FOXP3+ regulatory T cells are associated with the severity and prognosis of sarcoidosis.

Rationale: Sarcoidosis is an inflammatory granulomatous disease of unknown etiology with predominant lung involvement. Organ involvement and disease severity, as well as the nature of immune alterations, vary among patients leading to a range of clinical phenotypes and outcomes. Our objective was to evaluate the association of disease course and immune responses in pulmonary sarcoidosis. Methods: In this prospective cohort study of 30 subjects, most of whom were followed for one year, we evaluated 14 inflammatory markers in plasma, 13 Treg/T cell flow cytometry markers and 8 parameters of FOXP3+ Treg biology, including suppressive function, epigenetic features and stability. Results: We identified a set of 13 immunological parameters that differ in sarcoidosis subjects in comparison with healthy donors. Five of those were inversely correlated with suppressive function of Tregs in sarcoidosis, and six (TNFα, TNFR I and II, sCD25, Ki-67 and number of Tregs) were particularly upregulated or increased in subjects with thoracic lymphadenopathy. Treg suppressive function was significantly lower in patients with thoracic lymphadenopathy, and in patients with higher burdens of pulmonary and systemic symptoms. A combination of five inflammatory markers, Ki-67 expression, Treg function, and lung diffusion capacity evaluated at study entry predicted need for therapy at one year follow-up in 90% of cases. Conclusion: Tregs may suppress ongoing inflammation at local and systemic levels, and TNFα, TNFR I and II, sCD25 and Ki-67 emerge as attractive biomarkers for in vivo sarcoid inflammatory activity.

Identification and Prognosis of Patients With Interstitial Pneumonia With Autoimmune Features.

BACKGROUND/OBJECTIVE: Patients classified as interstitial pneumonia with autoimmune features (IPAF) have interstitial lung disease (ILD) and features of autoimmunity but do not fulfill criteria for connective tissue diseases (CTDs). Our goal was to identify patients classifiable as IPAF, CTD-ILD, and idiopathic pulmonary fibrosis (IPF) from a preexisting pulmonary cohort and evaluate the prognosis of patients with IPAF. METHODS: We reviewed the medical records of 456 patients from a single-center pulmonary ILD cohort whose diagnoses were previously established by a multidisciplinary panel that did not include rheumatologists. We reclassified patients as IPAF, CTD-ILD, or IPF. We compared transplant-free survival using Kaplan-Meier methods and identified prognostic factors using Cox models. RESULTS: We identified 60 patients with IPAF, 113 with CTD-ILD, and 126 with IPF. Transplant-free survival of IPAF was not statistically significantly different from that of CTD-ILD or IPF. Among IPAF patients, male sex (hazard ratio, 4.58 [1.77-11.87]) was independently associated with worse transplant-free survival. During follow-up, only 10% of IPAF patients were diagnosed with CTD-ILD, most commonly antisynthetase syndrome. CONCLUSION: Despite similar clinical characteristics, most patients with IPAF did not progress to CTD-ILD; those who did often developed antisynthetase syndrome, highlighting the critical importance of comprehensive myositis autoantibody testing in this population. As in other types of ILD, male sex may portend a worse prognosis in IPAF. The routine engagement of rheumatologists in the multidisciplinary evaluation of ILD will help ensure the accurate classification of these patients and help clarify prognostic factors.

A CT Algorithm Can Elevate the Differential Diagnosis of Interstitial Lung Disease by Non-specialists to Equal That of Specialist Thoracic Radiologists.

