To assess how computed tomography (CT) image reconstruction techniques affect perceived diagnostic image quality at varying radiation dose levels in chest imaging. A PBU-50 anthropomorphic phantom (small adult-sized model) and an air-dried human lung specimen were scanned on the same CT system (Revolution Apex™, GE Healthcare) at six dose levels (CTDIvol) from 0.07 to 2.19 mGy for the smallest phantom size. Images were reconstructed using deep learning image reconstruction-high (DLIR-H), adaptive statistical iterative reconstruction at 40 per cent (ASiR-V), and filtered back projection (FBP). Five radiologists assessed anatomical reproduction, noise, artefacts, and diagnostic quality using ViewDEX. Descriptive statistics and visual grading characteristics analysis were used. In general, DLIR-H scored higher than ASiR-V and FBP. While maintaining image quality, DLIR-H allowed dose reduction compared to FBP. All methods were deemed acceptable for diagnosing pulmonary nodules, fibrosis, and peribronchial pathology. The results indicate that DLIR-H improves image quality in comparison to FBP and ASiR-V and may enable radiation dose reduction while maintaining clinical image quality.

Background Pulmonary nodules (PNs) are clinically challenging because differentiation between benign and malignant PNs is not possible at CT detection; recurring CT examinations and invasive procedures are often required in PN follow-up. Purpose To investigate PN prevalence in a middle-aged population and the risk factors associated with these nodules. Materials and Methods In this secondary analysis of the cross-sectional population-based Swedish CArdioPulmonary bioImage Study (known as SCAPIS, from November 2013 to November 2018), participants aged 50-64 years with chest CT data were analyzed. Risk factors such as smoking history, occupational exposure (vapor, dust, gas, and fumes), and lung diseases were derived from comprehensive questionnaires. Robust Poisson regression was used to evaluate associations, adjusted for age and sex, between potential risk factors and the binary outcome of nodule presence or absence. Prevalence ratios (PRs), adjusted for age and sex, and 95% CIs were estimated. Results Among 29 574 participants (median age, 57.4 years; IQR, 53.7-61.2 years; 15 168 women), solid nodules sized 100-300 mm3, part-solid, and ground-glass nodules were found in 1420 (4.8%), 199 (0.7%), and 430 (1.5%), respectively. The prevalence of solid nodules among participants who never, formerly, and currently smoked was 32.5% (4713 of 14 515), 34.5% (3602 of 10 437), and 37.9% (1381 of 3644), respectively. Solid nodules sized 100-300 mm3 were associated with current smoking (PR, 1.38; 95% CI: 1.19, 1.60), chronic obstructive pulmonary disease (PR, 1.72; 95% CI: 1.17, 2.53), occupational exposure (PR, 1.31; 95% CI: 1.11, 1.54), emphysema (PR, 1.56; 95% CI: 1.31, 1.86), reticulation (PR, 1.96; 95% CI: 1.47, 2.61), and bronchiectasis (PR, 2.03; 95% CI: 1.64, 2.50). In participants who had never smoked, associations were found between solid nodules at least 100 mm3 and reticulation (PR, 2.28; 95% CI: 1.55, 3.36), reported lung disease other than asthma or chronic obstructive pulmonary disease (PR, 2.26; 95% CI: 1.49, 3.43), and bronchiectasis (PR, 2.17; 95% CI: 1.60, 2.94). Conclusion PN prevalence was approximately the same in a middle-aged population regardless of smoking history. In participants who had never smoked, nodules were linked to reported lung disease, reticulation, and bronchiectasis. © The Author(s) 2026. Published by the Radiological Society of North America under a CC BY 4.0 license. Supplemental material is available for this article.

