Interstitial Lung Abnormalities Detected by CT in Asbestos-Exposed Subjects Are More Likely Associated to Age

OBJECTIVE: the aim of this study was to evaluate the association between interstitial lung abnormalities, asbestos exposure and age in a population of retired workers previously occupationally exposed to asbestos. METHODS: previously occupationally exposed former workers to asbestos eligible for a survey conducted between 2003 and 2005 in four regions of France, underwent chest CT examinations and pulmonary function testing. Industrial hygienists evaluated asbestos exposure and calculated for each subject a cumulative exposure index (CEI) to asbestos. Smoking status information was also collected in this second round of screening. Expert radiologists performed blinded independent double reading of chest CT-scans and classified interstitial lung abnormalities into: no abnormality, minor interstitial findings, interstitial findings inconsistent with UIP, possible or definite UIP. In addition, emphysema was assessed visually (none, minor: emphysema 50% of the lung). Logistic regression models adjusted for age and smoking were used to assess the relationship between interstitial lung abnormalities and occupational asbestos exposure. RESULTS: the study population consisted of 2157 male subjects. Interstitial lung abnormalities were present in 365 (16.7%) and emphysema in 444 (20.4%). Significant positive association was found between definite or possible UIP pattern and age (OR adjusted =1.08 (95% CI: 1.02-1.13)). No association was found between interstitial abnormalities and CEI or the level of asbestos exposure. CONCLUSION: presence of interstitial abnormalities at HRCT was associated to aging but not to cumulative exposure index in this cohort of former workers previously occupationally exposed to asbestos

Deep Learning for the Automatic Quantification of Pleural Plaques in Asbestos-Exposed Subjects

OBJECTIVE: This study aimed to develop and validate an automated artificial intelligence (AI)-driven quantification of pleural plaques in a population of retired workers previously occupationally exposed to asbestos. METHODS: CT scans of former workers previously occupationally exposed to asbestos who participated in the multicenter APEXS (Asbestos PostExposure Survey) study were collected retrospectively between 2010 and 2017 during the second and the third rounds of the survey. A hundred and forty-one participants with pleural plaques identified by expert radiologists at the 2nd and the 3rd CT screenings were included. Maximum Intensity Projection (MIP) with 5 mm thickness was used to reduce the number of CT slices for manual delineation. A Deep Learning AI algorithm using 2D-convolutional neural networks was trained with 8280 images from 138 CT scans of 69 participants for the semantic labeling of Pleural Plaques (PP). In all, 2160 CT images from 36 CT scans of 18 participants were used for AI testing versus ground-truth labels (GT). The clinical validity of the method was evaluated longitudinally in 54 participants with pleural plaques. RESULTS: The concordance correlation coefficient (CCC) between AI-driven and GT was almost perfect (>0.98) for the volume extent of both PP and calcified PP. The 2D pixel similarity overlap of AI versus GT was good (DICE = 0.63) for PP, whether they were calcified or not, and very good (DICE = 0.82) for calcified PP. A longitudinal comparison of the volumetric extent of PP showed a significant increase in PP volumes (p < 0.001) between the 2nd and the 3rd CT screenings with an average delay of 5 years. CONCLUSIONS: AI allows a fully automated volumetric quantification of pleural plaques showing volumetric progression of PP over a five-year period. The reproducible PP volume evaluation may enable further investigations for the comprehension of the unclear relationships between pleural plaques and both respiratory function and occurrence of thoracic malignancy

Apport de l’imagerie TDM et IRM quantitative à l’étude des modifications structurales et fonctionnelles respiratoires dans les maladies obstructives chroniques des voies aériennes chez l’homme

