Real-time 3D Color Doppler for guidance of vibrating interventional devices

The goal of this investigation is to examine the feasibility of guiding interventional devices using piezoelectric buzzers to create a velocity source, which is imaged and tracked with real time 3D (RT3D) ultrasound and Color Doppler. Interventional devices include pacemaker lead stylet, cardiac septal puncture needle and RF ablation needles for cancer therapy. The vibrating devices were imaged using a RT3D ultrasound system (Duke U./Volumetrics Medical Imaging) with a 2.5 MHz transducer that scans a 65 degrees pyramid and displays up to 30 volumes per second. The velocities created by the vibrating devices were detected using real RT3D color Doppler. In vitro RT3D Doppler images acquired in tissue phantoms show strong vibration signals in 3D color Doppler mode, enabling real time tracking and guidance of the devices in three dimensions over the entire 656 pyramid at a minimum rate of one 3D color Doppler image volume per second. In an open chest sheep model, in vivo detection of the pacemaker lead stylet was performed in the superior vena cava as well as the right atrium using RT3D color Doppler images. The vibrating RF ablation needles were guided through the liver toward tumor targets in vivo with RT3D color Doppler images in a closed sheep model. From these results, we believe that using a vibrating buzzer to create a velocity source may enable interventional device visualization and guidance in RT3D images using Doppler methods.