In vivo assessment of corneal shear anisotropy using supersonic shear wave imaging

Thu-Mai Nguyen (1) , Jean-François Aubry (1) , David Touboul (2) , Jeremy Bercoff (1) , Mickaël Tanter (3)

1 LOA - Laboratoire Ondes et Acoustique (UMR 7587)
2 Hôpital Pellegrin
3 IL - Institut Langevin - Ondes et Images (UMR7587)

The cornea is mainly composed of fibrillar collagen. The fibers organization ensures the cornea transparency and determines its biomechanics. Understanding these properties is a crucial issue in ophthalmology to improve the management of refractive surgery. Here, we propose Supersonic Shear Wave Imaging (SSI) for the in vivo assessment of the corneal elastic anisotropy. The tissue shear modulus can be retrieved from the speed of a shear wave propagating through the tissue. In the SSI technique, the shear wave is induced and tracked using an ultrafast (30000 frames/sec) ultrasonic scanner (Aixplorer, SuperSonic Imagine). We performed in vivo 3D scans on porcine eyes. Elasticity maps exhibited significantly higher shear wave speed along the horizontal meridian of the cornea (8.7 ± 0.3 m/s) than along the diagonal and vertical directions (6.6 ± 0.2 m/s). Ex vivo X-ray diffraction measurements [The Anat. Rec. 290, 1542-1550 (2007)] have shown that the collagen fibers have one preferential orientation in porcine corneas. The elasticity maps obtained in vivo using SSI are consistent with ex vivo results reported in literature, demonstrating the sensitivity of SSI to collagen fibers orientation.

Mots clés: elastography; cornea; collagen; anisotropy

Domaines: Acoustique [physics.class-ph]

Thu-Mai Nguyen, Jean-François Aubry, David Touboul, Jeremy Bercoff, Mickaël Tanter. In vivo assessment of corneal shear anisotropy using supersonic shear wave imaging. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810812⟩