Reengineering a falloposcope imaging system for clinical use

Abstract

High-grade serous carcinoma of the ovary is believed to originate in the fallopian tubes (FTs). A submillimeter diameter endoscope with advanced imaging capabilities may take advantage of the natural pathway of the female reproductive tract to image the FTs in a minimally invasive procedure for early detection of cancer. Our lab previously built a prototype benchtop FT endoscope with pseudowhite light imaging, multispectral fluorescence imaging and optical coherence tomography. This endoscope was approximately 0.9 mm in diameter, flexible and steerable in one direction. Several modifications have been made to create a falloposcope imaging system which is ready for clinical use. This new design includes a multilumen extrusion, a revised handle design, simplified lens design and redesigned subsystems resulting in improved mechanical characteristics, biocompatibility and portability while maintaining image quality. Additionally, these clinical endoscopes are single use, considerably less expensive and faster to build as compared to the prototype.

Sub-millimeter endoscope demonstrates feasibility of in vivo reflectance imaging, fluorescence imaging, and cell collection in the fallopian tubes

“…The handheld endoscope utilizes many of the same design principles as the single-use, multimodal falloposcope described in a previous publication from our research group. 40 However, the endoscope previously described did not have cell collection capability. The CAFE has multiple components packed into a 70-cm-long insertable body that is 0.79 mm in diameter and is connected to a handle with unidirectional steering control.…”

“…The rest of the handheld endoscope design closely follows the design of the multimodal falloposcope for clinical use detailed in our research group’s previous publication. 40 In summary, multiple sections of optically transparent, thin-walled, medical grade heat shrink tubing [Nordson Medical Corp., PN: 103-0139, Westlake, Ohio] protect the distal tip of the endoscope, bringing the total outer diameter of the insertable portion of the endoscope to 0.79 mm. Multiple layers of thicker heat shrink [Nordson Medical Corp., PN: 103-0454] tubing are used on the rest of the PEEK MLE to create a biocompatible, smooth, sterilizable surface with an overall diameter of 0.79 mm.…”

“…The image collection fiber bundle passes through a straight, central channel in the handle, whereas the illumination fiber follows a separate, lateral channel that contains a custom mode scrambler for adjusting the output angle of illumination from the endoscope. 40 A 3-m long, vinyl-encased cable connects the endoscope to the console.…”

“…Simple optical endoscopes capable of navigating the fallopian tube lumen have been demonstrated in vivo , but they have primarily been used for the assessment of tubal patency and identification of stenoses with white-light imaging. 36 – 40 They have had outer diameters as small as 0.50 mm and captured images through a 2000- to 3000-element fiber bundle with optics to obtain up to magnification. 36 – 39 To distend the fallopian tube for improved imaging performance, these devices typically used either a liquid flush, or a linear-everting balloon.…”

Design, fabrication, and preclinical testing of a miniaturized, multispectral, chip-on-tip, imaging probe for intraluminal fluorescence imaging of the gastrointestinal tract

“…[9,10] Some miniaturized systems have now provided access to millimeter-sized lumens for collecting data using autofluorescence, reflectance, and optical coherence tomography modalities. [11] While fiber endoscopes provide powerful imaging capabilities, optical fibers are both expensive and prone to damage from crushing and excess bending, which can result in a reduction in image quality. As a result, chip-on-tip endoscopy as an alternative to fiber endoscopy has gained traction, with some camera module footprints as small as 0.55 mm x 0.55 mm.…”