2.Evaluating the optic nerve and retinal nerve fibre layer: the roles of Heidelberg retina tomography, scanning laser polarimetry and optical coherence tomography.
Annals of the Academy of Medicine, Singapore 2007;36(3):194-202
INTRODUCTIONFor many years, ophthalmologists have looked at the optic nerve head to evaluate the status of glaucoma. Clinical examination of the optic nerve head and retinal nerve fibre layer (RNFL) is however, subjective and sometimes variable. Recent developments in computer-based imaging technologies have provided a means of obtaining quantitative measurements of the optic nerve head topography and peripapillary retinal nerve fibre layer thickness.
METHODSMultiple searches using Medline were carried out. Additional searches were made using reference lists of published papers and book chapters.
RESULTSStudies involving three imaging technologies namely, confocal scanning laser ophthalmoscopy, scanning laser polarimetry and optical coherence tomography were reviewed. Overall, these technologies were reproducible and demonstrate good sensitivity and specificity in the range of 70 to 80%. Inclusion of age and ethnicity normative database will make these technologies more effective in screening and diagnosis. Quantitative measurements provide useful parameters for monitoring of patients.
CONCLUSIONThere is no consensus on the best technology for assessing structural damage in glaucomatous optic neuropathy. Therefore, as with any investigation, the clinician should exercise clinical correlation and judgment before instituting the appropriate treatment.
Female ; Humans ; Middle Aged ; Ophthalmoscopy ; methods ; Optic Nerve ; Retina ; Sensitivity and Specificity ; Tomography, Optical ; methods ; Tomography, Optical Coherence
3.Application of improved PCNN algorithm in retinal macular edema segmentation.
Zhinan XIE ; Min GU ; Yixiao WU ; Dong ZHENG
Chinese Journal of Medical Instrumentation 2012;36(6):411-414
In order to extract the outlines of macular edema from OCT images of macular, and estimate the volume of edema, we have to accurately segment the macular edema region. In this paper, an improved PCNN algorithm was proposed to conduct the above process. Combined with the adaptive base threshold, and the simplified neural network parameters, a binary image of macular edema was produced. According to the principle of maximum image entropy, the optimal number of iterations was determined as 8, which was evaluated by its misclassification rate. Simulation showed that the proposed algorithm could extract the macular edema region rapidly and accurately, providing the basis for further OCT image analysis.
Algorithms
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Fluorescein Angiography
;
methods
;
Humans
;
Macular Edema
;
diagnostic imaging
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Radiography
;
Tomography, Optical Coherence
;
methods
4.A segmentation algorithm of OCT image for macula edema.
Ping YANG ; Qing PENG ; Weiping LIN ; Xin YANG
Journal of Biomedical Engineering 2011;28(5):1001-1006
According to the characteristics of OCT images for macula edema, we studied a method for segmentation of the macula edema. Based on the Chan-Vese model, we proposed an improved level-set algorithm. With defining the integer-valued signed function directly, the curve could evolute outward or inward by changing the inside neighboring rid points and outside neighboring grid points into each other. We realized image segmentation which is much faster than the method of Chan-Vese model and smoothness regularization. We segmented 45 images and extracted the macula edema of each image. After achieving good segmentation results, we estimated the volume of the macular edema. The method provides quantitative analytic tools for clinical diagnosis and therapy.
Algorithms
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Humans
;
Image Interpretation, Computer-Assisted
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methods
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Macular Edema
;
diagnosis
;
pathology
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Tomography, Optical Coherence
;
methods
5.Efficacy of Strip Meniscometry for Dry Eye Syndrome Diagnosis.
Moon Kyoung KIM ; Yong Woo JI ; Hyung Keun LEE ; Kyoung Yul SEO ; Eung Kweon KIM ; Tae Im KIM
Journal of the Korean Ophthalmological Society 2016;57(10):1521-1526
PURPOSE: To evaluate the efficacy of strip meniscometry test for dye eye syndrome (DES) by measuring the correlation between strip meniscometry and conventional test measurements. METHODS: All subjects were examined using the Schirmer test, tear breakup time (TBUT) and strip meniscometry using SMTube (Echo Electricity Co., Ltd., Fukushima, Japan). Tear meniscus height (TMH), tear meniscus depth (TMD) and tear meniscus area (TMA) were measured using Fourier-domain optical coherence tomography. The DES group (n = 46 eyes) was compared with the normal group (n = 30 eyes) and correlation was assessed using Spearman's correlation coefficient. RESULTS: Strip meniscometry measurement was significantly correlated with Schirmer score (r = 0.6080, p < 0.01), TBUT (r = 0.5980, p < 0.01), TMH (r = 0.6210, p < 0.01), TMD (r = 0.6080, p < 0.01) and TMA (r = 0.6370, p < 0.01). Strip meniscometry was significantly lower in the DES group (4.58 ± 1.94 mm) than the normal group (7.07 ± 2.61 mm, p < 0.05). CONCLUSIONS: Strip meniscometry was significantly correlated with other conventional test measurements for dry eye syndrome. Strip meniscometry is less time consuming and a less invasive method than the Schirmer test. Strip meniscometry could be an efficient tool to evaluate patients with dry eye syndrome in a clinical setting.
