Abstract
Purpose::
To test the hypothesis that manganese-enhanced MRI (MEMRI) is a sensitive approach for simultaneously, non-invasively, and quantitatively correlating several key in vivo age-related changes in anterior and posterior segments in the DBA/2J mouse model of closed-angle glaucoma.
Methods::
In light adapted 3 mo C57BL/6 (n = 11) and DBA/2J (n = 9) mice, and in 10 month DBA/2J (n = 6) mice, 23.4 µm in-plane resolution MEMRI data were collected after MnCl2 injection i.p. From each image, chamber angle, ciliary body area, optic nerve head width, total and inner thickness in central and peripheral retina, and eye perimeter were measured. In addition, signal intensities in anterior and vitreous chambers were compared.
Results::
The 3 mo DBA/2J group had a significantly (P < 0.05) thinner inner retina and larger (P < 0.05) ocular perimeter than age-matched C57BL/6 mice; no statistical differences between the other parameters were noted. Considering both groups together, inner retinal thickness and perimeter were correlated (r = -0.77, P = 0.0001). Comparisons of 3 mo and 10 mo DBA/2J mice revealed the following significant (P < 0.05) changes with aging: total and inner retinal thinning, increased ocular perimeter, decreased ciliary body area, increased optic nerve head width, decreased chamber angle, and increased anterior chamber intensity; vitreous intensity was not different (p > 0.05). Considering both DBA/2J groups together, ocular perimeter was correlated with total (r = -0.74, P = 0.002) and inner (r = -0.83, P = 0.0001) retinal thickness, ciliary body area (r = -0.77, P = 0.0007), optic nerve head width (r = 0.80,P = 0.001), chamber angle (r = -0.92, P < 0.00001), and anterior intensity(r = 0.65, P = 0.009), but not vitreous intensity (r = -0.2, P = 0.45).
Conclusions::
Detection of changes in key ocular parameters in the DBA/2J mouse highlights MEMRI as a powerful tool for correlating structural and functional ocular responses to glaucomatous stressors in vivo.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina • anatomy