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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.

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.

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.)

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.)

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.

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.

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.

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.

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.

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.

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)

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.

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.

Purpose: To retrospectively analyze computed tomographic (CT) findings of chronic idiopathic interstitial pneumonia (IIP) and to determine which findings are most helpful for distinguishing IIP from usual interstitial pneumonia (UIP) with univariate and multivariate analyses., Materials and Methods: Institutional review board approval and informed consent were not required for this retrospective review of patient records and images. Two observers working independently and without knowledge of the diagnosis evaluated the extent and distribution of various thin-section CT findings (ground-glass opacity, consolidation, reticulation, and honeycombing) in 92 patients (51 men, 41 women; mean age, 56 years; age range, 29-81 years) with a histologic diagnosis of UIP (n = 20), cellular nonspecific interstitial pneumonia (NSIP) (n = 16), fibrotic NSIP (n = 16), respiratory bronchiolitis-associated interstitial lung disease (RB-ILD) (n = 11), desquamative interstitial pneumonia (DIP) (n = 15), or lymphoid interstitial pneumonia (LIP) (n = 14). Observers used univariate and multivariate statistical analyses to compare their findings with the extent and distribution of UIP., Results: Observers made the correct diagnosis in 145 (79%) of 184 readings. Multivariate logistic regression analysis showed that the independent findings that distinguished UIP from cellular NSIP were the extent of honeycombing and the most proximal bronchus with traction bronchiectasis (odds ratio, 5.16 and 0.37, respectively); the finding that distinguished UIP from fibrotic NSIP was the extent of honeycombing (odds ratio, 2.10). CT features that distinguished UIP from RB-ILD and DIP included extent of ground-glass opacity (odds ratio, 0.76), thickening of bronchovascular bundles (odds ratio, 1.58), the most proximal bronchus with traction bronchiectasis (odds ratio, 0.22), and the number of segments with traction bronchiectasis (odds ratio, 3.64)., Conclusion: UIP has a characteristic appearance that usually facilitates distinction from other types of chronic IIPs at thin-section CT. The most useful finding when differentiating UIP from NSIP was the extent of honeycombing., ((c) RSNA, 2006.)

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.

Background: Computed tomography (CT) scans are used extensively to investigate chest disease because of their cross-sectional perspective and superior contrast resolution compared with chest radiographs. These advantages lead to a more accurate imaging assessment of thoracic disease. The actual use and evaluation of the clinical impact of thoracic CT has not been assessed since scanners became widely available., Objective: To identify patterns of utilization, waiting times and the impact of CT scan results on clinical diagnoses., Design: A before and after survey of physicians who had ordered thoracic CT scans., Setting: Vancouver General Hospital--a tertiary care teaching centre in Vancouver, British Columbia., Subjects: Physicians who had ordered CT scans., Intervention: Physicians completed a standard questionnaire before and after the CT scan result was available., Measurements: Changes in the clinical diagnosis, estimates of the probabilities for the diagnosis both before and after the CT scan, and waiting times., Results: Four hundred fifty-four thoracic CT cases had completed questionnaires, of whom 80% were outpatients. A change in diagnosis was made in 48% of cases (25% with a normal CT scan and 23% with CT scan findings that indicated a different diagnosis). The largest change in probability scores for the clinical diagnosis before and after the CT scan was 43.9% for normal scans, while it was 36.3% for a different diagnosis and 26.3% for the same diagnosis. High-priority scans were associated with decreased waiting time (--7.89 days for each unit increase in priority)., Conclusions: The CT scan results were associated with a change in diagnosis in 48% of cases. Normal scans constituted 25% of the total and had the greatest impact scores. Waiting times were highly correlated with increased urgency of the presenting problem.

