Evaluation of Segmentation Procedures Using Spectral Domain Optical Coherence Tomography in Exudative Age-Related Macular Degeneration

Malamos, Panagiotis; Ahlers, C.; Mylonas, Giorgos; Schütze, Christopher; Deák, Gábor; Ritter, Markus; Sacu, Stefan; Schmidt‐Erfurth, Ursula

doi:10.1097/iae.0b013e3181eef031

Cited by 20 publications

(12 citation statements)

References 17 publications

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“…Such errors in the automated detection of Bruch’s membrane induce wrong quantification of retinal thickness and may lead to erroneous decision of retreatment. Based on this automated retinal thickness, our findings are comparable to results previously obtained with Cirrus SD-OCT and Spectralis SD-OCT [21,25,26,27]. While the inner limiting membrane is always well defined, Bruch’s membrane was poorly defined in several cases, particularly in geographic atrophy [28].…”

Section: Discussionsupporting

confidence: 77%

Assessment of a Spectral Domain OCT Segmentation Software in a Retrospective Cohort Study of Exudative AMD Patients

Tilleul

Querques²,

Canouï‐Poitrine³

et al. 2012

Ophthalmologica

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Background: To assess the ability of the Spectralis optical coherence tomography (OCT) segmentation software to identify the inner limiting membrane and Bruch’s membrane in exudative age-related macular degeneration (AMD) patients. Methods: Thirty-eight eyes of 38 naive exudative AMD patients were retrospectively included. They all had a complete ophthalmologic examination including Spectralis OCT at baseline, at month 1 and 2. Reliability of the segmentation software was assessed by 2 ophthalmologists. Reliability of the segmentation software was defined as good if both inner limiting membrane and Bruch’s membrane were correctly drawn. Results: A total of 38 patients charts were reviewed (114 scans). The inner limiting membrane was correctly drawn by the segmentation software in 114/114 spectral domain OCT scans (100%). Conversely, Bruch’s membrane was correctly drawn in 59/114 scans (51.8%). The software was less reliable in locating Bruch’s membrane in case of pigment epithelium detachment (PED) than without PED (42.5 vs. 73.5%, respectively; p = 0.049), but its reliability was not associated with SRF or CME (p = 0.55 and p = 0.10, respectively). Conclusion: Segmentation of the inner limiting membrane was constantly trustworthy but Bruch’s membrane segmentation was poorly reliable using the automatic Spectralis segmentation software. Based on this software, evaluation of retinal thickness may be incorrect, particularly in case of PED. PED is effectively an important parameter which is not included when measuring retinal thickness.

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Section: Discussionsupporting

confidence: 77%

Assessment of a Spectral Domain OCT Segmentation Software in a Retrospective Cohort Study of Exudative AMD Patients

Tilleul

Querques²,

Canouï‐Poitrine³

et al. 2012

Ophthalmologica

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“…These machines do not differentiate subretinal fluid (SRF) from neurosensory retina, nor do they separately quantify subretinal hyperreflective material (SRHM) or pigment epithelial detachment (PED). The measurements from volume maps generated using OCT can also be affected by artifacts, [14][15][16][17] poor signal, 18 operator errors, and decentration owing to poor fixation. 19 Even newer third-party automated algorithms for CNV lesions require human input and optimization.…”

Section: Introductionmentioning

confidence: 99%

“…21 We have also previously demonstrated that accurate retinal thickness and volume maps can be generated using only a small subset of B-scans (32 B-scans) in a volume cube; 13,20 however, this study included retinal pathologies of various origins and not specifically CNV, wherein significant disruption of the outer retina leads to more frequent and severe segmentation errors. 16,18,22 Furthermore, the accuracy of volumes of more localized pathologic features, such as PED or SRF, may be more severely compromised by lower sampling densities. Thus, in the present study, we address these issues by evaluating the impact of reduced B-scan frame sampling, specifically in eyes with neovascular AMD, and incorporating CNV lesion parameters such as SRF, SRHM, and PED.…”

Section: Introductionmentioning

confidence: 99%

Impact of optical coherence tomography scanning density on quantitative analyses in neovascular age-related macular degeneration

