Optimizing Microbubble Reduction to Facilitate IVUS Guidance During Endovascular Radiofrequency Wire Procedures

Area of Science:

• Medical Devices
• Ultrasound Technology
• Interventional Radiology

Background:

• Radiofrequency (RF) wire energy is utilized for tissue ablation and puncture.
• RF energy application generates microbubbles, which interfere with intravascular ultrasound (IVUS) imaging.
• Microbubble mitigation strategies exist for ablation but are less studied for RF wire puncture.

Purpose of the Study:

• To investigate methods for mitigating RF-generated microbubbles during tissue puncture.
• To evaluate the effectiveness of external ultrasound probes in clearing microbubbles for improved IVUS guidance.

Main Methods:

• An in vitro bench study using ex vivo bovine liver tissue and an IVUS catheter.
• Tissue puncture was performed using an RF guidewire to induce microbubble formation.
• Various methods were tested, including altering IVUS mechanical index and applying different external ultrasound probes (Siemens VF10-5, Philips L12-3).
• Pixel brightness in regions of interest was tracked as a proxy for microbubble presence.

Main Results:

• The L12-3 probe significantly reduced microbubble-induced brightness by 33.0% (p=0.046).
• Microbubble reduction was most effective at the RF wire puncture site.
• Improved tip visualization facilitated more precise wire trajectory adjustments.

Conclusions:

• External ultrasound, specifically the L12-3 probe, effectively dissipates microbubbles post-RF wire puncture.
• This technique shows promise for enhancing IVUS guidance in interventional procedures.
• The study provides an in vitro model for exploring microbubble mitigation strategies.