BACKGROUND: Diagnosis of diffuse parenchymal lung diseases (DPLD) on high resolution CT (HRCT) is difficult for non-expert radiologists due to varied presentation for any single disease and overlap in presentation between diseases. RATIONALE AND OBJECTIVES: To evaluate whether a pattern-based training algorithm can improve the ability of non-experts to diagnosis of DPLD. MATERIALS AND METHODS: Five experts (cardiothoracic-trained radiologists), and 25 non-experts (non-cardiothoracic-trained radiologists, radiology residents, and pulmonologists) were each assigned a semi-random subset of cases from a compiled database of DPLD HRCTs. Each reader was asked to create a top three differential for each case. The non-experts were then given a pattern-based training algorithm for identifying DPLDs. Following training, the non-experts were again asked to create a top three differential for each case that they had previously evaluated. Accuracy between groups was compared using Chi-Square analysis. RESULTS: A total of 400 and 1450 studies were read by experts and non-experts, respectively. Experts correctly placed the diagnosis as the first item on the differential versus having the correct diagnosis as one of their top three diagnoses at an overall rate of 48 and 64.3%, respectively. Pre-training, non-experts achieved a correct diagnosis/top three of 32.5 and 49.7%, respectively. Post-training, non-experts demonstrated a correct diagnosis/top three of 41.2 and 65%, a statistically significant increase (p < 0.0001). In addition, post training, there was no difference between non-experts and experts in placing the correct diagnosis within their top three differential. CONCLUSION: The diagnosis of DPLDs by HRCT imaging alone is relatively poor. However, use of a pattern-based teaching algorithm can improve non-expert interpretation and enable non-experts to include the correct diagnosis within their differential diagnoses at a rate comparable to expert cardiothoracic trained radiologists.

Lower Respiratory Tract Infection with Human Metapneumovirus: Chest CT Imaging Features and Comparison with Other Viruses.

PURPOSE: Human metapneumovirus has been increasingly identified as a cause of lower respiratory tract infection in adults worldwide. The CT imaging features of human metapneumovirus in adults have not been characterized. The purpose of this paper is to determine the imaging features of human metapneumovirus and to compare them with features of other viruses. METHODS: Two clinicians retrospectively reviewed the medical records of 104 adults with lower respiratory tract infection due to human metapneumovirus at four hospitals in the northeast USA over 32 months. CT images were evaluated by two chest radiologists for airspace consolidation, bronchiectasis, bronchial wall thickening, ground-glass opacities, pleural effusion and tree-in-bud opacities and the dominant imaging pattern. Results for human metapneumovirus were compared with results previously reported for other viruses. RESULTS: Human metapneumovirus predominantly caused an airway-centric pattern (71-81/104, 68-77%) of infection characterized by bronchial wall thickening, tree-in-bud opacities, peri-bronchial consolidation and/or peri-bronchial ground-glass opacities. The airway-centric pattern has been previously reported with other paramyxoviridae (parainfluenza virus and respiratory syncytial virus). However, human metapneumovirus was significantly more likely (p = 0.03-0.001) to cause bronchopneumonia (46-55%) than parainfluenza virus (17%) or respiratory syncytial virus (21%). Follow-up CT in 41 (39%) patients with hMPV revealed resolution of findings in 38/41 (91%). CONCLUSION: The paramyxoviridae, including human metapneumovirus, are known to have a propensity to infect ciliated respiratory cells and we have demonstrated this leads to a propensity to cause bronchitis, bronchiolitis and bronchopneumonia on CT scans. Of these, human metapneumovirus is most likely to cause bronchopneumonia. Healthcare providers should consider human metapneumovirus as a cause of pneumonia on chest CT.

