麻豆传媒

AUSTIN, Texas -- It's possible to go inside the vasculature remotely, according to pilot studies paving the way for angiography-free virtual reality (VR) endovascular procedures and robotic automated transradial access.

"We may soon be performing treatments seeing with great clarity inside even the smallest parts of a patient's body, in ways never before possible," said Wayne Monsky, MD, PhD, of the University of Washington Medical Center in Seattle, in his presentation at the annual meeting of the (SIR).

His group used a prototype catheter guided through a 3D-printed model of abdominopelvic vasculature while the operator watched from the catheter's perspective via holographic images created from CT angiography.

Compared with standard fluoroscopy, VR guidance made it significantly faster to steer from the femoral artery to the following vessels:

• Gastroduodenal artery: 17.6 vs 70.3 sec for fluoroscopy
• Right hepatic artery: 22.6 vs 73.5 sec
• Splenic arteries: 18.6 vs 66.1 sec

Monsky noted that operators who tested out this system said in a survey that it was easy to use and precise in most cases -- albeit unpleasant sometimes due to motion sickness.

Nevertheless, VR guidance has the potential to reduce X-ray exposure and to improve the ergonomics of interventional work, he suggested.

At the same SIR session, another group showed how they could mount an ultrasound probe on a robotic arm and have it automatically track the radial artery of a phantom arm from proximal to distal positions, as described by Matthew Czar Taon, MD, of Kaiser Permanente Los Angeles Medical Center.

The finding of a root mean squared error of 1.12 mm from the artery center was "favorable for our feasibility study" but means the technology may not be accurate enough for small arteries measuring 2 or 3 mm, Taon acknowledged.

The question, he said, was "Can we just remain in the vessel lumen itself?" and the robot did for the most part, as guided by a tracking algorithm based on grayscale pulsation and color flow. This algorithm had been trained and validated from sonograms of eight real people.

Another experiment found that the robotic arm was able to perform the Barbeau test on humans when equipped with a plethysmographic and pulse oximeter clamp sensor.

Finally, robot-assisted transradial access is a possibility as Taon's system -- having now been fit with a linear rail that advances a 21-G radial access needle -- was able to access the phantom radial artery with 0.2-mm accuracy, he told the audience.

The feasibility study lays the groundwork for the development of a completely automated robot-assisted percutaneous vascular access device, the researcher said.