Fluorodensimetry. A method for analyzing regional ventilation and diaphragm function

Abstract

Fluorodensimetry is a method for amplifying and recording changes in density which occur over the thorax during fluoroscopy, and thereby analyzing regional ventilation and diaphragm movement. This method was used to evaluate 13 normal subjects and over 300 patients with various ventilatory disturbances. Patients with chronic obstructive pulmonary disease (COPD) tended to shift ventilation toward upper lung zones, and diaphragm function was markedly altered in the presence of air trapping. Obese individuals without complicating COPD were able to increase diaphragm movement during voluntary deep breathing and thus shift ventilation toward the lower zones; obese patients with COPD did not. Localized air trapping in poorly communicating bullae or distal to obstructed major bronchi resulted in characteristic changes of regional ventilation.