Purpose: We aim to investigate the localization, visibility, and measurement of lung nodules in digital chest tomosynthesis (DTS). Approach Computed tomography (CT), maximum intensity projections (CT-MIP) (transaxial versus coronal orientation), and computer-aided detection (CAD) were used as location reference, and inter- and intra-observer agreement regarding lung nodule size was assessed. Five radiologists analyzed DTS and CT images from 24 participants with lung nodules >= 100 mm(3), focusing on lung nodule localization, visibility, and measurement on DTS. Visual grading was used to compare if coronal or transaxial CT-MIP better facilitated the localization of lung nodules in DTS. Results: The majority of the lung nodules (79%) were rated as visible in DTS, although less clearly in comparison with CT. Coronal CT-MIP was the preferred orientation in the task of locating nodules on DTS. On DTS, area-based lung nodule size estimates resulted in significantly less measurement variability when compared with nodule size estimated based on mean diameter (mD) (p<0.05). Also, on DTS, area-based lung nodule size estimates were more accurate (SEE=38.7 mm(3)) than lung nodule size estimates based on mean diameter (SEE=42.7 mm(3)). Conclusions: Coronal CT-MIP images are superior to transaxial CT-MIP images in facilitating lung nodule localization in DTS. Most nodules >= 100 mm(3) found on CT can be visualized, correctly localized, and measured in DTS, and area-based measurement may be the key to more precise and less variable nodule measurements on DTS.

Rationale: Chronic obstructive pulmonary disease (COPD) includes respiratory symptoms and chronic airflow limitation (CAL). In some cases, emphysema and impaired diffusing capacity of the lung for carbon monoxide (DlCO) are present, but characteristics and symptoms vary with smoking exposure. Objective: To study the prevalence of CAL, emphysema, and impaired DlCO in relation to smoking and respiratory symptoms in a middle-aged population. Methods: We investigated 28,746 randomly invited individuals (52% women) aged 50-64 years across six Swedish sites. We performed spirometry, DlCO testing, and high-resolution computed tomography and asked for smoking habits and respiratory symptoms. CAL was defined as post-bronchodilator forced expiratory volume in 1 second divided by forced vital capacity (FEV1/FVC) < 0.7. Results: The overall prevalence was 8.8% for CAL, 5.7% for impaired DlCO (DlCO < LLN), and 8.8% for emphysema, with a higher prevalence in current smokers than in ex-smokers and never-smokers. The proportion of never-smokers among those with CAL, emphysema, and impaired DlCO was 32%, 19%, and 31%, respectively. Regardless of smoking habits, the prevalence of respiratory symptoms was higher among people with CAL and impaired DlCO than those with normal lung function. Asthma prevalence in never-smokers with CAL was 14%. In this group, asthma was associated with lower FEV1 and more respiratory symptoms. Conclusions: In this large population-based study of middle-aged people, CAL and impaired DlCO were associated with common respiratory symptoms. Self-reported asthma was not associated with CAL in never-smokers. Our findings suggest that CAL in never-smokers signifies a separate clinical phenotype that may be monitored and, possibly, treated differently from smoking-related COPD.

Background The role of the lung for the initiation and progression of rheumatoid arthritis (RA) is still unclear. Up to 10% of RA patients develop interstitial lung disease which remains a clinical challenge. Understanding early disease mechanisms is of great importance. The objective of this study was to determine whether there is an association between peripheral neutrophil phenotypes and presence of pulmonary abnormalities (PA) on chest high-resolution computed tomography (HRCT) in untreated early RA (ueRA). Methods Clinical data and blood were collected, and HRCT performed at diagnosis on 30 consecutive anti-citrullinated protein antibody (ACPA) and/or rheumatoid factor (RF) positive ueRA patients. HRCTs were evaluated for the presence of RA-associated parenchymal, airway and/or pleural abnormalities. Expression of phenotype markers on neutrophils were determined by flow cytometry. Levels of calprotectin, ACPA and RF were measured using immunoassays. Results The frequency of having any PA was 60%. Airway abnormalities were present in 50%, parenchymal nodules in 43% and interstitial lung abnormalities (ILA) in 10%. Unsupervised multivariate data analysis showed clustering of any PA with neutrophil activation, parameters of inflammation and RF titres. In univariate analysis, the patients with PA displayed significantly increased CD11b and decreased CD62L expression on neutrophils (1.2-fold, p = 0.014; 0.8-fold, p = 0.012) indicating activation and significantly increased RF IgM titre and CRP (5.7-fold, p = 0.0025; 2.3-fold, p = 0.0035) as compared to no PA. Titres of RF, but not ACPA, correlated with expression of the neutrophil activation marker CD11b. A stratified analysis demonstrated that airway involvement was the PA subtype with the strongest association with neutrophil activation. Conclusion We report a strong association between radiographic airway findings and activation of circulating neutrophils in early RA supporting a role of innate immunity and the lung at disease onset. Our results also indicate different contributions of RF and ACPA in the RA pathogenesis.

