Evaluation of the distribution of air and blood in emphysema patients using radioisotopic tracers.
Continuous recording of the respiratory cycle with the simultaneous or sequential radionucleic exploration (gamma camera) of ventilation (133Xe) and perfusion (MAT-99) was performed to determine the V/Q index in regional areas (Polaroid photography, mini-computer, memory visualization system, Benson incremental tracer, etc.) from the level of 1,024 points. An average ratio per sector was calculated and only three median sectors were retained. The wash-in and wash-out curves were traced by computer, and the calculation of the average T 1/2 for the different compartments of each median sector (apex--middle and base) was done in about 22 observations: in 18 diffuse emphysema, 11 of which were associated with giant cystic emphysema (spirometric, plethysmographic and radiographic data), T 1/2 values were greater than those of normal subjects (compartments C1 and C2) in diffuse emphysema and can become indefinable in zones of cystic emphysema. The values of the index V/Q approach the normal in diffuse emphysema with a tendency toward equalization of the ratios from the apex to the base. Extremely large divergence is observed in the elevated V/Q ratios in cystic emphysema.
D000328:Adult; D000368:Aged; D003201:Computers; D004646:Emphysema / Q000503:physiopathology*; D006801:Humans; D008433:Mathematics; D008875:Middle Aged; D011652:Pulmonary Circulation; D012119:Respiration; D014692:Ventilation-Perfusion Ratio