Vessel-related structures predict UIP pathology in those with a non-IPF pattern on CT.

OBJECTIVES: To determine if a quantitative imaging variable (vessel-related structures [VRS]) could identify subjects with a non-IPF diagnosis CT pattern who were highly likely to have UIP histologically. METHODS: Subjects with a multidisciplinary diagnosis of interstitial lung disease including surgical lung biopsy and chest CT within 1 year of each other were included in the study. Non-contrast CT scans were analyzed using the Computer-Aided Lung Informatics for Pathology Evaluation and Rating (CALIPER) program, which quantifies the amount of various abnormal CT patterns on chest CT. Quantitative data were analyzed relative to pathological diagnosis as well as the qualitative CT pattern. RESULTS: CALIPER-derived volumes of reticulation (p = 0.012), honeycombing (p = 0.017), and VRS (p < 0.001) were associated with a UIP pattern on pathology on univariate analysis but only VRS was associated with a UIP pathology on multivariable analysis (p = 0.013). Using a VRS cut-off of 173 cm3, the sensitivity and specificity for pathological UIP were similar to those for standard qualitative CT assessment (55.9% and 80.4% compared to 60.6% and 80.4%, respectively). VRS differentiated pathological UIP cases in those with a non-IPF diagnosis CT category (p < 0.001) but not in other qualitative CT patterns (typical UIP, probable UIP, and indeterminate for UIP). The rate of pathological UIP in those with VRS greater than 173 cm3 (84.2%) was nearly identical to those who had a qualitative CT pattern of probable UIP (88.9%). CONCLUSIONS: VRS may be an adjunct to CT in predicting pathology in patients with interstitial lung disease. KEY POINTS: • Volume of vessel-related structures (VRS) was associated with usual interstitial pneumonia (UIP) on pathology. • This differentiation arose from those with CT scans with a non-IPF diagnosis imaging pattern. • Higher VRS has similar diagnostic ramifications for UIP as probable UIP, transitively suggesting in patients with high VRS, pathology may be obviated.

Computed Tomography Findings Suggestive of Connective Tissue Disease in the Setting of Usual Interstitial Pneumonia.

PURPOSE: A usual interstitial pneumonia (UIP) pattern is common in idiopathic pulmonary fibrosis (IPF) and connective tissue disease-related interstitial lung disease (CTD-ILD). The purpose of the study was to validate imaging findings differentiating CTD-ILD from IPF in UIP. METHODS: Patients with a multidisciplinary diagnosis of CTD-ILD or IPF and a UIP pattern on computed tomography and/or pathology were included in this study. Prevalence of 3 computed tomography findings shown to be associated with CTD-ILD (the straight edge sign [SES], the exuberant honeycombing sign, and the anterior upper lobe sign [AULS]) were tabulated in CTD-ILD and IPF subjects. The ability of each of these signs to discriminate between CTD-ILD and IPF was evaluated. Survival analysis was also performed using log-rank analysis. RESULTS: The study cohort included 50 CTD-ILD and 100 IPF subjects with UIP. The SES and the AULS were more common in CTD-ILD than IPF (prevalence, 36.0% and 34.9% in CTD-ILD vs 8.3% and 17.2% in IPF, respectively [P = 0.0105 - <0.001]). The highest specificity (95.7%) of CTD-ILD diagnosis was seen with bilateral SES. Moreover, the SES was associated with improved survival (P = 0.0383), which appeared to be largely because of improvement in survival in IPF subjects. The presence of AULS was associated with pulmonary functional abnormalities. CONCLUSIONS: A radiographic UIP pattern with evidence of SES or the AULS should raise suspicion for CTD-ILD rather than IPF. Patients with IPF and SES have an attenuated disease course and might represent a different phenotype than those without the SES.

Prognosticating Outcomes in Interstitial Lung Disease by Mediastinal Lymph Node Assessment. An Observational Cohort Study with Independent Validation.