Exposure to Ambient Particulate Matter Is Associated With Accelerated Functional Decline in Idiopathic Pulmonary Fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF), a progressive disease with an unknown pathogenesis, may be due in part to an abnormal response to injurious stimuli by alveolar epithelial cells. Air pollution and particulate inhalation of matter evoke a wide variety of pulmonary and systemic inflammatory diseases. We therefore hypothesized that increased average ambient particulate matter (PM) concentrations would be associated with an accelerated rate of decline in FVC in IPF. METHODS: We identified a cohort of subjects seen at a single university referral center from 2007 to 2013. Average concentrations of particulate matter < 10 and < 2.5 µg/m3 (PM10 and PM2.5, respectively) were assigned to each patient based on geocoded residential addresses. A linear multivariable mixed-effects model determined the association between the rate of decline in FVC and average PM concentration, controlling for baseline FVC at first measurement and other covariates. RESULTS: One hundred thirty-five subjects were included in the final analysis after exclusion of subjects missing repeated spirometry measurements and those for whom exposure data were not available. There was a significant association between PM10 levels and the rate of decline in FVC during the study period, with each µg/m3 increase in PM10 corresponding with an additional 46 cc/y decline in FVC (P = .008). CONCLUSIONS: Ambient air pollution, as measured by average PM10 concentration, is associated with an increase in the rate of decline of FVC in IPF, suggesting a potential mechanistic role for air pollution in the progression of disease.

Thoracic Manifestations of Klippel-Trenaunay Syndrome.

Klippel-Trenaunay syndrome (KTS) is a congenital disorder characterized by venous malformations and a predisposition to pulmonary embolism. We reviewed the imaging findings of 7 adult patients with KTS who underwent thoracic CT. While the superficial manifestations of KTS predominantly affect the extremities, patients frequently develop abnormalities of the pulmonary arterial system, particularly chronic thromboembolic pulmonary hypertension. Additionally, some patients are seen to develop pulmonary arteriolar aneurysms; the physiologic significance of this finding is unknown at this time. Radiologists should be aware of these potential findings and have a high index of suspicion for chronic PE in patients with KTS.

Interstitial Lung Disease in the Elderly.

BACKGROUND: Despite the relationship between idiopathic pulmonary fibrosis (IPF) and advancing age, little is known about the epidemiology of interstitial lung disease (ILD) in the elderly. We describe the diagnoses, clinical characteristics, and outcomes of patients who were elderly at the time of ILD diagnosis. METHODS: Among subjects from a prospective cohort study of ILD, elderly was defined as age ≥ 70 years. Diagnoses were derived from a multidisciplinary review. Differences between elderly and nonelderly groups were determined using the χ2 test and analysis of variance. RESULTS: Of the 327 subjects enrolled, 80 (24%) were elderly. The majority of elderly subjects were white men. The most common diagnoses were unclassifiable ILD (45%), IPF (34%), connective tissue disease (CTD)-ILD (11%), and hypersensitivity pneumonitis (8%). Most elderly subjects (74%) with unclassifiable ILD had an imaging pattern inconsistent with usual interstitial pneumonia (UIP). There were no significant differences in pulmonary function or 3-year mortality between nonelderly and elderly subjects combined or in a subgroup analysis of those with IPF. CONCLUSIONS: Although IPF was the single most common diagnosis, the majority of elderly subjects had non-IPF ILD. Our findings highlight the need for every patient with new-onset ILD, regardless of age, to be surveyed for exposures and findings of CTD. Unclassifiable ILD was common among the elderly, but for most, the radiographic pattern was inconsistent with UIP. Although the effect of ILD may be more pronounced in the elderly due to reduced global functionality, ILD was not more severe or aggressive in this group.

Back to the future: sagittal CT in the evaluation of COPD.

