title: Effect of image registration on longitudinal analysis of retinal nerve fiber layer thickness of non-human primates using Optical Coherence Tomography (OCT).
abstract: BACKGROUND
  In this paper we determined the benefits of image registration on estimating longitudinal retinal nerve fiber layer thickness (RNFLT) changes.
  
  
  METHODS
  RNFLT maps around the optic nerve head (ONH) of healthy primate eyes were measured using Optical Coherence Tomography (OCT) weekly for 30 weeks. One automatic algorithm based on mutual information (MI) and the other semi-automatic algorithm based on log-polar transform cross-correlation using manually segmented blood vessels (LPCC_MSBV), were used to register retinal maps longitudinally. We compared the precision and recall between manually segmented image pairs for the two algorithms using a linear mixed effects model.
  
  
  RESULTS
  We found that the precision calculated between manually segmented image pairs following registration by LPCC_MSBV algorithm is significantly better than the one following registration by MI algorithm (p < <0.0001). Trend of the all-rings and temporal, superior, nasal and inferior (TSNI) quadrants average of RNFLT over time in healthy primate eyes are not affected by registration. RNFLT of clock hours 1, 2, and 10 showed significant change over 30 weeks (p = 0.0058, 0.0054, and 0.0298 for clock hours 1, 2 and 10 respectively) without registration, but stayed constant over time with registration.
  
  
  CONCLUSIONS
  The LPCC_MSBV provides better registration of RNFLT maps recorded on different dates than the automatic MI algorithm. Registration of RNFLT maps can improve clinical analysis of glaucoma progression.
authors.affiliation: Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712 USA ; Present address: Clinical Neuroscience Imaging Center (CNIC), Department of Neurology, Yale School of Medicine, New Haven, CT 06510 USA.
authors.forename: Shuang
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78712 USA.
authors.forename: Anjali
authors.initials: A
authors.lastname: Datta
authors.affiliation: Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712 USA.
authors.forename: Derek
authors.initials: D
authors.lastname: Ho
authors.affiliation: Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712 USA.
authors.forename: Jordan
authors.initials: J
authors.lastname: Dwelle
authors.affiliation: Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78712 USA.
authors.forename: Daifeng
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712 USA.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Milner
authors.affiliation: Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712 USA.
authors.forename: Henry Grady
authors.initials: HG
authors.lastname: Rylander
authors.affiliation: Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712 USA ; Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA.
authors.forename: Mia K
authors.initials: MK
authors.lastname: Markey
keywords: Glaucoma; Image registration; Retinal nerve fiber layer thickness