RATIONALE: Mediastinal lymph node (MLN) enlargement on chest computed tomography (CT) is prevalent in patients with interstitial lung disease (ILD) and may reflect immunologic activation and subsequent cytokine-mediated immune cell trafficking. OBJECTIVES: We aimed to determine whether MLN enlargement on chest CT predicts clinical outcomes and circulating cytokine levels in ILD. METHODS: MLN measurements were obtained from chest CT scans of patients with ILD at baseline evaluation over a 10-year period. Patients with sarcoidosis and drug toxicity-related ILD were excluded. MLN diameter and location were assessed. Plasma cytokine levels were analyzed in a subset of patients. The primary outcome was transplant-free survival (TFS). Secondary outcomes included all-cause and respiratory hospitalizations, lung function, and plasma cytokine concentrations. Cox regression was used to assess mortality risk. Outcomes were assessed in three independent ILD cohorts. MEASUREMENTS AND MAIN RESULTS: Chest CT scans were assessed in 1,094 patients (mean age, 64 yr; 52% male). MLN enlargement (≥10 mm) was present in 66% (n = 726) and strongly predicted TFS (hazard ratio [HR], 1.53; 95% confidence interval [CI], 1.12-2.10; P = 0.008) and risk of all-cause and respiratory hospitalizations (internal rate of return [IRR], 1.52; 95% CI, 1.17-1.98; P = 0.002; and IRR, 1.71; 95% CI, 1.15-2.53; P = 0.008, respectively) when compared with subjects with MLN <10 mm. Patients with MLN enlargement had lower lung function and decreased plasma concentrations of soluble CD40L (376 pg/ml vs. 505 pg/ml, P = 0.001) compared with those without MLN enlargement. Plasma IL-10 concentration >45 pg/ml predicted mortality (HR, 4.21; 95% CI, 1.21-14.68; P = 0.024). Independent analysis of external datasets confirmed these findings. CONCLUSIONS: MLN enlargement predicts TFS and hospitalization risk in ILD and is associated with decreased levels of a key circulating cytokine, soluble CD40L. Incorporating MLN and cytokine findings into current prediction models might improve ILD prognostication.

Ontology-Based Radiology Teaching File Summarization, Coverage, and Integration.

Radiology teaching file repositories contain a large amount of information about patient health and radiologist interpretation of medical findings. Although valuable for radiology education, the use of teaching file repositories has been hindered by the ability to perform advanced searches on these repositories given the unstructured format of the data and the sparseness of the different repositories. Our term coverage analysis of two major medical ontologies, Radiology Lexicon (RadLex) and Unified Medical Language System (UMLS) Systematized Nomenclature of Medicine Clinical Terms (SNOMED CT), and two teaching file repositories, Medical Imaging Resource Community (MIRC) and MyPacs, showed that both ontologies combined cover 56.3% of terms in the MIRC and only 17.9% of terms in MyPacs. Furthermore, the overlap between the two ontologies (i.e., terms included by both the RadLex and UMLS SNOMED CT) was a mere 5.6% for the MIRC and 2% for the RadLex. Clustering the content of the teaching file repositories showed that they focus on different diagnostic areas within radiology. The MIRC teaching file covers mostly pediatric cases; a few cases are female patients with heart-, chest-, and bone-related diseases. The MyPacs contains a range of different diseases with no focus on a particular disease category, gender, or age group. MyPacs also provides a wide variety of cases related to the neck, face, heart, chest, and breast. These findings provide valuable insights on what new cases should be added or how existent cases may be integrated to provide more comprehensive data repositories. Similarly, the low-term coverage by the ontologies shows the need to expand ontologies with new terminology such as new terms learned from these teaching file repositories and validated by experts. While our methodology to organize and index data using clustering approaches and medical ontologies is applied to teaching file repositories, it can be applied to any other medical clinical data.

CT-Pathologic Correlation of Major Types of Pulmonary Fibrosis: Insights for Revisions to Current Guidelines.

OBJECTIVE: The purpose of this study was to assess the diagnostic significance of CT patterns that cannot be classified according to current idiopathic pulmonary fibrosis (IPF) guidelines and of specific findings of the inconsistent with usual interstitial pneumonitis (UIP) pattern. MATERIALS AND METHODS: Subjects with a multidisciplinary diagnosis of interstitial lung disease who had undergone surgical lung biopsy and chest CT within 1 year of each other were included in the study. The predominant distribution and pattern of disease were scored. Cases were classified as UIP, possible UIP, or inconsistent with UIP at chest CT according to 2011 IPF guidelines. Cases that could not be confidently categorized with current guidelines were annotated as indeterminate. RESULTS: UIP, possible UIP, and inconsistent with UIP CT patterns were associated with pathologic UIP in 89.6%, 81.6%, and 60.0% of subjects. An indeterminate CT pattern (7.7% [20/259]) was associated with a UIP pathologic diagnosis in 55.0% of cases. This finding was not statistically different from the findings in the group with the inconsistent with UIP CT pattern (p = 0.677) but was different from the findings in the UIP (p < 0.001) and possible UIP (p = 0.031) groups. In regard to specific findings of the inconsistent with UIP CT category, ground-glass opacity, air-trapping, consolidation, and axial distribution were associated with a non-UIP pathologic diagnosis; however, there was no significant association with zonal distribution. CONCLUSION: A substantial minority of cases cannot be confidently categorized according to current guidelines for IPF and differ diagnostically from the possible UIP and UIP CT categories. The term "inconsistent with UIP" is misleading and should be renamed.

