Robust, Standardized Quantification of Pulmonary Emphysema in Low Dose CT Exams Articles uri icon

publication date

  • November 2011

start page

  • 1382

end page

  • 1390


  • 11


  • 18

International Standard Serial Number (ISSN)

  • 1076-6332


  • Abstract: Rationale and Objectives: The aim of this study was to present and evaluate a fully automated system for emphysema quantification on low-dose computed tomographic images. The platform standardizes emphysema measurements against changes in the reconstruction algorithm and slice thickness. Materials and Methods: Emphysema was quantified in 149 patients using a fully automatic, in-house developed software (the Robust Automatic On-Line Pulmonary Helper). The accuracy of the system was evaluated against commercial software, and its reproducibility was assessed using pairs of volume-corrected images taken 1 year apart. Furthermore, to standardize quantifications, the effect of changing the reconstruction parameters was modeled using a nonlinear fit, and the inverse of the model function was then applied to the data. The association between quantifications and pulmonary function testing was also evaluated. The accuracy of the in-house software compared to that of commercial software was measured using Spearman's rank correlation coefficient, the mean difference, and the intrasubject variability. Agreement between the methods was studied using Bland-Altman plots. To assess the reproducibility of the method, intraclass correlation coefficients and Bland-Altman plots were used. The statistical significance of the differences between the standardized data and the reference data (soft-tissue reconstruction algorithm B40f; slice thickness, 1 mm) was assessed using a paired two-sample t test.


  • emphysema index; automatic quantification; low-dose ct; copd; carbon monoxide; hemoglobin; adult; algorithm; article; computer assisted tomography; computer program; controlled study; diagnostic accuracy; diagnostic test accuracy study; forced expiratory volume; human; lung diffusion capacity; lung emphysema; lung function test; lung volume; major clinical study; priority journal; quantitative analysis; reproducibility; sensitivity analysis; standardization; adult; algorithms; female; humans; male; pulmonary emphysema; radiation dosage; radiographic image iinterpretation; computer assisted; reproducibility of results; respiratory function tests; software; tomography; x-ray computed