title: Automatic segmentation of microcystic macular edema in OCT.
abstract: Microcystic macular edema (MME) manifests as small, hyporeflective cystic areas within the retina. For reasons that are still largely unknown, a small proportion of patients with multiple sclerosis (MS) develop MME-predominantly in the inner nuclear layer. These cystoid spaces, denoted pseudocysts, can be imaged using optical coherence tomography (OCT) where they appear as small, discrete, low intensity areas with high contrast to the surrounding tissue. The ability to automatically segment these pseudocysts would enable a more detailed study of MME than has been previously possible. Although larger pseudocysts often appear quite clearly in the OCT images, the multi-frame averaging performed by the Spectralis scanner adds a significant amount of variability to the appearance of smaller pseudocysts. Thus, simple segmentation methods only incorporating intensity information do not perform well. In this work, we propose to use a random forest classifier to classify the MME pixels. An assortment of both intensity and spatial features are used to aid the classification. Using a cross-validation evaluation strategy with manual delineation as ground truth, our method is able to correctly identify 79% of pseudocysts with a precision of 85%. Finally, we constructed a classifier from the output of our algorithm to distinguish clinically identified MME from non-MME subjects yielding an accuracy of 92%.
authors: Department of Electrical and Computer Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA.
authors: Andrew
authors: A
authors: Lang
authors: Department of Electrical and Computer Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA ; Department of Computer Science, The Johns Hopkins University, Baltimore, MD 21218, USA.
authors: Aaron
authors: A
authors: Carass
authors: Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA.
authors: Emily K
authors: EK
authors: Swingle
authors: Department of Neurology, The Johns Hopkins School of Medicine, Baltimore, MD 21287, USA.
authors: Omar
authors: O
authors: Al-Louzi
authors: Department of Neurology, The Johns Hopkins School of Medicine, Baltimore, MD 21287, USA.
authors: Pavan
authors: P
authors: Bhargava
authors: Department of Neurology, The Johns Hopkins School of Medicine, Baltimore, MD 21287, USA.
authors: Shiv
authors: S
authors: Saidha
authors: Wilmer Eye Institute, The Johns Hopkins School of Medicine, Baltimore, MD 21287, USA.
authors: Howard S
authors: HS
authors: Ying
authors: Department of Neurology, The Johns Hopkins School of Medicine, Baltimore, MD 21287, USA.
authors: Peter A
authors: PA
authors: Calabresi
authors: Department of Electrical and Computer Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA.
authors: Jerry L
authors: JL
authors: Prince
keywords: (100.0100) Image processing; (170.4470) Ophthalmology; (170.4500) Optical coherence tomography
references: Med Image Comput Comput Assist Interv. 2014;17(Pt 1):739-46
references: 25333185
references: Lancet Neurol. 2012 Nov;11(11):963-72
references: 23041237
references: Invest Ophthalmol Vis Sci. 2014 Feb 18;55(2):952-61
references: 24398089
references: IEEE Trans Biomed Eng. 2012 Apr;59(4):1109-14
references: 22271827
references: Brain. 2013 Jul;136(Pt 7):e239
references: 23396580
references: IEEE Trans Med Imaging. 2005 Aug;24(8):929-45
references: 16092326
references: IEEE Trans Med Imaging. 2012 Aug;31(8):1521-31
references: 22453610
references: Biomed Opt Express. 2012 May 1;3(5):1127-40
references: 22567602
references: Brain. 2013 Nov;136(Pt 11):3212-4
references: 24131594
references: Invest Ophthalmol Vis Sci. 2013 Jun 27;54(6):4385-93
references: 23737469
references: Neurology. 2013 Jan 1;80(1):47-54
references: 23267030
references: Am J Ophthalmol. 2013 Feb;155(2):277-286.e1
references: 23111180
references: Ophthalmology. 2006 Feb;113(2):324-32
references: 16406539
references: Biomed Opt Express. 2013 Jun 14;4(7):1133-52
references: 23847738
references: Brain. 2010 Jun;133(Pt 6):1591-601
references: 20410146
references: Brain. 2012 Jun;135(Pt 6):1786-93
references: 22539259
references: Biomed Opt Express. 2013 Nov 01;4(12):2712-28
references: 24409375
references: Lancet Neurol. 2010 Sep;9(9):921-32
references: 20723847
references: PLoS One. 2013 Aug 06;8(8):e71145
references: 23940706