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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., (Copyright © 2022 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Assessment of lung biopsies for the diagnosis of hypersensitivity pneumonitis (HP) is one of the most difficult diagnostic problems for surgical pathologists. It is a form of interstitial lung disease resulting from an immune reaction provoked by an inhaled antigen in susceptible individuals. Although this definition sounds simple, in practice, the diagnosis of HP can be challenging. To address these issues, the American College of Chest Physicians (CHEST) has recently published a guideline for the diagnosis of HP. In this review, we will explore the multidisciplinary diagnostic evaluation of HP with a focus on the pathologic features as outlined in the CHEST guidelines. The histologic criteria are divided into 4 diagnostic categories: (1) Typical nonfibrotic HP or fibrotic HP; (2) Compatible with nonfibrotic HP or fibrotic HP; (3) Indeterminate for nonfibrotic or fibrotic HP; and (4) Alternative Diagnosis. It is important to emphasize that patterns 1 to 3 do not represent discrete histologic entities or pathologic diagnoses. Rather, these categories are meant to serve as a practical guide for organizing a complex set of overlapping histologic patterns into an integrated diagnostic framework for facilitating multidisciplinary discussion. High-resolution computed tomography features are also summarized, emphasizing how the correlation of lung biopsies with computed tomography findings can help to favor the diagnosis, particularly in cases where biopsies are not typical for HP. This review highlights details of the histologic spectrum of HP as well as the utility of different types of biopsies and bronchoalveolar lavage. We also emphasize the importance of multidisciplinary discussion and the complex differential diagnosis., Competing Interests: Conflicts of Interest and Source of Funding: E.R.F.P. has grants from the Colorado office of economic development and international trade, Genentech, Boehringer Ingelheim, and the National Heart Lung and Blood Institute, and nonfinancial support from Boehringer Ingelheim. D.L. has personal fees from Boehringer Ingelheim, Parexel Inc., and Veracyte Inc. For the remaining authors none were declared., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

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.

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.

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

Purpose: The aim of the study was to describe the high-resolution computed tomography (CT) manifestations of chronic pulmonary microaspiration, a condition characterized by recurrent subclinical aspiration of small droplets of gastric contents or foreign particles into the lungs., Materials and Methods: We reviewed the CT findings in 13 consecutive patients with clinical (n=13) and histologic (n=1) diagnosis of chronic pulmonary microaspiration. Twelve patients presented with persistent cough, but none had a clinical history of acute aspiration. One patient was asymptomatic. All patients had volumetric CT of the chest reconstructed using thin sections (1 to 1.3 mm) at the time of diagnosis. The CT scans were interpreted by 3 chest radiologists who reached a final decision by consensus., Results: All 13 patients had centrilobular nodules and ground-glass opacities that involved mainly the dependent lung regions in 11 patients and had a random distribution in 2. Other common findings included branching opacities (n=10), small foci of consolidation (n=7), septal lines (n=5), and bronchiectasis (n=7). The 13 patients had at least 1 risk factor for aspiration including gastroesophageal reflux (n=9), hiatus hernia (n=6), esophageal dysfunction (n=3), oropharyngeal dysphagia (n=1), esophageal carcinoma (n=1), and use of sedatives (n=2)., Conclusions: The high-resolution CT manifestations of chronic pulmonary microaspiration consist mainly of centrilobular nodules and ground-glass opacities that tend to involve predominately the dependent regions. Branching opacities and small foci of consolidation are seen in the majority of cases.

We hypothesised that biomass smoke exposure is associated with an airway-predominant chronic obstructive pulmonary disease (COPD) phenotype, while tobacco-related COPD is associated with an emphysema-predominant phenotype. In this cross-sectional study, female never-smokers with COPD and biomass exposure (n=21) and female ex-cigarette smokers with COPD without biomass exposure (n=22) completed computed tomography (CT) at inspiration and expiration, pulmonary function, blood gas, exercise tolerance, and quality of life measures. Two radiologists scored the extent of emphysema and air trapping on CT. Quantitative emphysema severity and distribution and airway wall thickness were calculated using specialised software. Women in the tobacco group had significantly more emphysema than the biomass group (radiologist score 2.3 versus 0.7, p=0.001; emphysema on CT 27% versus 19%, p=0.046; and a larger size of emphysematous spaces, p=0.006). Women in the biomass group had significantly more air trapping than the tobacco group (radiologist score 2.6 and 1.5, respectively; p=0.02) and also scored lower on the symptom, activities and confidence domains of the quality of life assessment and had lower oxygen saturation at rest and during exercise (p<0.05). Biomass smoke exposure is associated with less emphysema but more air trapping than tobacco smoke exposure, suggesting an airway-predominant phenotype.

