Doppler Ultrasound-Visible SignalMark Microspheres are Better Identified than HydroMARK® Clips in a Simulated Intraoperative Setting in Breast and Lung Tissue

BackgroundPreoperative breast and lung markers have significant drawbacks, including migration, patient discomfort, and scheduling difficulties. SignalMark is a novel localizer device with a unique signal on Doppler ultrasound.ObjectiveWe aimed to evaluate intraoperative identification of SignalMark microspheres compared with HydroMARK® clips. We also assessed the safety and efficacy of SignalMark in the lung.MethodsTwelve breasts of lactating pigs were injected with SignalMark or HydroMARK® by a breast radiologist, and subsequently identified using a standard ultrasound machine by three surgeons blinded to marker location. Time to identification of each marker was recorded, with a maximum allotted time of 300s. To further demonstrate efficacy in lung parenchyma, a second cohort of pigs underwent lung injections.ResultsA total of eight SignalMark markers and four HydroMARK® clips were placed in pig breasts. Overall, the surgeons correctly identified SignalMark 95.8% of the time (n = 23/24) and HydroMARK® clips 41.7% of the time (n = 5/12) within 300 s (p