Wide-field Optical Coherence Tomography Images Research Articles

Wide-Field Optical Coherence Tomography Imaging Improves Rate of Change Detection in Progressing Glaucomatous Eyes Compared With Standard-Field Imaging.

To compare rates of retinal nerve fiber layer change over time in healthy, eyes with nonprogressing glaucoma and eyes with progressing glaucoma using single wide-field (SWF) and optic nerve head (ONH) cube scan optical coherence tomography (OCT) images. Forty-five eyes of 25 healthy individuals and 263 eyes of 161 glaucoma patients from the Diagnostic Innovations in Glaucoma Study were included. All eyes underwent 24-2 visual field testing and OCT (Spectralis SD-OCT) ONH and macular imaging. SWF images (up to 43° × 28°) were created by stitching together ONH cube scans centered on the optic disc and macular cube scans centered on the fovea. Visual field progression was defined as guided progression analysis likely progression and/or a significant (P < 0.01) mean deviation slope of less than -1.0dB/year. Mixed effects models were used to compare rates of change. Highly myopic eyes were included. Thirty glaucomatous eyes were classified as progressing. In eyes with glaucoma, mean global rate of change was -1.22 µm/year (P < 0.001) using SWF images and -0.83 µm/year (P = 0.003) using ONH cube scans. Rate of change was significantly greater in eyes with progressing glaucoma compared with eyes with nonprogressing glaucoma (-1.51 µm/year vs. -1.24 µm/year; P = 0.002) using SWF images and was similar using ONH cube scans (P = 0.27). In this cohort that includes eyes with and without high axial myopia, the mean rate of retinal nerve fiber layer thinning measured using SWF images was faster in eyes with progressing glaucoma than in eyes with nonprogressing glaucoma. Wide-field OCT images including the ONH and macula can be effective for monitoring glaucomatous progression in patients with and without high myopia.

Intraoperative Use of Wide-Field Optical Coherence Tomography to Evaluate Tissue Microstructure in the Oral Cavity and Oropharynx

Involvement of deep margins represents a significant challenge in the treatment of oropharyngeal cancer, and given practical limitations of frozen-section analysis, a need exists for real-time, nondestructive intraoperative margin analysis. Wide-field optical coherence tomography (WF-OCT) has been evaluated as a tool for high-resolution adjunct specimen imaging in breast surgery, but its clinical application in head and neck surgery has not been explored. To evaluate the utility of WF-OCT for visualizing microstructures at margins of excised oral and oropharyngeal tissue. This nonrandomized, investigator-initiated qualitative study evaluated the feasibility of the Perimeter Medical Imaging AI Otis WF-OCT device at a single academic center. Included participants were adults undergoing primary ablative surgery of the oral cavity or oropharynx for squamous cell carcinoma in 2018 and 2019. Data were analyzed in October 2019. Patients were treated according to standard surgical care. Freshly resected specimens were imaged with high-resolution WF-OCT prior to routine pathology. Interdisciplinary interpretation was performed to interpret WF-OCT images and compare them with corresponding digitized pathology slides. No clinical decisions were made based on WF-OCT image data. Visual comparisons were performed between WF-OCT images and hematoxylin and eosin slides. A total of 69 specimens were collected and scanned from 53 patients (mean [SD] age, 59.4 [15.2] years; 35 [72.9%] men among 48 patients with demographic data) undergoing oral cavity or oropharynx surgery for squamous cell carcinoma, including 42 tonsillar tissue, 17 base of the tongue, 4 buccal tissue, 3 mandibular, and 3 other specimens. There were 41 malignant specimens (59.4%) and 28 benign specimens (40.6%). In visual comparisons of WF-OCT images and hematoxylin and eosin slides, visual differentiation among mucosa, submucosa, muscle, dysplastic, and benign tissue was possible in real time using WF-OCT images. Microarchitectural features observed in WF-OCT images could be matched with corresponding features within the permanent histology with fidelity. This qualitative study found that WF-OCT imaging was feasible for visualizing tissue microarchitecture at the surface of resected tissues and was not associated with changes in specimen integrity or surgical and pathology workflow. These findings suggest that formal clinical studies investigating use of WF-OCT for intraoperative analysis of deep margins in head and neck surgery may be warranted.

