Elastographic contrast generation in optical coherence tomography from a localized shear stress

Abstract

A technique for generating contrast in two-dimensional shear strain elastograms from a localized stress is presented. The technique involves generating a non-uniform, localized stress via a magnetically actuated implant. Its effectiveness is demonstrated using finite-element simulations and a phantom study provides experimental verification of this. The method is applied to a superficial cancerous lesion model represented as a stiff inclusion in normal tissue. The lesion was best distinguished from its surroundings using total shear strain elastograms, rather than individual strain components. In experimental phantom studies, the lesion was imaged using optical coherence tomography (OCT) and could still be distinguished in elastograms when not readily identifiable in standard OCT images.

Review of tissue simulating phantoms with controllable optical, mechanical and structural properties for use in optical coherence tomography

“…These additives are introduced prior to adding the catalyst. For OCT phantoms, the following scatterers have been reported: titanium dioxide [5,12,37–40], silica microspheres [30], alumina [31], and, more recently, gold nanoshells [41]. The following absorbing agents have been reported: carbon black [31] and dye [39].…”

Development of a reliable and reproducible phantom manufacturing method using silica microspheres in silicone

“…Previous studies assumed that hexane had fully evaporated prior to curing. 7,8,19 This, however, appears to be untrue as swelling and subsequent shrinking are evident after curing, from visible marks on the phantom surface, formed by the uneven shrinking of the phantom leading to its pulling away from the cast in some areas. Although swelling cannot be entirely avoided, hexane can be encouraged to evaporate prior to curing.…”

Multi-Channel Optical Coherence Elastography Using Relative and Absolute Shear-Wave Time of Flight

“…Therefore, a reconstructed A-line would consist of sections taken from four A-lines obtained at different times in the scan. The system has been used previously to create quasistatic microscopic strain images [22], and to show that propagating shear-waves can be observed and their arrival time detected manually using visual analysis of an M-mode display [23]. …”