AbstractAimsThe aims of the present study were to, for both a full‐dose protocol and an ultra‐low dose (ULD) protocol, compare the image quality of chest CT examinations reconstructed using TrueFidelity (Standard kernel) with corresponding examinations reconstructed using ASIR‐V (Lung kernel) and to evaluate if post‐processing using an edge‐enhancement filter affects the noise level, spatial resolution and subjective image quality of clinical images reconstructed using TrueFidelity.MethodsA total of 25 patients were examined with both a full‐dose protocol and an ULD protocol using a GE Revolution APEX CT system (GE Healthcare, Milwaukee, USA). Three different reconstructions were included in the study: ASIR‐V 40%, DLIR‐H, and DLIR‐H with additional post‐processing using an edge‐enhancement filter (DLIR‐H + E2). Five observers assessed image quality in two separate visual grading characteristics (VGC) studies. The results from the studies were statistically analyzed using VGC Analyzer. Quantitative evaluations were based on determination of two‐dimensional power spectrum (PS), contrast‐to‐noise ratio (CNR), and spatial resolution in the reconstructed patient images.ResultsFor both protocols, examinations reconstructed using TrueFidelity were statistically rated equal to or significantly higher than examinations reconstructed using ASIR‐V 40%, but the ULD protocol benefitted more from TrueFidelity. In general, no differences in observer ratings were found between DLIR‐H and DLIR‐H + E2. For the three investigated image reconstruction methods, ASIR‐V 40% showed highest noise and spatial resolution and DLIR‐H the lowest, while the CNR was highest in DLIR‐H and lowest in ASIR‐V 40%.ConclusionThe use of TrueFidelity for image reconstruction resulted in higher ratings on subjective image quality than ASIR‐V 40%. The benefit of using TrueFidelity was larger for the ULD protocol than for the full‐dose protocol. Post‐processing of the TrueFidelity images using an edge‐enhancement filter resulted in higher image noise and spatial resolution but did not affect the subjective image quality.

Abstract Purpose: Digital tomosynthesis (DTS) is currently undergoing validation for potential clinical implications. The aim of this study was to investigate the potential for DTS as a low-dose alternative to computed tomography (CT) in imaging of pulmonary pathology in patients with cystic fibrosis (CF). Methods: DTS and CT were performed as part of the routine triannual follow-up in 31 CF patients. Extent of disease was quantified according to modality-specific scoring systems. Statistical analysis included Spearman’s rank correlation coefficient (r) and Krippendorff’s alpha (α). Major findings: The median effective dose was 0.14 for DTS and 2.68 for CT. Intermodality correlation was very strong for total score and the subscores regarding bronchiectasis and bronchial wall-thickening (r = 0.82–0.91, P < 0.01). Interobserver reliability was high for total score, bronchiectasis and mucus plugging (α = 0.83–0.93) in DTS. Conclusion: Chest tomosynthesis could be a low-dose alternative to CT in quantitative estimation of structural lung disease in CF.