Choroidal vascularity profile in diabetic eyes using wide field optical coherence tomography.

To report the wide-field choroidal vascularity up to the mid-equator area in diabetic retinopathy (DR) subjects using wide-field optical coherence tomography (WF-OCT). Prospective, Cross-sectional study. Forty-seven eyes of 25 DR subjects. WF-OCT images (55 degrees) were obtained using Spectralis HRA + OCT (Heidelberg Engineering, Germany) in extremes of gazes in all quadrants and manual montages were created to obtain wide field images up to mid equator. A previously reported semi-automated algorithm was used to calculate choroidal vascularity profile (CVI). Regression analysis was performed to identify the factors influencing CVI. Forty-seven eyes from 25 patients were enrolled in the study. The mean age was 68.4 ± 10.6 years. The refractive error (spherical equivalent) ranged from -2.25 to +3.75 diopters. Most common DR grade among study subjects was moderate NPDR (29.41%) and 74.5% eyes had diabetic macular edema (DME). The mean CVI in the macular area (58.29 ± 3.63) was significantly lower than in any of the other fundus areas (all p ˂ 0.01). The maximum CVI was seen in the nasal region (66.60 ± 5.61), followed by temporal (65.69 ± 3.81), superior (65.01 ± 4.87), and inferior (63.80 ± 5.42). The vertical macular area had the least coefficient of variation (CV) of CVI (0.06) while the inferior quadrant had the highest CV (0.08). The current study describes the CVI profile on WF-OCT in DR eyes up to mid-equator. The significant increase of the CVI compared to healthy subjects and its significant regional variations introduce this novel quantitative parameter as a reliable biomarker of the diabetes-induced choroidal microangiopathy.

Abstract B021: Use of wide field optical coherence tomography (WF-OCT) in margin assessment during breast conserving surgery (BCS) for ductal carcinoma in situ (DCIS)

Abstract Purpose: To assess the utility of a novel imaging technology for intraoperative margin assessment in breast conserving surgery (BCS) for ductal carcinoma in situ (DCIS). Background: The multi-focal nature of DCIS presents a challenge to ensuring negative margins during BCS. Routine methods for intraoperative margin assessment, such as specimen radiography, ultrasound, cavity margins, and touch prep cytology each have specific limitations, including operator skill, time delay, probe position, and specimen completeness. A more recent method, wide field optical coherence tomography (WF-OCT), enables real-time tissue visualization at up to 2 mm of depth with the ability to use image-based machine learning to identify regions of interest suspicious for residual malignancy. Methods: Two adult females with biopsy-proven DCIS and one with invasive carcinoma underwent BCS following routine surveillance mammography and were prospectively evaluated. Primary lesions were imaged intraoperatively with specimen radiography and a WF-OCT imaging device (OTIS, Perimeter Medical AI, Toronto, Canada); images from both modalities were read to identify potential residual malignancy, and additional tissue was excised as indicated. Permanent histopathology was compared to imaging results. Results: The first patient (76 y/o, BI-RADS 4B, 1.6 cm) underwent BCS and the excised sample was 4 x 3.7 x 3.2 cm. By radiography, the biopsy clip and localization reflector were within the specimen and margins appeared satisfactory; WF-OCT demonstrated residual disease at the inferior margin and additional tissue was excised. Permanent histology showed DCIS involvement of inferior primary margin; additional margin excision contained DCIS and was negative. The second patient (64 y/o, BI-RADS 4B, 1 cm) underwent BCS and the excised sample was 4 x 3.5 x 3.5. By radiography, the biopsy clip and reflector were within the specimen and margins appeared satisfactory; WF-OCT showed residual disease at the inferior and posterior margins and additional tissue was excised. Permanent histology demonstrated DCIS within 1 mm and pleomorphic lobular carcinoma in situ (LCIS) microns from primary inferior margin; the additional inferior sample was margin negative, and posterior sample contained pleomorphic LCIS and was margin negative. The last patient (76 y/o, BI-RADS 5, 1.9 x 1.9 x 1.7 cm) underwent BCS and the excised sample was 6.5 x 5.3 x 4.2 cm. By radiography, the biopsy clip and localization reflector were within the specimen and margins appeared satisfactory; WF-OCT showed residual disease at the lateral margin and also revealed occult DCIS not found on biopsy. Additional tissue was taken until margin clearance by WF-OCT. Permanent histology demonstrated DCIS to &amp;lt;1 mm of primary lateral margin; the additional excision contained DCIS and was margin negative. Conclusions: In this case series of 3 adult females undergoing BCS for breast carcinoma, WF-OCT was a beneficial adjunctive imaging modality to specimen radiography for margin assessment. Citation Format: Amelia B. Tower, Andrew Berkeley. Use of wide field optical coherence tomography (WF-OCT) in margin assessment during breast conserving surgery (BCS) for ductal carcinoma in situ (DCIS) [abstract]. In: Proceedings of the AACR Special Conference on Rethinking DCIS: An Opportunity for Prevention?; 2022 Sep 8-11; Philadelphia, PA. Philadelphia (PA): AACR; Can Prev Res 2022;15(12 Suppl_1): Abstract nr B021.

