Session Title: Imaging III
Session Date/Time: Saturday 19/09/2015 | 16:30-18:00
Paper Time: 17:42
First Author: : K.Li SINGAPORE
Co Author(s): : C. Tan T. Lim
PURPOSE:Retinal thickness measurements on optical coherence tomography (OCT) is important in the assessment of retinal diseases. Different OCT machines generate different retinal thicknesses due to their individual segmentation algorithms. We aim to achieve comparability of retinal thickness between Spectral-Domain (SD) and Time-Domain (TD) OCTs by the adjustment of segmentation lines.
The study was conducted at Tan Tock Seng Hospital.
SD-OCT (Spectralis) and TD-OCTs (Stratus) were performed on 200 eyes of 100 healthy volunteers. Central retinal thickness (CRT), central point thickness (CPT) and 1mm volume of the Early Treatment Diabetic Retinopathy Study (ETDRS) grid were compared between the two machines. Subsequently, a trained operator manually adjusted the segmentation lines on the TD-OCT and the parameters were compared again. The segmentation lines were also edited separately by other trained operators and the inter- and intra-operator repeatability were assessed.
The mean CRTs of Spectralis and Stratus OCTs were significantly different (268.2 µm vs 193.9 µm, P<0.001). After segmentation line adjustments, the adjusted Spectralis CRT was 197.3 µm. The difference between SD-OCT and TD-OCT measurements decreased from 74.3 µm to 3.4 µm (P<0.001). Similar trends were observed for CPT and central 1mm volumes. Inter- and intra-operator repeatability were good with an intra-class correlation of 0.99 for both.
Manual adjustment of segmentation lines reliably achieves comparability between TD-OCT and SD-OCT. This simple and effective method is useful in multi-centred clinical trials where retinal measurements may be obtained using different machines.