomenon | a word in a report acting on the patient before any treatment does | phenomenon | the paper's words | |
| method | expert-consensus also in: expert-consensus | method | the paper's words | |
| mechanisms | THE WORD ITSELF ACTS ON THE PATIENT: `including `COVID-19` in a radiology report could trigger a cascade of events including infection control measures and anxiety for both the managing provider and the patient`, and `Ordering providers may also feel that having `COVID-19` or `coronavirus` documented in a radiology report constrains their clinical decision making and treatment options`. The shortest path in this corpus from which word to what happens | mechanisms[0] | 0.95 | the tagger's words |
| mechanisms | SO A DELIBERATELY BROADER TERM IS RECOMMENDED: `These incidental findings do not necessarily need to be reported as COVID-19 pneumonia, with `VIRAL PNEUMONIA` as a reasonable and inclusive alternative` - a word chosen for its consequences rather than its precision | mechanisms[1] | 0.95 | the tagger's words |
| mechanisms | AND THE COST OF THE BROADER TERM IS NAMED IN THE SAME DOCUMENT: `the term viral pneumonia encompasses a range of imaging findings some of which are not typical for COVID-19`. Nothing else in this corpus recommends an imprecise term and states the imprecision in the next paragraph | mechanisms[2] | 0.95 | the tagger's words |
| mechanisms | AND THE VOCABULARY REFUSES TO CARRY A PROBABILITY, ON PURPOSE: `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 ... the typicality of these features`. Four categories that are statements about THE IMAGE and explicitly not about the patient's probability - and they ship with `unique coding identifiers in brackets that can then be used for future data mining`, which is this project's own move made in March 2020 under pressure | mechanisms[3] | 0.95 | the tagger's words |
| mechanisms | AND EVERY NUMBER AROUND IT IS A RANGE, FOR THE RIFLE REASON: `The reported sensitivities and specificities of CT for COVID-19 vary widely (60%-98% and 25%-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` | mechanisms[4] | 0.95 | the tagger's words |
| limitations | THE REFERENCE STANDARD IS ITSELF A RANGE: `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`. The thing the imaging is scored against is between two-fifths and seven-tenths right | limitations[0] | 0.95 | the tagger's words |
| limitations | AND THE COLLECTION METHOD HALVES THE ANSWER: `in a recently published series of 1070 patients, the majority of samples collected were throat swabs, and throat swabs detected only approximately half of the positive cases that were detected by nasal swabs`, while `Eleven different RT-PCR tests were approved for use in China ... with varying levels of sensitivity` | limitations[1] | 0.95 | the tagger's words |
| limitations | AND A NEGATIVE IS A CLAIM ABOUT THE INSTRUMENT AND THE TIMING, NOT THE PATIENT: `A slight majority of patients had a negative CT during the first 2 days after symptom onset ... Therefore, a negative CT should not be used to exclude the possibility of COVID-19, particularly early in the disease` | limitations[2] | 0.95 | the tagger's words |
| limitations | AND THE CATEGORY SYSTEM'S OWN COST IS PRINTED: `Reporting `ATYPICAL FEATURES` may result in false-negative cases, and the risk of missing COVID-19 can have broad implications` | limitations[3] | 0.95 | the tagger's words |
| limitations | AND THE CATEGORIES MEET CASES THEY CANNOT HOLD: `We anticipate cases with mixed imaging findings, that is, those that have both typical and atypical imaging features ... OVER 20% of patients with COVID-19 may have coexistent infections complicating the categorization of imaging observations. The radiologist will have to determine whether or not these findings are part of the same process or are unrelated` | limitations[4] | 0.95 | the tagger's words |
| limitations | AND THE VOCABULARY DECLARES ITSELF PROVISIONAL: `Imaging appearances ... 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 ... As radiologists' experience with COVID-19 increases, our categorization of these findings as typical, indeterminate, or atypical may evolve` | limitations[5] | 0.95 | the tagger's words |
