title: THz and mm-Wave Sensing of Corneal Tissue Water Content:In VivoSensing and Imaging Results.
abstract: A pulsed terahertz (THz) imaging system and millimeter-wave reflectometer were used to acquire images and point measurements, respectively, of five rabbit corneain vivo. These imaging results are the first ever produced ofin vivocornea. A modified version of a standard protocol using a gentle stream of air and a Mylar window was employed to slightly dehydrate healthy cornea. The sensor data and companion central corneal thickness (CCT) measurements were acquired every 10-15 min over the course of two hours using ultrasound pachymmetry.. Statistically significant positive correlations were established between CCT measurements and millimeter wave reflectivity. Local shifts in reflectivity contrast were observed in the THz imagery; however, the THz reflectivity did not display a significant correlation with thickness in the region probed by the 100 GHz and CCT measurements. This is explained in part by a thickness sensitivity at least 10× higher in the mm-wave than the THz systems. Stratified media and effective media modeling suggest that the protocol perturbed the thickness and not the corneal tissue water content (CTWC). To further explore possible etalon effects, an additional rabbit was euthanized and millimeter wave measurements were obtained during death induced edema. These observations represent the first time that the uncoupled sensing of CTWC and CCT have been achievedin vivo.
authors.affiliation: Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA.
authors.forename: Zachary D
authors.initials: ZD
authors.lastname: Taylor
authors.affiliation: Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA.
authors.forename: James
authors.initials: J
authors.lastname: Garritano
authors.affiliation: Department of Electrical Engineering, University of California (UCLA), Los Angeles, CA 90095 USA.
authors.forename: Shijun
authors.initials: S
authors.lastname: Sung
authors.affiliation: Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA.
authors.forename: Neha
authors.initials: N
authors.lastname: Bajwa
authors.affiliation: Department of Electrical Engineering, University of California (UCLA), Los Angeles, CA 90095 USA. He is now with Fitbit, San Francisco, CA 94105 USA.
authors.forename: David B
authors.initials: DB
authors.lastname: Bennett
authors.affiliation: Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA. He is now with Mimeo Labs Inc, Santa Monica, CA 90404 USA.
authors.forename: Bryan
authors.initials: B
authors.lastname: Nowroozi
authors.affiliation: Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA. She is now with Elsevier Life Science solutions, San Francisco, CA 94105 USA.
authors.forename: Priyamvada
authors.initials: P
authors.lastname: Tewari
authors.affiliation: Department of Biostatistics, University of California (UCLA), Los Angeles, CA 90095 USA.
authors.forename: James W
authors.initials: JW
authors.lastname: Sayre
authors.affiliation: Department of Ophthalmology, University of California (UCLA), Los Angeles, CA 90095 USA.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Hubschman
authors.affiliation: Department of Ophthalmology, University of California (UCLA), Los Angeles, CA 90095 USA.
authors.forename: Sophie X
authors.initials: SX
authors.lastname: Deng
authors.affiliation: Department. of Electrical Engineering, Wright State University, Dayton, OH 45435 USA.
authors.forename: Elliott R
authors.initials: ER
authors.lastname: Brown
authors.affiliation: Department of Bioengineering, University of California (UCLA), Los Angeles, CA 90095 USA, and also with the Center for Advanced Surgical and Interventional Technology (CASIT), University of California (UCLA), Los Angeles, CA 90095 USA.
authors.forename: Warren S
authors.initials: WS
authors.lastname: Grundfest
keywords: Biological and medical imaging; clinical instruments; medical diagnostics; tissue water content interactions