Background: Emphysema is a key contributor to airflow limitation in chronic obstructive pulmonary disease (COPD) and can be quantified using CT scanning. We investigated the change in CT lung density in a longitudinal, international cohort of patients with COPD. We also explored the potential relation between emphysema and patient characteristics, and investigated if certain circulating biomarkers were associated with decline in CT lung density., Methods: We used a random coefficient model to assess predictors of both CT lung density and its longitudinal change over 3 years in 1928 patients with COPD enrolled in the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) study. Lung density was measured for every voxel in the CT scan and after correcting for lung volume was expressed as the density at lowest 15th percentile point of the distribution. This study is registered with ClinicalTrials.gov, number NCT00292552., Findings: Lung density at baseline was influenced by age, sex, body-mass index, current smoking status and smoking history, and severity of airflow limitation. The observed decline in lung density was variable (mean decline -1·13 g/L [SE 0·06] per year). The annual decline in lung density was more rapid in women (additional -0·41 [SE 0·14] g/L per year, p=0·003) than men and in current smokers (additional -0·29 [SE 0·14] g/L per year, p=0·047) than in former smokers. Circulating levels of the biomarkers surfactant protein D (SP-D) and soluble receptor for advanced glycation endproduct (sRAGE) were significantly associated with both baseline lung density and its decline over time., Interpretation: This study shows that decline in lung density in COPD can be measured, that it is variable, and related to smoking and gender. We identified potential biochemical predictors of the presence and progression of emphysema., Funding: GlaxoSmithKline., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Purpose: To quantify observer agreement and analyze causes of disagreement in identifying honeycombing at chest computed tomography (CT)., Materials and Methods: The institutional review board approved this multiinstitutional HIPAA-compliant retrospective study, and informed patient consent was not required. Five core study members scored 80 CT images with a five-point scale (5 = definitely yes to 1 = definitely no) to establish a reference standard for the identification of honeycombing. Forty-three observers from various subspecialties and geographic regions scored the CT images by using the same scoring system. Weighted κ values of honeycombing scores compared with the reference standard were analyzed to investigate intergroup differences. Images were divided into four groups to allow analysis of imaging features of cases in which there was disagreement: agreement on the presence of honeycombing, agreement on the absence of honeycombing, disagreement on the presence of honeycombing, and other (none of the preceding three groups applied)., Results: Agreement of scores of honeycombing presence by 43 observers with the reference standard was moderate (Cohen weighted κ values: 0.40-0.58). There were no significant differences in κ values among groups defined by either subspecialty or geographic region (Tukey-Kramer test, P = .38 to >.99). In 29% of cases, there was disagreement on identification of honeycombing. These cases included honeycombing mixed with traction bronchiectasis, large cysts, and superimposed pulmonary emphysema., Conclusion: Identification of honeycombing at CT is subjective, and disagreement is largely caused by conditions that mimic honeycombing.

The purpose of this article is to illustrate the various manifestations that can be encountered on thoracic computed tomography of tuberous sclerosis in adults. The pulmonary findings include lymphangioleiomyomatosis and multifocal micronodular pneumocyte hyperplasia. The extrapulmonary manifestations are divided into cardiac, vascular, mediastinal, osseous, and upper abdominal findings., (Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.)

Objectives: To determine high-resolution computed tomography (HRCT) findings helpful in predicting mortality in patients with acute exacerbation of idiopathic pulmonary fibrosis (AEx-IPF)., Methods: Sixty patients with diagnosis of AEx-IPF were reviewed retrospectively. Two groups (two observers each) independently evaluated pattern, distribution, and extent of HRCT findings at presentation and calculated an HRCT score at AEx based on normal attenuation areas and extent of abnormalities, such as areas of ground-glass attenuation and/or consolidation with or without traction bronchiectasis or bronchiolectasis and areas of honeycombing. The correlation between the clinical data including the HRCT score and mortality (cause-specific survival) was evaluated using the univariate and multivariate Cox-regression analyses., Results: Serum KL-6 level, PaCO(2), and the HRCT score were statistically significant predictors on univariate analysis. Multivariate analysis revealed that the HRCT score was an independently significant predictor of outcome (hazard ratio, 1.13; 95% confidence interval, 1.06-1.19, P = 0.0002). The area under receiver operating characteristics curve for the HRCT score was statistically significant in the classification of survivors or nonsurvivors (0.944; P < 0.0001). Survival in patients with HRCT score ≥245 was worse than those with lower score (log-rank test, P < 0.0001)., Conclusion: The HRCT score at AEx is independently related to prognosis in patients with AEx-IPF.

Aim: This study aimed to retrospectively evaluate the computed tomographic (CT) appearance of cases of swine-origin influenza A(H1N1) viral infection (S-OIV) in immunocompetent and immunocompromised patients confirmed with reverse transcription-polymerase chain reaction and to determine whether the timing of CT relative to the onset of symptoms affected the overall imaging appearance [corrected]., Methods: A total of 23 patients (15 men and 8 women) from 2 tertiary care centers formed the final study population. Patients were divided into 2 groups based on their immune status: group 1 (n = 14) were patients who were immunocompromised, whereas group 2 (n = 9) were patients who were immunocompetent. The radiologic appearances of pulmonary abnormalities, distribution, and extent of involvement on the initial chest CT scan were documented, and correlation with the onset of symptoms was performed., Results: The most common CT pattern in both groups of S-OIV patients was ground-glass opacities and consolidation (group 1, 86%; group 2, 71%) in a bilateral, subpleural, and peribronchovascular pattern. Small airways disease [corrected] was seen only in a minority of patients (group 1, 7%; group 2, 11%. Onset of symptoms to time of CT showed a mean duration of 9.7 days in group 1 and 6.7 days in group 2 and did not affect the overall imaging appearance., Conclusions: The most common abnormalities on CT scans of both immunocompetent and immunocompromised S-OIV patients were ground-glass opacities and consolidation in a bilateral, subpleural, and peribronchovascular distribution, resembling organizing pneumonia. This appearance was seen regardless of the timing of CT relative to the onset of symptoms.

