Multi-Spectral Imaging (MSI) enables improved visual discrimination of retinal and sub-retinal structures through spectral and depth-enhanced differential visibility, using manual and automated processing to highlight targeted features for examination.
The capability of capturing images at a number of wavelengths allows additional information to be extracted by comparing these images by visual inspection or automation. Figures 1 (a), (b), and (c) show three images of the same area of the retina from a patient with diabetic retinopathy (DR). As one moves from the green (a) through the amber (b) to the red (c) wavelengths, intraretinal hemorrhages are highlighted differently. The green wavelength (a) highlights the nerve fiber layers while the red wavelength (c) highlights the deep layers.
Figure 1 (a)
Figure 1 (b)
Figure 1 (c)
The next series of multi-spectral images is from a patient with a choroidal neovascular membrane (CNVM). In the five images, the CNVM can be seen clearly with subtle and systematic differences emerging as the wavelengths increase from short in Figure 2(a) to long in Figure 2(e).
Figure 2 (a)
Figure 2 (b)
Figure 2 (c)
Figure 2 (d)
Figure 2 (e)
An example of automated processing can be seen below in Figure 3. This is an MSI oxy/deoxy hemoglobin map of neovascularization of the disc associated with diabetic retinopathy. Hyper-reflective (bright) oxygenated vessels are seen overlying the optic nerve.