OBJECTIVES: To identify features of obstructive airway disease on sagittal reconstruction, compare the accuracy of findings to traditional imaging characteristics of COPD, and determine the fraction of additional cases identified using new characteristics. METHODS: The study was approved by the centre's Institutional Review Board and is HIPAA compliant. Two hundred sixteen patients with HRCT and spirometry within a 3-month window were included. Four radiologists evaluated each HRCT for traditional characteristics of COPD and new quantitative and qualitative features of obstruction on axial and sagittal reconstructions. Imaging characteristics were assessed for correlation with the spirometric diagnosis of obstructive airway disease. RESULTS: Quantitative and qualitative findings on sagittal reconstruction are highly specific for COPD (specificity >90 %). Features of hyperinflation on sagittal reconstruction are more accurate predictors of obstruction than traditional axial measures, with greater interobserver reliability (hyperinflation left hemidiaphragm: accuracy: 70.08 % ± 2.49 %; kappa: 0.511 versus traditional measures: accuracy: 62.00 % ± 5.38 %; kappa: 0.407). Sagittal reconstruction identified 27-70 % more patients with COPD than traditional axial findings (p < 0.05). CONCLUSIONS: Analysis of sagittal reconstruction enables greater accuracy and specificity in the diagnosis of obstructive airway disease compared to traditional measures on axial imaging. Use of sagittal reconstructions can help identify up to 70 % more patients with COPD than traditional imaging findings alone. KEY POINTS: • HRCT sagittal reconstruction is useful in the evaluation of obstructive lung disease. • Findings on sagittal reconstructions allow physicians to more accurately diagnose COPD. • Routine use of sagittal reconstructions increases the sensitivity for diagnosing COPD.

Small pulmonary artery defects are not reliable indicators of pulmonary embolism.

OBJECTIVES: To evaluate the rate of agreement of pulmonary embolism diagnosis in computed tomography (CT) pulmonary angiogram studies and to evaluate the rate of inaccurate interpretations in the community hospital setting. METHODS: Using the keywords "pulmonary embolism/embolus/emboli," the radiology information system was searched for CT pulmonary angiograms performed over a 3-year period at three U.S. community hospitals. Studies containing probable or definite pulmonary emboli were independently reviewed by four subspecialty thoracic radiologists. MEASUREMENTS AND MAIN RESULTS: Agreement about the presence of pulmonary embolism progressively decreased with decreasing diameter of pulmonary vascular lesions (P < 0.0001). There was a sharp fall in observer agreement for pulmonary embolism of subsegmental lesions (P < 0.0001). The frequency of agreement decreased with decreasing quality of the imaging examination (P < 0.0001). Community radiologists were prone to false-positive pulmonary embolism diagnosis of subsegmental and/or small pulmonary arterial defects. The probability of a false-positive diagnosis and indeterminate examinations progressively increased with: (1) more peripheral location of the lesion, (2) decreased size (short-axis diameter) of the lesion, and (3) diminishing quality of the CT examination. Forty-eight of 177 (27%) of subsegmental vascular defects identified by community radiologists were deemed indeterminate, and 27 of 177 (15%) of subsegmental vascular defects were judged to be false positive for pulmonary embolism by the consensus diagnosis. Fifty-four of 274 (20%) vascular defects with short axis less than 6 mm were indeterminate for pulmonary embolism, and 37 of 274 (14%) of vascular defects with short axis less than 6 mm were false positive for pulmonary embolism. Eleven of 13 (85%) of vascular lesions identified as pulmonary emboli on the lowest-quality CT examinations were false positive or indeterminate for pulmonary embolism. False-positive examinations were most often due to respiratory motion artifact (19/38, 50%). CONCLUSIONS: There is relatively poor interobserver agreement for subsegmental and/or small pulmonary artery defects, especially in CT pulmonary angiograms degraded by technical artifacts. These factors can lead to an increased frequency of inaccurate interpretation or indeterminate diagnosis of subsegmental and/or small defects. Caution is indicated in interpreting the significance of small vascular defects in CT pulmonary angiograms.

Streptococcus anginosus infections: crossing tissue planes.

Streptococcus anginosus has long been recognized to cause invasive pyogenic infections. This holds true for thoracic infections where S. anginosus has a propensity for abscess and empyema formation. Early diagnosis is important given the significant morbidity and mortality associated with thoracic S. anginosus infections. Yet, distinguishing thoracic S. anginosus clinically is difficult. We present three cases of thoracic S. anginosus that demonstrated radiographic extension across tissue planes, including the interlobar fissure, diaphragm, and chest wall. Few infectious etiologies are known to cross tissue planes. Accordingly, we propose S. anginosus be considered among the differential diagnosis of potential infectious etiologies causing radiographic extension across tissue planes.

