Members of the Fleischner Society compiled a glossary of terms for thoracic imaging that replaces previous glossaries published in 1984 and 1996 for thoracic radiography and computed tomography (CT), respectively. The need to update the previous versions came from the recognition that new words have emerged, others have become obsolete, and the meaning of some terms has changed. Brief descriptions of some diseases are included, and pictorial examples (chest radiographs and CT scans) are provided for the majority of terms.

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Fleischner Society: Glossary of Terms for Thoracic Imaging

Non-thrombotic PE does not represent a distinct clinical syndrome. It may be due to a variety of embolic materials and result in a wide spectrum of clinical presentations, making the diagnosis difficult. With the exception of severe air and fat embolism, the haemodynamic consequences of non-thrombotic emboli are usually mild. Treatment is mostly supportive but may differ according to the type of embolic material and clinical severity.

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Guidelines on the Diagnosis and Management of Acute Pulmonary Embolism: The Task Force for the Diagnosis and Management of Acute Pulmonary Embolism of the European Society of Cardiology (ESC)

Background: In 2002 the American Thoracic Society/European Respiratory Society (ATS/ERS) classification of idiopathic interstitial pneumonias (IIPs) defined seven specific entities, and provided standardized terminology and diagnostic criteria. In addition, the historical “gold standard” of histologic diagnosis was replaced by a multidisciplinary approach. Since 2002 many publications have provided new information about IIPs.Purpose: The objective of this statement is to update the 2002 ATS/ERS classification of IIPs.Methods: An international multidisciplinary panel was formed and developed key questions that were addressed through a review of the literature published between 2000 and 2011.Results: Substantial progress has been made in IIPs since the previous classification. Nonspecific interstitial pneumonia is now better defined. Respiratory bronchiolitis–interstitial lung disease is now commonly diagnosed without surgical biopsy. The clinical course of idiopathic pulmonary fibrosis and nonspecific inte...

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An Official American Thoracic Society/European Respiratory Society Statement: Update of the International Multidisciplinary Classification of the Idiopathic Interstitial Pneumonias

Background: This document provides clinical recommendations for the diagnosis of idiopathic pulmonary fibrosis (IPF). It represents a collaborative effort between the American Thoracic Society, Eur...

https://www.atsjournals.org/doi/pdf/10.1164/rccm.201807-1255ST

Diagnosis of Idiopathic Pulmonary Fibrosis. An Official ATS/ERS/JRS/ALAT Clinical Practice Guideline.

Background Chest CT is used to assess the severity of lung involvement in coronavirus disease 2019 (COVID-19). Purpose To determine the changes in chest CT findings associated with COVID-19 from initial diagnosis until patient recovery. Materials and Methods This retrospective review included patients with real-time polymerase chain reaction-confirmed COVID-19 who presented between January 12, 2020, and February 6, 2020. Patients with severe respiratory distress and/or oxygen requirement at any time during the disease course were excluded. Repeat chest CT was performed at approximately 4-day intervals. Each of the five lung lobes was visually scored on a scale of 0 to 5, with 0 indicating no involvement and 5 indicating more than 75% involvement. The total CT score was determined as the sum of lung involvement, ranging from 0 (no involvement) to 25 (maximum involvement). Results Twenty-one patients (six men and 15 women aged 25-63 years) with confirmed COVID-19 were evaluated. A total of 82 chest CT scans were obtained in these patients, with a mean interval (±standard deviation) of 4 days ± 1 (range, 1-8 days). All patients were discharged after a mean hospitalization period of 17 days ± 4 (range, 11-26 days). Maximum lung involved peaked at approximately 10 days (with a calculated total CT score of 6) from the onset of initial symptoms (R2 = 0.25, P < .001). Based on quartiles of chest CT scans from day 0 to day 26 involvement, four stages of lung CT findings were defined. CT scans obtained in stage 1 (0-4 days) showed ground-glass opacities (18 of 24 scans [75%]), with a mean total CT score of 2 ± 2; scans obtained in stage 2 (5-8 days) showed an increase in both the crazy-paving pattern (nine of 17 scans [53%]) and total CT score (mean, 6 ± 4; P = .002); scans obtained in stage 3 (9-13 days) showed consolidation (19 of 21 scans [91%]) and a peak in the total CT score (mean, 7 ± 4); and scans obtained in stage 4 (≥14 days) showed gradual resolution of consolidation (15 of 20 scans [75%]) and a decrease in the total CT score (mean, 6 ± 4) without crazy-paving pattern. Conclusion In patients recovering from coronavirus disease 2019 (without severe respiratory distress during the disease course), lung abnormalities on chest CT scans showed greatest severity approximately 10 days after initial onset of symptoms. © RSNA, 2020.

https://pubs.rsna.org/doi/pdf/10.1148/radiol.2020200370

Time Course of Lung Changes at Chest CT during Recovery from Coronavirus Disease 2019 (COVID-19).

