The Education Resource Fund’s (www.ERF.Science) human embryo and fetus imagery was initially derived by teams of physician researchers and clinicians employing endoscopy (and its subsets, embryoscopy and fetoscopy) to diagnose and treat prenatal disorders in utero. Endoscopes are medical imaging devices which permit the minimally invasive, high resolution observation of tissues inside the human body. At the distal end of these instruments is an objective lens designed for imaging. At the proximal end is an eyepiece, or sensor, which enables viewing.

HOW THEY WORK

These scopes generally consist of a tube which encloses a relay lens system (in rigid endoscopes) or a fiber bundle (for fiber-optic, or flexible, endoscopes) for illumination and to transmit an image from the objective lens inside the body to the proximal end outside.

Said differently, endoscopes use optical elements to direct light to the area sought to be illuminated and transmit the resulting image to the eye or detector. Rigid endoscopes generally offer superior resolution or magnification. But an endoscope’s objective lens is only approximately 1/5 of an inch in diameter, and this relatively small size substantially narrows the observer’s field of view (even with the addition of supplemental lenses such as “negative” or “prism” optics, etc.).

CONSTRAINTS

This limitation is further compounded by the need to use the scope in very confined spaces, with only short distances separating the objective lens from the anatomical structures being imaged. As a consequence, only a small segment of the embryo or fetus is observable at any point along the timeline of the scan. An endoscope’s construction must also accommodate frequently conflicting design considerations. The resulting compromises can involve not only fields of view, but depths of field (meaning thickness of the plane of focus) and image illumination and magnification, as well as distortion issues (i.e., stretched or compressed perspective), etc.

WORK-AROUNDS

So to depict a high quality, single image of the entire embryo or fetus, large numbers of smaller, more detailed pictures must be joined together in a manner suggestive of the process by which puzzle pieces are assembled to form a completed picture.

This technique employs a complex proprietary process which combines segmental scans to create a final composite image. The resulting picture is digitally adjusted to preserve each segment’s original color, resolution, contrast, illumination, etc. Technicians also correct for vignetting (image degradation or loss at the periphery of the frame).