title: Monitoring of cornea elastic properties changes during UV-A/riboflavin-induced corneal collagen cross-linking using supersonic shear wave imaging: a pilot study.
abstract: OBJECTIVE
  Keratoconus disease or post-LASIK corneal ectasia are increasingly treated using UV-A/riboflavin-induced corneal collagen cross-linking (CXL). However, this treatment suffers from a lack of techniques to provide an assessment in real-time of the CXL effects. Here, we investigated the potential interest of corneal elasticity as a biomarker of the efficacy of this treatment.
  
  
  METHODS
  For this purpose, supersonic shear wave imaging (SSI) was performed both ex vivo and in vivo on porcine eyes before and after CXL. Based on ultrasonic scanners providing ultrafast frame rates (~30 kHz), the SSI technique generates and tracks the propagation of shear waves in tissues. It provides two- and three-dimensional (2-D and 3-D) quantitative maps of the corneal elasticity.
  
  
  RESULTS
  After CXL, quantitative maps of corneal stiffness clearly depicted the cross-linked area with a typical 200-μm lateral resolution. The CXL resulted in a 56% ± 15% increase of the shear wave speed for corneas treated in vivo (n = 4).
  
  
  CONCLUSIONS
  The in vivo CXL experiments performed on pigs demonstrated that the quantitative estimation of local stiffness and the 2-D elastic maps of the corneal surface provide an efficient way to monitor the local efficacy of corneal cross-linking.
authors.affiliation: Institut Langevin Ondes et Images, ESPCI ParisTech, Paris, France. thu-mai.nguyen@espci.fr
authors.forename: Thu-Mai
authors.initials: TM
authors.lastname: Nguyen
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Aubry
authors.forename: David
authors.initials: D
authors.lastname: Touboul
authors.forename: Mathias
authors.initials: M
authors.lastname: Fink
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Gennisson
authors.forename: Jeremy
authors.initials: J
authors.lastname: Bercoff
authors.forename: Mickael
authors.initials: M
authors.lastname: Tanter
mesh_terms: D000818:Animals; D003094:Collagen / Q000378:metabolism*; D003315:Cornea / Q000187:drug effects / Q000502:physiology*; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D004548:Elasticity / Q000502:physiology*; D054459:Elasticity Imaging Techniques; D008991:Monitoring, Physiologic; D017319:Photosensitizing Agents / Q000494:pharmacology*; D010865:Pilot Projects; D012256:Riboflavin / Q000494:pharmacology*; D013552:Swine; D014463:Ultrasonography; D014466:Ultraviolet Rays
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin