Retinal Cysts are formed by leakage and accumulation of fluid in the retina due to the incompetence of retinal vasculature. These cystic spaces have significance in several ocular diseases such as age-related macular degeneration, diabetic macular edema, etc. Optical coherence tomography is one of the predominant diagnosing techniques for imaging retinal pathologies. Segmenting and quantification of intraretinal cysts plays the vital role in predicting visual acuity. In literature, several methods have been proposed for automatic segmentation of intraretinal cysts. As cystoid macular edema becomes a major problem to humankind, we need to quantify it accurately and operate it out, else it might cause many problems later on. Though research is being carried out in this area, not much of progress has been made and accuracy achieved so far is 68% which is very less. Also, the methods depend on the quality of the image and give very low results for high noise images like topcon. This work uses ResNet CNN (Convolutional Neural Network) approach of segmentation by the way of patchwise classification for training on image set from cyst segmentation challenge dataset and testing on test data set given by 2 different graders for all 4 vendors in the challenge. It also compares these methods using first publicly available novel cyst segmentation challenge dataset. The methods were evaluated using quantitative measures to assess their robustness against the challenges of intraretinal cyst segmentation. The results are found to be better than the previous state of the art approaches giving more than 70% dice coefficient on all vendors irrespective of their quality.
Figures & tables
Fig. 1: Figure(above) represents 7 intra retinal layers with cyst in it. Figure(below) shows true cystic regions in its ground truth image.
Fig. 2: Feedforward network
Fig. 3: Feedback network.
Fig. 4: Residual Network information flow.
Fig. 5: Feedforward Network vs Residual Network
Set
Cirrus
Spectralis
Topcon
Nidek
Total
Training
4
4
4
4
15
Testing 1
2
2
2
2
8
Testing 2
2
2
2
1
7
TABLE I: Description of Dataset
Fig. 6: Two actual classes or observed labels
Fig. 7: Predicted classes of a perfect classifier
Fig. 8: Predicted classes of a classifier
Fig. 9: Four outcomes of a classifier
Volume
Dice Coefficient
Sensitivity/Recall
Precision
Cirrus_1
0.8893
0.8018
0.9982
Cirrus_2
0.8156
0.6892
0.9986
Cirrus_3
0.917
0.8475
0.999
Cirrus_4
0.93
0.8721
0.9961
Mean
0.888
0.8027
0.998
Std
0.0511
0.0810
0.0013
TABLE II: Test Results for Grader 1
Volume
Dice Coefficient
Sensitivity/Recall
Precision
Cirrus 1
0.8893
0.8019
0.9981
Cirrus_2
0.8155
0.6892
0.9986
Cirrus_3
0.9171
0.8476
0.999
Cirrus_4
0.9302
0.8726
0.996
Mean
0.8880
0.8028
0.9979
Std
0.0513
0.0812
0.0013
TABLE III: Test Results for Grader 2
Volume
Dice Coefficient
Sensitivity/Recall
Precision
Cirrus 1
0.8893
0.802
0.9979
Cirrus_2
0.8154
0.6892
0.9981
Cirrus_3
0.9171
0.8477
0.9988
Cirrus_4
0.9305
0.8733
0.9957
Mean
0.8880
0.8031
0.9976
Std
0.0514
0.0814
0.0013
TABLE IV: Test Results for Grader 3 (Intersection of Grader 1 & 2)
Team
Mean Dice Coeff
Std. Deviation
de Sisternes et al
0.68
0.14
Venhuizen et al.
0.601
0.18
Oguz et al.
0.596
0.14
Esmaeili et al.
0.55
0.24
Haritz et al.
0.23
0.15
Proposed approach
0.82
0.08
TABLE V: Results of various State of art methods compared with the Proposed Approach
Dept. of CSE East West University Dhaka, Bangladesh · Dept. of CSE American International University-Bangladesh Dhaka, Bangladesh · Dept. of ICT Bangladesh Army University of Engineering and Technology Dhaka, Bangladesh