A team of scientists at RTI International, a leading research institute, have developed a 3D imaging catheter aimed at providing cardiologists with a live view from inside the heart during cardiac catheterizations. The catheter contains an ultrasound microarray made using semiconductor circuit fabrication that can provide unprecedented volumetric field-of-view, in real time.

Fig. 1 – This shows the tip of an intracardiac catheter, which contains a piezoelectric ultrasound microarray with 512 elements.
The technology, called a live volumetric imaging (LVI) intracardiac catheter has the potential to improve catheter-based interventional heart procedures, such as transcatheter valve therapies and cardiac ablation for arrhythmias. They say that providing a live 3D view could help improve accuracy and reduce the risk of complications during cardiac interventions. And, the improved visualization could shorten the time needed for interventional procedures, which currently can take several hours to complete due to their complex nature and limited ability to see inside the heart.

“Unlike other silicon-based ultrasound devices, this microarray technology combines the performance benefits of conventional piezoelectric devices with the miniaturization and manufacturing efficiency of semiconductor microfabrication,” said study lead David Dausch, PhD, Technical Director at RTI.

Existing intracardiac echo catheters produce two-dimensional image “slices” that limit a surgeon’s field of view. Using innovative matrix transducer array technology, LVI produces ultrasound arrays with up to 512 piezoelectric elements, 8 times more than conventional 2D ultrasound catheters. (See Figure 1) This offers a much wider field of view with a high frame rate and deep penetration depth which allows the surgeon to see many angles of the heart.

The first ever real-time 3D ultrasound images with field-of-view of 60 by 60 degrees were obtained in a live porcine model with frame rates of up to 30 volumes per second.

RTI teamed with a medical device consultant, Dr. Paul Zalesky, to form Envisage Medical, Inc., a startup company aimed at developing the volumetric imaging system. According to Zalesky, the silicon-based manufacturing platform will reduce cost, ultimately providing 3D imaging at a cost lower than today’s 2D imaging. In addition, RTI is collaborating with Dr. Kalyanam Shivkumar, Director and Chief of Interventional Cardiovascular Programs at UCLA Medical Center, with the goal of implementing this technology in the catheter lab.

The project team’s next steps are to integrate the 3D catheters onto a clinical ultrasound system and demonstrate efficacy in a series of animal studies. The team hopes that in the near future its real-time volumetric imaging technology can be used by interventional cardiologists to guide the repair and replacement of heart valves, correction of dangerous arrhythmias, and other least invasive cardiac procedures.

Medical Design Briefs Magazine

This article first appeared in the April, 2015 issue of Medical Design Briefs Magazine.

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