CT Features of the Usual Interstitial Pneumonia Pattern: Differentiating Connective Tissue Disease-Associated Interstitial Lung Disease From Idiopathic Pulmonary Fibrosis.

OBJECTIVE: A substantial proportion of cases of usual interstitial pneumonia (UIP) are due to connective tissue disease (CTD)-associated interstitial lung disease (ILD). The purpose of this study was to determine whether specific CT findings can help differentiate a UIP pattern of CTD-ILD from a UIP pattern of idiopathic pulmonary fibrosis (IPF) and whether these signs are associated with survival. MATERIALS AND METHODS: Adults visiting an ILD clinic from 2006 to 2015 enrolled in a research registry with a multidisciplinary diagnosis of CTD-ILD or IPF and a UIP pattern at high-resolution CT were included in the study. In these subjects with CT findings of UIP due to either IPF or CTD-ILD, three CT findings anecdotally associated with CTD-ILD were assessed for diagnostic accuracy: the "straight-edge" sign, the "exuberant honeycombing" sign, and the "anterior upper lobe" sign. Survival assessments were performed with univariate and multivariable techniques. RESULTS: The subjects included 63 patients who had CTD-ILD and 133 patients who had IPF with a UIP pattern at CT. All three CT signs were significantly more common in subjects with CTD-ILD than those with IPF (prevalence, 22.2-25.4% for CTD-ILD, 6.0-12.8% for IPF; p = 0.028 to < 0.001). The highest specificity (94.0%) and sensitivity (25.4%) were seen for the straight-edge sign. No CT sign was associated with survival in multivariable analysis. CONCLUSION: Although UIP is usually associated with IPF, the index of suspicion for CTD-ILD should be raised in the care of patients with any of the three CT signs. A thorough workup for CTD-ILD should be pursued, including referral to the rheumatology department.

CT findings associated with survival in chronic hypersensitivity pneumonitis.

OBJECTIVES: To identify CT findings in chronic hypersensitivity pneumonitis (cHP) associated with survival. MATERIAL AND METHODS: Two thoracic radiologists assessed CT scans for specific imaging findings and patterns in 132 subjects with cHP. Survival analyses were performed. RESULTS: The majority of subjects had an inconsistent with usual interstitial pneumonitis pattern on CT (55.3%,73/132). Hypersensitivity pneumonitis (HP) diagnosis on CT was less common in those with fibrosis (66.1%, 74/112) than those without fibrosis (85%,17/20). Smoking was associated with a lower prevalence of HP on CT (p=0.04). CT features of pulmonary fibrosis, especially traction bronchiectasis (HR 8.34, 95% CI 1.98-35.21) and increased pulmonary artery (PA)/aorta ratio (HR 2.49, 95% CI 1.27-4.89) were associated with worse survival, while ground-glass opacity (HR 0.31, 95% CI 0.12-0.79) was associated with improved survival. Survival association with imaging was less pronounced after adjustment for gender, age and physiology score. CONCLUSIONS: A substantial proportion of cHP cases have a non-HP-like appearance. Ground-glass opacity, pulmonary fibrosis features and elevated PA/aorta ratio on CT likely reflect varying degrees of disease severity in cHP and may inform future clinical prediction models. KEY POINTS: • A substantial proportion of subjects with chronic HP have a UIP-like pattern. • A UIP pattern in HP may be potentiated by smoking. • A diagnosis of HP should not be excluded based solely on CT appearance. • CT fibrosis and increased PA/aorta ratio signal worse survival.

CT Findings, Radiologic-Pathologic Correlation, and Imaging Predictors of Survival for Patients With Interstitial Pneumonia With Autoimmune Features.

