Effect of interfacial tension on flow of fluorochemicals in the vasculature of the lung: a theoretical and experimental study.

Perfluorocarbons can be selectively imaged using magnetic resonance. When introduced in the vasculature they do not flow beyond a certain level. This level depends on the driving pressure. We consider here such flow stoppage in the case of the vascular bed of rat lung. A theoretical analysis based on the assumption that interfacial tension is primarily responsible for this phenomenon leads to a formula that predicts a "critical" radius of the vessels at where the flow stops. This radius depends on the driving pressure. The predicted result was verified experimentally using direct measurements on histological sections and was found to confirm the hypothesis.