PURPOSE:To evaluate two chest tomosynthesis (CTS) scoring systems for cystic fibrosis (CF), one system developed by Vult von Steyern et al. (VvS) and one system based on the Brody scoring system for high-resolution computed tomography (HRCT) (modified Brody (mB)). Brody scoring of HRCT was used as reference.METHODS:In conjunction with routine control HRCT at clinical follow-up, 10 consecutive adult CF patients underwent CTS for research purposes. Four radiologists scored the CTS examinations using the mB and VvS scoring systems. All scores were compared to the Brody HRCT scores. The agreement between the evaluated CTS scoring systems and the reference HRCT scoring system was determined using Spearman's rank correlation coefficient and the intraclass correlation coefficient (ICC).MAJOR FINDINGS:Spearman's rank correlation coefficient showed strong correlations between HRCT score and both the mB and the VvS CTS total scores (median rs = 0.81 and 0.85, respectively). The ICC showed strong correlation between the CTS scoring systems and the reference: 0.88 for mB and 0.85 for VvS scoring. The median time for scoring was 20 and 10 minutes for the mB and VvS scoring systems, respectively.CONCLUSIONS:Both evaluated CTS scoring systems correlate well with the reference standard Brody HRCT scoring. The VvS CTS scoring system has a shorter reading time, suggesting its advantage in clinical practice.

The Global Lung Function Initiative (GLI) has recently published international reference values for diffusing capacity of the lung for carbon monoxide (DLCO). Lower limit of normal (LLN), i.e. the 5th percentile, usually defines impaired D-LCO. We examined if the GLI LLN for D-LCO differs from the LLN in a Swedish population of healthy, never-smoking individuals and how any such differences affect identification of subjects with respiratory burden. Spirometry, D-LCO, chest high-resolution computed tomography (HRCT) and questionnaires were obtained from the first 15 040 participants, aged 50-64 years, of the Swedish CArdioPulmonary bioImage Study (SCAPIS). Both GLI reference values and the lambda-mu-sigma (LMS) method were used to define the LLN in asymptomatic never-smokers without respiratory disease (n=4903, of which 2329 were women). Both the median and LLN for D-LCO from SCAPIS were above the median and LLN from the GLI (p<0.05). The prevalence of D-LCO GLI LLN but GLI LLN but GLI LLN and >SCAPIS LLN). No differences were found with regard to physician-diagnosed asthma. The GLI LLN for D-LCO is lower than the estimated LLN in healthy, never-smoking, middle-aged Swedish adults. Individuals with D-LCO above the GLI LLN but below the SCAPIS LLN had, to a larger extent, an increased respiratory burden. This suggests clinical implications for choosing an adequate LLN for studied populations.

Emphysema is visible on computed tomography (CT) as low-density lesions representing the destruction of the pulmonary alveoli. To train a machine learning model on the emphysema extent in CT images, labeled image data is needed. The provision of these labels requires trained readers, who are a limited resource. The purpose of the study was to test the reading time, inter-observer reliability and validity of the multi-reader–multi-split method for acquiring CT image labels from radiologists. The approximately 500 slices of each stack of lung CT images were split into 1-cm chunks, with 17 thin axial slices per chunk. The chunks were randomly distributed to 26 readers, radiologists and radiology residents. Each chunk was given a quick score concerning emphysema type and severity in the left and right lung separately. A cohort of 102 subjects, with varying degrees of visible emphysema in the lung CT images, was selected from the SCAPIS pilot, performed in 2012 in Gothenburg, Sweden. In total, the readers created 9050 labels for 2881 chunks. Image labels were compared with regional annotations already provided at the SCAPIS pilot inclusion. The median reading time per chunk was 15 s. The inter-observer Krippendorff’s alpha was 0.40 and 0.53 for emphysema type and score, respectively, and higher in the apical part than in the basal part of the lungs. The multi-split emphysema scores were generally consistent with regional annotations. In conclusion, the multi-reader–multi-split method provided reasonably valid image labels, with an estimation of the inter-observer reliability.

