Treatment of deeply located acute intravascular thrombi with therapeutic ultrasound guided by diagnostic ultrasound and intravenous microbubbles.

Objective: We sought to determine the added value of simultaneous imaging of intravenously infused microbubbles that are being used to dissolve an intravascular thrombus with therapeutic ultrasound (TUS).

Methods: In a chronic canine arteriovenous graft occluded by a thrombus, TUS (1 MHz) was applied through a 6-cm-thick tissue-mimicking phantom (measured mean +/- SD peak negative pressure through the phantom, 958 +/- 104 kPa) during an intravenous infusion of either saline (n = 6 occlusions) or lipid-encapsulated microbubbles (ImaRx Therapeutics, Inc, Tucson, AZ). Therapeutic ultrasound was intermittently applied during the microbubble infusion either at set time intervals (n = 6 occlusions) or when simultaneous diagnostic ultrasound (DUS) indicated a sustained presence of microbubbles (n = 12 occlusions).