Wide-field optical coherence tomography imaging in diabetic retinopathy.

To report the individual retinal layer thicknesses up to mid-equator in patients with diabetic retinopathy (DR) using Spectralis (Heidelberg Engineering, Heidelberg, Germany) wide-field optical coherence tomography (OCT). Retinal layers were segmented using a custom designed semi-automated algorithm, where reference points were marked by the examiner to enable software to automatically compute the thickness values of each retinal sublayer at an interval of 1 mm from reference points. The values of individual retinal thicknesses in eyes with varying severity of DR were compared with the values of healthy subjects. Generalized estimating equation was performed to compensate for inclusion of both eyes of patients. A total of 64 patients (119 eyes) with a mean age of 68.97 ± 10.27 years were included. Overall, ganglion cell layer (GCL)/ inner plexiform layer (IPL) complex (-31.67 microns, p < 0.001), outer plexiform layer (-6.78 microns, p = 0.002) and photoreceptor layer (-22.90 microns, p < 0.001) showed significant thinning, while outer nuclear layer thickening ( + 68.19 microns, <0.001) was noted in eyes with DM compared to healthy subjects. Thickness changes were significantly more in the macular segment compared to nasal and temporal segments. GCL/ IPL complex and photoreceptor layers were found to be significantly thin in all grades of DR. Retinal thicknesses vary significantly in patients with diabetic retinopathy and understanding patterns of these changes across different segments of the wide field OCT may help better elucidate the natural progression of the disease in terms of retinal anatomy.

Deep Learning-based Diagnosis of Glaucoma Using Wide-field Optical Coherence Tomography Images.

