Assessment of retinal disruption
Systems and methods for improving the assessment of disruption or abnormalities to retinal layers are presented. The disruptions are detected by analyzing at least one segmented boundary of optical coherence tomography data. Several different types of analysis can be used alone or in combination to make an assessment of the level of disruption to the particular boundary or layer defined by the boundary. The results can be presented as an end face image and quantified to report an amount of disruption. In one embodiment, a method for determining the disruption to the photoreceptor outer segment is described.
1. A method of analyzing 3D optical coherence tomography imaging data of an eye of a patient, said method comprising:
collecting OCT image data over a plurality of transverse locations of the retina of a patient;
segmenting the 3D data to identify boundaries associated with the retinal pigment epithelium (RPE), the photoreceptor inner segment (IS) and the photoreceptor outer segment (OS);
calculating the photoreceptor outer segment thickness and the variability of the thickness of the photoreceptor outer segment based on the differences in the depths of the RPE and the IS/OS boundary;
generating an index value at each of a plurality of transverse locations said index values corresponding to an integrated assessment of disruption, said index values being generated by combining the calculated photoreceptor outer segment thickness and the variability of thickness of the photoreceptor outer segment at each of the plurality of transverse locations using a factor associated with each selected parameter, said factor being based on the weight that the analysis of that parameter has on the overall determination of disruption;
generating an en face image based upon the generated index values; and
displaying the en face image.
2. The method as recited in claim 1 , further comprising comparing the calculated parameters to expected values at a plurality of transverse locations and displaying an en face image of the comparison, said expected values being determined based on a collection of normative data.
3. The method as recited in claim 2 , further comprising quantifying the amount of disruption and displaying the amount.
4. The method as recited in claim 1 , further comprising weighting the parameters based on the transverse location within the retina.
5. The method as recited in claim 4 , further comprising determining the percentage of disruption and displaying the percentage.
6. The method as recited in claim 1 , where the en face image of disruption is presented in a manner that is aligned to an image that contains anatomical information, such as a fundus image that shows blood vessels and the optic disc.
7. A method of analyzing 3D optical coherence tomography imaging data of an eye of a patient, said method comprising:
collecting OCT image data over a plurality of transverse locations of the retina of a patient;
segmenting the 3D data to identify the boundaries associated with the Ganglion Cell Layer (GCL) and the Nerve Fiber Layer (NFL);
calculating the thicknesses of the GCL and the NFL;
generating an index value at each of a plurality of transverse locations, said index values corresponding to a statistically estimated likelihood of abnormality, said index values being generated by combining the calculated GCL and NFL thicknesses in view of a map of local correlations between each macular location and a set of peripapillary locations;
generating an en face image based upon the generated index values; and
displaying the en-face image.
8. The method as recited in claim 7 , further comprising comparing the index values to expected values, said expected values being determined based on a collection of normative data.
9. The method as recited in claim 7 , where the en face image is presented in a manner that is aligned to an image that contains anatomical information, such as a fundus image that shows blood vessels, neovascular membranes, the optic disc or the fovea.