Chronic airflow limitation (CAL) can be defined as fixed ratio of forced expiratory volume in 1 s (FEV1 )/forced vital capacity (FVC) < 0.70 after bronchodilation. It is unclear which is the most optimal ratio in relation to respiratory morbidity. The aim was to investigate to what extent different ratios of FEV1 /FVC were associated with any respiratory symptom. In a cross-sectional general population study, 15,128 adults (50-64 years of age), 7,120 never-smokers and 8,008 ever-smokers completed a respiratory questionnaire and performed FEV1 and FVC after bronchodilation. We calculated different ratios of FEV1 /FVC from 0.40 to 1.0 using 0.70 as reference category. We analysed odds ratios (OR) between different ratios and any respiratory symptom using adjusted multivariable logistic regression. Among all subjects, regardless of smoking habits, the lowest odds for any respiratory symptom was at FEV1 /FVC = 0.82, OR 0.48 (95% CI 0.41-0.56). Among never-smokers, the lowest odds for any respiratory symptom was at FEV1 /FVC = 0.81, OR 0.53 (95% CI 0.41-0.70). Among ever-smokers, the odds for any respiratory symptom was lowest at FEV1 /FVC = 0.81, OR 0.43 (95% CI 0.16-1.19), although the rate of inclining in odds was small in the upper part, that is FEV1 /FVC = 0.85 showed similar odds, OR 0.45 (95% CI 0.38-0.55). We concluded that the odds for any respiratory symptoms continuously decreased with higher FEV1 /FVC ratios and reached a minimum around 0.80-0.85, with similar results among never-smokers. These results indicate that the optimal threshold associated with respiratory symptoms may be higher than 0.70 and this should be further investigated in prospective longitudinal studies.

RATIONALE AND OBJECTIVES:To evaluate the effect of reduction in effective dose on the reproduction of anatomical structures in chest tomosynthesis (CTS).MATERIALS AND METHODS:Twenty-four CTS examinations acquired at exposure settings resulting in an effective dose of 0.12 mSv for an average sized patient were included in the study. The examinations underwent simulated dose reduction to dose levels corresponding to 32%, 50%, and 70% of the original dose using a previously described and validated method. The image quality was evaluated by five thoracic radiologists who rated the fulfillment of specified image quality criteria in a visual grading study. The ratings for each image quality criterion in the dose-reduced images were compared to the corresponding ratings for the full-dose examinations using visual grading characteristics (VGC) analysis. The area under the resulting VGC curve (AUCVGC) provides a measure of the difference between the ratings, where an AUCVGC of 0.5 indicates no difference.RESULTS:The dose reductions resulted in inferior reproduction of structures compared to the original dose level (AUCVGC <0.5). Structures in the central region of the lung obtained the lowest AUCVGC for each dose level whereas the reproduction of structures in the parenchyma was least affected by the dose reduction.CONCLUSION:Although previous studies have shown that dose reduction in CTS is possible without affecting the performance of certain clinical tasks, the reproduction of normal anatomical structures is significantly degraded even at small reductions. It is therefore important to consider the clinical purpose of the CTS examinations before deciding on a permanent dose reduction.

Background The diagnosis of chronic obstructive pulmonary disease is based on the presence of persistent respiratory symptoms and chronic airflow limitation (CAL). CAL is based on the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV 1 :FVC) after bronchodilation, and FEV 1 :FVC less than the fifth percentile is often used as a cut-off for CAL. The aim was to investigate if increasing percentiles of FEV 1 :FVC were associated with any respiratory symptom (cough with phlegm, dyspnoea or wheezing) in a general population sample of never-smokers and ever-smokers. Methods In a cross-sectional study comprising 15 128 adults (50–64 years), 7120 never-smokers and 8008 ever-smokers completed a respiratory questionnaire and performed FEV 1 and FVC after bronchodilation. We calculated their z -scores for FEV 1 :FVC and defined the fifth percentile using the Global Lung Function Initiative (GLI) reference value, GLI 5 and increasing percentiles up to GLI 25 . We analysed the associations between different strata of percentiles and prevalence of any respiratory symptom using multivariable logistic regression for estimation of OR. Results Among all subjects, regardless of smoking habits, the odds of any respiratory symptom were elevated up to the GLI 15–20 strata. Among never-smokers, the odds of any respiratory symptom were elevated at GLI <5 (OR 3.57, 95% CI 2.43 to 5.23) and at GLI 5–10 (OR 2.57, 95% CI 1.69 to 3.91), but not at higher percentiles. Among ever-smokers, the odds of any respiratory symptom were elevated from GLI <5 (OR 4.64, 95% CI 3.79 to 5.68) up to GLI ≥25 (OR 1.33, 95% CI 1.00 to 1.75). Conclusions The association between percentages of FEV 1 :FVC and respiratory symptoms differed depending on smoking history. Our results support a higher percentile cut-off for FEV 1 :FVC for never-smokers and, in particular, for ever-smokers.