Objective: The purpose of this study was to compare conventional high-resolution CT (HRCT) with helical 16-MDCT in the detection of bronchiectasis., Materials and Methods: We retrospectively evaluated 80 patients including 61 with bronchiectasis (mean age, 64 years; range, 22-87 years) and a control group of 19 patients with normal MDCT of the chest. Two sets of images were blindly, randomly analyzed by two observers: contiguous 1-mm slices (MDCT set) and 1-mm slices every 10 mm (HRCT set) derived from the MDCT set. Images were scored independently for presence, extent, and severity of bronchiectasis, followed by a consensus interpretation. Kappa analysis assessed inter- and intraobserver agreement. MDCT was the radiologic gold standard., Results: Of the 61 patients with bronchiectasis diagnosed with MDCT, 56 (92%) were positive for bronchiectasis on conventional HRCT. Seven patients had positive MDCT scans only, and two patients had positive HRCT scans only. Of 479 lobes, 59 were positive for bronchiectasis on MDCT and negative on HRCT, and 19 lobes were positive for bronchiectasis on HRCT and negative on MDCT (p < 0.0001). MDCT showed 25 more lobes with cylindric, 11 more lobes with varicose, and four more lobes with cystic bronchiectasis than did HRCT. Sensitivity, specificity, and positive and negative predictive values of HRCT in detecting bronchiectasis were 71%, 93%, 88%, and 81%, respectively. Interobserver agreement for presence, extent, and severity of bronchiectasis ranged from moderate to good for MDCT (kappa values, 0.64, 0.5, and 0.48, respectively) and poor to good for HRCT (kappa values, 0.65, 0.46, and 0.25, respectively)., Conclusion: Contiguous helical 16-MDCT with 1-mm collimation is superior to HRCT at 10-mm intervals in showing the presence and extent of bronchiectasis.

The purpose of this study was to compare the high-resolution computed tomography (HRCT) findings of pulmonary invasive aspergillosis and candidiasis in immunocompromised patients. The study included 54 immunocompromised patients (32 men, 22 women; 10 to 68 years of age, median 40 years) with a diagnosis of Aspergillus (n=32) or Candida (n=22) pulmonary infection obtained by sputum culture, bronchoalveolar lavage culture, transbronchial biopsy, surgical biopsy, or autopsy. High-resolution CT images were assessed for the presence and distribution of nodules, consolidation and ground-glass opacities. Presence of the CT halo sign and cavitation was also recorded and the overall distribution of abnormalities was assessed. Comparison was made using the Fisher exact test. Nodules were the most common finding, present in 84% (27 of 32) of patients with aspergillosis and 95% (21 of 22) of patients with candidiasis (P>0.3, Fisher exact test). Centrilobular nodules were more common in patients with aspergillosis (26 of 27, 96%) than in those with candidiasis (11 of 21, 52%) (P<0.001) and random nodules more common in candidiasis (10 of 21, 48%) than in aspergillosis (1 of 27, 4%) (P<0.001). Presence of the CT halo sign, cavitation, and ground-glass opacities was similar in both groups. In summary, pulmonary aspergillosis and candidiasis in immunocompromised patients manifest with similar high-resolution CT findings. Centrilobular nodules and consolidation are more common in aspergillosis. The presence of halo sign or cavitation is not helpful in the differential diagnosis.

Objective: The aim of the study was to evaluate the interstitial changes adjacent to pleural inflammation on multidetector computed tomography., Methods: The multidetector computed tomography scans of 30 patients with pleural inflammation were retrospectively and blindly evaluated by 2 observers. A control group of 7 patients with documented fibrothorax was also included. The number, appearance, thickness, and extent of septal lines were analyzed., Results: More than 10 septal lines immediately adjacent to the abnormal pleura were seen in 22 of the 30 patients with pleural inflammation and 2 of the 7 patients with fibrothorax (P<0.01). Septal lines that are more than 1 mm thick were seen in 13 of the 30 patients with acute inflammation and none of the patients with fibrothorax (P<0.01). Differences between focal and diffuse pleural inflammation included 10 cm or greater craniocaudal extent and more smooth septal lines with diffuse pleural inflammation., Conclusions: Pleural inflammation is associated with increased number and thickening of septal lines in the immediately adjacent lung parenchyma.

Drug-induced lung disease is an increasingly common cause of morbidity and mortality. The diagnosis is based on clinical history and consistent radiologic findings. Lung biopsy is performed in a small percentage of cases. High-resolution CT may demonstrate parenchymal abnormalities in patients with normal radiographs and provides a better depiction of the pattern and distribution of findings. Knowledge of the most common high-resolution CT manifestations and the corresponding histologic patterns is important for early recognition and proper management of drug-induced lung disease.

