Improved Nerve Visualization in Head and Neck Surgery Using Mueller Polarimetric Imaging: Preclinical Feasibility Study in a Swine Model

Abstract

Background and ObjectivesMeticulous dissection and identification of nerves during head and neck surgery are crucial for preventing nerve damage. At present, nerve identification relies heavily on the surgeon's knowledge of anatomy, optionally combined with intraoperative neuromonitoring. Recently, optical techniques such as Mueller polarimetric imaging (MPI) have shown potential to improve nerve identification.Study Design/Materials and MethodsWith institutional approval, seven 25–35 kg Yorkshire pigs underwent cervical incision in the central neck. Intraoperative images were obtained using our in‐house MPI system. Birefringence maps from the MPI system were processed to quantify the values between 0 and 255 from different tissue types; an active contour model was applied to further improve nerve visualization on the corresponding color images.ResultsAmong the seven pigs, the vagus nerves and recurrent laryngeal nerves were successfully differentiated with a mean intensity of 130.954 ± 20.611, which was significantly different (P < 0.05) from those of arteries (78.512 ± 27.78) and other surrounding tissues (82.583 ± 35.547). There were no imaging‐related complications during the procedure. © 2021 Wiley Periodicals LLC.ConclusionsMPI is a potentially complementary intraoperative tool for nerve identification in adjacent tissues.

Label-free intraoperative nerve detection and visualization using ratiometric diffuse reflectance spectroscopy

“…Adding polarization imaging capabilities could further improve the label-free discriminatory power of the current approach. As fat accounted for many of the false positives in the fiber-based studies and reduced the SBR in the imaging data, incorporating polarization could further help distinguish fat from nerve based on the intrinsic depolarization and birefringence of fat and nerve respectively 36 – 39 . Moreover, orthogonal polarization filtering would also significantly reduce the contributions of specular reflections in clinical imaging systems as seen with the animal imaging pictures (Fig.…”

“…In order to provide adequate spatial resolution for nerve visualization, a variety of optical techniques are being evaluated including photoacoustic imaging 24 , 25 , optical coherence tomography 26 , 27 , fluorescence imaging 28 – 32 , non-linear imaging 33 – 35 , and polarization imaging 36 – 39 . Many of these techniques are limited by expensive and/or technically complex instrumentation, intricate image and/or postprocessing, slow imaging speeds, or the administration of exogenous contrast agents.…”

DXM-TransFuse U-net: Dual Cross-Modal Transformer Fusion U-net for Automated Nerve Identification

“…The ventral portion of the superficial neck muscle was exposed. Vagus nerves, recurrent laryngeal nerves, and superior laryngeal nerves were dissected and targeted for imaging using an in-house dual-RGB/polarimetric imaging system (Ning et al, 2021) similar to the previous work (Cha et al, 2018).…”

“…However, this tech-nique requires intermittent electrical stimulations via an electrode probe to confirm the neuromuscular activity, which can interrupt surgical workflows. As an alternative, our group recently proposed and successfully demonstrated an optical imaging nerve identification using the Mueller polarimetric imaging (Ning et al, 2021), which calculates intrinsic birefringence patterns from fibrous nerve structures. In our previous study (Ning et al, 2021), the system showed a promise but had a limitation of nerve-specific segmentation due to the presence of similar birefringence signals from other surrounding fibrous anatomies of tendons and collagenous muscle tissues.…”

“…As an alternative, our group recently proposed and successfully demonstrated an optical imaging nerve identification using the Mueller polarimetric imaging (Ning et al, 2021), which calculates intrinsic birefringence patterns from fibrous nerve structures. In our previous study (Ning et al, 2021), the system showed a promise but had a limitation of nerve-specific segmentation due to the presence of similar birefringence signals from other surrounding fibrous anatomies of tendons and collagenous muscle tissues. Therefore, we concluded that more advanced image processing with larger imaging data would further improve the specificity of the optical nerve identification.…”