BACKGROUND:Digital tomosynthesis (DTS) might be a low-dose/low-cost alternative to computed tomography (CT). PURPOSE:To investigate DTS relative to CT for surveillance of incidental, solid pulmonary nodules. MATERIAL AND METHODS:Recruited from a population study, 106 participants with indeterminate solid pulmonary nodules on CT underwent surveillance with concurrently performed CT and DTS. Nodule size on DTS was assessed by manual diameter measurements and semi-automatic nodule segmentations were independently performed on CT. Measurement agreement was analyzed according to Bland-Altman with 95% limits of agreement (LoA). Detection of nodule volume change > 25% by DTS in comparison to CT was evaluated with receiver operating characteristics (ROC). RESULTS:A total of 81 nodules (76%) were assessed as measurable on DTS by two independent observers. Inter- and intra-observer LoA regarding change in average diameter were ± 2 mm. Calculation of relative volume change on DTS resulted in wide inter- and intra-observer LoA in the order of ± 100% and ± 50%. Comparing relative volume change between DTS and CT resulted in LoA of -58% to 67%. The area under the ROC curve regarding the ability of DTS to detect volumetric changes > 25% on CT was 0.58 (95% confidence interval [CI] = 0.40-0.76) and 0.50 (95% CI = 0.35-0.66) for the two observers. CONCLUSION:The results of the present study show that measurement variability limits the agreement between DTS and CT regarding nodule size change for small solid nodules.

RATIONALE AND OBJECTIVES:Emphysema is a hallmark of chronic obstructive pulmonary disease. The primary aim of this study was to investigate inter- and intraobserver agreement of visual assessment of mild emphysema in low-dose multidetector computed tomography of subjects in the pilot SCAPIS in order to certify consistent detection of mild emphysema. The secondary aim was to investigate the performance of quantitative densitometric measurements in the cohort. MATERIALS AND METHODS:Participants with emphysema (n = 100, 56 males and 44 females) reported in the electronic case report form of pilot SCAPIS and 100 matched controls (gender, age, height, and weight) without emphysema were included. To assess interobserver variability the randomized examinations were evaluated by two thoracic radiologists. For intraobserver variability three radiologists re-evaluated randomized examinations which they originally evaluated. The results were evaluated statistically by Krippendorff's α. The dataset was also assessed quantitively for % lung attenuation value -950 HU (LAV950), mean lung density and total lung volume by commercially available software. RESULTS:Emphysema was visually scored as mild and Krippendorff's α was ≥0.8 for both the inter- and intraobserver agreement regarding presence of emphysema and approaching 0.8 regarding presence and extent of emphysema by location in the upper lobes. Mean LAV950 was not different between the emphysematous and the nonemphysematous participants; 8.3% and 8.4%, respectively. CONCLUSION:The inter- and intraobserver agreement for visual detection of mild emphysema in low-dose multidetector computed tomography was good. Surprisingly, quantitative analysis could not reliably identify participants with mild emphysema, which hampers the use of automatic evaluation.

<b>In this general population sample with detailed control for smoking habits there is an association between blood cadmium and emphysema based on lung computed tomography</b>http://bit.ly/2K9S39J

