Visual and Quantitative Evaluation of Emphysema: A Case-Control Study of 1111 Participants in the Pilot Swedish CArdioPulmonary BioImage Study (SCAPIS)

Vikgren, Jenny; Khalil, Mohammad; Cederlund, Kerstin; Sørensen, Kaspar; Boijsen, Marianne; Brandberg, John; Lampa, Erik; Sköld, Magnus; Wollmer, Per; Lindberg, Eva; Engvall, Jan; Bergström, Göran; Johnsson, Åse A.

doi:10.1016/j.acra.2019.06.019

Cited by 11 publications

(21 citation statements)

References 23 publications

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“…Cadmium (B-Cd) was analysed in whole blood, as described previously [11]. The pulmonary computed tomography (CT) investigations were performed and assessed according to international guidelines [12]. Chronic airflow limitation according to Global Initiative for Obstructive Lung Disease (CAL GOLD ) was defined as an FEV 1 /FVC ratio <0.7.…”

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confidence: 99%

The association between cadmium exposure and chronic airflow limitation and emphysema: the Swedish CArdioPulmonary BioImage Study (SCAPIS pilot)

et al. 2019

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To the Editor:Cadmium is a metal that is widely spread in the environment and human populations are exposed to it through food, mainly grains and vegetables. The tobacco plants accumulate cadmium, and tobacco smokers accumulate the cadmium in tobacco smoke, which is absorbed in the lungs [1]. Occupational exposure to cadmium has been linked to the development of emphysema and impaired lung function [2, 3]. Increased levels of blood cadmium (B-Cd) or urinary cadmium are associated with lower lung function, and it has been suggested that cadmium, in the low-dose interval, is a risk factor for impaired lung function [1,4].The aim of this study was to examine whether cadmium exposure in the low-dose interval was associated with increased prevalence of emphysema and impaired pulmonary function.The study population comprised subjects aged 50-64 years randomly selected from the population in Gothenburg (n=1111) [5]. All subjects answered a questionnaire and performed dynamic spirometry including forced expiratory volume in 1 s (FEV 1 ) and forced vital capacity (FVC). From diffusing capacity measurements for carbon monoxide, diffusing capacity (D LCO ) and transfer coefficient (K CO ) of the lung for carbon monoxide were obtained [6]. A Jaeger Master Screen pulmonary function testing (Vyaire Medical, Mettawa, IL, USA) was used for all measurements. Residual volume (RV) and total lung capacity (TLC) were measured using a body box. All procedures were performed after inhalation of 400 µg of salbutamol and according to American Thoracic Society/European Respiratory Society standards, as previously described [5]. Predicted values and lower limits of normal (LLN) were based on published equations [7][8][9][10]. Predicted values (FEV 1 and FVC) were based on recently developed equations from same source population [7]. Cadmium (B-Cd) was analysed in whole blood, as described previously [11]. The pulmonary computed tomography (CT) investigations were performed and assessed according to international guidelines [12]. Chronic airflow limitation according to Global Initiative for Obstructive Lung Disease (CAL GOLD ) was defined as an FEV 1 /FVC ratio <0.7. Chronic airflow limitation (CAL LLN ) was defined as FEV 1 /FVC ratio below the LLN. Emphysema was defined as having at least mild emphysema in any zone of the lungs. Centrilobular emphysema was defined as having centrilobular emphysema in any zone of the lungs. Smoking was categorised as current smoker, former smoker or never-smoker. Pack-years (cumulative tobacco exposure) were calculated for all participants with a history of smoking. Never-smokers were assigned 0 (zero) pack-years. Socioeconomic status was defined according to the highest level of education achieved. Body mass index was defined as measured weight/height 2 (kg•m −2 ). Occupational exposure to vapour, gas, dust or fumes was based on an affirmative answer to the item "Have you ever been exposed to vapour, gas, dust or fumes at your workplace?". B-Cd was classified in quartiles: <0.16 µg•L −1 ; 0.16-<0.23 µg•L ...