| controls | four named categories with fixed language and unique coding identifiers eliminates: reporting variability between radiologists facing the same image - the stated aim, 'decrease reporting variability, reduce uncertainty in reporting findings' · outcome: held | controls[0] | 0.95 | the tagger's words |
| controls | a likelihood or probability attached to each category eliminates: nothing - deliberately absent: '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' · outcome: absent-declared-unreported | controls[1] | 0.95 | the tagger's words |
| controls | a reference standard against which the categories could be scored eliminates: nothing dependable - RT-PCR sensitivity is '42% TO 71%', the collection method halves the yield, and 'Eleven different RT-PCR tests' were in use with varying sensitivity · outcome: failed | controls[2] | 0.95 | the tagger's words |
| controls | a category for images carrying both typical and atypical features eliminates: nothing - the case is anticipated and handed to the reader: 'over 20% of patients with COVID-19 may have coexistent infections complicating the categorization ... The radiologist will have to determine' · outcome: absent-declared-unreported | controls[3] | 0.95 | the tagger's words |
| concepts | COVID-19 also in: COVID-19 | concepts[0] | 0.95 | the paper's words |
| concepts | cascade of events also in: cascade of events | concepts[1] | 0.95 | the paper's words |
| concepts | viral pneumonia also in: viral pneumonia | concepts[2] | 0.95 | the paper's words |
| concepts | COVID-19 pneumonia also in: COVID-19 pneumonia | concepts[3] | 0.95 | the paper's words |
| concepts | atypical features also in: atypical features | concepts[4] | 0.95 | the paper's words |
| concepts | false-negative cases also in: false-negative cases | concepts[5] | 0.95 | the paper's words |
| senses | `typical` - NOT a probability but a statement about the literature: features `reported in the literature to be frequently and more specifically seen in COVID-19 pneumonia in the current pandemic`. The category is indexed to a moment | senses[0] | 0.95 | the tagger's words |
| senses | `indeterminate` - features `REPORTED IN COVID-19 PNEUMONIA BUT NOT SPECIFIC ENOUGH TO ARRIVE AT A relatively confident radiologic diagnosis`. A named slot for `the image cannot decide` | senses[1] | 0.95 | the tagger's words |
| senses | `atypical` - `uncommon or not occurring in COVID-19 pneumonia AND MORE TYPICAL OF OTHER DISEASES`, and the paper prints a positive-RT-PCR case that falls in it: the category is about the image, not the patient | senses[2] | 0.95 | the tagger's words |
| senses | `negative for pneumonia` - `no parenchymal abnormalities that could be attributable to infection. Specifically, GGO and consolidation are absent` - and immediately: `there may be no findings on CT early in COVID-19` | senses[3] | 0.95 | the tagger's words |
| senses | `viral pneumonia` (as recommended here) - the DELIBERATELY BROADER term, `a reasonable and inclusive alternative` whose breadth is stated as a cost: it `encompasses a range of imaging findings some of which are not typical for COVID-19` | senses[4] | 0.95 | the tagger's words |
| alternatives | claim_type: method a second reading reaching the same value. Recorded: method — note: A BLIND second reading by the project on 2026-08-25: the record's own claim type/method/phenomenon were not looked at until every value here was written and substring-verified. Not applied - a person decides. Sampling frame: the 504 staged records carrying no alternatives block, so this never re-measures the 202. All 11 records with 130+ tags were taken as a census and 19 more spread one per discipline across 22 disciplines - the dense non-neuroscience cell is the one the 202 do not contain (inside them, 94-100% of the densest bands are neuroscience; among these 11, one is)., | alternatives.claim_type | 0.85 | the tagger's words |