Objective: To assess the reproducibility of a new high-resolution computed tomography (CT) visual semiquantitative method for pleural plaques in asbestos-exposed workers., Material and Methods: We performed thin-section CT in 752 chrysotile asbestos mining workers and ex-workers. Institutional review board approval and signed written informed consent from subjects were obtained. Two readers independently evaluated the 752 CT scans and identified 57 workers (mean age +/- SD, 61.8 years +/- 8.1; range, 37 to 81 years) who had pleural plaques and no other pleural or parenchymal abnormality. Three independent radiologists then quantified the plaque burden in these 57 workers using a scoring system based on the evaluation of the maximum thickness of parietal pleural plaques and percentage of parietal pleural surface involvement. We also calculated the proportion between the number of CT slices with diaphragmatic plaques and the total number of slices in which the diaphragm was seen (pdiaph). The intraobserver and interobserver agreements were analyzed using weighted Kappa coefficient., Results: Interobserver agreements were good for the pleural plaque score (k = 0.61, 0.75, and 0.79) and ranged from good (k = 0.61) to excellent (k = 0.86) for the pdiaph. Intraobserver agreements ranged from good to excellent for the pleural plaque score (k = 0.79 and 1.00) and for the pdiaph (k = 0.79 and 0.93)., Conclusion: The method proposed for high-resolution CT pleural plaque quantification in asbestos-exposed workers has a high reproducibility.

Objective: To assess the high-resolution computed tomography appearances of drug-associated organizing pneumonia (OP)., Materials and Methods: Nine patients with clinical and biopsy proven drug-associated OP were included in the study. High-resolution computed tomography exams were retrospectively reviewed by 2 observers for the presence, extent, and distribution of parenchymal abnormalities., Results: The commonest findings consisted of air space consolidation (n = 8) and ground-glass opacification (n = 7). The air space consolidation was bilateral and asymmetric in 7 patients, symmetric in 1 patient and in all cases involved mainly the peribronchial or subpleural regions or both. The ground-glass opacities were predominantly bilateral and asymmetric in 6 patients and unilateral in 1 patient. They had a patchy distribution in 4 patients, were diffuse in 2 patients, and subpleural in 1 patient., Conclusion: Drug-associated OP most commonly presents with bilateral, asymmetrical air space consolidation in a predominantly peribronchial and subpleural distribution.

Objective: The purpose of this study was to evaluate the high-resolution CT findings of drug-induced eosinophilic pneumonias., Conclusion: Drug-induced eosinophilic pneumonias usually manifest as areas of consolidation and ground-glass opacity most commonly involving the outer third of the lungs.

Objective: Characteristic high-resolution CT (HRCT) findings of idiopathic pulmonary fibrosis (IPF) include reticulation, architectural distortion, and honeycombing involving mainly the lung periphery and the lower lobes. In 50% of IPF patients, HRCT is nonspecific. This article illustrates the HRCT findings of IPF correlating with the pathology., Conclusion: The spectrum of HRCT manifestations varies from typical findings that allow confident diagnosis to atypical patterns mimicking other diseases, including predominance of ground-glass opacity, consolidation, nodules, and atypical distribution of lesions.

Hard metal lung disease (HMLD) is a rare form of interstitial lung disease caused by sensitization to cobalt. It occurs in patients exposed to hard metal (tungsten carbide) and in diamond workers who use cobalt-containing polishes. The chest radiograph may be normal or show a nodular, reticulonodular, or reticular pattern. The high-resolution CT findings have been described in a small number of patients. Reported abnormalities include patchy lobular ground glass opacities, consolidation, reticulation, centrilobular nodularity, and, occasionally, honeycombing.We describe the high-resolution CT findings in a patient with pathologically proven HMLD who demonstrated interval improvement in the ground glass opacities and persistence of the centrilobular nodules following cessation of exposure to hard metal and treatment with corticosteroids. To our knowledge, this is the first described case of HMLD with follow-up CT examination.