Chronic obstructive airway diseases are a major public health problem, characterized by chronic inflammation and airways remodeling. Imaging of the structural elements of the lungs (bronchi, bronchioles, vessels...) is essential for defining, phenotyping and following-up these diseases. Visual assessment is prone to inter-observer variability that affects its reliability. Therefore, the development of reliable and reproducible new quantitative methods is necessary. CT and MRI are the two complete imaging methods of the various structural and functional compartments of the lung. This work focused on the development and the validation of quantitative methods using CT and MRI of the lung.Using quantitative CT, we have shown that measurements of bronchial and vascular remodeling in patients with severe pulmonary hypertension (PH), a particular phenotype in COPD patients, contributed to highlight interactions between the cardiovascular and respiratory systems. We have developed a method for small airway disease quantification, tested in a chronic hypersensitivity pneumonitis cohort, that may contribute to evaluate and monitor chronic obstructive airway diseases.Using quantitative MRI, we have developed a fully automated quantification technique to assess the severity of emphysema extent in COPD patients. In addition, transposing bronchial measurement methods from CT to MRI has become possible thanks to the new ultra short echo time (UTE) sequences. Thus, the quantification of bronchial remodeling at 3DUTE MRI in patients with cystic fibrosis, for whom it is necessary to reduce exposure to ionizing radiation, has shown morphological information similar to that of CT. We have also shown that automatic quantification of destructive and inflammatory phenomena by 3DUTE MRI in cystic fibrosis is a reliable and reproducible method for assessing the severity of structural alterations. Furthermore, the feasibility of an automatic quantification of T2 high signal intensity on MRI has been demonstrated and its relevance as a specific biomarker for inflammatory airway disease has been assessed.Thus, the quantitative analysis, in both CT and MRI, of various structural and functional modifications in chronic obstructive airway diseases could be a reliable method in the follow-up and the evaluation of the response to treatment in these diseases.Les maladies bronchiques obstructives chroniques constituent un problème majeur de santé publique. Leur pathogénie est caractérisée par l’inflammation chronique et le remodelage des voies aériennes. L’étude en imagerie des différents éléments structuraux des poumons (bronches, bronchioles, vaisseaux…) est primordiale dans la définition, le phénotypage, la compréhension des mécanismes obstructifs et le suivi de l’évolution et de ces maladies. Les méthodes d’évaluation visuelles qualitatives sont sujettes à une subjectivité d’analyse et à une variabilité inter observateurs qui altèrent leur fiabilité. Le développement de nouvelles méthodes quantitatives fiables et reproductibles est donc une nécessité. La TDM et l’IRM sont les deux méthodes d’imagerie complètes à la fois des différents compartiments structuraux et fonctionnels du poumon, la première ayant pour avantage son excellente résolution spatiale et la seconde son innocuité. Les travaux ont porté sur la mise au point et la validation de méthodes d’imagerie quantitatives TDM et IRM. Avec la TDM quantitative, nous avons montré que les mesures du remodelage bronchique et vasculaire chez les patients atteints d’une hypertension pulmonaire (HTP) sévère, phénotype particulier à la bronchopneumopathie chronique obstructive (BPCO), permettaient d’appréhender les interactions entre les systèmes cardiovasculaire et respiratoire. D’autre part nous avons mis au point et évalué une méthode de quantification de l’atteinte des voies aériennes distales dans une population de pneumonie chronique d’hypersensibilité. Cette méthode pourrait apporter une contribution à l’étude et au suivi des maladies bronchiques obstructives chroniques.Avec l’IRM quantitative, les solutions que nous avons proposées dans la quantification de l’emphysème à l’IRM protonique permettent une analyse automatisée de la sévérité de l’extension de l’emphysème chez des patients atteints de BPCO. En outre, la transposition des méthodes de mesure des paramètres bronchiques de la TDM à l’IRM est devenue possible grâce aux nouvelles séquences à temps d’écho ultra court (UTE). Ainsi, la quantification du remodelage bronchique à l’IRM 3DUTE chez des patients atteints de mucoviscidose, chez lesquels il est nécessaire de réduire l’exposition aux rayons ionisants, permet d’obtenir des informations morphologiques similaires à celles de la TDM. Nous avons aussi montré que la quantification automatique des phénomènes destructifs et inflammatoires par l’IRM 3DUTE dans l’atteinte pulmonaire de la mucoviscidose était une méthode fiable et reproductible pour évaluer la sévérité de l’atteinte structurale. Par ailleurs, la faisabilité d’une quantification automatique des hypersignaux T2 à l’IRM a été démontrée et sa pertinence comme biomarqueur spécifique de l’atteinte inflammatoire des voies aériennes évaluée. Ainsi, l’étude quantitative, en TDM comme en IRM, de diverses modifications structurales et fonctionnelles des maladies bronchiques obstructives chroniques ouvre le champ d’une analyse objective et fiable par l’imagerie aux évaluations du suivi et de la réponse au traitement

