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We describe a target sign on chest CT characterized by a combination of peripheral ring-like opacity and a central nodular groundglass opacity surrounding a vessel in a couple with COVID-19 pneumonia confirmed by real-time reverse transcriptase fluorescence polymerase chain reaction sputum analysis. [ABSTRACT FROM AUTHOR]

Asthma and COPD are the most prevalent of lung diseases and contribute an enormous burden of morbidity in North America and globally. In both conditions, inflammation leads to airway remodeling, which contributes to airway narrowing. To date, airway remodeling has only been assessed using histological examination of airways. However, it may now be possible to assess and quantify the extent of airway remodeling in vivo using high-resolution CT (HRCT). The aim of this article is to review the use of HRCT in the investigation of airway remodeling. A number of investigators have reported techniques to make measurements of airway dimensions using CT and an increasing number of quantitative methods are being developed. Using these techniques, airway dimensions have been examined in patients with asthma and COPD. In patients with asthma, the airway wall area was increased without a decrease in luminal area, whereas in patients with COPD, the airway luminal area was decreased and airway wall area was increased. The different pattern of remodeling may reflect fundamental differences in the inflammatory processes in asthma and COPD and could influence the reversibility of the narrowing. It has also been shown that, by quantifying both the extent of emphysema and of airway remodeling, CT is useful in differentiating COPD patients who have primarily parenchymal disease from those who have primarily airway pathology. With additional advances in technology, it is likely that quantitative assessment of airway wall dimensions will ultimately provide a valuable tool for the study of airway disease. [ABSTRACT FROM AUTHOR]

Context.-The concept of respiratory bronchiolitis/interstitial lung disease (RBILD) was introduced to explain the presence of interstitial lung disease in individuals whose only finding on surgical lung biopsy was smoker's respiratory bronchiolitis (RB). Over time, the diagnostic criteria for RBILD have become progressively more confused. Objective.-To review the diagnostic criteria for RBILD. Design.-The review was based on the literature and personal experience. Conclusions.-The concept of RBILD has changed over time with the recognition that, histologically and radiologically, RB and RBILD are usually indistinguishable. Most authors accept mild alveolar wall fibrosis extending away from the respiratory bronchioles as a part of both RB and RBILD, and occasional cases show quite marked, but probably localized, interstitial fibrosis. What has not been appreciated is that RB is not only an extremely common disease in cigarette smokers but also is ordinarily associated with airflow obstruction. Further, interstitial fibrosis is sometimes found in centrilobular emphysema, and this phenomenon has probably lead to some cases of centrilobular emphysema being misclassified as RB or RBILD. Despite the presence of fibrosis, centrilobular emphysema is still associated with airflow obstruction. We suggest that RBILD be restricted to the clinical setting in which cigarette smokers have a restrictive or mixed obstructive and restrictive functional abnormality, have a marked decrease in diffusing capacity with minimal evidence of airflow obstruction, or have imaging studies showing ground glass opacities/centrilobular nodules plus reticulation and no other lesion besides RB on biopsy to account for these changes. In this setting, the presence of RB-associated interstitial fibrosis probably causes the functional changes. [ABSTRACT FROM AUTHOR]

The article discusses the alternative way of classifying idiopathic interstitial pneumonias based on pathological and radiological conditions. In terms of pathology, it can be classified by purely cellular processes, processes that show the type of linear fibrosis and the process that demonstrates the fibrotic architectural distortion. While radiological findings classify them based on airspace opacification without reticulation including the cryptogenic organizing pneumonia.

Describes the clinical, chest radiographic, high-resolution computed tomography (CT), and histopathologic features of clay dye "sendo" dust pneumoconiosis in seven rush mat workers in Japan. Duration of exposure from 15 to 45 years; Indication that rush mat workers' sendo dust pneumoconiosis is caused by dust containing free silica; Small nodular opacities and bronchial and bronchiolar abnormalities as indicated in the radiographic and high-resolution CT.

Examines cryptogenic fibrosing alveolitis. Research by Scadding, 1964; Traits of fibrosing alveolitis; Alternative names for disease; Generally unknown cause; Prevalence; Etiology; Pathology and pathogenesis; Clinical features; Diagnosis; Treatment.

