ABSTRACT
?AIM:To compare the coherence and difference on the fundus examination made with two kinds of optical coherence tomography ( OCT): Angio-OCT and fourier domain-optical coherence tomography ( FD-OCT) .?METHODS:Using Angio-OCT and FD-OCT to measure the retinal nerve fiber layer ( RNFL ) thickness, optic parameters, and ganglion cell complexes ( GCC ) thickness from 20 subjects respectively.The coherence was tested with Pearson's correlation coefficient, the difference was tested with paired Student t testing.?RESULTS:The total correlation of the RNFL thickness, optic parameters, GCC thickness made with two kinds of OCT was between 0.7-0.8;the RNFL thickness, optic disk area etc.made with the Angio-OCT were lower than those made with FD-OCT except for the GCC thickness.?CONCLUSION: The results made with two kinds of OCT from the same subject has certain coherence, but cannot be compared directly.
ABSTRACT
<p><b>BACKGROUND</b>In vivo quantification of choroidal neovascularization (CNV) based on noninvasive optical coherence tomography (OCT) examination and in vitro choroidal flatmount immunohistochemistry stained of CNV currently were used to evaluate the process and severity of age-related macular degeneration (AMD) both in human and animal studies. This study aimed to investigate the correlation between these two methods in murine CNV models induced by subretinal injection.</p><p><b>METHODS</b>CNV was developed in 20 C57BL6/j mice by subretinal injection of adeno-associated viral delivery of a short hairpin RNA targeting sFLT-1 (AAV.shRNA.sFLT-1), as reported previously. After 4 weeks, CNV was imaged by OCT and fluorescence angiography. The scaling factors for each dimension, x, y, and z (μm/pixel) were recorded, and the corneal curvature standard was adjusted from human (7.7) to mice (1.4). The volume of each OCT image stack was calculated and then normalized by multiplying the number of voxels by the scaling factors for each dimension in Seg3D software (University of Utah Scientific Computing and Imaging Institute, available at http://www.sci.utah.edu/cibc-software/seg3d.html). Eighteen mice were prepared for choroidal flatmounts and stained by CD31. The CNV volumes were calculated using scanning laser confocal microscopy after immunohistochemistry staining. Two mice were stained by Hematoxylin and Eosin for observing the CNV morphology.</p><p><b>RESULTS</b>The CNV volume calculated using OCT was, on average, 2.6 times larger than the volume calculated using the laser confocal microscopy. The correlation statistical analysis showed OCT measuring of CNV correlated significantly with the in vitro method (R 2 =0.448, P = 0.001, n = 18). The correlation coefficient for CNV quantification using OCT and confocal microscopy was 0.693 (n = 18, P = 0.001).</p><p><b>CONCLUSIONS</b>There is a fair linear correlation on CNV volumes between in vivo and in vitro methods in CNV models induced by subretinal injection. The result might provide a useful evaluation of CNV both for the studies using CNV models induced by subretinal injection and human AMD studies.</p>