Contribution of quantitative CT and MRI to the study of structural and functional respiratory changes in chronic obstructive airway diseases in humans

Les maladies bronchiques obstructives chroniques constituent un problème majeur de santé publique. Leur pathogénie est caractérisée par l’inflammation chronique et le remodelage des voies aériennes. L’étude en imagerie des différents éléments structuraux des poumons (bronches, bronchioles, vaisseaux…) est primordiale dans la définition, le phénotypage, la compréhension des mécanismes obstructifs et le suivi de l’évolution et de ces maladies. Les méthodes d’évaluation visuelles qualitatives sont sujettes à une subjectivité d’analyse et à une variabilité inter observateurs qui altèrent leur fiabilité. Le développement de nouvelles méthodes quantitatives fiables et reproductibles est donc une nécessité. La TDM et l’IRM sont les deux méthodes d’imagerie complètes à la fois des différents compartiments structuraux et fonctionnels du poumon, la première ayant pour avantage son excellente résolution spatiale et la seconde son innocuité. Les travaux ont porté sur la mise au point et la validation de méthodes d’imagerie quantitatives TDM et IRM. Avec la TDM quantitative, nous avons montré que les mesures du remodelage bronchique et vasculaire chez les patients atteints d’une hypertension pulmonaire (HTP) sévère, phénotype particulier à la bronchopneumopathie chronique obstructive (BPCO), permettaient d’appréhender les interactions entre les systèmes cardiovasculaire et respiratoire. D’autre part nous avons mis au point et évalué une méthode de quantification de l’atteinte des voies aériennes distales dans une population de pneumonie chronique d’hypersensibilité. Cette méthode pourrait apporter une contribution à l’étude et au suivi des maladies bronchiques obstructives chroniques.Avec l’IRM quantitative, les solutions que nous avons proposées dans la quantification de l’emphysème à l’IRM protonique permettent une analyse automatisée de la sévérité de l’extension de l’emphysème chez des patients atteints de BPCO. En outre, la transposition des méthodes de mesure des paramètres bronchiques de la TDM à l’IRM est devenue possible grâce aux nouvelles séquences à temps d’écho ultra court (UTE). Ainsi, la quantification du remodelage bronchique à l’IRM 3DUTE chez des patients atteints de mucoviscidose, chez lesquels il est nécessaire de réduire l’exposition aux rayons ionisants, permet d’obtenir des informations morphologiques similaires à celles de la TDM. Nous avons aussi montré que la quantification automatique des phénomènes destructifs et inflammatoires par l’IRM 3DUTE dans l’atteinte pulmonaire de la mucoviscidose était une méthode fiable et reproductible pour évaluer la sévérité de l’atteinte structurale. Par ailleurs, la faisabilité d’une quantification automatique des hypersignaux T2 à l’IRM a été démontrée et sa pertinence comme biomarqueur spécifique de l’atteinte inflammatoire des voies aériennes évaluée. Ainsi, l’étude quantitative, en TDM comme en IRM, de diverses modifications structurales et fonctionnelles des maladies bronchiques obstructives chroniques ouvre le champ d’une analyse objective et fiable par l’imagerie aux évaluations du suivi et de la réponse au traitement.Chronic obstructive airway diseases are a major public health problem, characterized by chronic inflammation and airways remodeling. Imaging of the structural elements of the lungs (bronchi, bronchioles, vessels...) is essential for defining, phenotyping and following-up these diseases. Visual assessment is prone to inter-observer variability that affects its reliability. Therefore, the development of reliable and reproducible new quantitative methods is necessary. CT and MRI are the two complete imaging methods of the various structural and functional compartments of the lung. This work focused on the development and the validation of quantitative methods using CT and MRI of the lung.Using quantitative CT, we have shown that measurements of bronchial and vascular remodeling in patients with severe pulmonary hypertension (PH), a particular phenotype in COPD patients, contributed to highlight interactions between the cardiovascular and respiratory systems. We have developed a method for small airway disease quantification, tested in a chronic hypersensitivity pneumonitis cohort, that may contribute to evaluate and monitor chronic obstructive airway diseases.Using quantitative MRI, we have developed a fully automated quantification technique to assess the severity of emphysema extent in COPD patients. In addition, transposing bronchial measurement methods from CT to MRI has become possible thanks to the new ultra short echo time (UTE) sequences. Thus, the quantification of bronchial remodeling at 3DUTE MRI in patients with cystic fibrosis, for whom it is necessary to reduce exposure to ionizing radiation, has shown morphological information similar to that of CT. We have also shown that automatic quantification of destructive and inflammatory phenomena by 3DUTE MRI in cystic fibrosis is a reliable and reproducible method for assessing the severity of structural alterations. Furthermore, the feasibility of an automatic quantification of T2 high signal intensity on MRI has been demonstrated and its relevance as a specific biomarker for inflammatory airway disease has been assessed.Thus, the quantitative analysis, in both CT and MRI, of various structural and functional modifications in chronic obstructive airway diseases could be a reliable method in the follow-up and the evaluation of the response to treatment in these diseases

