Browsing by Subject "Endoscopy"

Minimally invasive surgical procedures using arthroscopic, catheterized, or laparoscopic devices are an increasingly preferred alternative to more labor-intensive open surgeries and typically associated with less pain, shorter hospital stays and fewer complications [1, 2]. However, these surgical models rely heavily on a combination of preoperative imaging and white-light intraoperative imaging technologies for guidance, which often severely limit the surgeon's depth perception and visualization of critical surface and sub-surface anatomy during endoscopic surgery.Optical coherence tomography (OCT) is a noninvasive optical imaging technique that captures volumetric imaging data of tissues at nearly cellular resolution [3]. Endoscopic OCT presents significant advantages over traditional white-light intraoperative imaging technologies enabling real-time volumetric visualization and quantitative feedback during surgery [4]. However, although this technology has been well demonstrated in research settings, endoscopic OCT has yet to find widespread use in the operating suite. This is primarily due to a lack of effective instrumentation for obtaining adequate depth penetration in highly scattering tissue, surgical/ergonomic useability in a minimally invasive setting, and a limited proof-of-concept demonstrations in non-retinal tissues. To address these challenges, this dissertation presents a collection of scientific works to extend the range of OCT for surgery by v adapting low-cost OCT technology and a dual-axis architecture to solve unmet clinical needs. First, a method for extending the imaging plane of a low-cost OCT system using a commercially available narrow rigid borescope is reported. This approach enables the application of the system in otherwise hard-to-access regions necessary for endoscopic adoption. This design's clinical potential is demonstrated by quantifying articular cartilage thickness, a primary biomarker of joint health during osteoarthritis (OA), for real-time feedback during arthroscopic surgery at a substantial reduction in cost compared to current protocols. Second, OCT is applied to evaluate the small bowel tissues of two rhesus macaques undergoing intestinal transplantation of the ileum using a handheld surgical probe. The correspondence between traditional assessment from routine histological observation and structures visualized with OCT were compared to assess the diagnostic capabilities of OCT for revealing changes associated with intestinal transplant rejection. Third, the image penetration of OCT is extended at a clinically relevant scale by adopting Dual-Axis OCT (DA-OCT) technology for increased depth priority in highly-scattering media. OCT imaging past 2 mm is measured using 1.3 μm wavelengths and enhanced depth of field (DOF) using a dynamic focusing method. Deep imaging performance for DA-OCT and conventional OCT is extensively compared using contrast-to-noise (CNR) analysis, highlighting the importance of high-order scattering anisotropy in tissue to maintain DA-OCT's depth advantage. Finally, DA-OCT vi is translated from a proof-of-concept research device into a low-cost and portable handheld device suitable for adoption in the operating suite. A handheld deep-tissue imaging device was developed with a narrow distal profile required for oral surgery. Preliminary studies are reported to validate the system's ability to image dental tissue. By making OCT more accessible and expanding the range of tissues that may be evaluated in vivo, these advancements demonstrate the potential of OCT for broad EMIS adoption.