Rationale and Objectives: This study investigated what factors radiologists take into account when estimating emphysema severity and assessed quantitative computed tomography (CT) measurements of low attenuation areas., Materials and Methods: CT scans and spirometry were obtained on 1519 chronic obstructive pulmonary disease (COPD) subjects, 269 smoker controls, and 184 nonsmoker controls from the Evaluation of COPD Longitudinally to Indentify Surrogate Endpoints (ECLIPSE) study. CT scans were analyzed using the threshold technique (%<-950HU) and a low attenuation cluster analysis. Two radiologists scored emphysema severity (0 to 5 scale), described the predominant type and distribution of emphysema, and the presence of suspected small airways disease., Results: The percent low attenuation area (%LAA) and visual scores of emphysema severity correlated well (r = 0.77, P < .001). %LAA, low attenuation cluster analysis, and absence of radiologist described gas trapping, distribution, and predominant type of emphysema were predictors of visual scores of emphysema severity (all P < .001). CT scans scored as showing regions of gas trapping had smaller lesions for a similar %LAA than those without (P < .001)., Conclusions: Visual estimates of emphysema are not only determined by the extent of LAA, but also by lesion size, predominant type, and distribution of emphysema and presence/absence of areas of small airways disease. A computer analysis of low attenuation cluster size helps quantitative algorithms discriminate low attenuation areas from gas trapping, image noise, and emphysema., (Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.)

This document is an international evidence-based guideline on the diagnosis and management of idiopathic pulmonary fibrosis, and is a collaborative effort of the American Thoracic Society, the European Respiratory Society, the Japanese Respiratory Society, and the Latin American Thoracic Association. It represents the current state of knowledge regarding idiopathic pulmonary fibrosis (IPF), and contains sections on definition and epidemiology, risk factors, diagnosis, natural history, staging and prognosis, treatment, and monitoring disease course. For the diagnosis and treatment sections, pragmatic GRADE evidence-based methodology was applied in a question-based format. For each diagnosis and treatment question, the committee graded the quality of the evidence available (high, moderate, low, or very low), and made a recommendation (yes or no, strong or weak). Recommendations were based on majority vote. It is emphasized that clinicians must spend adequate time with patients to discuss patients' values and preferences and decide on the appropriate course of action.

Background: Pulmonary function tests (PFT), particularly spirometry and lung diffusing capacity for carbon monoxide (DL(CO) ), have been considered useful methods for the detection of the progression of interstitial asbestos abnormalities as indicated by high-resolution computed tomography (HRCT). However, it is currently unknown which of these two tests correlates best with anatomical changes over time., Methods: In this study, we contrasted longitudinal changes (3-9 years follow-up) in PFTs at rest and during exercise with interstitial abnormalities evaluated by HRCT in 63 ex-workers with mild-to-moderate asbestosis., Results: At baseline, patients presented with low-grade asbestosis (Huuskonen classes I-II), and most PFT results were within the limits of normality. In the follow-up, most subjects had normal spirometry, static lung volumes and arterial blood gases. In contrast, frequency of DL(CO) abnormalities almost doubled (P < 0.05). Twenty-three (36.5%) subjects increased the interstitial marks on HRCT. These had significantly larger declines in DL(CO) compared to patients who remained stable (0.88 vs. 0.31 ml/min/mm Hg/year and 3.5 vs. 1.2%/year, respectively; P < 0.05). In contrast, no between-group differences were found for the other functional tests, including spirometry (P > 0.05)., Conclusions: These data demonstrate that the functional consequences of progression of HRCT abnormalities in mild-to-moderate asbestosis are better reflected by decrements in DL(CO) than by spirometric changes. These results might have important practical implications for medico-legal evaluation of this patient population., (Copyright © 2010 Wiley-Liss, Inc.)

Minute pulmonary meningothelial-like nodules are common incidental pathologic findings but are sparsely described in the radiology literature. They are of uncertain origin and significance, but they can occasionally manifest as mild restrictive lung disease or as incidental micronodules on computed tomography. We present a case of multiple incidentally detected, randomly distributed, cavitating micronodules with pathologic correlation. Awareness of the rare presentation of this entity is important because it may simulate neoplastic or other nonneoplastic diseases.

The objective of this new Brazilian consensus is to update and to continue the standardization of the principal terms and fundamental patterns in chest CT scans in Portuguese. There is a succinct definition of the principal terms used to describe chest CT findings, as well as illustrations of classic examples. The group of authors comprised radiologists specializing in chest radiology and holding membership in the Brazilian College of Radiology and Diagnostic Imaging, as well as pulmonologists having a special interest in diagnostic imaging and holding membership in the Brazilian Thoracic Association.

The purpose of this paper is to demonstrate the potential role of CT in the early diagnosis of swine-origin influenza A (H1N1) virus (S-OIV) pneumonia. We present a case of acute influenza-like illness in which the CT findings of peribronchovascular and subpleural ground-glass opacities and consolidation resembled organizing pneumonia, and lead the radiologist to prospectively and correctly suggest the diagnosis of S-OIV infection.

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.

Objective: The objective of our study was to review the chest radiographic and CT findings in patients with swine-origin influenza A (H1N1) virus (S-OIV) infection., Conclusion: The most common radiographic and CT findings in seven patients with S-OIV infection are unilateral or bilateral ground-glass opacities with or without associated focal or multifocal areas of consolidation. On MDCT, the ground-glass opacities and areas of consolidation had a predominant peribronchovascular and subpleural distribution, resembling organizing pneumonia.

The idiopathic interstitial pneumonias (IIPs) are a group of diffuse parenchymal lung diseases of unknown etiology characterized by the presence of various degrees of inflammation and fibrosis. Confident definitive diagnosis of the various IIPs requires dynamic interaction among clinicians, radiologists, and pathologists to arrive at a clinico-radiologic-pathologic diagnosis. The aims of this manuscript are to summarize the characteristic clinical and histologic manifestations, and to describe and illustrate the high-resolution computed tomography manifestations of the IIPs. The focus will be on idiopathic pulmonary fibrosis (idiopathic usual interstitial pneumonia), nonspecific interstitial pneumonia, cryptogenic organizing pneumonia, and acute interstitial pneumonia. High-resolution computed tomography plays an important role in the initial diagnosis, the assessment of disease extent, the likelihood of response to treatment and prognosis, and the assessment of complications.

