Optical System to Identify Preterm Labor Receives Patent

JOEL WILLIAMS, ASSOCIATE EDITOR
joel.williams@photonics.com

Jessica Ramella-Roman of Florida International University (FIU) received a patent for an optical technology designed to identify preterm labor. The patent is the culmination of years of research into polarized light and its utility in the study of tissue.

Determinations of preterm labor typically use an ultrasound to measure cervical length to assess preterm risk. The new technology instead looks at the collagen fibers that compose 70% of the cervix. Collagen fibers are birefringent and are aligned around the cervical os, which is the orifice providing access to the uterus. During birth, the cervix undergoes a process that changes it from a rather rigid closed structure to a more pliant one to provide safe passage of the fetus.

“The polarization signature that is present in the nonpregnant cervix is gradually lost during pregnancy,” Ramella-Roman told Photonics Media. “This is what we use to determine a pathologic occurrence. Since premature cervical remodeling resulting from structural defects, infection, or unknown causes precedes the onset of preterm birth, we believe that this signature could be used to determine preterm birth risks.”

The device is composed of two main components, an LED-based illuminator capable of switching between different states through two liquid crystal variable waveplates and a camera that is also fitted with two liquid crystal variable waveplates and a polarizer. This is a typical layout of a Mueller matrix polarimeter, Ramella-Roman said. “The illuminator switches sequentially through four illumination polarization states, and for each incident polarization we collect four images at different polarization.”

Ramella-Roman and her team continue to advance and refine the technology. The team is currently building a hand-held, insertable colposcope with Mueller matrix capability using polarized cameras and an LED-based ring illuminator, as opposed to liquid crystal variable waveplates. The development is a collaboration with the University of Miami.