Applications of Regional Lung Parenchyma Analysis in Thoracic CT Data

Purpose of the Study: To demonstrate the clinical potential of automated parenchyma analysis software in the quantification and visualization of functional CT parameters within anatomically (r/l lung, lobes) or geometrically (halves, thirds, core/peel) defined lung regions in patients with chronic obstructive lung disease. Methods: Using a prototypical research software (MeVisPULMO 3D) that allows automated calculation and 3 D-visualization of CT parameters (eg, MLD, low attenuation volumes) for the left and right lung, geometrically defined subregions, and lung lobes, several clinical studies were performed by different clinical researchers with respect to the following diagnostic and interventional questions: (1) Partitioning strategies for region based emphysema assessment, (2) gender differences in emphysema phenotype in non-COPD smokers, (3) therapy planning of patients undergoing endobronchial valve implantation, and (4) therapy monitoring of patients undergoing airway bypass procedure. Results: Overall, the prototypical parenchyma evaluation software was successfully applied to more than 1500CT datasets. Regionbased CT histogram evaluation was determined to correlate well with conventional techniques while in many cases providing valuable additional information: (1) Lobe based analysis is superior to geometric analysis in mild emphysema whereas differences between core and rind become significant in patients with severe emphysema. (2) For women as compared to men emphysema is less extensive in each pulmonary lobe, is characterized by smaller emphysematous areas, and is slightly less concentrated in the core of the lung. (3) Lobe based quantification is helpful in therapy planning for patients with end stage emphysema when localized emphysema is present. (4) Therapy response to airway bypass procedure is significantly associated with changes in quantitative CT parameters. Conclusions: Regional lung parenchyma analysis is helpful for assisting diagnosis, treatment planning and follow-up of parenchymal diseases such as pulmonary emphysema.