<p>Assessing pulmonary hypertension in COPD. Is there a role for computed tomography?</p>

International audiencePulmonary hypertension (PH) is a common complication of chronic obstructive pulmonary disease (COPD) and is associated with increased morbidity and mortality. Reference standard method to diagnose PH is right heart catheterization. Several non-invasive imaging techniques have been employed in the detection of PH. Among them, computed tomography (CT) is the most commonly used for phenotyping and detecting complications of COPD. Several CT findings have also been described in patients with severe PH. Nevertheless, CT analysis is currently based on visual findings which can lead to reproducibility failure. Therefore, there is a need for quantification in order to assess objective criteria. In this review, progresses in automated analyses of CT parameters and their values in predicting PH and COPD outcomes are presented

Lung CT Synthesis Using GANs with Conditional Normalization on Registered Ultrashort Echo-Time MRI

International audienceIn clinical practice, the modality of choice for lung diagnosis is usually computed tomography (CT), which exposes patients to ionizing radiations and could potentially affect patients' health. Conversely, MR scan is considered safe and non-invasive but seems challenging due to the low proton density of the lungs and respiratory artifacts. Recently, ultrashort echo-time (UTE) MRI has been developed for lung assessment and shows promising results. In this work, we propose generating 2D synthetic CT slices from UTE MR slices, to improve the image quality and interpretability. Lung MR and CT volumes of 110 patients acquired on the same day were registered using an accurate edge-based non-rigid registration method. We trained and compared paired state-of-the-art generative models based on adversarial, feature-matching and perceptual losses, and also evaluated the impact of conditional batch normalization, namely SPADE [17], on image synthesis. Quantitative and qualitative evaluations showed that this approach was able to synthesize CT images that closely approximate ground truth CT images, and also enables the use of algorithms originally designed for real CT

MR to CT synthesis using GANs : a practical guide applied to thoracic imaging

International audienceIn medical imaging, MR-to-CT synthesis has been extensively studied. The primary motivation is to benefit from the quality of the CT signal, i.e. excellent spatial resolution, high contrast, and sharpness, while avoiding patient exposure to CT ionizing radiation, by relying on the safe and non-invasive nature of MRI. Recent studies have successfully used deep learning methods for cross-modality synthesis, notably with the use of conditional Generative Adversarial Networks (cGAN), due to their ability to create realistic images in a target domain from an input in a source domain. In this study, we examine in detail the different steps required for cross-modality translation using GANs applied to MR-to-CT lung synthesis, from data representation and pre-processing to the type of method and loss function selection. The different alternatives for each step were evaluated using a quantitative comparison of intensities inside the lungs, as well as bronchial segmentations between synthetic and ground truth CTs. Finally, a general guideline for crossmodality medical synthesis is proposed, bringing together best practices from generation to evaluation

