3-modality fusion imaging may illuminate surgical guidance

Researchers at Pohang University in South Korea have demonstrated a three-modality method of fusion imaging that uses a photoacoustic component to deliver high-resolution visualization, suggesting the potential to supply comprehensive image guidance in real time during various surgeries.

Their study posted online April 24 in IEEE Transactions on Medical Imaging.

In introducing their work, Chulhong Kim, PhD, formerly of the State University of New York at Buffalo, and colleagues note that real-time fusion imaging combining pre-acquired MR images with real-time ultrasound has proven popular, most commonly as a surgical guide.

However, this dual-modality approach is suboptimal due to ultrasound’s being limited to displaying structural information with relatively low resolution, the authors point out.

The Pohang team added photoacoustic imaging to the ultrasound/MR combo, integrating the three modalities with an optical tracking-based navigation subsystem.

Photoacoustic imaging uses a pulsed laser to produce mechanical energy in soft tissue caused by molecular vibrations that indicate the thermal absorption of the light. Anatomic structures are visualized via algorithmic reconstructions of energy distributions across the structure.

The authors showed that, through co-registration of pre-acquired MR and real-time photoacoustic/ultrasound images, overlaid images from all three can be concurrently displayed in real time.

“We successfully acquired fusion images from a phantom and a blood vessel in a human forearm,” they write in their abstract. “This fusion imaging can complementarily delineate the morphological and vascular structure of tissues with good contrast and sensitivity, has a well-established user interface and can be flexibly integrated with clinical environments.”