Purpose: The RSNA expert consensus statement and CO-RADS reporting system assist radiologists in describing lung imaging findings in a standardized manner in patients under investigation for COVID-19 pneumonia and provide clarity in communication with other healthcare providers. We aim to compare diagnostic performance and inter-/intra-observer among chest radiologists in the interpretation of RSNA and CO-RADS reporting systems and assess clinician preference. Methods: Chest CT scans of 279 patients with suspected COVID-19 who underwent RT-PCR testing were retrospectively and independently examined by 3 chest radiologists who assigned interpretation according to the RSNA and CO-RADS reporting systems. Inter-/intra-observer analysis was performed. Diagnostic accuracy of both reporting systems was calculated. 60 clinicians participated in a survey to assess end-user preference of the reporting systems. Results: Both systems demonstrated almost perfect inter-observer agreement (Fleiss kappa 0.871, P < 0.0001 for RSNA; 0.876, P < 0.0001 for CO-RADS impressions). Intra-observer agreement between the 2 scoring systems using the equivalent categories was almost perfect (Fleiss kappa 0.90-0.92, P < 0.001). Positive predictive values were high, 0.798-0.818 for RSNA and 0.891-0.903 CO-RADS. Negative predictive value were similar, 0.573-0.585 for RSNA and 0.573-0.58 for CO-RADS. Specificity differed between the 2 systems, 68-73% for CO-RADS and 52-58% for RSNA with superior specificity of CO-RADS. Of 60 survey participants, the majority preferred the RSNA reporting system rather than CO-RADS for all options provided (66.7-76.7%; P < 0.05). Conclusions: RSNA and CO-RADS reporting systems are consistent and reproducible with near perfect inter-/intra-observer agreement and excellent positive predictive value. End-users preferred the reporting language in the RSNA system. [ABSTRACT FROM AUTHOR]

Purpose: To assess the interobserver variability between chest radiologists in the interpretation of the Radiological Society of North America (RSNA) expert consensus statement reporting guidelines in patients with suspected coronavirus disease 2019 (COVID-19) pneumonia in a setting with limited reverse transcription polymerase chain reaction testing availability. Methods: Chest computed tomography (CT) studies in 303 consecutive patients with suspected COVID-19 were reviewed by 3 fellowship-trained chest radiologists. Cases were assigned an impression of typical, indeterminate, atypical, or negative for COVID-19 pneumonia according to the RSNA expert consensus statement reporting guidelines, and interobserver analysis was performed. Objective CT features associated with COVID-19 pneumonia and distribution of findings were recorded. Results: The Fleiss kappa for all observers was almost perfect for typical (0.815), atypical (0.806), and negative (0.962) COVID-19 appearances (P <.0001) and substantial (0.636) for indeterminate COVID-19 appearance (P <.0001). Using Cramer V analysis, there were very strong correlations between all radiologists' interpretations, statistically significant for all (typical, indeterminate, atypical, and negative) COVID-19 appearances (P <.001). Objective CT imaging findings were recorded in similar percentages of typical cases by all observers. Conclusion: The RSNA expert consensus statement on reporting chest CT findings related to COVID-19 demonstrates substantial to almost perfect interobserver agreement among chest radiologists in a relatively large cohort of patients with clinically suspected COVID-19. It therefore serves as a reliable reference framework for radiologists to accurately communicate their level of suspicion based on the presence of evidence-based objective findings. [ABSTRACT FROM AUTHOR]

Recent clinical practice guidelines have addressed the diagnosis of idiopathic pulmonary fibrosis (IPF) and fibrotic hypersensitivity pneumonitis (fHP). These disease-specific guidelines were developed independently, without clear direction on how to apply their respective recommendations concurrently within a single patient, where discrimination between these two fibrotic interstitial lung diseases represents a frequent diagnostic challenge. The objective of this review, created by an international group of experts, was to suggest a pragmatic approach on how to apply existing guidelines to distinguish IPF and fHP. Key clinical, radiologic, and pathologic features described in previous guidelines are integrated in a set of diagnostic algorithms, which then are placed in the broader context of multidisciplinary discussion to guide the generation of a consensus diagnosis. Although these algorithms necessarily reflect some uncertainty wherever strong evidence is lacking, they provide insight into the current approach favored by experts in the field based on currently available knowledge. The authors further identify priorities for future research to clarify ongoing uncertainties in the diagnosis of fibrotic interstitial lung diseases. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To assess the CT and magnetic resonance (MR) imaging findings of thymic epithelial tumors classified according to the current World Health Organization (WHO) histologic classification and to determine useful findings in differentiating the main subtypes. Materials and methods: Sixty patients with thymic epithelial tumor who underwent both CT and MR imaging were reviewed retrospectively. All cases were classified according to the 2004 WHO classification. The following findings were assessed in each case on both CT and MRI: size of tumor, contour, perimeter of capsule; homogeneity, presence of septum, hemorrhage, necrotic or cystic component within tumor; presence of mediastinal lymphadenopathy, pleural effusion, and great vessel invasion. These imaging characteristics of 30 low-risk thymomas (4 type A, 12 type AB, and 14 type B1), 18 high-risk thymomas (11 type B2 and seven type B3), and 12 thymic carcinomas on CT and MR imaging were compared using the chi-square test. Comparison between CT and MR findings was performed by using McNemar test. Results: On both CT and MR imaging, thymic carcinomas were more likely to have irregular contours (P <.001), necrotic or cystic component (P <.05), heterogeneous contrast-enhancement (P <.05), lymphadenopathy (P <.0001), and great vessel invasion (P <.001) than low-risk and high-risk thymomas. On MR imaging, the findings of almost complete capsule, septum, and homogenous enhancement were more commonly seen in low-risk thymomas than high-risk thymomas and thymic carcinomas (P <.05). MR imaging was superior to CT in the depiction of capsule, septum, or hemorrhage within tumor (all comparison, P <.05). Conclusion: The presence of irregular contour, necrotic or cystic component, heterogeneous enhancement, lymphadenopathy, and great vessel invasion on CT or MR imaging are strongly suggestive of thymic carcinomas. On MR imaging, the findings of contour, capsule, septum, and homogenous enhancement are helpful in distinguishing low-risk thymomas from high-risk thymomas and thymic carcinomas. [Copyright &y& Elsevier]