(1) To evaluate the performance of deep learning (DL) classifier in detecting glaucoma, based on wide-field swept-source optical coherence tomography (SS-OCT) images. (2) To assess the performance of DL-based fusion methods in diagnosing glaucoma using a variety of wide-field SS-OCT images and compare their diagnostic abilities with that of conventional parameter-based methods. Overall, 675 eyes, including 258 healthy eyes and 417 eyes with glaucoma were enrolled in this retrospective observational study. Each single-page wide-field report (12×9 mm) of wide-field SS-OCT imaging provides different types of images that reflect the state of the eyes. A DL-based automated diagnosis system was proposed to detect glaucoma and identify its stage based on such images. We applied the convolutional neural network to each type of image to detect glaucoma. In addition, 2 fusion strategies, fusion by convolution network (FCN) and fusion by fully connected network (FFC) were developed; they differ in terms of the level of fusion of features derived from convolutional neural networks. The diagnostic models were trained using 382 and 293 images in the training and test data sets, respectively. The diagnostic ability of this method was compared with conventional parameters of the thickness of the retinal nerve fiber layer and ganglion cell complex. FCN achieved an area under the receiver operating characteristic curve (AUC) of 0.987 (95% confidence interval, CI: 0.968-0.996) and an accuracy of 95.22%. In contrast, FFC achieved an AUC of 0.987 (95% CI, 0.971-0.998) and an accuracy of 95.90%. Both FCN and FFC outperformed the conventional method (P<0.001). In detecting early glaucoma, both FCN and FFC achieved significantly higher AUC and accuracy than the conventional approach (P<0.001). In addition, the classification performance of the DL-based fusion methods in identifying the 5 stages of glaucoma is presented via a confusion matrix. DL protocol based on wide-field OCT images outperformed the conventional method in terms of both AUC and accuracy. Therefore, DL-based diagnostic methods using wide-field OCT images are promising in diagnosing glaucoma in clinical practice.

Wide-field Optical Coherence Tomography Imaging of Excised Breast Tissue.

Wide-field Optical Coherence Tomography Imaging of Excised Breast Tissue.

Posterior Staphylomas in Pathologic Myopia Imaged by Widefield Optical Coherence Tomography

To examine posterior staphylomas by widefield optical coherence tomography (WF-OCT) and three-dimensional magnetic resonance imaging (3D-MRI). Highly myopic patients (myopic refractive error >8.0 diopters or axial length >26.5 mm) who had previously undergone orbital 3D-MRI were examined by WF-OCT. The study included 100 eyes of 57 patients with a mean age of 67.9 ± 10.7 years (range, 44-85 years) and mean axial length of 30.0 ± 2.3 mm (range, 25.1-36.5 mm). All staphylomas detected on the 3D-MRI, except for two very large staphylomas, were visualized on the WF-OCT images. Morphologic hallmarks of the staphylomas were smoothly configured staphyloma border with a gradual thinning of the choroid and an inward protrusion of the sclera at the staphyloma edge. Comparing the detectability of the staphylomas on the WF-OCT images versus 3D-MRI revealed no significant difference between both techniques (P = 0.12; χ2 test). Comparing the staphyloma classification between both techniques showed a good concordance with a concordance index kappa of 0.61 (95% confidence interval: 0.50-0.72). A spatial relationship between the staphylomatous areas and the macula and optic nerve head was observed by WF-OCT. WF-OCT can provide tomographic images of posterior staphylomas in a resolution and size unachievable so far, and may replace 3D-MRI in assessing posterior staphylomas. Future studies using WF-OCT may explore the detailed morphologic characteristics of posterior staphylomas and give clues to the etiology of staphylomas.

Abstract P4-03-05: Wide-field optical coherence tomography (WF-OCT) for near real-time, point-of-care assessment of margin status in breast-conserving surgery specimens: Results of a feasibility study at a high-volume single-centre

