Quantified elasticity mapping of retinal layers using synchronized acoustic radiation force optical coherence elastography - PubMed (original) (raw)

. 2018 Aug 2;9(9):4054-4063.

doi: 10.1364/BOE.9.004054. eCollection 2018 Sep 1.

Affiliations

Quantified elasticity mapping of retinal layers using synchronized acoustic radiation force optical coherence elastography

Yueqiao Qu et al. Biomed Opt Express. 2018.

Abstract

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly (over the age of 60 years) in western countries. In the early stages of the disease, structural changes may be subtle and cannot be detected. Recently it has been postulated that the mechanical properties of the retina may change with the onset of AMD. In this manuscript, we present a novel, non-invasive means that utilizes synchronized acoustic radiation force optical coherence elastography (ARF-OCE) to measure and estimate the elasticity of cadaver porcine retina. Both regions near the optic nerve and in the peripheral retina were studied. An acoustic force is exerted on the tissue for excitation and the resulting tissue vibrations, often in the nanometer scale, are detected with high-resolution optical methods. Segmentation has been performed to isolate individual layers and the Young's modulus has been estimated for each. The results have been successfully compared and mapped to corresponding histological results using H&E staining. Finally, 64 elastograms of the retina were analyzed, as well as the elastic properties, with stiffness ranging from 1.3 to 25.9 kPa in the ganglion to the photoreceptor sides respectively. ARF-OCE allows for the elasticity mapping of anatomical retinal layers. This imaging approach needs further evaluation but has the potential to allow physicians to gain a better understanding of the elasticity of retinal layers in retinal diseases such as AMD.

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Conflict of interest statement

Dr. Zhongping Chen has a financial interest in OCT Medical Inc., which, however, did not support this work.

Figures

Fig. 1

Fig. 1

Schematic diagram of system setup. SLD: superluminescent diode, L: lens, G: diffraction grating, CMOS: camera, C: coupler, A: attenuator, M: mirror, MS: mechanical stage, GM: galvo mirror, UT: ultrasound transducer, S: sample, RFA: radio-frequency amplifier, FG: function generator, CO: collimator. Red beam: light path. Yellow beam: ARF path.

Fig. 2

Fig. 2

Timing diagram of system showing excitation and detection.

Fig. 3

Fig. 3

Optical disc and peripheral retina imaging. a) OCT cross-section of optical disc. b) OCE phase cross-section of optical disc. c) OCT cross-section of peripheral retina. d) OCE phase cross-section of peripheral retina. Phase is measured in radians from 0 to 5. White arrow indicates ganglion side and yellow arrow points to the photoreceptor side.

Fig. 4

Fig. 4

Retina segmentation and elastogram. a) OCT segmentation. b) Corresponding segments of OCE displacement mapping. c) Corresponding elastogram. d) H&E staining of porcine retina with the anatomical layers labeled. White arrow point to outer nuclear layer region with low elasticity. Blue arrow point to outer nuclear layer portion with high elasticity.

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