Abstract: Metabolic lung disease includes pulmonary alveolar proteinosis (PAP), pulmonary amyloidosis, metastatic pulmonary calcification, dendritic pulmonary ossification, pulmonary alveolar microlithiasis, and storage diseases. In pulmonary alveolar proteinosis, CT demonstrates air-space consolidation with thickened interlobular septa, producing the so-called “crazy paving” appearance. Pulmonary amyloidosis can appear as parenchymal nodules (nodular parenchymal form), diffuse interstitial deposit (diffuse interstitial form), or submucosal deposits in the airways (tracheobronchial form). Metastatic pulmonary calcification may appear on high-resolution CT as numerous 3- to 10-mm diameter calcified nodules or, more commonly as fluffy and poorly defined nodular opacities. In pulmonary microlithiasis, high-resolution CT demonstrates diffuse punctuate micronodules showing slight perilobular predominance resulting in apparent calcification of interlobular septa. Niemann–Pick disease appears as ground-glass attenuation in the upper lung zone and thickening of the interlobular septa in the lower lung zone. Radiologic study including high-resolution CT will be helpful for the diagnosis and follow-up of these diseases. [Copyright &y& Elsevier]

Abstract: Objective: To review the computed tomography (CT) imaging findings of pleural mesothelioma at presentation and to correlate the CT with the histological subtype. Materials and methods: Pathology reports from 1997 to 2006 were reviewed at two academic institutions to identify patients with proven pleural mesothelioma. Diagnosis was based on histologic findings in specimens obtained by transthoracic needle biopsy, surgical biopsy or resection. All histology slides were reviewed by a lung pathologist. CT scans, available in 92 patients, were reviewed blindly and in random order by two independent radiologists. Kappa analysis was completed to assess inter-observer agreement. Eighty patients in whom there was no significant delay between CT imaging and histological diagnosis were assessed by logistic regression analysis to correlate CT and histologic findings. Results: Seventy-two of the 92 mesotheliomas were epithelial, 15 sarcomatous, and 5 of mixed histology. All patients (77 male, 15 female, mean age 68 years) had pleural thickening on CT; the thickening was nodular in 79 patients (86%) and mediastinal in 87 (95%). Ipsilateral volume loss was seen in 42 patients (46%). Pleural effusions were present in 80 patients (87%), being large (>2/3 hemithorax) in 19 patients (21%). Atypical features at presentation included bilateral disease in three patients (3%), and spontaneous pneumothoraces in nine patients (10%). Internal mammary lymphadenopathy was observed in 48 patients (52%) and cardiophrenic lymphadenopathy in 42 (46%). Inter-observer agreement was excellent (average kappa=0.89). Ipsilateral volume loss was associated with sarcomatous or mixed mesothelioma (p =0.004). Using logistic regression analysis, other CT findings did not correlate with histological subtype. Conclusions: Ipsilateral volume loss is most frequently associated with sarcomatous or mixed mesothelioma. The remaining imaging findings are not helpful in predicting the histological subtype of malignant mesothelioma. [Copyright &y& Elsevier]