Velaga

Nittala

Konduru

et al. 2016

Eye

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Purpose To assess the influence of varying B-scan frame-sampling densities on retinal thickness and volume measurements from spectral domain optical coherence tomography (OCT) in eyes with neovascular age-related macular degeneration (AMD). Methods Volume OCT data (512 × 128 macular cube over 6 × 6 mm) were collected from 39 eyes with neovascular AMD. All 128 B-scans in each image set were manually segmented, allowing quantification of the neurosensory retina, subretinal fluid (SRF), subretinal hyperreflective material (SRHM), and pigment epithelium detachment (PED). Thickness maps were generated for less dense subsets of scans, ranging from every other (64 B-scans) to every 64th (2 B-scans). For each less dense subset, foveal central subfield thickness and total macular volume (TMV) were compared with values obtained using all 128 scans (considered the reference). Results For each parameter, the mean absolute difference compared with the reference increased with reducing B-scan density. However, these differences did not reach statistical significance until framesampling density was reduced to every eighth scan (ie, 16 B-scans spaced 375 μm apart) for neurosensory retina, and every fourth scan (ie, 32 B-scans spaced 188 μm apart) for SRF, SRHM, and PED. For neurosensory retina, the mean (% error) and maximum (% error) absolute differences in TMV were 0.02 mm 3 (0.24%) and 0.06 mm 3 (0.79%), respectively. Similarly, at a density of 32 B-scans, mean and maximum differences for SRF were 0.004 mm 3 (3.47%) and 0.02 mm 3 (22.22%), respectively. The mean differences for SRHM and PED were 0.01 mm 3 (8.03%) and 0.01 mm 3 (4.04%), respectively. ConclusionsA minimum of 16 equally spaced B-scans, covering a 6 × 6 mm area, appears necessary to generate retinal thickness measurements similar to those obtained using all 128 B-scans in eyes with choroidal neovascularization (CNV). When considering other CNV lesion features, a minimum of 16 B-scans for SRF and PED, and 32 B-scans for SRHM are required to generate volume maps similar to ground-truth values. These findings may have implications for the design of acquisition and grading protocols for clinical trials using OCT in neovascular AMD.

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“…They found that RPE and ILM segmentation were excellent in both scan patterns, and severe failures were less common with the 200 × 200 raster scan pattern. 21 For this reason, we decided to use both of the Cirrus SD-OCT scan options in our study. The choice of scan patterns on the Spectralis OCT is not known to have an effect on the segmentation, which is consistent with the fact that the algorithm works on each B-scan separately.…”

Section: Discussionmentioning

confidence: 99%

“…A change in the retinal thickness measurement along with qualitative assessment of the B-scans is often used to determine re-treatment in eyes undergoing anti-VEGF therapy, and vascularized PEDs are often a component of the neovascular lesions. [19][20][21][22] Due to the importance of retinal thickness measurements in the presence of PEDs when re-treating patients with anti-VEGF therapy and when recruiting patients with neovascular AMD into clinical studies, we evaluated the segmentation performance of two SD-OCT instruments, the Cirrus SD-OCT (Carl Zeiss Meditec, Dublin, CA) and the Spectralis OCT (Heidelberg Engineering, Heidelberg, Germany) in patients with PEDs.…”

Section: Discussionmentioning

confidence: 99%

Identifying the Boundaries of Retinal Pigment Epithelial Detachments Using Two Spectral-Domain Optical Coherence Tomography Instruments

Penha¹,

Gregori²,

Yehoshua³

et al. 2013

Ophthalmic Surg Lasers Imaging Retina

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BACKGROUND AND OBJECTIVE: To compare two spectral-domain optical coherence tomography (SD-OCT) instruments in identifying the boundaries of retinal pigment epithelium detachment (PED). PATIENTS AND METHODS: 27 eyes were scanned with Cirrus and Spectralis SD-OCT instruments during a single visit. Two Cirrus scan patterns were used: the 512 × 128 and 200 × 200 covering a 6 × 6 mm (20° × 20°) area. The Spectralis scan pattern consisted of seven B-scans, averaged 51 times, covering a 30° × 5° area. The main outcome measures were the retinal thickness at the foveal center and the number of segmentation failures on the central B-scan. RESULTS: The Spectralis algorithm failed to follow the proper retinal contour in 25 eyes (92.6%), while the segmentation on the Cirrus instrument was successful in every central B-scan. Spectralis yielded greater retinal thickness measurements in all cases, and the average difference between Cirrus and Spectralis was 139 μm ( P < .001). The intraclass correlation coefficient between the two Cirrus scan patterns was 0.998, and Cirrus versus Spectralis was 0.21. CONCLUSIONS: The Cirrus SD-OCT instrument identifies the appropriate segmentation boundaries in the presence PED. The Spectralis SD-OCT algorithm was unreliable in segmenting PEDs, leading to inaccurate retinal thickness measurements unless manual adjustments were performed.

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Evaluation of Segmentation Procedures Using Spectral Domain Optical Coherence Tomography in Exudative Age-Related Macular Degeneration

Abstract: Automated algorithms of SD-OCT demonstrate a substantial rate of alignment failures in the assessment of exudative age-related macular degeneration pathologies, which are usually associated with misinterpretation of boundaries at the (sub) RPE level.

Cited by 20 publications

References 17 publications

Assessment of a Spectral Domain OCT Segmentation Software in a Retrospective Cohort Study of Exudative AMD Patients

Assessment of a Spectral Domain OCT Segmentation Software in a Retrospective Cohort Study of Exudative AMD Patients

Impact of optical coherence tomography scanning density on quantitative analyses in neovascular age-related macular degeneration

Identifying the Boundaries of Retinal Pigment Epithelial Detachments Using Two Spectral-Domain Optical Coherence Tomography Instruments

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