Chronic obstructive pulmonary disease: evaluation with spirometrically controlled CT lung densitometry.

Abstract

To compare the computed tomographic (CT) lung densitometry results in patients with chronic obstructive pulmonary disease (COPD) and in control subjects (healthy persons). Spirometrically gated CT sections at 5 cm above and 5 cm below the carina at 90% and 10% vital capacity (VC) were imaged in patients and controls. Various densitometric parameters were derived from the CT data, and results were compared between the two levels of inspiration. Densitometric results in patients with emphysema were substantially different from those in patients with chronic bronchitis and in controls at 90% and 10% VC. Differences in patients with chronic bronchitis and in controls were not significant at 90% VC but were significant at 10% VC (P < .001). The mean changes in densitometric parameters between 90% and 10% VC were substantially greater in controls than in patients with COPD. It may be possible to classify lung disease with only two CT sections obtained at the same anatomic level, one at 90% and one at 10% VC, irrespective of the densitometric parameter used.