The relative frequencies of causes of widespread ground-glass opacity: a retrospective cohort.

PURPOSE: The purpose of our study was to determine the relative frequencies of causes of widespread ground-glass opacity (GGO) in an unselected, consecutive patient population and to identify any associated imaging findings that can narrow or reorganize the differential. MATERIALS AND METHODS: The study was approved by the center's IRB and is HIPPA compliant. Cases with widespread GGO in the radiology report were identified by searching the Radiology Information System. Medical records and CT scan examinations were reviewed for the causes of widespread GGO. Associations between a less dominant imaging finding and a particular diagnosis were analyzed with the chi square test. Our study group consisted of 234 examinations with 124 women and 110 men and a mean age of 53.7 years. RESULTS: A cause was established in 204 (87.2%) cases. Hydrostatic pulmonary edema was most common with 131 cases (56%). Interstitial lung diseases (ILD) were the next most common, most often hypersensitivity pneumonitis (HP) (n=12, 5%) and connective tissue disease related ILD (n=7, 3%). Infection accounted for 5% (12 cases). A few miscellaneous diseases accounted for 5 cases (2.1%). The combination of septal thickening and pleural effusions had a specificity of 0.91 for hydrostatic pulmonary edema (P<.001) while centrilobular nodules and air trapping had a specificity of 1.0 for HP. In 24 (10.2%) patients, increased opacification from expiration was incorrectly interpreted as representing widespread ground glass opacity. The relative frequency of disease dramatically changed according to the setting. In the inpatient setting, diffuse alveolar disease and diffuse infection accounted for all of the known diagnoses. Pulmonary edema accounted for 75% of the diagnoses and diffuse infection accounted for approximately 7%. In the outpatient setting, interstitial lung disease was the most common cause, accounting for 26 of 53 cases (49%). Regarding immunocompromised patients, hydrostatic pulmonary edema was still the most common cause (46%) with diffuse infection (24%) the next most likely diagnosis. For patients with bone marrow suppression, 80% of the cases were due to opportunistic viral infection. CONCLUSION: Widespread GGO is most commonly a manifestation of hydrostatic pulmonary edema. Outpatients will most often have HP or connective tissue disease related ILD. Associated findings are helpful for the diagnosis of hydrostatic pulmonary edema and HP.

Expiratory air trapping on thoracic computed tomography. A diagnostic subclassification.

RATIONALE: Multiple causes for air trapping as identified by expiratory computed tomography (CT) have been reported, but a unified evaluation schema has never been proposed. OBJECTIVES: It was our purpose to identify imaging features that would help distinguish etiologies of mosaic air trapping. METHODS: Cases with the term "air trapping" in the radiology report in 2010 were identified by searching the Radiology Information System of an academic tertiary care center and associated community hospital. Medical records and CT examinations were reviewed for the causes of air trapping. MEASUREMENTS AND MAIN RESULTS: Causes for moderate to severe air trapping could be identified in 201 of 230 (87.4%) cases and could be subdivided into those associated with bronchiectasis (76 of 201, 38%), those associated with interstitial lung disease (62 of 201, 31%), those associated with tree-in-bud opacities (5 of 201, 2%), and those with air trapping alone (58 of 201, 29%). When found with bronchiectasis, nontuberculous mycobacteria, cystic fibrosis, idiopathic bronchiectasis, and transplant-related bronchiolitis obliterans were the most common causes of air trapping. When found with interstitial lung disease, sarcoidosis, hypersensitivity pneumonitis, or unspecified interstitial lung disease were the most common cause of air trapping. When found in isolation, chronic bronchitis, asthma, bronchiolitis obliterans, and unspecified small airways disease were the most common causes of air trapping. Unusual conditions causing isolated air trapping included vasculitis and diffuse idiopathic neuroendocrine cell hyperplasia. CONCLUSION: A variety of conditions can cause air trapping. Associated imaging findings can narrow the differential diagnosis.

