Nerve imaging tool

This project leverages our research outcome from RT-II. Our novel approach devises a new functional imaging technology to visualize a nerve map in a non-intrusive way during robotic-assisted radial proctectomy (RaRP). Our proposed imaging technology leverages the state-of-the-art VSD and electrical erectile stimulation. We anticipate that the successful development and deployment of the proposed approach will provide clear localization of nerves and NVB during RaRP, leading to an increase in successful cases and improvement in recovery time. We have recently validated this technology in an in vivo rat model. The 200µl of 1mM VSD (IR780 perchlorate) in DSMO + cremaphore solvent was directly administrated to the exposed rat prostate. After 10 min of staining, the VSD not bound to the tissue was flushed out with 2-ml PBS solution. The coherent fiber bundle (Myriad Fiber Imaging, US) comprised with 50K fiber cores was coupled to the sCMOS camera (ORCA Flash 4.0, Hamamatsu K.K., Japan) through a long-pass emission filter at 800nm (Figure 8a). For the laser illumination, a 100mW laser diode at 780nm was used. The bipolar electrical electrode was installed to the right erectogenic cavernous nerve, and 4-volt 16-Hz square-wave pulse at 5ms duration was applied for 1 min in the middle of recording. An intracavernosal pressure (ICP) was recorded to validate the stimulation of erectile function.Histopathological analysis validated the successful VSD staining through the levator fascia whose thickness is few hundred of µm. The round cross-sections of CNB were successfully differentiated (Figure 8b). Figure 8d presents that the FL images revealed the functional contrast on branching cavernous nerve branch structures with up to 10 % of F/F0 with stimulation, while it was vanished back to basal level in the post-stimulation phase.

Figure 8: Preliminary in vivo results on nerve localization on rat prostate. (a) White-light and FL images; (b) FL microscopic validation of direct VSD administration; (c) ICP; (d) F/F0 trace of sequential fluorescence frames. ICP, intracavernous pressure; CW: continuous-wave; OL, objective lens; EF, emission filter; PrG, prostate gland; N: nerve branches; MPG, major pelvic ganglion; RCN, right cavernous nerve.


  1. Kang J, Le HND, Karakus S, Malla AP, Harraz MM, Kang JU, Burnett AL, Boctor EM. Real-time, functional intra-operative localization of rat cavernous nerve network using near-infrared cyanine voltage-sensitive dye imaging. Scientific Report – Nature 2020 (accepted).