Objective: To determine whether the subtypes of nonspecific interstitial pneumonia (NSIP) could be differentiated from other idiopathic interstitial pneumonias (IIPs) on the basis of findings on high-resolution computed tomography (CT)., Methods: Two observers evaluated the high-resolution CT findings in 90 patients with IIPs. The patients included 36 with NSIP, 11 with usual interstitial pneumonia (UIP), 8 with cryptogenic organizing pneumonia (COP), 10 with acute interstitial pneumonia (AIP), 14 with desquamative interstitial pneumonia (DIP) or respiratory bronchiolitis-associated interstitial lung disease (RB-ILD), and 11 with lymphoid interstitial pneumonia (LIP). The NSIP cases were subdivided into group 1 NSIP (n = 6), group 2 NSIP (n = 15), and group 3 NSIP (n = 15)., Results: Observers made a correct diagnosis with a high level of confidence in 65% of NSIP cases, 91% of UIP cases, 44% of COP cases, 40% of AIP cases, 32% of DIP or RB-ILD cases, and 82% of LIP cases. Group 1 NSIP was misdiagnosed as AIP, DIP or RB-ILD, and LIP in 8.3% of patients, respectively. Group 2 NSIP was misdiagnosed as COP in 10% of patients, LIP in 6.7%, AIP in 3.3%, and DIP or RB-ILD in 3.3%. Group 3 NSIP was misdiagnosed as UIP in 6.7% of patients, COP in 6.7%, and DIP or RB-ILD in 3.3%., Conclusions: In most patients, NSIP can be distinguished from other IIPs based on the findings on high-resolution CT. Only a small percentage of patients with predominantly fibrotic NSIP (group 3 NSIP) show overlap with the high-resolution CT findings of UIP.

Objective: The purpose of this study was to review the high-resolution CT findings in patients with pulmonary infection after bone marrow transplantation and to determine distinguishing features among the various types of infection., Materials and Methods: This study included 111 consecutive bone marrow transplant recipients who had documented pulmonary infection, high-resolution CT of the chest performed within 24 hr of the beginning of symptoms, and proven diagnosis within 1 week of the onset of symptoms. Two radiologists analyzed the CT scans and reached final decisions regarding the findings by consensus. Statistical analysis was performed using the Fisher's exact test and multivariate analysis; a p value of less than 0.05 was considered statistically significant., Results: The pulmonary infections were due to viruses (n = 57), bacteria (n = 26), fungi (n = 21), and protozoa (n = 1). Six patients had more than one organism responsible for the infection. Nodules that were 1 cm or more in diameter were seen in 13 (62%) of 21 patients with fungal pneumonia, five (19%) of 26 patients with bacterial pneumonia (p = 0.0059), three (10%) of 30 with respiratory syncytial virus (RSV) pneumonia (p = 0.0001), and three (14%) of 22 with cytomegalovirus pneumonia (p = 0.0016). The halo sign was present in 10 of 21 patients with fungal pneumonia, two of 26 with bacterial pneumonia (p = 0.0026), three of 30 with RSV pneumonia (p = 0.0036), and one of 22 with cytomegalovirus pneumonia (p = 0.0015). There was no statistically significant difference in the prevalence of the other CT patterns including small nodules, ground-glass attenuation, and air-space consolidation among viral, bacterial, and fungal infections (all p > 0.05)., Conclusion: The presence of large nodules and visualization of the halo sign are most suggestive of fungal infection. Other high-resolution CT patterns are not helpful in distinguishing among the various types of infection seen in bone marrow transplant recipients.

Objective: The aim of our study was to review the CT findings of pulmonary cryptococcosis in 12 immunocompetent patients., Conclusion: The CT manifestations of pulmonary cryptococcosis consist of pulmonary nodules or masses measuring 5-52 mm in diameter and focal areas of consolidation. The nodules and masses have a predominantly peripheral distribution in 80% of the cases. Cavitation of nodules or consolidation is seen in approximately 40% of the cases. The infection can be due to Cryptococcus neoformans var gattii or var neoformans.