Causes and imaging patterns of tree-in-bud opacities.

BACKGROUND: Multiple causes for tree-in-bud (TIB) opacities have been reported. However, to our knowledge the relative frequencies of the causes have not been evaluated. The purpose of this study was to determine the relative frequency of causes of TIB opacities and identify patterns of disease associated with TIB opacities. METHODS: Cases with TIB opacities in the radiology report in 2010 were identified by searching the Radiology Information System. Medical records and CT scan examinations were reviewed for the causes of TIB opacities. Patterns of disease associated with TIB opacities were evaluated. RESULTS: Causes for TIB opacities were established in 166 of 406 (40.9%) cases. Respiratory infections (119 of 166, 72%) with mycobacteria (65 of 166, 39%), bacteria (44 of 166, 27%), viruses (four of 166, 3%), or multiple organisms (six of 166, 4%) were most common. Aspiration was the cause in 42 of 166 (25%). Alternating areas of normal lung with regions of small airways disease (TIB opacities, bronchiectasis) (random small airways pattern) was specific (0.92) for Mycobacterium avium complex infection. Nearly uniform distribution of bronchiectasis (widespread bronchiectasis pattern) was specific for "diseases predisposing to airway infection" (specificity 0.92), such as cystic fibrosis, primary ciliary dyskinesia, allergic bronchopulmonary aspergillosis, and immunodeficiency states. Consolidation and TIB opacities (bronchopneumonia pattern) were usually due to bacterial infection or aspiration. Dependent distribution (specificity 0.79) and esophageal abnormality (specificity 0.86) with TIB opacities were associated with aspiration. Chronicity of findings was associated with mycobacterial infection (P < .0001, sensitivity 0.96). Acuteness of findings was associated with bacterial infection (P < .001, specificity 0.87). CONCLUSIONS: TIB opacities are most often a manifestation of infections or aspiration. Patterns of disease can provide clues to the most likely diagnosis.

The CT appearance of lower respiratory infection due to parainfluenza virus in adults.

OBJECTIVE: We retrospectively reviewed the CT findings of lower respiratory tract infection (LRTI) due to parainfluenza virus (PIV) to determine the imaging features of PIV infection and to identify any differences compared with the CT appearances of LRTIs due to respiratory syncytial virus (RSV), adenovirus, and influenza virus. MATERIALS AND METHODS: The imaging features of LRTI from PIV over a 51-month period were retrospectively reviewed. The specific CT findings and overall pattern of infection in patients with LRTI due to PIV were recorded and were then compared with the CT appearances of RSV, adenovirus, and influenza LRTIs using data from a previous study. RESULTS: Twenty-four chest CT examinations of 24 patients with PIV infection were analyzed. Tree-in-bud opacities were the most common finding (13/24, 54%), and the airway-centric pattern of disease--characterized by combinations of bronchial wall thickening, tree-in-bud opacities, and peribronchiolar consolidation (bronchitis, bronchiolitis, and bronchopneumonia)--was the most common pattern (16/24, 67%). In comparison with previous data on RSV, adenovirus, and influenza virus, PIV showed tree-in-bud opacities and airway-centric patterns significantly more often than adenovirus or influenza virus. PIV and RSV showed similar CT findings and patterns of disease. CONCLUSION: Despite varying CT appearances of PIV LRTI, it most often shows airway-centric disease and is similar to the appearance of RSV infection, both of which are members of the Paramyxoviridae family of viruses.

Focal ground-glass opacities in non-small cell lung carcinoma resection patients.

