Key Points
- To measure the transit time dispersion occurring within pulmonary arterial and venous trees and assess their contribution to overall pulmonary vascular transit time distribution.
- Acquired X-ray microfocal angiographic images of a contrast bolus traversing the vasculature of pump-perfused dog lung lobes.
- Calculated time-absorbance curves and their statistical moments (mean transit time and variance) at the lobar artery, lobar vein, and intermediate arterial branches down to 200-micrometer diameters.
- Mean transit times for arterial pathways upstream from 200-micrometer vessels accounted for less than approximately 20% of the total lung lobe mean transit time.
- Interpathway transit time variance among these arterial pathways was less than approximately 5% of the total lobar variance, with negligible intrapathway dispersion and similar findings in the venous tree.
- Most intrapulmonary transit time dispersion localizes to the pulmonary capillary bed rather than the conducting arterial or venous trees.
Structured PICO
PPopulationPump-perfused dog lung lobes
IInterventionBolus of contrast medium passing through the vasculature imaged by X-ray microfocal angiography
OOutcomeDispersion of blood transit times within the pulmonary arterial and venous treessurrogate
Most of the variation in transit time in the intrapulmonary vasculature occurs within the pulmonary capillary bed rather than in conducting arteries or veins.