Measuring elastic contrast in tissue using OCT needle probes

Abstract

Optical coherence elastography (OCE) provides images of tissue elasticity and has potential for several clinical applications, including guidance of tumor resection. However, advancement toward clinical implementation of OCE is currently limited by the technique?s small imaging depth in tissue (1-2 mm), as well as a lack of validation of the elastic contrast generated in OCE. We have overcome the depth limitation of current OCE techniques by developing a method for performing OCE via a needle probe. Our technique, needle OCE, uses an OCT needle probe to perform axial measurements of tissue deformation during needle insertion, and has demonstrated potential for subsurface detection of the boundaries of diseased tissue. In this paper, we demonstrate how elastic contrast is generated in needle OCE by performing measurements in tissue phantoms and porcine airway wall. In addition, we have developed a finite element model of tissue deformation in compression OCE as a first step toward better understanding of the generation and interpretation of contrast in OCE images. We show initial results demonstrating excellent agreement between measured and simulated deformation in a tissue phantom.