Abstract Wide-Field Optical Coherence Tomography (WF-OCT) is a non-destructive, non-contact light imaging modality capable of label-free visualization of the internal microscopic architecture of breast tissue specimens. Its unique combination of high-resolution imaging in near real-time with tissue penetration depths approaching 2-mm makes it a promising imaging modality for obtaining detailed surgical margin status in breast-conserving surgery (BCS) specimens. A prototype WF-OCT imaging platform developed by Perimeter Medical Imaging, Inc. (Toronto, Canada) has permitted fully-automated, dynamically-focused visualization of margin widths around the intact surfaces of freshly excised BCS specimens. Herein are reported the results of a feasibility study at a high-volume single-centre evaluating the routine use of WF-OCT for sampling of surgical margin status in BCS specimens at the point-of-care. Methods: Women with biopsy confirmed breast cancer and scheduled for primary BCS were recruited at Princess Margaret Cancer Centre (Toronto, Canada). Standard medical care was not altered. Freshly excised BCS specimens including all lumpectomy samples were imaged by WF-OCT immediately prior to standard histological processing. The system acquired dynamically-focused, hemispherical coverage over two contra-lateral surfaces of the intact BCS specimen within the time constraints of the cold ischemic time window. High-resolution (10 μm) images of the tissue surface down to a 1 to 2-mm depth were obtained. Blinded assessments were performed on image data sets by two clinical readers (surgeon and radiologist) trained on a validated and unrelated data set correlating OCT images with histology slides. The readers were first asked to independently assess margin status using only blinded pre- and intra-operative knowledge (without OCT). Upon completion, the readers were provided OCT images of all scanned surface and similarly asked to assess the margin status with the additional OCT information. These assessments were subsequently evaluated by a breast pathologist comparing the OCT images and corresponding histopathology sections. The added utility of WF-OCT imaging information for margin prediction was studied. Results: [Pending study completion in August 2015]. Through accurate correlation with the histopathologic gold standard, OCT demonstrated capability to differentiate tissue microstructures, including: distinctive patterns for adipose tissue, fibrous stroma, breast lobules and ducts, cysts and microcysts, as well as in-situ and invasive carcinomas. Implications: The fully-automated WF-OCT imaging platform can integrate conveniently into standard pathological processing workflows to provide comprehensive sampling of surgical margin status in BCS specimens at the point-of-care. Clinical readers from surgical and radiological backgrounds can be trained to competently interpret WF-OCT images of BCS specimens for accurate prediction margin status. The implementation of WF-OCT at the point-of-care for routine surgical margin assessments will be further explored in future clinical trials. Citation Format: Valic MS, Leong WL, Done SJ, Wilson BC, Kulkarni S, McCready DR, Niu CJ, Atachia Y, Munro EA, Rempel D. Wide-field optical coherence tomography (WF-OCT) for near real-time, point-of-care assessment of margin status in breast-conserving surgery specimens: Results of a feasibility study at a high-volume single-centre. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-03-05.

Application of Extended Field Imaging to Optical Coherence Tomography

Since its invention, optical coherence tomography (OCT) has made remarkable advancements in both image resolution and acquisition speed. 1 Huang D. Swanson E.A. Lin C.P. et al. Optical coherence tomography. Science. 1991; 254: 1178-1181 Crossref PubMed Scopus (12098) Google Scholar , 2 Hangai M. Ojima Y. Gotoh N. et al. Three-dimensional imaging of macular holes with high-speed optical coherence tomography. Ophthalmology. 2007; 114: 763-773 Abstract Full Text Full Text PDF PubMed Scopus (164) Google Scholar With improvements in both hardware and software, higher resolution and less noisy retinal cross-sectional images can be obtained noninvasively. 3 Drexler W. Morgner U. Ghanta R.K. et al. Ultrahigh-resolution ophthalmic optical coherence tomography. Nat Med. 2001; 7: 502-507 Crossref PubMed Scopus (844) Google Scholar Recent improvements to commercially available OCT systems have also included increasing scan length. For example, most spectral-domain OCT machines provide line scans that are approximately 9 mm in length. Therefore, a single scan can include the macula and part of the optic disc. The new DRI OCT-1 (Topcon, Tokyo, Japan), a commercially available, swept-source OCT system, is capable of producing a 12-mm scan that allows the entire optic disc to be imaged with macula. 4 Akagi T. Hangai M. Kimura Y. et al. Peripapillary scleral deformation and retinal nerve fiber damage in high myopia assessed with swept-source optical coherence tomography. Am J Ophthalmol. 2013; 155: 927-936 Abstract Full Text Full Text PDF PubMed Scopus (38) Google Scholar Wide-field OCT imaging is advantageous over conventional OCT imaging because a more comprehensive assessment of the posterior pole can be made with fewer scans. In this study, we examined the use and efficacy of obtaining wide-field OCT images with a novel extended field imaging (EFI) technique. Not only is this technique easy to use, it can be done with readily available items and with existing, unmodified OCT systems.