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.

Objective: To assess the potential role of multiple bronchoalveolar lavages (BALs) in the treatment of children with lipoid pneumonia (LP)., Materials and Methods: This prospective study included 10 children (7 female, 3 male) with LP secondary to mineral oil aspiration. The age ranged from 3 months to 7 years and 1-60 days history of mineral oil intake, with a 6 months clinic follow-up. High-resolution computer tomography (CT) was performed 1-7 days prior to treatment and 2-20 days after the last therapeutic BAL, and reviewed by two experienced chest radiologists. Oxygen saturation was measured with digital oximetry. Therapeutic BAL was performed weekly until BAL fluid was nearly transparent and the cell count returned to normal range values., Results: In all children, the initial CT scans showed multifocal bilateral consolidation involving mainly the dorsal and central regions. The areas of consolidation had foci of decreased attenuation in eight patients. Following a total of 4-10 therapeutic BALs, the CT scans returned to normal in 3 patients, improved considerably in 5, and showed only slight improvement in 2. Oxygen saturation increased from 88.8 +/- 3.4% at presentation to 96.2 +/- 0.8% after treatment (P < 0.0001). Multiple lavages reduced (P < 0.003) numbers of lipid-laden macrophages and restored BAL cellularity to normal range values., Conclusion: Multiple therapeutic BAL of children with LP results in significant improvement of CT findings, oxygen saturation, restoration of BAL fluid cellularity and clinical recover without any evidence of respiratory distress at the end of treatment and 6 months after the last BAL., ((c) 2009 Wiley-Liss, Inc.)

Objective: The purpose was to characterize the spectrum of imaging findings of nontuberculous mycobacterial immune reconstitution syndrome in patients infected with the human immunodeficiency virus., Methods: A retrospective review of 33 human immunodeficiency virus-infected patients with nontuberculous mycobacterial immune reconstitution syndrome was performed. Radiography, ultrasound, and computed tomography (CT) imaging was reviewed., Results: Intrathoracic and intra-abdominal abnormalities were identified in 16 and 14 patients, respectively. Lymphadenopathy was detected on chest radiographs in 11 patients and on CT in 13. Focal consolidation (n = 8) and centrilobular nodularity (n = 8) were common CT findings. Lymphadenopathy was the predominant abdominal finding (n = 10). Splenomegaly (n = 9), ascites (n = 7), and multiple hypoattenuating splenic lesions (n = 6) were additional findings. Peripheral lymph node masses were detected in 7 patients., Conclusions: The most common manifestation of nontuberculous mycobacterial immune reconstitution syndrome is lymphadenopathy. Other common findings are pulmonary consolidation and centrilobular nodularity, ascites, splenomegaly, multiple hypoattenuating splenic lesions, and peripheral lymphadenopathy.

Purpose: To evaluate the changes over time in the pattern and extent of parenchymal abnormalities in asbestos-exposed workers after cessation of exposure and to compare 3 proposed semiquantitative methods with a careful side-by-side comparison of the initial and the follow-up computed tomography (CT) images., Materials and Methods: The study included 52 male asbestos workers (mean age+/-SD, 62.2 y+/-8.2) who had baseline high-resolution CT after cessation of exposure and follow-up CT 3 to 5 years later. Two independent thoracic radiologists quantified the findings according to the scoring systems proposed by Huuskonen, Gamsu, and Sette and then did a side-by-side comparison of the 2 sets of scans without awareness of the dates of the CT scans., Results: There was no difference in the prevalence of the 2 most common parenchymal abnormalities (centrilobular small dotlike or branching opacities and interstitial lines) between the initial and follow-up CT scans. Honeycombing (20%) and traction bronchiectasis and bronchiolectasis (50%) were seen more commonly on the follow-up CT than on the initial examination (10% and 33%, respectively) (P=0.01). Increased extent of parenchymal abnormalities was evident on side-by-side comparison in 42 (81%) patients but resulted in an increase in score in at least 1 semiquantitative system in only 16 (31%) patients (all P>0.01, signed test)., Conclusions: The majority of patients with previous asbestos exposure show evidence of progression of disease on CT at 3 to 5 years follow-up but this progression is usually not detected by the 3 proposed semiquantitative scoring schemes.

Objective: The purpose of this study was to describe the thoracic radiologic findings of chronic granulomatous disease in adults., Materials and Methods: We retrospectively analyzed the chest radiographic and CT findings in four adults with chronic granulomatous disease during five episodes of lower respiratory tract infection., Results: Chest radiographic findings included areas of consolidation (60%), diffuse reticulonodular opacities (40%), pleural effusion (20%), and pulmonary artery enlargement (20%). CT findings included areas of consolidation (60%), pulmonary nodules in a random distribution (60%), centrilobular nodules (60%), tree-in-bud opacities (40%), areas of scarring and traction bronchiectasis (100%), emphysematous changes (75%), areas of decreased attenuation and vascularity associated with air trapping on expiratory CT (50%), mediastinal and/or hilar lymphadenopathy (60%), pulmonary artery enlargement (50%), and pleural effusion (20%). Areas of consolidation and nodules were the most prominent findings and at histologic examination were found to be associated with infection or granulomatous inflammation., Conclusion: The pulmonary radiologic findings of chronic granulomatous disease include consolidation, nodules, areas of scarring, traction bronchiectasis, emphysema, air trapping, mediastinal and hilar lymphadenopathy, pulmonary artery enlargement, and pleural effusion.

