Alexander C Wright1, Jonathon H Yoder2, Edward J Vresilovic3, Dawn M Elliott4. 1. Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA. alexander.wright@uphs.upenn.edu. 2. Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA, USA. 3. Department of Orthopaedics and Rehabilitation, Pennsylvania State University, Hershey, PA, USA. 4. Department of Biomedical Engineering, University of Delaware, Newark, DE, USA.
Abstract
OBJECTIVE: Here we develop a three-dimensional analytic model for MR image contrast of collagen lamellae in the annulus fibrosus of the intervertebral disc of the spine, based on the dependence of the MRI signal on collagen fiber orientation. MATERIALS AND METHODS: High-resolution MRI scans were performed at 1.5 and 7 T on intact whole disc specimens from ovine, bovine, and human spines. An analytic model that approximates the three-dimensional curvature of the disc lamellae was developed to explain inter-lamellar contrast and intensity variations in the annulus. The model is based on the known anisotropic dipolar relaxation of water in tissues with ordered collagen. RESULTS: Simulated MRI data were generated that reproduced many features of the actual MRI data. The calculated inter-lamellar image contrast demonstrated a strong dependence on the collagen fiber angle and on the circumferential location within the annulus. CONCLUSION: This analytic model may be useful for interpreting MR images of the disc and for predicting experimental conditions that will optimize MR image contrast in the annulus fibrosus.
OBJECTIVE: Here we develop a three-dimensional analytic model for MR image contrast of collagen lamellae in the annulus fibrosus of the intervertebral disc of the spine, based on the dependence of the MRI signal on collagen fiber orientation. MATERIALS AND METHODS: High-resolution MRI scans were performed at 1.5 and 7 T on intact whole disc specimens from ovine, bovine, and human spines. An analytic model that approximates the three-dimensional curvature of the disc lamellae was developed to explain inter-lamellar contrast and intensity variations in the annulus. The model is based on the known anisotropic dipolar relaxation of water in tissues with ordered collagen. RESULTS: Simulated MRI data were generated that reproduced many features of the actual MRI data. The calculated inter-lamellar image contrast demonstrated a strong dependence on the collagen fiber angle and on the circumferential location within the annulus. CONCLUSION: This analytic model may be useful for interpreting MR images of the disc and for predicting experimental conditions that will optimize MR image contrast in the annulus fibrosus.
Authors: Jonathon H Yoder; John M Peloquin; Gang Song; Nick J Tustison; Sung M Moon; Alexander C Wright; Edward J Vresilovic; James C Gee; Dawn M Elliott Journal: J Biomech Eng Date: 2014-11 Impact factor: 2.097
Authors: Alexander C Wright; Rostislav Lemdiasov; Thomas J Connick; Yusuf A Bhagat; Jeremy F Magland; Hee Kwon Song; Steven P Toddes; Reinhold Ludwig; Felix W Wehrli Journal: J Magn Reson Date: 2011-02-23 Impact factor: 2.229
Authors: Richard Kasch; Birger Mensel; Florian Schmidt; Wolf Drescher; Ralf Pfuhl; Sebastian Ruetten; Harry R Merk; Ralph Kayser Journal: PLoS One Date: 2012-07-25 Impact factor: 3.240
Authors: Amy A Claeson; Edward J Vresilovic; Brent L Showalter; Alexander C Wright; James C Gee; Neil R Malhotra; Dawn M Elliott Journal: J Biomech Eng Date: 2019-05-29 Impact factor: 2.097
Authors: Tristan Langlais; Pierre Desprairies; Raphael Pietton; Pierre-Yves Rohan; Jean Dubousset; Judith R Meakin; Peter C Winlove; Raphael Vialle; Wafa Skalli; Claudio Vergari Journal: Biomech Model Mechanobiol Date: 2019-06-20