For this study, Bell's team first placed an optical fiber inside a catheter's hollow core, with one end of the fiber connected to a laser to transmit light; this way, the optical fiber's visualization coincided with the visualization of the catheter tip.

Bell's team then performed cardiac catherization on two pigs under anesthesia and used fluoroscopy to initially map the catheter's path on its way to the heart.


Bell's team also successfully used robotic technology to hold the ultrasound probe and maintain constant visualization the photoacoustic signal, receiving image feedback every few millimeters.

Finally, the team looked at the pig's cardiac tissue after the procedures and found no laser-related damage. While the team needs to perform more experiments to determine whether the robotic photoacoustic imaging system can be miniaturized and used to navigate more complicated pathways, as well as perform clinical trials to definitively prove safety, they say these findings are a promising step forward.

"We envision that ultimately, this technology will be a complete system that serves the four-fold purpose of guiding cardiologists towards the heart, determining their precise locations within the body, confirming contact of catheter tips with heart tissue and concluding whether damaged hearts have been repaired during cardiac radiofrequency ablation procedures," says Bell.


Other authors on this study include Michelle Graham, Fabrizio Assis, Derek Allman, Alycen Wiacek, Eduardo Gonzalez, Mardava Gubbi, Jinxin Dong, Huayu Hou, Sarah Beck and Jonathan Chrispin, all of Johns Hopkins.

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