| alternatives | method: expert-consensus a second reading DIFFERING from the recorded value. Recorded: expert-consensus — note: A BLIND second reading by the project on 2026-08-25: the record's own claim type/method/phenomenon were not looked at until every value here was written and substring-verified. Not applied - a person decides. Sampling frame: the 504 staged records carrying no alternatives block, so this never re-measures the 202. All 11 records with 130+ tags were taken as a census and 19 more spread one per discipline across 22 disciplines - the dense non-neuroscience cell is the one the 202 do not contain (inside them, 94-100% of the densest bands are neuroscience; among these 11, one is)., | alternatives.method | 0.8 | the tagger's words |
| alternatives | phenomenon: standardized language for reporting chest CT findings related to COVID-19 a second reading DIFFERING from the recorded value. Recorded: a word in a report acting on the patient before any treatment does — note: A BLIND second reading by the project on 2026-08-25: the record's own claim type/method/phenomenon were not looked at until every value here was written and substring-verified. Not applied - a person decides. Sampling frame: the 504 staged records carrying no alternatives block, so this never re-measures the 202. All 11 records with 130+ tags were taken as a census and 19 more spread one per discipline across 22 disciplines - the dense non-neuroscience cell is the one the 202 do not contain (inside them, 94-100% of the densest bands are neuroscience; among these 11, one is)., | alternatives.phenomenon | 0.85 | the tagger's words |
| claim_relations | extends → the ACR Practice Parameter for Communication of Diagnostic Imaging Findings, which the document repeatedly defers to for how findings are communicated | claim_relations[0] | 0.95 | the tagger's words |
| claim_relations | contrasts-with → the professional guidance recommending against screening CT for COVID-19, which this document accepts while writing the language for the reports that happen anyway | claim_relations[1] | 0.95 | the tagger's words |
| concept_edges | COVID-19 —causes→ cascade of events strength of the relation: 0.95 · note: `As a result, including `COVID-19` in a radiology report could trigger a cascade of events including infection control measures and anxiety for both the managing provider and the patient.` The cause is the WORD IN THE REPORT, not the virus - which is why the same document then recommends a different word
Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but the span says including the TERM 'COVID-19' in a report COULD trigger a cascade; causes is loose. also in: COVID-19 · cascade of events | concept_edges[0] | 0.95 | the tagger's words |
| concept_edges | atypical features —causes→ false-negative cases strength of the relation: 0.9 · note: `Reporting `ATYPICAL FEATURES` may result in false-negative cases, and the risk of missing COVID-19 can have broad implications.` Weight 0.9 because the paper says `may result`, and the tag should not be more certain than the sentence
Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but the span says reporting atypical features MAY result in false negatives; hedged. also in: atypical features · false-negative cases | concept_edges[1] | 0.95 | the tagger's words |
| concept_edges | COVID-19 pneumonia —is-a→ viral pneumonia strength of the relation: 0.85 · note: APPLIED TO MY OWN TAG. The cue is KINDHOOD 'encompasses', in 'the term viral pneumonia encompasses a range of imaging findings some of which are not typical for COVID-19' - and its object is 'a range of imaging findings', NOT 'COVID-19'. The relation is real, the passage supports it, and the cue's arguments are one step from the edge's. That is the exact fault I spent today measuring in other tags, so this carries 0.85 and this note rather than 0.95 and silence
Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but the span offers 'viral pneumonia' as a reasonable alternative LABEL; is-a is loose. also in: COVID-19 pneumonia · viral pneumonia | concept_edges[2] | 0.85 | the tagger's words |
| content_tags | THE WORD ITSELF ACTS ON THE PATIENT: `including COVID-19 in a radiology report COULD TRIGGER A CASCADE OF EVENTS including infection control measures and anxiety`, and it `constrains their clinical decision making and treatment options` | content_tags.findings[0] | 0.95 | the tagger's words |