Eur Radiol

OBJECTIVES: The study aimed to validate automated quantification of high and low signal intensity volumes using ultrashort echo-time MRI, with CT and pulmonary function test (PFT) as references, to assess the severity of structural alterations in cystic fibrosis (CF). METHODS: This prospective study was performed in a single center between May 2015 and September 2017. Participants with CF completed clinical examination, CT, MRI, and PFT the same day during routine clinical follow-up (M0), and then 1 year after (M12) except for CT. Using MRI, percentage high (%MR-HSV), low (%MR-LSV), and total abnormal (%MR-TSV) signal intensity volumes were recorded, as well as their corresponding attenuation values using CT (%CT-HAV, %CT-LAV, %CT-TAV, respectively). Automated quantifications and visual Bhalla score were evaluated independently by two observers. Correlations were assessed using the Spearman test, comparisons using the Mann-Whitney test, and reproducibility using the intraclass correlation coefficient (ICC). RESULTS: A total of 30 participants were enrolled (median age 27 years, 18 men). At M0, there was a good correlation between %MR-HSV and %CT-HAV (ρ = 0.70; p \textbackslashtextless 0.001) and %MR-LSV and %CT-LAV (ρ = 0.60; p \textbackslashtextless 0.001). Automated MR metrics correlated to PFTs and Bhalla score (p \textbackslashtextless 0.05) while %MR-TSV was significantly different between CF with and without respiratory exacerbation (p = 0.01) at both M0 and M12. The variation of %MR-HSV correlated to the variation of FEV1% at PFT (ρ = - 0.49; p = 0.008). Reproducibility was almost perfect (ICCs \textbackslashtextgreater 0.95). CONCLUSIONS: Automated quantification of abnormal signal intensity volumes relates to CF severity and allows reproducible cross-sectional and longitudinal assessment. TRIAL REGISTRATION: Clinical trial identifier: NCT02449785 KEY POINTS: • Cross-sectionally, the automated quantifications of high and low signal intensity volumes at UTE correlated to the quantification of high and low attenuation using CT as reference. • Longitudinally, the variation of high signal intensity volume at UTE correlated to the variation of pulmonary function test and was significantly reduced in CF with an improvement in exacerbation status. • Automated quantification of abnormal signal intensity volumes are objective and reproducible tools to assess structural alterations in CF and follow-up longitudinally, for both research and clinical purposes

J Magn Reson Imaging

BACKGROUND: Imaging has played a pivotal role in the diagnosis of idiopathic pulmonary fibrosis (IPF). Recent reports suggest that T2 -weighted MRI could be sensitive to monitor signal-intensity modifications of the lung parenchyma, which may relate to the disease activity in IPF. However, there is a lack of automated tools to reproducibly quantify the extent of the disease, especially using MRI. PURPOSE: To assess the feasibility of T2 interstitial lung disease signal-intensity volume quantification using a semiautomated method in IPF. STUDY TYPE: Single center, retrospective. POPULATION: A total of 21 adult IPF patients and four control subjects without lung interstitial abnormalities. FIELD STRENGTH/SEQUENCE: Both free-breathing ultrashort echo time (TE) lung MRI using the spiral volume interpolated breath hold examination (VIBE) sequence (3D-UTE) and T2 -BLADE at 1.5T. ASSESSMENT: Semiautomated segmentation of the lung volume was done using 3D-UTE and registered to the T2 -BLADE images. The interstitial lung disease signal-intensity volume (ISIV) was quantified using a Gaussian mixture model clustering and then normalized to the lung volume to calculate T2 -ISIV. The composite physiological index (CPI) and forced vital capacity (FVC) were measured as known biomarkers of IPF severity. Measurements were performed independently by three readers and averaged. The reproducibility between measurements was also assessed. STATISTICAL TESTS: Reproducibility was assessed using the intraclass correlation coefficient (ICC) and Bland-Altman analysis. Correlations were assessed using Spearman test. Comparison of median was assessed using the Mann-Whitney test. RESULTS: The reproducibility of T2 -ISIV was high, with ICCs = 0.99. Using Bland-Altman analysis, the mean differences were found between -0.8 to 0.1. T2 -ISIV significantly correlated with CPI and FVC (rho = 0.48 and 0.50, respectively; P < 0.05). T2 -ISIV was significantly higher in IPF than in controls (P < 0.05). DATA CONCLUSION: T2 -ISIV appears to be able to reproducibly assess the volumetric extent of abnormal interstitial lung signal-intensity modifications in patients with IPF, and correlate with disease severity. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY STAGE: 1