Aspergillosis is a serious pathologic condition caused by Aspergillus organisms and is frequently seen in immunocompromised patients. At computed tomography (CT), saprophytic aspergillosis (aspergilloma) is characterized by a mass with soft-tissue attenuation within a lung cavity. The mass is typically separated from the cavity wall by an airspace ("air crescent" sign) and is often associated with thickening of the wall and adjacent pleura. CT findings in allergic bronchopulmonary aspergillosis consist primarily of mucoid impaction and bronchiectasis involving predominantly the segmental and subsegmental bronchi of the upper lobes. Aspergillus necrotizing bronchitis may manifest as an endobronchial mass, obstructive pneumonitis or collapse, or a hilar mass. Bronchiolitis is characterized by centrilobular nodules and branching linear or nodular areas of increased attenuation ("tree-in-bud" pattern). Obstructing bronchopulmonary aspergillosis mimics allergic bronchopulmonary aspergillosis at CT and manifests as bilateral bronchial and bronchiolar dilatation, large mucoid impactions, and diffuse lower lobe consolidation caused by postobstructive atelectasis. Characteristic CT findings in angioinvasive aspergillosis consist of nodules surrounded by a halo of ground-glass attenuation ("halo sign") or pleura-based, wedge-shaped areas of consolidation. Although imaging findings in pulmonary aspergillosis may be nonspecific, in the appropriate clinical setting, familiarity with the CT findings may suggest or even help establish the diagnosis.

Spectrum of pulmonary aspergillosis: histologic, clinical, and radiologic findings.

Even experienced radiologists may disagree on the identification of the presence of honeycombing, and this disagreement is caused mainly by the misinterpretation of conditions that may mimic honeycombing, such as traction bronchiectasis and emphysema

https://pubs.rsna.org/doi/pdf/10.1148/radiol.12112516?hits=20

Interobserver Variability in the CT Assessment of Honeycombing in the Lungs

Imaging and clinical manifestations of viral pneumonia are protean and not reliably predictive of its origin; although definitive diagnosis cannot be made on the basis of imaging features alone, the use of a combination of clinical and radiographic findings can substantially improve the accuracy of diagnosis in this disease.

https://pubs.rsna.org/doi/pdf/10.1148/radiol.11092149

Imaging of Pulmonary Viral Pneumonia

The "crazy-paving" pattern is a common finding at thin-section computed tomography (CT) of the lungs. It consists of scattered or diffuse ground-glass attenuation with superimposed interlobular septal thickening and intralobular lines. This finding has a variety of causes, including infectious, neoplastic, idiopathic, inhalational, and sanguineous disorders. Specific disorders that can cause the crazy-paving pattern include Pneumocystis carinii pneumonia, mucinous bronchioloalveolar carcinoma, pulmonary alveolar proteinosis, sarcoidosis, nonspecific interstitial pneumonia, organizing pneumonia, exogenous lipoid pneumonia, adult respiratory distress syndrome, and pulmonary hemorrhage syndromes. Knowledge of the many causes of this pattern can be useful in preventing diagnostic errors. In addition, although the causes of this pattern are frequently indistinguishable at radiologic evaluation, differences in the location of the characteristic attenuation in the lungs, as well as the presence of additional radiologic findings, the patient's history, and the clinical presentation, can often be useful in suggesting the appropriate diagnosis.

https://pubs.rsna.org/doi/pdf/10.1148/rg.236035101

"Crazy-paving" pattern at thin-section CT of the lungs: radiologic-pathologic overview.

The aspiration of different substances into the airways and lungs may cause a variety of pulmonary complications. These disease entities most commonly involve the posterior segment of the upper lobes and the superior segment of the lower lobes. Esophagography and computed tomography (CT) are especially useful in the evaluation of aspiration disease related to tracheoesophageal or tracheopulmonary fistula. Foreign body aspiration typically occurs in children and manifests as obstructive lobar or segmental overinflation or atelectasis. An extensive, patchy bronchopneumonic pattern may be observed in patients following massive aspiration of gastric acid or water. CT is the modality of choice in establishing the diagnosis of exogenous lipoid pneumonia, which can result from aspiration of hydrocarbons or of mineral oil or a related substance. Aspiration of infectious material manifests as necrotizing consolidation and abscess formation. The relatively low diagnostic accuracy of chest radiography in aspiration diseases can be improved with CT and by being familiar with the clinical settings in which specific complications are likely to occur. Recognition of the varied clinical and radiologic manifestations of these disease entities is imperative for prompt, accurate diagnosis, resulting in decreased morbidity and mortality rates.

https://pubs.rsna.org/doi/pdf/10.1148/radiographics.20.3.g00ma01673

Tomás Franquet

Papers

Spectrum of pulmonary aspergillosis: histologic, clinical, and radiologic findings.

Interobserver Variability in the CT Assessment of Honeycombing in the Lungs

Imaging of Pulmonary Viral Pneumonia

"Crazy-paving" pattern at thin-section CT of the lungs: radiologic-pathologic overview.

Aspiration Diseases: Findings, Pitfalls, and Differential Diagnosis