Objective: The purpose of this study was to determine whether the predominant findings at high-resolution CT influence the accuracy of diagnosis of diffuse lung disease., Materials and Methods: The cases of 100 patients with diffuse lung disease who underwent high-resolution CT and tissue diagnosis were studied. Three thoracic radiologists reviewed high-resolution CT images blindly and independently for patterns of abnormality, listing their three main diagnoses and level of confidence in the first choice. The effect of the findings on accuracy was analyzed., Results: For honeycombing, the accuracy of the main diagnosis was 96.6%, 92.2%, and 92.3% for the three readers, and that of the three main diagnoses was 96.6%, 96.1%, and 92.3%. For cysts, the accuracy of the main diagnosis was 88.9%, 80%, and 81.8% and of the three main diagnoses was 100%, 90%, and 90.9%. For bronchovascular thickening, the accuracy of the main diagnosis was 91.7%, 87.5%, and 90.9% and of the three main diagnoses was 91.7%, 100%, and 90.9%. For ground-glass opacification (GGO), the accuracy of the main diagnosis was 75.5%, 55%, and 44.2% and of the three main diagnoses was 89.8%, 75%, and 65.4%. Only combining honeycombing with GGO improved the accuracy of GGO. Anatomic craniocaudal distribution improved reader accuracy when GGO was predominantly present in the lower part of the lung. Interobserver agreement on the presence of major findings was a mean kappa value of 0.45 for honeycombing, 0.74 for lung cysts, 0.63 for bronchovascular thickening, and 0.56 for GGO. Agreement for the craniocaudal distribution of major findings was a mean kappa value of 0.48 for honeycombing, 0.52 for bronchovascular thickening, and 0.32 for GGO., Conclusion: The predominant findings of honeycombing and bronchovascular thickening are associated with more than 90% accuracy in the first-choice diagnosis of diffuse lung disease; the finding of lung cysts has 80-89% accuracy. GGO as a predominant pattern had unreliable accuracy, but the accuracy improved when GGO was combined with either honeycombing or lower-lung distribution.

Rationale: It is unclear whether airway wall thickening and emphysema make independent contributions to airflow limitation in chronic obstructive pulmonary disease (COPD) and whether these phenotypes cluster within families., Objectives: To determine whether airway wall thickening and emphysema (1) make independent contributions to the severity of COPD and (2) show independent aggregation in families of individuals with COPD., Methods: Index cases with COPD and their smoking siblings underwent spirometry and were offered high-resolution computed tomography scans of the thorax to assess the severity of airway wall thickening and emphysema., Measurements and Main Results: A total of 3,096 individuals were recruited to the study, of whom 1,159 (519 probands and 640 siblings) had technically adequate high-resolution computed tomography scans without significant non-COPD-related thoracic disease. Airway wall thickness correlated with pack-years smoked (P < or = 0.001) and symptoms of chronic bronchitis (P < 0.001). FEV(1) (expressed as % predicted) was independently associated with airway wall thickness at a lumen perimeter of 10 mm (P = 0.0001) and 20 mm (P = 0.0013) and emphysema at -950 Hounsfield units (P < 0.0001). There was independent familial aggregation of both the emphysema (adjusted odds ratio, 2.1; 95% confidence interval, 1.1-4.0; P < or = 0.02) and airway disease phenotypes (P < 0.0001) of COPD., Conclusions: Airway wall thickening and emphysema make independent contributions to airflow obstruction in COPD. These phenotypes show independent aggregation within families of individuals with COPD, suggesting that different genetic factors influence these disease processes.

Rationale: The 2002 American Thoracic Society/European Respiratory Society classification of idiopathic interstitial pneumonias identified nonspecific interstitial pneumonia (NSIP) as a provisional diagnosis. Concern was expressed that NSIP was a "wastebasket" category, difficult to distinguish from other idiopathic interstitial pneumonias., Objectives: The following questions were addressed: (1) Is idiopathic NSIP a distinct entity? 2) If so, what are its clinical, radiologic and pathologic characteristics? (3) What is the role of radiology and pathology in establishing the diagnosis? (4) To make a diagnosis of idiopathic NSIP, what other disorders need to be excluded and how should this be done?, Methods: Investigators who had previously reported cases of idiopathic NSIP were invited to submit cases for review (n = 305). After initial review, cases with complete clinical, radiologic, and pathologic information (n = 193) were reviewed in a series of workshops., Measurements and Main Results: Sixty-seven cases were identified as NSIP. Mean age was 52 years, 67% were women, 69% were never-smokers, and 46% were from Asian countries. The most common symptoms were dyspnea (96%) and cough (87%); 69% had restriction. By high-resolution computed tomography, the lower lung zones were predominantly involved in 92% of cases; 46% had a peripheral distribution; 47% were diffuse. Most showed a reticular pattern (87%) with traction bronchiectasis (82%) and volume loss (77%). Lung biopsies showed uniform thickening of alveolar walls with a spectrum of cellular to fibrosing patterns. Five-year survival was 82.3%., Conclusions: Idiopathic NSIP is a distinct clinical entity that occurs mostly in middle-aged women who are never-smokers. The prognosis of NSIP is very good.

