Comparison of computed density and microscopic morphometry in pulmonary emphysema

Am J Respir Crit Care Med. 1996 Jul;154(1):187-92. doi: 10.1164/ajrccm.154.1.8680679.


The purpose of this prospective study was to verify whether the percentage area of lung occupied by lowest attenuation values on high-resolution computed tomography (HRCT) scans reflects microscopic emphysema and to compare this quantification with the information yielded by the most widely used pulmonary function tests (PFT). Preoperative HRCT scans were obtained with 1-cm intervals in 38 subjects. With a semiautomatic evaluation procedure, the percentage areas occupied by attenuation values inferior to thresholds ranging from -900 Hounsfield units (HU) to -970 HU were calculated for the lobe or lung to be resected. Emphysema was microscopically quantified by using a computer-based method, measuring the perimeters and interwall distances of alveoli and alveolar ducts. The strongest correlation was found for -950 HU. As a second step, we evaluated possible correlations between PFT and microscopic measurements. Finally, considering the microscopic measurements as a standard, we tried to investigate their relationships with each of the PFT and with the relative area occupied by attenuation values lower than -950 HU for both lungs. This revealed that the diffusing capacity for carbon monoxide associated with HRCT quantification is sufficient to predict microscopic measurements. We concluded that the percentage area of lung occupied by attenuation values lower than -950 HU is a valid index of pulmonary emphysema.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Female
  • Humans
  • Lung / diagnostic imaging
  • Lung / pathology
  • Male
  • Middle Aged
  • Prospective Studies
  • Pulmonary Emphysema / diagnostic imaging*
  • Pulmonary Emphysema / pathology*
  • Pulmonary Emphysema / physiopathology
  • Respiratory Mechanics
  • Tomography, X-Ray Computed