| content_tags | SO A BROADER TERM IS RECOMMENDED FOR ITS CONSEQUENCES: `VIRAL PNEUMONIA AS A reasonable and inclusive alternative` - and the cost is printed in the same document: it `encompasses a range of imaging findings some of which are not typical for COVID-19` | content_tags.findings[1] | 0.95 | the tagger's words |
| content_tags | THE VOCABULARY REFUSES TO CARRY A PROBABILITY, ON PURPOSE: `The reporting language does not offer an exact likelihood ... Rather ... the typicality of these features` - and ships with `unique coding identifiers in brackets ... for future data mining` | content_tags.findings[2] | 0.95 | the tagger's words |
| content_tags | EVERY NUMBER IS A RANGE FOR THE RIFLE REASON: CT sensitivity `60%-98%` and specificity `25%-53%`, `likely due to ... lack of strict diagnostic criteria for imaging and procedural differences for confirming infection` | content_tags.findings[3] | 0.95 | the tagger's words |
| content_tags | in one 1,070-patient series, throat swabs detected only about half the positive cases found by nasal swabs | content_tags.findings[4] | 0.95 | the tagger's words |
| content_tags | A NEGATIVE IS A CLAIM ABOUT THE INSTRUMENT AND THE TIMING: `a negative CT should not be used to exclude the possibility of COVID-19, particularly early in the disease` | content_tags.findings[5] | 0.95 | the tagger's words |
| content_tags | AND THE CATEGORY SYSTEM PRINTS ITS OWN COST: `Reporting ATYPICAL FEATURES MAY RESULT IN FALSE-NEGATIVE CASES, and the risk of missing COVID-19 can have broad implications` | content_tags.findings[6] | 0.95 | the tagger's words |
| content_tags | AND IT MEETS CASES IT CANNOT HOLD: `over 20% of patients with COVID-19 may have coexistent infections complicating the categorization ... The radiologist will have to determine whether or not these findings are part of the same process` | content_tags.findings[7] | 0.95 | the tagger's words |
| content_tags | AND THE VOCABULARY DECLARES ITSELF PROVISIONAL: `As radiologists' experience with COVID-19 increases, our categorization of these findings as typical, indeterminate, or atypical may evolve` | content_tags.findings[8] | 0.95 | the tagger's words |
| content_tags | features `reported in the literature to be frequently and more specifically seen in COVID-19 pneumonia in the current pandemic` also in: typical | content_tags.definitions[0] | 0.95 | the tagger's words |
| content_tags | features `REPORTED IN COVID-19 PNEUMONIA BUT NOT SPECIFIC ENOUGH TO ARRIVE AT A relatively confident radiologic diagnosis` also in: indeterminate | content_tags.definitions[1] | 0.95 | the tagger's words |
| content_tags | features `uncommon or not occurring in COVID-19 pneumonia AND MORE TYPICAL OF OTHER DISEASES` also in: atypical | content_tags.definitions[2] | 0.95 | the tagger's words |
| content_tags | `no parenchymal abnormalities that could be attributable to infection. Specifically, GGO and consolidation are absent` also in: negative for pneumonia | content_tags.definitions[3] | 0.95 | the tagger's words |
| content_tags | 60-98 — the reported range for chest CT in COVID-19, attributed by the authors to the lack of strict diagnostic criteria for imaging | content_tags.quantities[0] | 0.95 | the tagger's words |
| content_tags | 25-53 — the matching specificity range for the same instrument | content_tags.quantities[1] | 0.95 | the tagger's words |
| content_tags | 42-71 — the reported range for RT-PCR - the reference standard the imaging is scored against | content_tags.quantities[2] | 0.95 | the tagger's words |
| content_tags | 11 — the number approved for use in China between 26 January and 12 March 2020, with varying levels of sensitivity | content_tags.quantities[3] | 0.95 | the tagger's words |
| content_tags | 20 — the share of COVID-19 patients who may have coexistent infections, complicating which of the four categories an image belongs to | content_tags.quantities[4] | 0.95 | the tagger's words |
| content_tags | the term recommended in place of COVID-19 for incidental findings, chosen for what it avoids rather than for what it says also in: viral pneumonia | content_tags.variables[0] | 0.95 | the tagger's words |
Tags that could not be placed in the text:
What was deliberately not tagged, and why, is recorded per paper by the tagger. Where a paper has no such record, this page says so rather than implying that nothing was declined.