Objective: The purpose of our study was to compare the high-resolution CT and pulmonary function test findings of smokers and nonsmokers with pulmonary sarcoidosis., Materials and Methods: Full inspiratory and expiratory high-resolution CT of the thorax and pulmonary function tests were performed in 46 patients (23 smokers and 23 lifelong nonsmokers) with histologically proven sarcoidosis. The median interval between high-resolution CT and pulmonary function tests was 8 days (range, 0-27 days). High-resolution CT findings were categorized into six patterns, and the overall extent of each pattern was scored independently (high-resolution CT score). Correlation between each high-resolution CT score with each pulmonary functional parameter was performed using Spearman's rank correlation and stepwise multiple regression analysis., Results: Air trapping on expiration (45/46 patients, 98%) and small nodules on inspiration (all 46 patients, 100%) were the most common findings. Smokers had a greater extent of emphysema than nonsmokers (p = 0.002). No significant difference was seen in the extent of air trapping, consolidation, ground-glass attenuation, reticular opacities, or small nodules between smokers and nonsmokers. On Spearman's rank correlation, the extent of air trapping negatively correlated with forced vital capacity in smokers (p < 0.05) but not in nonsmokers. The extent of small nodules negatively correlated with forced vital capacity and positively correlated with the ratio of forced expiratory volume in 1 sec to forced vital capacity in nonsmokers (p < 0.05, both) but not in smokers, respectively. On stepwise multiple regression analysis, the extent of air trapping on CT was independently associated with decreased forced vital capacity (p < 0.05), and cigarette smoking was the main determinant of decrease in maximum midexpiratory flow and forced expiratory flow at 50% of vital capacity (p < 0.01)., Conclusion: Cigarette smoking confounds the correlation between the CT and pulmonary function test findings in patients with sarcoidosis. Therefore, smoking history must be taken into account when correlating the extent of parenchymal sarcoidosis on CT with functional impairment.

Purpose: To retrospectively evaluate thin-section computed tomographic (CT) findings in hematopoietic stem cell transplant (ie, bone marrow transplant) patients with histopathologically proved pulmonary candidiasis., Materials and Methods: Ethical approval was obtained from the institutional review board of each of the three institutions; informed consent was not required. The study included 17 hematopoietic stem cell transplant recipients with proved pulmonary candidiasis. Histopathologic specimens were acquired at transbronchial biopsy (n = 8), open lung biopsy (n = 6), and autopsy (n = 3). The patients included seven men and 10 women (age range, 20-62 years; mean age, 37 years). The thin-section CT scans were retrospectively reviewed by two thoracic radiologists for the presence, appearance, and distribution of parenchymal abnormalities., Results: Multiple nodules were present in 15 (88%) patients, including centrilobular nodules and tree-in-bud pattern in seven (41%) patients. Nodules were bilateral in 12 patients and unilateral in three. An associated halo of ground-glass opacity was identified in five (33%) patients. Nodules were the only CT finding in five patients (29%). Areas of air-space consolidation were identified in 11 (65%) patients. Areas of ground-glass opacity were seen in six (35%) of 17 patients and were always associated with other abnormalities. Other less common CT findings included pleural effusion (n = 3), thickening of the bronchial walls (n = 2), and cavitation (n = 1)., Conclusion: The most common thin-section CT findings of pulmonary candidiasis in hematopoietic stem cell transplant patients are multiple bilateral nodular opacities often associated with areas of consolidation., (Copyright RSNA, 2005)

