MR elastography of the ex vivo bovine globe.
OBJECTIVE
To evaluate the feasibility of using MR elastography (MRE) to assess the mechanical properties of the eye.


METHODS
The elastic properties of the corneoscleral shell of an intact, enucleated bovine globe specimen were estimated using MRE and finite element modeling (FEM), assuming linear, isotropic behavior. The two-dimensional (2D), axisymetric model geometry was derived from a segmented 2D MR image, and estimations of the Young's modulus in both the cornea and sclera were made at various intraocular pressures using an iterative flexural wave speed matching algorithm.


RESULTS
Estimated values of the Young's moduli of the cornea and sclera varied from 40 to 185 kPa and 1 to 7 MPa, respectively, over an intraocular pressure range of 0.85 to 9.05 mmHg (1.2 to 12.3 cmH(2)O). They also varied exponentially as functions of both wave speed and intraocular dP/dV, an empirical measure of "ocular rigidity."


CONCLUSIONS
These results show that it is possible to estimate the intrinsic elastic properties of the corneoscleral shell in an ex vivo bovine globe, suggesting that MRE may provide a useful means to assess the mechanical properties of the eye and its anatomy. Further development of the technique and modeling process will enhance its potential, and further investigations are needed to determine its clinical potential.
Litwiller
Daniel V
DV
Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
Lee
Sung J
SJ
Kolipaka
Arunark
A
Mariappan
Yogesh K
YK
Glaser
Kevin J
KJ
Pulido
Jose S
JS
Ehman
Richard L
RL
D000818:Animals; D002417:Cattle; D003315:Cornea / Q000033:anatomy & histology / Q000502:physiology*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005240:Feasibility Studies