Purpose: To retrospectively assess the change in disease pattern of nonspecific interstitial pneumonia (NSIP) and idiopathic pulmonary fibrosis (IPF) findings seen at thin-section computed tomography (CT) at long-term follow-up and to compare the same with initial findings at CT., Materials and Methods: The study included 48 patients (28 men, 20 women; mean age, 57.5 years) with biopsy-proved NSIP (n = 23) or IPF (n = 25) who underwent CT at initial diagnosis and at follow-up 34-155 months later. The CT scans were randomized and reviewed by two independent thoracic radiologists for pattern and distribution of ground-glass opacity (GGO), reticulation, traction bronchiectasis and bronchiolectasis, and honeycombing. Statistical analysis was performed by using nonparametric methods and univariate logistic regression., Results: Follow-up CT in patients with NSIP showed marked decrease in the extent of GGO, increase in reticulation, and a greater likelihood of peripheral distribution (all P < .05). At presentation, the CT findings were interpreted as suggestive of NSIP in 18 of 23 patients with NSIP and indeterminate or suggestive of IPF in five. In five (28%) of 18 patients with initial findings suggestive of NSIP, the follow-up CT scans were interpreted as more suggestive of IPF. No CT features seen at presentation allowed distinction between patients with NSIP that maintained an NSIP pattern at follow-up and those that progressed to an IPF pattern., Conclusion: At follow-up CT, 28% of patients with initial CT findings suggestive of NSIP progressed to findings suggestive of IPF. Similar initial CT findings for NSIP may have different imaging outcomes.

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., ((c) RSNA, 2008.)

Rationale: Patients with a clinicopathological diagnosis of idiopathic pulmonary fibrosis (IPF) may have typical findings of usual interstitial pneumonia (UIP) on computed tomography (CT) or nonspecific or atypical findings, including those often seen in nonspecific interstitial pneumonia., Objectives: The aims of this study were to revisit the high-resolution CT findings of IPF and to clarify the correlation between the CT findings and mortality., Methods: The study included 98 patients with a histologic diagnosis of UIP and a clinical diagnosis of IPF. Two observers evaluated the CT findings independently and classified each case into one of the following three categories: (1) definite UIP, (2) consistent with UIP, or (3) suggestive of alternative diagnosis. The correlation between the CT categories and mortality was evaluated using the Kaplan-Meier method and the log-rank test, as well as Cox proportional hazards regression models., Measurements and Main Results: Thirty-three of the 98 CT scans were classified as definite UIP, 36 as consistent with UIP, 29 as suggestive of an alternative diagnosis. The mean survival was 45.7, 57.9, and 76.9 months, respectively. There was no significant difference in survival among the three categories (all P > 0.05). Traction bronchiectasis and fibrosis scores were significant predictors of outcome (hazard ratios: 1.30 and 1.10, respectively; 95% confidence intervals: 1.18-14.2 and 1.03-1.19, respectively)., Conclusions: In patients with IPF and UIP pattern on the biopsy, the pattern of abnormality on thin-section CT, whether characteristic of UIP or suggestive of alternative diagnosis, does not influence prognosis. Prognosis is influenced by traction bronchiectasis and fibrosis scores.

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.

Objective: The aim of our study was to review the radiologic findings of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) pneumonia., Materials and Methods: The hospital infection control computer database was used to identify patients who had a CA-MRSA infection with organisms isolated from blood, bronchoalveolar lavage fluid, or pleural fluid samples. Criteria for CA-MRSA pneumonia were consolidation seen on chest radiography or computed tomography (CT), growth of MRSA from sputum and/or sterile pulmonary site, clinical complaints of cough and/or shortness of breath. Chest radiographs and CT scans for 9 patients (5 men, mean age 45 y, range 35 to 71 y) were retrospectively reviewed by 2 chest radiologists., Results: The most common chest radiographic finding was consolidation, which was bilateral in 7 patients and unilateral in 2 patients. The consolidation was patchy and nonsegmental in 5 and segmental in 4 patients. Two patients had cavitation evident on the chest radiograph. The most common CT scan findings were bilateral (n=8), often symmetric (n=5) consolidation, bilateral septal lines (n=7), and multiple nodules (n=5). Cavitation was present in 5 patients, either in regions of consolidation (n=5) or in large nodules (n=3). Five patients with CA-MRSA pneumonia had rapid clinical deterioration requiring ventilatory support. Two patients died., Conclusions: CA-MRSA pneumonia is characterized by extensive bilateral consolidation and frequent cavitation and is commonly associated with rapid progression and clinical deterioration. CT is superior to radiography in demonstrating the presence of cavitation.

Organizing pneumonia (OP) is a nonspecific response to various forms of lung injury. Although patients with human immunodeficiency virus (HIV) infection tend to develop several respiratory disorders, especially infections and malignances, the association of HIV infection and OP is unusual. Pneumocystis jiroveci infection is also rarely associated with OP. We describe the radiologic findings in 2 HIV-positive patients who shortly after introduction of highly active antiretroviral therapy, presented with clinical and radiologic deterioration, despite elevation of the CD4 cell count and viral load decrease. In both patients, clinical and radiologic features were consistent with OP and lung biopsy revealed OP associated with P. jiroveci infection. These findings are consistent with immune reconstitution syndrome due to P. jiroveci.

Purpose: To retrospectively assess the accuracy of thin-section computed tomography (CT) in distinguishing chronic hypersensitivity pneumonitis (HP) from idiopathic pulmonary fibrosis (IPF) and nonspecific interstitial pneumonia (NSIP), with histologic results as the reference standard., Materials and Methods: This retrospective study was approved by the institutional research boards of the participating centers, and informed consent was waived. There was HIPAA compliance for all U.S. patients. The study included 66 patients (36 men, 30 women; mean age, 58.8 years +/- 10.9 [standard deviation]) with proved chronic HP (n = 18), IPF (n = 23), or NSIP (n = 25) who underwent CT. Two independent readers assessed the CT images, made a first-choice diagnosis, and noted the degree of confidence in the diagnosis. A general linear model was used to identify CT features that independently differentiated chronic HP from IPF and NSIP. Weighted kappa statistic was used to assess interobserver agreement., Results: The CT features that best differentiated chronic HP were lobular areas with decreased attenuation and vascularity, centrilobular nodules, and absence of lower zone predominance of abnormalities (P < or = .008). The features that best differentiated NSIP were relative subpleural sparing, absence of lobular areas with decreased attenuation, and lack of honeycombing (P < or = .002). The features that best differentiated IPF were basal predominance of honeycombing, absence of relative subpleural sparing, and absence centrilobular nodules (P < or = .004). A confident diagnosis was made in 70 (53%) of 132 readings. This diagnosis was correct in 66 (94%) of 70 readings. The accuracy for the entire cohort was 80%. Interobserver agreement for confident diagnosis was good to excellent (kappa = 0.77-0.96)., Conclusion: Characteristic CT features of chronic HP, IPF, and NSIP allow confident distinction between these entities in approximately 50% of patients., (RSNA, 2008)

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.

