Original Research ARTICLE
Normative data and minimally detectable change for inner retinal layer thicknesses using a semi-automated OCT image segmentation pipeline
- 1NeuroCure, Charité Medical University of Berlin, Germany
- 2Experimental and Clinical Research Center, Charite University Medicine Berlin, Germany
- 3Department of Neurology with Experimental Neurology, Charité Medical University of Berlin, Germany
- 4Department of Neurology, School of Medicine, University of California, Irvine, United States
Neurodegenerative and neuroinflammatory diseases regularly cause optic nerve and retinal
damage. Evaluating retinal changes using optical coherence tomography (OCT) in diseases like
multiple sclerosis has thus become increasingly relevant. However, intraretinal segmentation,
a necessary step for interpreting retinal changes in the context of these diseases, is not
standardized and often requires manual correction. Here we present a semi-automatic intraretinal
layer segmentation pipeline and establish normative values for retinal layer thicknesses at the
macula, including dependencies on age, sex, and refractive error. Spectral domain OCT macular
3D volume scans were obtained from healthy participants using a Heidelberg Engineering
Spectralis OCT. A semi-automated segmentation tool (SAMIRIX) based on an interchangeable
third-party segmentation algorithm was developed and employed for segmentation, correction,
and thickness computation of intraretinal layers. Normative data is reported from a 6 mm Early
Treatment Diabetic Retinopathy Study (ETDRS) circle around the fovea. An interactive toolbox
for the normative database allows surveying for additional normative data. We cross-sectionally
evaluated data from 218 healthy volunteers (144 females/74 males, age 36.5±12.3 years, range
18-69 years). Average macular thickness (MT) was 313.70±12.02 μm, macular retinal nerve
fiber layer thickness (mRNFL) 39.53±3.57 μm, ganglion cell and inner plexiform layer thickness
(GCIPL) 70.81±4.87 μm, and inner nuclear layer thickness (INL) 35.93±2.34 μm. All retinal
layer thicknesses decreased with age. MT and GCIPL were associated with sex, with males
showing higher thicknesses. Layer thicknesses were also positively associated with each other.
Repeated-measurement reliability for the manual correction of automatic intraretinal segmentation results was excellent, with intra-class correlation coefficient greater than 0.99 for all layers.. The SAMIRIX toolbox can simplify intraretinal segmentation in research applications, and the normative data application may serve
as an expandable reference for studies, in which normative data cannot be otherwise obtained.
Keywords: Optical coherence tomograhy (OCT), Retina, normative data, Inner retinal layer, segmentation, macula, healthy population, Minimally detectable change
Received: 08 May 2019;
Accepted: 07 Oct 2019.
Copyright: © 2019 Motamedi, Gawlik, Ayadi, Zimmermann, Asseyer, Bereuter, Mikolajczak, Paul, Kadas and Brandt. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Prof. Alexander U. Brandt, NeuroCure, Charité Medical University of Berlin, Berlin, 10117, Berlin, Germany, email@example.com