Optical coherence tomography of the rat cavernous nerves

Abstract

Improvements in identification, imaging, and visualization of the cavernous nerves during radical prostatectomy, which are responsible for erectile function, may improve nerve preservation and postoperative potency. Optical coherence tomography (OCT) is capable of real-time, high-resolution, cross-sectional, in vivo tissue imaging. The rat prostate serves as an excellent model for studying the use of OCT for imaging the cavernous nerves, as the rat cavernous nerve is a large, visible, and distinct bundle allowing for easy identification with OCT in addition to histologic confirmation. Imaging was performed with the Niris OCT system and a handheld 8 Fr probe, capable of acquiring real-time images with 11-&mgr;m axial and 25-&mgr;m lateral resolution in tissue. Open surgical exposure of the prostate was performed on a total of 6 male rats, and OCT images of the prostate, cavernous nerve, pelvic plexus ganglion, seminal vesicle, blood vessels, and periprostatic fat were acquired. Cavernous nerve electrical stimulation with simultaneous intracorporeal pressure measurements was performed to confirm proper identification of the cavernous nerves. The prostate and cavernous nerves were also processed for histologic analysis and further confirmation. Cross-sectional and longitudinal OCT images of the cavernous nerves were acquired and compared with histologic sections. The cavernous nerve and ganglion could be differentiated from the surrounding prostate gland, seminal vesicle, blood vessels, bladder, and fatty tissue. We report preliminary results of OCT images of the rat cavernous nerves with histologic correlation and erectile stimulation measurements, thus providing interpretation of prostate structures as they appear in OCT images.