OBJECTIVE: The objective of this study is to determine the CT findings and patterns of interstitial pneumonia with autoimmune features (IPAF) and to assess whether imaging can predict survival for patients with IPAF. MATERIALS AND METHODS: The study included 136 subjects who met the criteria for IPAF and had diagnostic-quality chest CT scans obtained from 2006 to 2015; a total of 74 of these subjects had pathologic samples available for review within 1 year of chest CT examination. CT findings and the presence of an usual interstitial pneumonitis (UIP) pattern of disease were assessed, as was the UIP pattern noted on pathologic analysis. Analysis of chest CT findings associated with survival was performed using standard univariate and multivariate Cox proportional hazards methods as well as the unadjusted log-rank test. Survival data were visually presented using the Kaplan-Meier survival curve estimator. RESULTS: Most subjects with IPAF (57.4%; 78/136) had a high-confidence diagnosis of a UIP pattern on CT. Substantially fewer subjects (28.7%; 39/136) had a pattern that was inconsistent with UIP noted on CT. The presence of a UIP pattern on CT was associated with smoking (p < 0.01), male sex (p < 0.01), and older age (p < 0.001). Approximately one-fourth of the subjects had a nonspecific interstitial pneumonitis pattern on CT. Of interest, nearly one-tenth of the subjects had a CT pattern that was most consistent with hypersensitivity pneumonitis rather than the customary CT patterns ascribed to lung disease resulting from connective tissue disease. Most subjects with a possible UIP pattern on CT (83.3%) had UIP diagnosed on the basis of pathologic findings. Focused multivariate analysis showed that honeycombing on CT (hazard ratio, 2.17; 95% CI, 1.05-4.47) and pulmonary artery enlargement on CT (hazard ratio, 2.08; 95% CI, 1.02-4.20) were independent predictors of survival. CONCLUSION: IPAF most often presents with a UIP pattern on CT and is associated with worse survival when concomitant honeycombing or pulmonary artery enlargement is present.

Prevalence of Burnout Among Cardiothoracic Radiologists: Stress Factors, Career Satisfaction, and Modality-specific Imaging Volumes.

PURPOSE: We investigated the impact of modality-specific volumes and other potential stressors on burnout and career-choice satisfaction. MATERIALS AND METHODS: An anonymous survey of 36 questions was sent by email to all 875 faculty members of the STR. These included 11 multiple-choice questions, 23 Likert questions, and 2 free-text questions. The Maslach Burnout Index was used to assess the prevalence of the 3 components of burnout (emotional exhaustion, depersonalization, and low professional accomplishment), and we assessed variations among the potential sources of stress with respect to the respondent sex, career stage, and practice setting. Respondents were asked to estimate daily work volume as if interpreting only chest radiographs (CXRs) or only chest/cardiac computed tomography (CT). Statistical analysis was performed using Excel (Microsoft), open-source statistical computing package pandas and SciPy for Python, and Jupyter Notebook, an open-source interactive computing platform. RESULTS: Although financial concerns (49.3%), lack of input into decisions (48.6%), and inadequate staffing (45.2%) were additional stressors, the major sources were work-life balance (67.4%) and workload (66.8%), which were more frequently cited by women than men (78.9% vs. 60.8%, P=0.001). Emotional exhaustion and depersonalization were related to higher CXR volumes. Although 83.2% were satisfied being a diagnostic radiologist, 18.8% had thought of leaving medicine. More than half of all radiologists interpreted ≥150 CXRs daily (51.1% vs. 53.6%); more in private practice read ≥200 CXRs (23.2% vs. 14.7%). Of the academic radiologists, 80.2% interpreted 21 to 49 CTs; twice as many in private practice read ≥50 CTs (25.5% vs. 12.7%). CONCLUSIONS: The contributing factors to cardiothoracic radiologist burnout vary by sex, career stage, and practice setting. Several stressors, especially work-life balance, were associated with higher burnout prevalence. Most respondents expressed career-choice satisfaction. Defining threshold work volumes associated with higher rates of burnout is an important first step in defining burnout prevention guardrails.

Prevalence of Burnout Among Cardiothoracic Radiologists.

