Measurement of myometrial blood flow in rabbits by washout of xenon-133 after atraumatic local labelling.

In vivo experiments were performed on the uterine tissue of non-pregnant estradiol treated rabbit anesthetized with sodium pentobarbitone. The average blood flow calculated from the washout of Xenon-133 after atraumatic labelling from the uterine surface was 25.4 ml . min-1.(100 g)-1 (range 7.4-66.6), and after local injection of a tracer in isotonic saline directly into the myometrium 24.4 ml.min-1.(100 g)-1(range 8.7-45.3). During the experiments a monoexponential washout curve was found for the whole washout process both after atraumatic labelling and when the injected volume was 5 microliter. No trauma of injection was observed using this injection volume. The results support the applicability of a monocompartmental model for the washout of inert gas from the myometrium. Thus myometrial blood flow can be calculated from the Xenon-133 washout rate at any time interval during the washout process.