Pulmonary hemorrhage is a relatively common complication of blunt chest trauma. Occasionally, it may result from pulmonary barotrauma after scuba diving or from sports activities not associated with barotrauma such as long breath-hold diving. We report a case of symmetric diffuse upper lobe hemorrhage resulting from a bungee jump in a previously healthy man. Bungee jumping is an increasingly popular sport with relatively few reported injuries. To our knowledge pulmonary hemorrhage in this setting has not yet been described.

Objective: The purpose of this study was to analyze the radiologic features of pulmonary Kaposi sarcoma-associated immune reconstitution syndrome. The syndrome is a phenomenon characterized by clinical deterioration of the condition of HIV-positive patients after initiation of highly active antiretroviral therapy., Materials and Methods: The study included four patients at our institution who fulfilled the diagnostic criteria for pulmonary Kaposi sarcoma-associated immune reconstitution syndrome from 2001 to 2006. All patients were men (mean age, 43 years; range, 31-59 years). Images reviewed included chest radiographs obtained before highly active antiretroviral therapy, radiographs and chest CT scans obtained at appearance of the symptoms of Kaposi sarcoma-associated immune reconstitution syndrome, and follow-up radiographs and chest CT scans during immune reconstitution syndrome., Results: The radiographic findings of Kaposi sarcoma-associated immune reconstitution syndrome included reticular and reticulonodular opacities (n = 4), areas of consolidation (n = 3), septal lines (n = 3), and pleural effusion (n = 3). The CT findings in all four patients were ill-defined pulmonary nodules and interlobular septal thickening. Three of the patients had a CT halo sign, areas of consolidation, ground-glass opacities, lymphadenopathy, and pleural effusion. The areas of consolidation in three subjects who did not receive chemotherapy increased markedly after 14-20 days. CT performed during the initial symptoms of immune reconstitution syndrome in these three subjects showed less than 5% parenchymal involvement. Follow-up CT showed 26-50% involvement in two patients and more than 50% involvement in one patient., Conclusion: The radiologic findings of pulmonary Kaposi sarcoma-associated immune reconstitution syndrome are similar to the findings described in patients with Kaposi sarcoma without the syndrome, but the extent of abnormalities tends to increase with the development of the syndrome.

Smoking-related illnesses contribute to a large number of deaths in the industrialized world and their treatment comprises a substantial percentage of total healthcare dollars. The most common and most well-known smoking-related illnesses include chronic obstructive pulmonary disease, bronchogenic carcinoma, and ischemic heart disease. However, the role of cigarette smoking in the pathogenesis of other lung diseases is becoming increasingly apparent. Knowledge of both the histologic and radiographic manifestations of smoking-related lung disease is important to the radiologist as imaging findings can be nonspecific. Finally, correlation of imaging and clinical information may obviate the need for open lung biopsy.

Hematopoietic stem cell transplantation (HSCT) is the treatment of choice for many hematologic malignancies and nonmalignant disorders of bone marrow function. Pulmonary infections from bacterial, fungal, and viral organisms are a major cause of morbidity and mortality in patients after HSCT. The radiographic and high-resolution computed tomography (HRCT) findings of the different lower respiratory tract viral infections are quite similar. Findings of viral pneumonia on HRCT include small poorly defined centrilobular nodules and patchy, often bilateral, areas of peribronchial ground-glass opacity and consolidation. Air trapping may be present because of associated bronchiolitis. Interlobular septal thickening, bronchial wall thickening, and tree-in-bud opacities may also be present. Advanced viral pneumonia with diffuse alveolar damage is characterized by patchy or confluent consolidation and ground-glass opacities. Although nonspecific, in the correct clinical setting, these HRCT findings can help suggest the diagnosis of viral pneumonia in recipients of HSCT.

Purpose: To review the high-resolution computed tomography (CT) and histologic findings of acute exacerbation of chronic interstitial pneumonia and to assess the potential value of CT and histologic findings in predicting prognosis., Materials and Methods: The study included 24 patients with clinical and histologic diagnosis of acute exacerbation of chronic interstitial pneumonia who underwent CT within 1 month before biopsy or autopsy. The final diagnosis was acute exacerbation of idiopathic pulmonary fibrosis (n=12), usual interstitial pneumonia associated with connective tissue disorders (n=5), idiopathic nonspecific interstitial pneumonia (n=4), and nonspecific interstitial pneumonia associated with connective tissue disorders (n=3)., Results: The main CT findings consisted of bilateral ground-glass opacities (100%) and consolidation (71%) superimposed on a reticular pattern. The ground-glass opacities and/or consolidation were diffuse in 54% of the cases, multifocal in 21%, and peripheral in 25%. The histologic patterns of acute injury consisted of diffuse alveolar damage (n=20), acute organizing pneumonia (OP) (n=3), and extensive fibroblastic foci (n=1). Eight (33%) patients survived the acute episode, including all 3 patients with OP and the patient with extensive fibroblastic foci (P=0.01). The survivors included 3 of 13 (23%) patients with diffuse parenchymal opacification, 2 of 5 (40%) patients with multifocal, and 3 of 6 (50%) patients with peripheral opacification on CT., Conclusions: The CT findings of acute exacerbation of chronic interstitial pneumonia consist of diffuse, multifocal, or peripheral parenchymal opacification superimposed on reticulation. Histologic findings of OP are superior to CT in predicting prognosis.