PURPOSE: Burnout is a psychological syndrome in response to chronic occupational stressors. The prevalence of burnout among medical professionals has been increasing, and recent studies have shown that radiologists are among those affected. We investigated the prevalence of burnout and assessed associated factors among cardiothoracic radiologists. MATERIALS AND METHODS: Society of Thoracic Radiology members were invited to complete an anonymous cross-sectional survey that included an adapted Maslach Burnout Inventory and questions about demographics, work place characteristics, and stressors. RESULTS: The survey response rate was 33.1% (290/874). Per-item response rate ranged from 94% to 100% with a median of 99%. The prevalence of emotional exhaustion was 66.8% (186/283), depersonalization was 79% (223/283), and low personal accomplishment was 23% (65/280). There were no statistically significant differences between academic and private practice. There was a trend toward worse burnout in women, but this was not statistically significant. Being in early career (0 to 10 y since fellowship) was associated with low personal accomplishment [odds ratio (OR): 2.07, 95% confidence interval (CI): 1.08-3.99]. Those working fewer than 51 hours per week were significantly less likely to report emotional exhaustion (OR: 0.55, 95% CI: 0.33-0.90). The odds of emotional exhaustion for those producing fewer than 7500 work relative value units per year were approximately half of those exceeding that number (OR: 0.46, 95% CI: 0.22-0.95). CONCLUSIONS: The prevalence of burnout among cardiothoracic radiologists is comparable to that reported for radiologists in other subspecialties such as musculoskeletal and interventional radiology. High work relative value unit productivity and longer work hours are associated with higher prevalence of burnout.

Differentiation of Idiopathic Pulmonary Fibrosis from Connective Tissue Disease-Related Interstitial Lung Disease Using Quantitative Imaging.

A usual interstitial pneumonia (UIP) imaging pattern can be seen in both idiopathic pulmonary fibrosis (IPF) and connective tissue disease-related interstitial lung disease (CTD-ILD). The purpose of this multicenter study was to assess whether quantitative imaging data differ between IPF and CTD-ILD in the setting of UIP. Patients evaluated at two medical centers with CTD-ILD or IPF and a UIP pattern on CT or pathology served as derivation and validation cohorts. Chest CT data were quantitatively analyzed including total volumes of honeycombing, reticulation, ground-glass opacity, normal lung, and vessel related structures (VRS). VRS was compared with forced vital capacity percent predicted (FVC%) and percent predicted diffusing capacity of the lungs for carbon monoxide (DLCO%). There were 296 subjects in total, with 40 CTD-ILD and 85 IPF subjects in the derivation cohort, and 62 CTD-ILD and 109 IPF subjects in the validation cohort. VRS was greater in IPF across the cohorts on univariate (p < 0.001) and multivariable (p < 0.001-0.047) analyses. VRS was inversely correlated with DLCO% in both cohorts on univariate (p < 0.001) and in the derivation cohort on multivariable analysis (p = 0.003) but not FVC%. Total volume of normal lung was associated with DLCO% (p < 0.001) and FVC% (p < 0.001-0.009) on multivariable analysis in both cohorts. VRS appears to have promise in differentiating CTD-ILD from IPF. The underlying pathophysiological relationship between VRS and ILD is complex and is likely not explained solely by lung fibrosis.

Automated CT Analysis of Major Forms of Interstitial Lung Disease.

This study aimed to determine diagnostic and prognostic differences in major forms of interstitial lung disease using quantitative CT imaging. A retrospective study of 225 subjects with a multidisciplinary diagnosis of idiopathic pulmonary fibrosis (IPF), interstitial pneumonia with autoimmune features (IPAF), connective tissue disease (CTD), or chronic hypersensitivity pneumonitis (cHP) was conducted. Non-contrast CT scans were analyzed using the Computer Aided Lung Informatics for Pathology Evaluation and Rating (CALIPER) program. Resulting data were analyzed statistically using ANOVA and Student's t-test. Univariate, multivariable, and receiver operating characteristic analyses were conducted on patient mortality data. CALIPER analysis of axial distribution on CT scans in those with IPF demonstrated greater peripheral volumes of reticulation than either CTD (p = 0.033) or cHP (p = 0.007). CTD showed lower peripheral ground-glass opacity than IPF (p = 0.005) and IPAF (p = 0.004). Statistical analysis of zonal distributions revealed reduced lower zone ground-glass opacity in cHP than IPF (p = 0.044) or IPAF (p = 0.018). Analysis of pulmonary vascular-related structure (VRS) volume by diagnosis indicated greater VRS volume in IPF compared to CTD (p = 0.003) and cHP (p = 0.003) as well as in IPAF compared to CTD (p = 0.007) and cHP (p = 0.007). Increased reticulation (p = 0.043) and ground glass opacity (p = 0.032) were predictive of mortality on univariate analysis. Increased pulmonary VRS volume was predictive of mortality (p < 0.001) even after multivariate analysis (p = 0.041). Quantitative CT imaging revealed significant differences between ILD diagnoses in specific CT findings in axial and, to a lesser degree, zonal distributions. Increased pulmonary VRS volume seems to be associated with both diagnosis and survival.

