Differences of airway dimensions between patients with and without bronchiolitis obliterans syndrome after lung transplantation-Computer-assisted quantification of computed tomography

Automated CT Image Processing for the Diagnosis, Prediction, and Differentiation of Phenotypes in Chronic Lung Allograft Dysfunction After Lung Transplantation

BACKGROUND

Chronic lung allograft dysfunction (CLAD) after lung transplantation is a common complication with a poor prognosis. We assessed the utility of quantitative computed tomography (CT) for the diagnosis, prediction, and discrimination of CLAD phenotypes.

METHODS

We retrospectively analyzed routine inspiratory and expiratory CT scans from 78 patients at different time points after lung transplantation. Mean lung density (MLD), parametric response mapping (PRM), percentage of air trapping, and airway wall morphology parameters were calculated using the image processing software YACTA. Diagnostic and predictive utility was determined by receiver operating characteristic analysis and Pearson correlation.

RESULTS

Markers of air trapping showed promise for the diagnosis and prediction of bronchiolitis obliterans syndrome (BOS); for example, expiratory MLD showed areas under the curve (AUCs) of 0.905 for diagnosis and 0.729 for 1-year prediction. For diagnosis of CLAD with mixed phenotype, peripheral measurements (e.g., PRM of peripheral functional small airway disease: AUC 0.893) were most suitable. Markers of airway thickening (e.g., expiratory wall thickness at an inner perimeter of 10 mm: AUC 0.767) gave good diagnostic values for the undefined phenotype. CT biomarkers differed significantly among CLAD phenotypes.

CONCLUSIONS

Different CT biomarkers are suitable for the diagnosis of CLAD phenotypes, prediction of BOS, and differentiation of CLAD phenotypes.

Automatic quantitative evaluation of high-resolution computed tomography scans of patients with interstitial lung diseases

PURPOSE

High-resolution computed tomography (HRCT) is essential in clinical evaluation and management of interstitial lung diseases (ILDs). Quantitative analysis can assist in both accurate diagnosis and longitudinal assessment. The aim was to verify the role of automatic quantitative analysis of HRCT images in the diagnosis and classification of ILD.

METHODS

Retrospective single-center study evaluating patients undergoing investigation for fibrosing ILD between 2010 and 2019. HRCT images were re-evaluated, ILD patterns were classified according to the 2018 ATS/ERS/JRS/ALAT consensus. Demographic and clinical variables, distribution of fibrosis and honeycombing pattern, and variables obtained from the quantitative analysis performed by YACTA scientific program were compared between ILD groups according to the 2018 ATS/ERS/JRS/ALAT consensus and to the radiological patterns of idiopathic interstitial pneumonia (IIP), using ANOVA, Kruskal-Wallis H test or Pearson's chi-squared test.

RESULTS

481 patients (mean age 57.7 ± 14 years, 277 women, 204 men) were evaluated. Patients with radiological pattern of usual interstitial pneumonia (UIP) exhibited lower lung volumes, higher mean lung densities (UIP group, -698.8 ± 66.3; probable UIP group, -743.8 ± 47.9; alternative diagnosis to UIP, -712.7 ± 73.7; p = 0.01), and higher absolute vascular lung volumes. Among tomographic patterns of IIP, bronchiolocentric interstitial pneumonia demonstrated smaller lung volume and higher lung density. Collagen vascular disease was the most prevalent.

CONCLUSION

This study demonstrated that, in a large dataset of exams, the fully automated quantitative analysis of HRCTs is an objective method, which can help in the diagnostic workup of ILDs.

Biomarkers for Chronic Lung Allograft Dysfunction: Ready for Prime Time?

Chronic lung allograft dysfunction (CLAD) remains a major hurdle impairing lung transplant outcome. Parallel to the better clinical identification and characterization of CLAD and CLAD phenotypes, there is an increasing urge to find adequate biomarkers that could assist in the earlier detection and differential diagnosis of CLAD phenotypes, as well as disease prognostication. The current status and state-of-the-art of biomarker research in CLAD will be discussed with a particular focus on radiological biomarkers or biomarkers found in peripheral tissue, bronchoalveolar lavage' and circulating blood' in which significant progress has been made over the last years. Ultimately, although a growing number of biomarkers are currently being embedded in the follow-up of lung transplant patients, it is clear that one size does not fit all. The future of biomarker research probably lies in the rigorous combination of clinical information with findings in tissue, bronchoalveolar lavage' or blood. Only by doing so, the ultimate goal of biomarker research can be achieved, which is the earlier identification of CLAD before its clinical manifestation. This is desperately needed to improve the prognosis of patients with CLAD after lung transplantation.

Chronic Lung Allograft Dysfunction Post Lung Transplantation: A Review of Computed Tomography Quantitative Methods for Detection and Follow-Up

Chronic lung allograft dysfunction (CLAD) remains the leading cause of morbidity and mortality after lung transplantation. The term encompasses both obstructive and restrictive phenotypes, as well as mixed and undefined phenotypes. Imaging, in addition to pulmonary function tests, plays a major role in identifying the CLAD phenotype and is essential for follow-up after lung transplantation. Quantitative imaging allows for the performing of reader-independent precise evaluation of CT examinations. In this review article, we will discuss the role of quantitative imaging methods for evaluating the airways and the lung parenchyma on computed tomography (CT) images, for an early identification of CLAD and for prognostic estimation. We will also discuss their limits and the need for novel approaches to predict, understand, and identify CLAD in its early stages.

Update in Chronic Lung Allograft Dysfunction

Chronic lung allograft dysfunction (CLAD) is the major limitation to posttransplant survival. This review highlights the evolving definition of CLAD, risk factors, treatment, and expected outcomes after the development of CLAD.