PURPOSE: To retrospectively determine the frequency, natural progression, radiographic characteristics, and primary cancer cell type of focal ground-glass opacities (GGOs) identified on serial radiographic examinations in patients with prior non-small cell lung carcinoma (NSCLC) resection. METHODS: One thousand three hundred and seventy-nine CT examinations in 154 patients with NSCLC resection between 1997 and 2008 were reviewed by two radiologists to determine the frequency of postoperative focal GGOs. Percentages, imaging characteristics and primary cancer cell types of GGOs that persisted, resolved, or resected were recorded. For persistent GGOs, growth rate was determined. RESULTS: Of 154 patients, 67 (44%) developed 174 GGO during a mean follow-up of 2.7 years (standard deviation 2.23 years, range 1 month to 10 years). Of these 174 opacities, 110 (63%) spontaneously resolved within 6 months. Of the remaining 64 lesions, 5 (3%) were resected and 59 (34%) persisted and demonstrated indolent growth with a median annual growth rate of 2.02 mm. Of the 59 persistent GGOs, 41 (69%) were nodularly shaped, 58 (95%) indistinctly marginated, 17 (29%) with pseudocavitation and 25 (42%) contained solid elements. Adenocarcinoma was the original resected cancer in more than half of these lesions (37 of 59, 63%). CONCLUSIONS: In individuals who have undergone NSCLC resection, approximately 44% will develop focal GGO on follow-up CT examination. A majority of these GGOs will spontaneously resolve by 6 months after initial identification. As most persistent GGOs are indolent, we propose an initial 6-month interval reimaging once postoperative GGOs are detected followed by subsequent annual surveillance.

CT of viral lower respiratory tract infections in adults: comparison among viral organisms and between viral and bacterial infections.

OBJECTIVE: We retrospectively compared the CT findings of consecutive viral and bacterial lower respiratory tract infections (LRTIs) to determine their imaging appearance and any definable differences among the causative viruses and between the viral and bacterial infections. MATERIALS AND METHODS: Imaging features of LRTI caused by influenza virus, respiratory syncytial virus (RSV), parainfluenza, adenovirus, and bacteria over a 33-month period were reviewed by three radiologists blinded to clinical and diagnostic information. Individual CT features and the dominant pattern of infection were recorded for each examination. Imaging characteristics were compared among the four respiratory viruses and between viral and bacterial infections. RESULTS: One hundred fifteen chest CT scans were analyzed (60 influenza virus, 19 RSV, 10 adenovirus, four parainfluenza virus, and 22 bacterial pneumonia LRTIs). Individual imaging findings and imaging patterns were seen in similar frequencies when we compared viral and bacterial LRTIs, with the exception of the diffuse airspace pattern, which was seen more frequently in bacterial infections. Although there was overlap in the imaging appearance of individual viruses, RSV and adenovirus tended to have characteristic imaging appearances. RSV presented with an airway-centric pattern of disease (13/19 cases [68%]) characterized by varying mixtures of tree-in-bud opacities and bronchial wall thickening, with or without peribronchiolar consolidation. Adenovirus typically appeared as multifocal consolidation or ground-glass opacity without airway inflammatory findings (7/10 cases [70%]). CONCLUSION: There is considerable overlap in the imaging appearance of viral and bacterial respiratory infections. However, some characteristic differences can be seen, especially with RSV and adenovirus infections.

Chest computed tomographic imaging characteristics of viral acute lower respiratory tract illnesses: a case-control study.

OBJECTIVE: This study aimed to determine whether computed tomographic (CT) findings can distinguish viral lower respiratory tract illness (LRTI) from other conditions. METHODS: Three radiologists reviewed CT images of patients with LRTI who underwent testing for respiratory viral infection. Imaging findings in subjects with positive viral assays were compared with subjects with negative assays. RESULTS: Of 334 subjects, 93 were positive for viral LRTI. Tree-in-bud opacities and bronchial wall thickening were observed more often in subjects with viral LRTI (P < 0.05). Multifocal airspace disease occurred with similar frequency in both groups. Diffuse airspace opacification was negatively associated with viral LRTI. Pleural effusion was observed more often among subjects without viral LRTI (P < 0.001). CONCLUSIONS: Airway inflammatory changes such as tree-in-bud opacities, bronchial wall thickening, and peribronchiolar consolidation are associated with community-acquired viral LRTI. Recognition of these findings should prompt testing for viral infection. Multifocal consolidation is commonly found in cases of viral LRTI but is nonspecific.