Objective: The aim of this manuscript is to summarize an approach to the differential diagnosis of the pulmonary complications of illicit drug use based on the computed tomography findings., Conclusions: The various pulmonary complications of illicit drug use result in 5 main patterns of parenchymal abnormality: nodules, ground-glass opacities, consolidation, air trapping, and emphysema. Other thoracic manifestations of illicit drug use include pulmonary arterial hypertension, pneumomediastinum, bacterial endocarditis, discitis, and septic arthritis.

Objective: The purpose of this pictorial essay is to illustrate the radiologic manifestations of pulmonary artery aneurysms and pseudoaneurysms with emphasis on the findings on contrast-enhanced CT., Conclusion: Pulmonary artery aneurysms and pseudoaneurysms are uncommon. Most are caused by trauma, often iatrogenic, infection, and Behçet's syndrome. Less common causes include pulmonary hypertension, congenital heart disease, neoplasms, and connective tissue disease. Recognition of pulmonary artery aneurysms and pseudoaneurysms is important because of the high morbidity and mortality rates of rupture.

Acute exacerbation of usual interstitial pneumonia (UIP) is a condition in which patients with UIP, and occasionally other forms of fibrotic interstitial lung disease, develop rapid respiratory failure, accompanied by extensive radiologic infiltrates. The pathologic features of this condition are ill-defined in the literature and the outcome is unclear. We report 12 such patients, 9 with underlying UIP, 2 with underlying fibrotic nonspecific interstitial pneumonia, and 1 with underlying chronic hypersensitivity pneumonitis, who underwent surgical lung biopsy for diagnosis. High-resolution computed tomography data were available in 11 cases and showed the presence of extensive bilateral ground-glass opacities, sometimes accompanied by focal consolidation, superimposed on underlying fibrosis. Three microscopic patterns of acute lung injury were seen: diffuse alveolar damage (DAD), organizing pneumonia (OP), and a pattern of numerous very large fibroblast foci superimposed on underlying fibrosis. After the biopsy, all patients were treated with steroids, in some instances accompanied by cyclophosphamide or azathioprine. Ten patients survived the acute episode and were discharged with survival times of 1 to 11 months; of these cases, 6 showed a pattern of OP or OP plus extensive fibroblast foci; 2 a pattern of extensive fibroblast foci only; and 2 a pattern of DAD. Both patients who died had histologic DAD. We conclude that acute exacerbation of UIP and other fibrotic lung diseases produces a variety of pathologic patterns on biopsy, and that patients with OP or extensive fibroblast foci as the acute pattern seem to do better than those with DAD. Our data also imply that survival (of the acute episode) may be better than the literature suggests.

Objective: The purpose of this article is to illustrate the spectrum of pathologic and high-resolution CT features of hypersensitivity pneumonitis (HP)., Conclusion: High-resolution CT plays an important role in the diagnosis of HP. A confident diagnosis of subacute HP is based on the presence of ground-glass opacities, poorly defined centrilobular nodules, and mosaic attenuation on inspiratory images and of air trapping on expiratory CT images. Chronic HP is characterized on high-resolution CT by the presence of reticulation due to fibrosis superimposed on findings of subacute HP. Histologically, subacute HP is characterized by the presence of cellular bronchiolitis, noncaseating granulomas, and bronchiolocentric lymphocytic interstitial pneumonitis. Areas of organizing pneumonia also may be seen. The high-resolution CT and pathologic features of chronic HP frequently overlap with those of nonspecific interstitial pneumonia and usual interstitial pneumonia. Awareness of the various manifestations of HP is important for early diagnosis and management.

Objective: The purpose of this study was to compare the dynamic contrast-enhanced MRI enhancement characteristics of malignant and benign solitary pulmonary nodules., Materials and Methods: The characteristics of 202 solitary pulmonary nodules (diameter, 1-3 cm; 144 cases of primary lung cancer, 31 cases of focal organizing pneumonia, 15 tuberculomas, 12 hamartomas) were reviewed retrospectively. In all cases dynamic MR images were obtained before and 1, 2, 3, 4, 5, 6, and 8 minutes after bolus injection of gadopentetate dimeglumine. Maximum enhancement ratio, time at maximum enhancement ratio, slope of time-enhancement ratio curves, and washout ratio were assessed. Statistical analyses were performed with the Kruskal-Wallis test with Bonferroni correction, chi-square test, and receiver operating characteristic curves., Results: For 122 (85%) of 144 primary lung cancers, time at maximum enhancement ratio was 4 minutes or less. For all tuberculomas and hamartomas, time at maximum enhancement ratio was greater than 4 minutes or gradual enhancement occurred without a peak time (p < 0.0001). Lung cancers had different maximum enhancement ratios and slopes than benign lesions (all p < 0.005). With 110% or lower maximum enhancement ratio as a cutoff value, the positive predictive value for malignancy was 92%; sensitivity, 63%; and specificity, 74%. With 13.5%/min or greater slope as a cutoff value, sensitivity, specificity, positive predictive value, and negative predictive value for malignancy were 94%, 96%, 99%, and 74%, respectively., Conclusion: Dynamic contrast-enhanced MRI is helpful in differentiating benign from malignant solitary pulmonary nodules. Absence of significant enhancement is a strong predictor that a lesion is benign.