Quantitative assessment of emphysema distribution in smokers and patients with alpha1-antitrypsin deficiency

Respir Med. 2006 Jan;100(1):94-100. doi: 10.1016/j.rmed.2005.04.001.


Introduction: Identification of upper lobe emphysema is mandatory before lung volume reduction surgery (LVRS). Here we introduce a CT-based objective model for describing the distribution of different types of emphysema.

Methods: Fifty COPD patients were included in the study. Half had alpha1-antitrypsin deficiency (alpha1-COPD) and the rest had smoking-induced emphysema (usual COPD). All patients were scanned 3 times. The relative area of emphysema in each CT slice was plotted against table position, and the cranio-caudal distribution was calculated as the slope of the regression line.

Results: The variation in slopes within a patient was much less than the variation in slopes between patients (P<0.0001). There was a significant difference between slopes in the alpha1-COPD and the usual COPD groups (P<0.0001). In the alpha1-COPD group, 24/25 patients had lower lobe emphysema. In the usual COPD group, 4 patients had upper lope predominance, 5 patients had heterogeneous distributions, and 16 patients had lower lobe predominance.

Conclusions: The majority of patients with smoking-related emphysema have a homogeneous distribution and lower lobe predominance although not as noticeable as in alpha1-antitrypsin deficiency. An objective and quantitative method for determining the distribution of emphysema should be applied when selecting candidates for LVRS.

Publication types

  • Evaluation Study

MeSH terms

  • Aged
  • Cohort Studies
  • Female
  • Humans
  • Male
  • Middle Aged
  • Pulmonary Disease, Chronic Obstructive / complications*
  • Pulmonary Disease, Chronic Obstructive / diagnostic imaging
  • Pulmonary Emphysema / complications*
  • Pulmonary Emphysema / diagnostic imaging*
  • Reproducibility of Results
  • Smoking / adverse effects*
  • Tomography, X-Ray Computed / standards*
  • alpha 1-Antitrypsin Deficiency / complications*