Lipiodol visibility under ultrasound

Lipiodol is an oil-based solution commonly used in hysterosalpingogram (HSG), but not hysterosalpingo contrast sonography (HyCoSy). In women with unexplained infertility, evidence suggests that tubal flushing with Lipiodol results in improved fertility post-procedure. We propose that Lipiodol can be visualised under ultrasound similar to commonly used saline, and hence utilised for HyCoSy, allowing the benefit of an oil-based tubal flushing to occur with HyCoSy.

To examine whether Lipiodol is visible sonographically, assess optimal agitated Lipiodol mix and ultrasound settings for visibility, and compare visibility to agitated saline, routinely used for HyCoSy.

Two separate sonographers with identical ultrasound machines and model pelvises recorded images with varying degrees of agitated Lipiodol and ultrasound settings, in addition to capturing images with no fluid and agitated saline. Each test was performed in quadruplicate and in random order. Images were read by 47 blinded reporters and visibility reported on a scale of one (not visible) to five (clearly visible).

The mean visibility score for images captured where the Lipiodol sample was agitated five times prior to injection to allow the formation of air microbubbles, regardless of ultrasound setting, were higher than or not different from that for agitated saline (all P > 0.7 when not different, <0.001 when higher).

Sonographic visualisation of agitated Lipiodol is similar or better than that of agitated saline. Lipiodol may therefore present a possibility for use with HyCoSy, with the added benefit of oil-based tubal flushing, avoiding the radiation exposure of HSG and concurrently providing pelvic soft-tissue evaluation.