Objective: We wanted to demonstrate and compare the serial high-resolution CTs (HRCT) and the pulmonary function test (PFT) findings of the usual interstitial pneumonia (UIP) and the non-specific interstitial pneumonia (NSIP)., Materials and Methods: The serial HRCT scans and the PFT results were retrospectively analysed and compared for 35 patients having UIP without significant honeycombing (UIP-w/o hc, < 5% of honeycombing at CT), 35 patients having UIP with honeycombing (UIP-w/i hc, > or = 5% of honeycombing), and 25 patients with NSIP. The mortality rates were also compared. Follow-up CT scans were available in 75 patients (29 UIP-w/o hc patients, 22 UIP-w/i hc patients and 24 NSIP patients) and the follow-up periods ranged from 150 to 2,370 days. The initial and follow-up PFT data were available for 71 patients., Results: On the initial CT, significant differences were present between the UIP-w/i hc patients and both the UIP-w/o hc patients and the NSIP patients in the overall extent, ground-glass opacity (GGO) away from the reticulation, reticulation and honeycombing (all p < 0.05). Improvement was noticed in five (17%) of 29 UIP-w/o hc patients, none of 22 UIP-w/i hc patients, and 9 (37%) of 24 NSIP patients; deterioration was noted in six (21%) UIP-w/o hc patients, two (9%) UIPw/i hc patients and three (13%) NSIP patients (p = 0.044 between UIP-w/o and UIP-w/i hc; p = 0.637 between UIP-w/o hc and NSIP; p = 0.007 between UIP-w/i hc and NSIP). The serial changes of the pulmonary function in the NSIP patients were different from those noted for the UIP-w/i hc and UIP-w/o hc patients (p = 0.440 between UIP-w/o and UIP-w/i hc; p = 0.022 between UIP-w/o hc and NSIP; p = 0.003 between UIP-w/i hc and NSIP). Five (14%) of the 35 patients with UIPw/o hc, 16 (46%) of the 35 patients with UIP-w/i hc and three (12%) of the 25 patients with NSIP died (p = 0.002, comparison for the three groups)., Conclusion: On CT, NSIP and UIP-w/o hc patients have similar patterns of parenchymal abnormalities and a similar likelihood of change in the extent of disease on follow-up. Patients with UIP-w/i hc have distinctive features and a worst prognosis.

Idiopathic interstitial pneumonias comprise usual interstitial pneumonia (UIP), nonspecific interstitial pneumonia (NSIP), desquamative interstitial pneumonia (DIP), respiratory bronchiolitis-associated interstitial lung disease (RB-ILD), cryptogenic organizing pneumonia (COP), acute interstitial pneumonia (AIP), and lymphoid interstitial pneumonia (LIP). Each of these entities has a typical imaging and histologic pattern, although in practice the imaging patterns may be variable. Each entity may be idiopathic or may be secondary to a recognizable cause such as collagen vascular disease or inhalational exposure. The diagnosis of idiopathic interstitial pneumonia is made by means of correlation of clinical, imaging, and pathologic features. The characteristic computed tomographic (CT) features of UIP are predominantly basal and peripheral reticular pattern with honeycombing and traction bronchiectasis. NSIP is characterized by predominantly basal ground-glass opacity and/or reticular pattern, often with traction bronchiectasis. DIP and RB-ILD are smoking-related lung diseases characterized by ground-glass opacity and centrilobular nodules. COP is characterized by patchy peripheral or peribronchovascular consolidation. AIP manifests as diffuse lung consolidation and ground-glass opacity. LIP is associated with a CT pattern of ground-glass opacity sometimes associated with perivascular cysts., (Copyright RSNA, 2005)

Objective: The purpose of this study was to evaluate the prevalence of the reversed halo sign in pulmonary paracoccidioidomycosis., Materials and Methods: The high-resolution CT scans (1- or 2-mm collimation scans) of 148 consecutive patients with proven pulmonary paracoccidioidomycosis were reviewed to determine the prevalence of the reversed halo sign in these patients. The reversed halo sign was defined as central ground-glass opacity surrounded by a crescent or ring of consolidation. The images were reviewed by two radiologists who reached a decision by consensus., Results: A reversed halo sign was found in 15 patients (10%), including 13 men and two women ranging in age from 20 to 58 years (mean, 48 years). Three patients had only one reversed halo sign, one had two lesions, and the remaining had multiple lesions. The size of the sign ranged from 10 to 50 mm (average, 20 mm). In two cases the reversed halo sign was the only finding on CT. The most common associated findings seen in the remaining 13 patients included bilateral patchy areas of ground-glass attenuation (n = 10), parenchymal bands (n = 8), and small centrilobular nodules (n = 8). Three patients underwent surgical lung biopsy. Histologically the central area of the lesions consisted of an inflammatory infiltrate in the alveolar septa, composed of macrophages, lymphocytes, plasma cells, and some giant cells, with relative preservation of the alveolar spaces. The periphery of the lesion consisted of dense and homogeneous intraalveolar cellular infiltrate. There was no evidence of organizing pneumonia., Conclusion: The reversed halo sign is seen in approximately 10% of patients with paracoccidioidomycosis. In these patients, this sign reflects the presence of a central area of predominantly interstitial inflammation surrounded by predominantly air-space infiltration.