Tracheobronchopathia osteochondroplastica presenting as a single dominant tracheal mass.

Tracheobronchopathia osteochondroplastica is a rare, benign disorder of upper airways characterized by multiple submucosal metaplastic cartilaginous and bony nodules arising from the tracheal cartilage. We report an unusual presentation of tracheobronchopathia osteochondroplastica as a single dominant nodule arising from the anterior tracheal rings in a young adult man who presented with wheezing and symptoms of airway obstruction. The differential diagnosis of cartilaginous and bony endotracheal lesions is discussed.

Recurrent spontaneous pneumothorax in a patient with Birt-Hogg-Dubé syndrome.

Recurrent spontaneous pneumothorax is a disorder often managed by thoracic surgeons. Most etiologies are benign in nature; however, there are several syndromes that are associated with potentially fatal pulmonary or systemic manifestations. One such example is Birt-Hogg-Dubé syndrome, a rare inheritable syndrome characterized by papular skin lesions involving the scalp, head, face and neck; pulmonary cysts; and a propensity to develop renal carcinoma. In our report, we describe a patient, who was diagnosed with Birt-Hogg-Dubé syndrome after presenting with a history of recurrent spontaneous pneumothorax, and a family history of spontaneous pneumothorax and renal cell carcinoma. This case is of particular interest to the cardiothoracic surgery community as the patient described as well as several of his family members were managed by multiple thoracic surgeons, who did not appreciate the diagnosis.

Chest CT features of community-acquired respiratory viral infections in adult inpatients with lower respiratory tract infections.

PURPOSE: The appearance of respiratory virus infection on thoracic computed tomography (CT) has been described only to a limited extent in the current literature, and viral pneumonias may be under-recognized by radiologists. Our objective was to describe thoracic CT findings in a broad range of adult inpatients with respiratory virus infections. MATERIALS AND METHODS: A retrospective analysis of chest CTs was performed on symptomatic adult inpatients presenting with positive nucleic acid-based assays for 1 of 4 common community-acquired respiratory viruses. Forty-two patients with viral respiratory tract infections who underwent chest CT imaging were evaluated. The reviewer was blinded to virus type and patient information. CT findings were compared with CT reports produced at the time of the original study and correlated with clinical outcome measures. RESULTS: Influenza (n=21), adenovirus (n=9), respiratory syncytial virus (n=8), and parainfluenza (n=4) were represented among the cohort. Three patterns of the disease were seen with viral infection: (1) limited infection with normal imaging (21%), (2) bronchitis/bronchiolitis characterized by bronchial wall thickening and tree-in bud opacities (31%), and (3) pneumonia characterized by multifocal consolidation or ground-glass opacities (36%). Viral infection was suggested in only 4/42 (10%) of the original radiology reports, all of which had evidence of bronchitis/bronchiolitis on chest CT. Viral pneumonia, characterized by multifocal ground-glass opacities or multifocal consolidations, was interpreted as aspiration pneumonia or bacterial pneumonia in 15/16 (94%) of the original CT reports. CONCLUSIONS: CT scans of the inpatients with community-acquired viral infections most commonly show 1 of 2 patterns: consolidation and ground-glass opacities or bronchial wall thickening and tree-in-bud opacities. It is important that physicians interpreting CTs with multifocal consolidations and/or multifocal ground-glass opacities consider viral pneumonia when these findings are observed and recommend appropriate diagnostic testing when clinically warranted.