An abnormal increase in proteolytic enzymes is thought to play a key role in pulmonary emphysema. Alveolar macrophage proteolytic enzymes include cathepsin L, cathepsin S, matrix metalloproteinase 1, 9, and 12, and a number of studies have implicated these proteinases in the alveolar destruction that characterizes emphysema. The aim of this study was to investigate cathepsin L, cathepsin S, matrix metalloproteinase 1, 9, and 12 mRNA expression in alveolar macrophages isolated from patients with varying degrees of emphysema and to correlate their level of expression with measures of emphysema. Alveolar macrophages were isolated from fifty-four patients who underwent surgical resection for lung carcinoma. The level of mRNA expression was determined using real-time PCR. Emphysema was quantified using high-resolution CT scans. Alveolar macrophages were also cultured for 24 h and 48 h; the effect of proinflammatory mediators and promoter polymorphisms on expression was analyzed. There was a significant correlation between matrix metalloproteinase 1 mRNA expression and emphysema. A higher level of matrix metalloproteinase 1 mRNA was associated with more severe emphysema. Matrix metalloproteinase 12 mRNA expression was increased in current smokers as compared with former smokers. Furthermore, there was a negative correlation between matrix metalloproteinase 12 gene expression and carbon monoxide diffusing capacity. The matrix metalloproteinase 9 C-1562T polymorphism significantly influenced matrix metalloproteinase 9 mRNA expression in alveolar macrophages. These results suggest that alveolar macrophage matrix metalloproteinase 1 and 12 may have a role in the lung structural changes leading to the development of emphysema. Furthermore, these data provide evidence to support the concept that multiple proteinases, causing both elastin and collagen degradation, are important in the pathogenesis of pulmonary emphysema. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to review and revise the undergraduate radiology curriculum at the University of British Columbia to improve radiology education to medical students and to meet the needs of a medical program with province-wide distribution. Methods: We identified the radiology content of the curriculum from the Curriculum Management and Information Tool online database, from personal interviews with curriculum heads, and from published information. Undergraduates' and recent graduates' opinions were solicited by means of surveys. Information on radiology curricula at medical schools across Canada was gathered from email surveys and personal contacts with members of the Canadian Heads of Academic Radiology (CHAR). Results: Review of our curriculum indicated that lack of a unified syllabus resulted in redundant content, gaps in knowledge, and lack of continuity in the curriculum. Results from the survey of programs across Canada indicated that most schools also lacked a formal radiology curriculum for medical students. By adapting the guidelines from the Association of Medical Student Education in Radiology, we revised our undergraduate radiology curriculum to emphasize integration and self-learning. The modified curriculum includes a combination of instructional technology, focused lectures in preclinical years, and in-context seminars in clerkship rotations. Conclusion: Most medical schools in Canada do not have a formal radiology curriculum for medical students. A structured curriculum is required to improve the quality of radiology teaching for medical students. [ABSTRACT FROM AUTHOR]

Study Objectives: The purpose of this study was to describe the clinical, chest radiographic, high-resolution CT, and histopathologic features of clay dye "sendo" dust pneumoconiosis in seven rush mat ("tatami") workers.Patients: Seven patients with a history of occupational exposure to sendo dust and radiographic changes suggestive of pneumoconiosis were retrospectively reviewed.Results: The duration of exposure ranged from 15 to 45 years (median, 30 years). Three patients had cough, and four patients had abnormal pulmonary function test results. Chest radiographs showed nodular opacities < 3 mm in diameter (types p and q) in all patients. The standard International Labor Office profusion score ranged from 0/1 to 1/1 (median, 1/0). High-resolution CT demonstrated small nodular opacities (types p and q) in all seven patients. In four patients, high-resolution CT demonstrated branching centrilobular structures, airway ectasia, airway wall thickening, and emphysematous changes. None of the patients had conglomerate nodules, large opacities, honeycombing, pleural effusion, or lymphadenopathy. Microscopic examination of the specimens obtained by open lung biopsy or transbronchial lung biopsy revealed nodular fibrosis with accumulation of dust-laden macrophages, but no silicotic nodules. Needle-like particles of 1 to 20 microm in length were evident among the dust deposits, and birefringent crystals were identified under polarizing microscopy. Four of seven patients showed intra-alveolar fibroblastic foci similar to Masson bodies, accompanied by dust deposition.Conclusion: Rush mat workers' sendo dust pneumoconiosis is caused by dust containing free silica. The radiographic and high-resolution CT findings consist of small nodular opacities < 3 mm in diameter and bronchial and bronchiolar abnormalities. [ABSTRACT FROM AUTHOR]

Objective: The aim of this article is to describe the high-resolution CT (HRCT) findings in mild cases of fat embolism syndrome (FES). Material and methods: Nine patients with FES were examined with HRCT of the lungs (collimation, 1 mm/edge-enhancement algorithm). The median age of the patients was 26 years (range, 17 to 35 years). Five cases were included prospectively, and four cases were reviewed retrospectively. Of the major clinical criteria for FES, respiratory signs were present in six patients, CNS signs were present in two patients, and petechiae was present in six patients. HRCT patterns were recorded and analyzed. The type of injury and FES-associated clinical findings were also recorded. Results: HRCT findings included ground-glass opacities in seven patients, associated with thickened interlobular septa in five patients and a patchy distribution resulting in a geographic appearance in four patients. A nodular pattern was observed in two patients. Resolution of the abnormalities occurred within 16.4 days (range, 7 to 25 days). Conclusion: The HRCT findings of mild fat embolism consist of bilateral ground-glass opacities and thickening of the interlobular septa. Centribular nodular opacities are present in some patients. [ABSTRACT FROM AUTHOR]