Emphysema may be used for subclassification of chronic obstructive pulmonary disease (COPD) and is also a risk factor for lung cancer. Emphysema can be directly visualized by low dose computed tomography (CT). As visual assessment of emphysema is time-consuming, our aim was to detect emphysema by quantitative densitometry (% Low Attenuation Value below -950 Hounsfield Units, LAV950) using the software CTPulmo3D (Syngo.via, Siemens Healthineers). Participants from the pilot study of The Swedish CArdioPulmonary Bioimage Study (SCAPIS) with visually detected emphysema (n=100, 56 males and 44 females) and 100 matched controls (gender, age, height and weight) without emphysema were included in this study. In more than 80% of the participants the emphysema was visually graded as mild (1% to ≤25% of the lung parenchyma). Inter- and intraobserver variability for visual assessment of emphysema was reliable with Krippendorff alpha values ranging from 0.80 to 0.85. Patients with emphysema were more obstructive (FEV1/FVC 0.72 versus 0.78) and had a higher tobacco burden (27 versus 20 pack-years) compared to the matched controls. The mean difference in LAV950 between matched pairs of emphysema and controls was -0.1% (CI -1.3 to 1.2%), limits of agreement from -12.3 to 12.1%. When defining emphysema as LAV950 being ≥ 10%, the sensitivity of finding emphysema was 27%. In conclusion, visual assessment of emphysema is reliable. Quantitative measurements of LAV950 by the software used in this study were not able to distinguish patients with or without visually detected mild emphysema. Other quantitative methods need to be evaluated for use in large-scale studies.

Purpose To investigate the performance of digital tomosynthesis (DTS) for detection and characterization of incidental solid lung nodules. Materials and Methods This prospective study was based on a population study with 1111 randomly selected participants (age range, 50-64 years) who underwent a medical evaluation that included chest computed tomography (CT). Among these, 125 participants with incidental nodules 5 mm or larger were included in this study, which added DTS in conjunction with the follow-up CT and was performed between March 2012 and October 2014. DTS images were assessed by four thoracic radiologists blinded to the true number of nodules in two separate sessions according to the 5-mm (125 participants) and 6-mm (55 participants) cut-off for follow-up of incidental nodules. Pulmonary nodules were directly marked on the images by the readers and graded regarding confidence of presence and recommendation for follow-up. Statistical analyses included jackknife free-response receiver operating characteristic, receiver operating characteristic, and Cohen κ coefficient. Results Overall detection rate ranges of CT-proven nodules 5 mm or larger and 6 mm or larger were, respectively, 49%-58% and 48%-62%. Jackknife free-response receiver operating characteristics figure of merit for detection of CT-proven nodules 5 mm or larger and 6 mm or larger was 0.47 and 0.51, respectively, and area under the receiver operating characteristic curve regarding recommendation for follow-up was 0.62 and 0.65, respectively. Conclusion Routine use of DTS would result in lower detection rates and reduced number of small nodules recommended for follow-up. © RSNA, 2018.

BACKGROUND:The aim of this study was to estimate the occupational burden of airflow limitation, chronic airflow limitation, COPD, and emphysema. MATERIALS AND METHODS:Subjects aged 50-64 years (n=1,050) were investigated with forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC). Airflow limitation was defined as FEV1/FVC <0.7 before bronchodilation. Chronic airflow limitation was defined after bronchodilation either according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) as FEV1/FVC <0.7 or according to the lower limit of normal (LLN) approach as FEV1/FVC < LLN. COPD was defined as chronic airflow limitation (GOLD) in combination with dyspnea, wheezing, or chronic bronchitis. Emphysema was classified according to findings from computed tomography of the lungs. Occupational exposure was defined as self-reported occupational exposure to vapor, gas, dust, or fumes (VGDF). Odds ratios (OR) were calculated in models adjusted for age, gender, and smoking; population-attributable fractions and 95% CI were also calculated. RESULTS:There were significant associations between occupational exposure to VGDF and COPD (OR 2.7, 95% CI 1.4-51), airflow limitation (OR 1.8, 95% CI 1.3-2.5), and emphysema (OR 1.8, 95% CI 1.1-3.1). The associations between occupational exposure to VGDF and chronic airflow limitation were weaker, and for the OR, the CIs included unity. The population-attributable fraction for occupational exposure to VGDF was 0.37 (95% CI 0.23-0.47) for COPD and 0.23 (95% CI 0.05-0.35) for emphysema. CONCLUSION:The occupational burden of COPD and computed tomography-verified emphysema is substantial.