Differentiating Usual Interstitial Pneumonia From Nonspecific Interstitial Pneumonia Using High-resolution Computed Tomography: The "Straight-edge Sign".

PURPOSE: The purpose of this article was to determine whether a novel finding on coronal computed tomography (CT) can help differentiate usual interstitial pneumonia (UIP) from nonspecific interstitial pneumonia (NSIP) in order to obviate lung biopsy. MATERIALS AND METHODS: Two chest radiologists, blinded to clinical data, reviewed 3 preselected coronal images from CT scans, performed within 1 year of surgical lung biopsy (SLB), from 51 patients with biopsy-proven UIP and 15 with biopsy-proven NSIP. The 198 (66×3) images were anonymized and randomized. The radiologists assessed each coronal image for the presence or absence of the straight-edge sign (SES) on both the right and left sides, anecdotally thought to be more common in NSIP than in UIP. The SES was defined as reticulation isolated to the lung bases with sharp demarcation in the craniocaudal plane and without substantial extension along the lateral margins of the lungs. A validation cohort from a second medical center was also evaluated to reassess our findings. RESULTS: The absence of a bilateral SES yielded a sensitivity, specificity, positive predictive value (PPV), and negative predictive value of 56.9%, 93.3%, 96.7%, and 38.9%, respectively, for UIP on SLB. The unilateral or bilateral absence of the SES yielded a sensitivity, specificity, PPV, and negative predictive value of 76.5%, 66.7%, 88.6%, and 45.5%, respectively, for UIP on SLB. For the 11 subjects with an overall CT pattern consistent with NSIP but a pathologic diagnosis of UIP, the SES was absent in 6 (54.5%) subjects. In the validation cohort, the SES was much more common in NSIP than in UIP (46.6% compared with 3.3%, respectively; P<0.001). CONCLUSION: The absence of the SES has a high PPV for biopsy-proven UIP. Bilateral absence of the SES has high specificity (93.3%) for biopsy-proven UIP. The SES may be useful for differentiating UIP from NSIP.

Phenotypic Clusters Predict Outcomes in a Longitudinal Interstitial Lung Disease Cohort.

BACKGROUND: The current interstitial lung disease (ILD) classification has overlapping clinical presentations and outcomes. Cluster analysis modeling is a valuable tool in identifying distinct clinical phenotypes in heterogeneous diseases. However, this approach has yet to be implemented in ILD. METHODS: Using cluster analysis, novel ILD phenotypes were identified among subjects from a longitudinal ILD cohort, and outcomes were stratified according to phenotypic clusters compared with subgroups according to current American Thoracic Society/European Respiratory Society ILD classification criteria. RESULTS: Among subjects with complete data for baseline variables (N = 770), four clusters were identified. Cluster 1 (ie, younger white obese female subjects) had the highest baseline FVC and diffusion capacity of the lung for carbon monoxide (Dlco). Cluster 2 (ie, younger African-American female subjects with elevated antinuclear antibody titers) had the lowest baseline FVC. Cluster 3 (ie, elderly white male smokers with coexistent emphysema) had intermediate FVC and Dlco. Cluster 4 (ie, elderly white male smokers with severe honeycombing) had the lowest baseline Dlco. Compared with classification according to ILD subgroup, stratification according to phenotypic clusters was associated with significant differences in monthly FVC decline (Cluster 4, -0.30% vs Cluster 2, 0.01%; P < .0001). Stratification by using clusters also independently predicted progression-free survival (P < .001) and transplant-free survival (P < .001). CONCLUSIONS: Among adults with diverse chronic ILDs, cluster analysis using baseline characteristics identified four distinct clinical phenotypes that might better predict meaningful clinical outcomes than current ILD diagnostic criteria.

Imaging of Hypersensitivity Pneumonitis.

The management of hypersensitivity pneumonitis (HP) depends on early identification of the disease process, which is complicated by its nonspecific clinical presentation in addition to variable and diverse laboratory and radiologic findings. HP is the result of exposure and sensitization to myriad aerosolized antigens. HP develops in the minority of antigenic exposures, and conversely has been documented in patients with no identifiable exposure, complicating the diagnostic algorithm significantly. Prompt diagnosis and early intervention are critical in slowing the progression of irreversible parenchymal damage, and additionally in preserving the quality of life of affected patients.