Diagnosis*
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Dry Eye Syndromes*
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Electricity
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Humans
;
Methods
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Tears
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Tomography, Optical Coherence
6.Identification of Vulnerable Plaque in a Stented Coronary Segment 17 Years after Implantation Using Optical Coherence Tomography.
Jeong Hoon YANG ; Kyeongmin BYEON ; Hyeon Cheol GWON ; Jeong Euy PARK ; Young Bin SONG
Yonsei Medical Journal 2012;53(2):450-453
A patient presented with exertional chest pain two months prior to admission. Coronary angiography revealed a subocclusive stenosis within the boundaries of the stent. Optical coherence tomography showed remarkable intimal growth inside the stent, which demonstrated a heterogeneous appearance including low-intensity areas. These findings were congruent with the morphology of fibroatheroma in the native coronary artery and suggested that new atherosclerotic progression of the intima within the stent had occurred over 17 years following bare metal stent implantation. To the best of our knowledge, this is one of the most delayed instances of a bare metal stent restenosis described in the medical literature.
Aged
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Angioplasty, Balloon, Coronary
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Coronary Restenosis/*diagnosis
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Female
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Humans
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Tomography, Optical Coherence/*methods
7.Improved accuracy in periodontal pocket depth measurement using optical coherence tomography.
Sul Hee KIM ; Se Ryong KANG ; Hee Jung PARK ; Jun Min KIM ; Won Jin YI ; Tae Il KIM
Journal of Periodontal & Implant Science 2017;47(1):13-19
PURPOSE: The purpose of this study was to examine whether periodontal pocket could be satisfactorily visualized by optical coherence tomography (OCT) and to suggest quantitative methods for measuring periodontal pocket depth. METHODS: We acquired OCT images of periodontal pockets in a porcine model and determined the actual axial resolution for measuring the exact periodontal pocket depth using a calibration method. Quantitative measurements of periodontal pockets were performed by real axial resolution and compared with the results from manual periodontal probing. RESULTS: The average periodontal pocket depth measured by OCT was 3.10±0.15 mm, 4.11±0.17 mm, 5.09±0.17 mm, and 6.05±0.21 mm for each periodontal pocket model, respectively. These values were similar to those obtained by manual periodontal probing. CONCLUSIONS: OCT was able to visualize periodontal pockets and show attachment loss. By calculating the calibration factor to determine the accurate axial resolution, quantitative standards for measuring periodontal pocket depth can be established regardless of the position of periodontal pocket in the OCT image.
Calibration
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Gingiva
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Image Interpretation, Computer-Assisted
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Methods
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Periodontal Pocket*
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Tomography, Optical Coherence*
8.Optical Coherence Tomography to Evaluate Dengue.
Korean Journal of Ophthalmology 2014;28(4):351-352
No abstract available.
Dengue/*complications
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Female
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Humans
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Tomography, Optical Coherence/*methods
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Vision Disorders/*diagnosis
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*Visual Acuity
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*Visual Fields
9.Detection of Occludable Angles with the Pentacam and the Anterior Segment Optical Coherence Tomography.
Samin HONG ; Jeong Ho YI ; Sung Yong KANG ; Gong Je SEONG ; Chan Yun KIM
Yonsei Medical Journal 2009;50(4):525-528
PURPOSE: To assess efficacy of the Pentacam (PTC) and the anterior segment optical coherence tomography (AOCT) for detection of occludable angles. MATERIALS AND METHODS: Fourty-one eyes with gonioscopically diagnosed occludable angles and 32 normal open-angle eyes were included. Anterior chamber angle (ACA) and anterior chamber depth (ACD) were measured with PTC and AOCT. Receiver operating characteristic (ROC) curve was constructed for each parameter and the area under the ROC curve (AUC) was calculated. RESULTS: Values of ACA and ACD measured by PTC and AOCT were similar not only in normal open angle eyes but also in occludable angle eyes. For detection of occludable angle, the AUCs of PTC with ACA and ACD were 0.935 and 0.969, respectively. The AUCs of AOCT with ACA and ACD were 0.904 and 0.947, respectively. CONCLUSION: Both PTC and AOCT allow accurate discrimination between open and occludable angle eyes, so that they may aid to screening the occludable angles.
Aged
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Aged, 80 and over
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Anterior Chamber/*anatomy & histology
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Humans
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Middle Aged
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Tomography, Optical Coherence/*methods
10.Erratum: Optical Coherence Tomography for the Diagnosis and Evaluation of Human Otitis Media.
Nam Hyun CHO ; Sang Heun LEE ; Woonggyu JUNG ; Jeong Hun JANG ; Stephen A BOPPART ; Jeehyun KIM
Journal of Korean Medical Science 2015;30(6):834-834
We made two mistakes in our recently published article. We are correcting the authorship and funding information.
Ear, Middle/*pathology
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Humans
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Otitis Media/*pathology
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Reproducibility of Results
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Sensitivity and Specificity
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Tomography, Optical Coherence/*methods