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The association between cadmium exposure and chronic airflow limitation and emphysema: the Swedish CArdioPulmonary BioImage Study (SCAPIS pilot)

et al. 2019

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“…For any emphysema type, the degree was assessed as mild (1-25%), moderate (> 25-50%), or severe (> 50%). These regional annotations were obtained prior to the present study, by experienced senior thoracic radiologists, and were used for comparison with the multi-readermulti-split annotations obtained in this study [7].…”

Section: Scapis Pilot Image Data and Annotationsmentioning

confidence: 99%

“…From the SCAPIS pilot, thoracic CT scans from a subset of 100 subjects with visible emphysema, and 100 matched controls without emphysema, have previously been selected [7]. The images in the present study were extracted from these scans.…”

Section: Image Data and Chunk Preparationmentioning

confidence: 99%

“…In four subjects in the pre-selected emphysema cohort, thin-slice CT images were not available; these patients were excluded. The severity of emphysema in most patients in the emphysema cohort was mild, with many regions without emphysema according to the eCRF [7]. To avoid worsening the skewed distribution of regional emphysema scores, only six randomly selected subjects from the matched controls were included in the present study.…”

Section: Image Data and Chunk Preparationmentioning

confidence: 99%

“…By giving the volume of the low attenuating area in the lungs, quantitative CT (qCT) has shown an important correlation to the severity of COPD, and is an independent predictor of morbidity and mortality in COPD patients [4][5][6]. However, counting low-density pixels does not gather all image information, since visual emphysema scoring is an independent predictor even in models where qCT is included, and qCT may show similar results in patients with and without visual emphysema [6,7]. Machine learning models can learn image features from training data, and there are expectations of improved quantitative emphysema scoring [8].…”

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Multi-Reader–Multi-Split Annotation of Emphysema in Computed Tomography

et al. 2020

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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.

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Machine learning slice-wise whole-lung CT emphysema score correlates with airway obstruction

Lidén,

Spahr,

Hjelmgren

et al. 2023

Eur Radiol

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Objectives Quantitative CT imaging is an important emphysema biomarker, especially in smoking cohorts, but does not always correlate to radiologists’ visual CT assessments. The objectives were to develop and validate a neural network-based slice-wise whole-lung emphysema score (SWES) for chest CT, to validate SWES on unseen CT data, and to compare SWES with a conventional quantitative CT method. Materials and methods Separate cohorts were used for algorithm development and validation. For validation, thin-slice CT stacks from 474 participants in the prospective cross-sectional Swedish CArdioPulmonary bioImage Study (SCAPIS) were included, 395 randomly selected and 79 from an emphysema cohort. Spirometry (FEV1/FVC) and radiologists’ visual emphysema scores (sum-visual) obtained at inclusion in SCAPIS were used as reference tests. SWES was compared with a commercially available quantitative emphysema scoring method (LAV950) using Pearson’s correlation coefficients and receiver operating characteristics (ROC) analysis. Results SWES correlated more strongly with the visual scores than LAV950 (r = 0.78 vs. r = 0.41, p < 0.001). The area under the ROC curve for the prediction of airway obstruction was larger for SWES than for LAV950 (0.76 vs. 0.61, p = 0.007). SWES correlated more strongly with FEV1/FVC than either LAV950 or sum-visual in the full cohort (r = − 0.69 vs. r = − 0.49/r = − 0.64, p < 0.001/p = 0.007), in the emphysema cohort (r = − 0.77 vs. r = − 0.69/r = − 0.65, p = 0.03/p = 0.002), and in the random sample (r = − 0.39 vs. r = − 0.26/r = − 0.25, p = 0.001/p = 0.007). Conclusion The slice-wise whole-lung emphysema score (SWES) correlates better than LAV950 with radiologists’ visual emphysema scores and correlates better with airway obstruction than do LAV950 and radiologists’ visual scores. Clinical relevance statement The slice-wise whole-lung emphysema score provides quantitative emphysema information for CT imaging that avoids the disadvantages of threshold-based scores and is correlated more strongly with reference tests than LAV950 and reader visual scores. Key Points • A slice-wise whole-lung emphysema score (SWES) was developed to quantify emphysema in chest CT images. • SWES identified visual emphysema and spirometric airflow limitation significantly better than threshold-based score (LAV950). • SWES improved emphysema quantification in CT images, which is especially useful in large-scale research.

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Visual and Quantitative Evaluation of Emphysema: A Case-Control Study of 1111 Participants in the Pilot Swedish CArdioPulmonary BioImage Study (SCAPIS)

Cited by 11 publications

References 23 publications

The association between cadmium exposure and chronic airflow limitation and emphysema: the Swedish CArdioPulmonary BioImage Study (SCAPIS pilot)

The association between cadmium exposure and chronic airflow limitation and emphysema: the Swedish CArdioPulmonary BioImage Study (SCAPIS pilot)

Multi-Reader–Multi-Split Annotation of Emphysema in Computed Tomography

Machine learning slice-wise whole-lung CT emphysema score correlates with airway obstruction

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