Ability Of Optical Coherence Tomography Research Articles

Optical coherence tomography (OCT) changes after achieving target intraocular pressure

Purpose The aim of this study was to evaluate the ability of optical coherence tomography (OCT) to detect the changes in retinal nerve fiber layer (RNFL) after reaching target intraocular pressure (IOP) in glaucomatous patients. Patients and methods Thirty-two (58 eyes) patients with a clinical diagnosis of primary open-angle glaucoma were assessed as regards peripapillary RNFL thickness and optic nerve head parameters by 3D-OCT for a follow-up period of 6 months. The drugs used to reach target IOP were Twinzol (dorzolamide 2%/timolol 0.5%) eye drops 5 ml and Ioprost (Latanoprost) 0.005% (50 mcg/ml) eye drops 3 ml. Eleven patients were treated with Twinzol only and reached target IOP after adding Ioprost. Eight patients were treated with Ioprost only and reached target IOP after adding Twinzol, and 13 patients had no added treatment, where four reached target IOP by Ioprost only, six reached target IOP by Twinzol only, and three reached target IOP by both drugs. OCT was done for all patients after achieving target IOP and was repeated after 6 months of medical control. Results The mean IOP before treatment was 29.89 mmHg and decreased significantly (P Conclusion Achieving target IOP in patients with glaucoma results in a significant change in the RNFL and ganglion cell complexes layer as shown by spectral-domain OCT.

Opticalcoherence tomography versus perimetry in follow-up of glaucoma

Objective The objective of this study was to evaluate the ability of optical coherence tomography (OCT) to detect glaucoma in its early stages and follow-up progression of the disease compared with visual field (VF) examination aiming for better control of the disease and decreasing the incidence of morbidity (blindness) resulting from this disease. Background Primary open angle glaucoma is the leading cause of irreversible world blindness. VF deficits are thought to be the functional expression of ganglion cell losses. OCT provides high-resolution images that allow in-vivo measurements of the retinal nerve fiber layer in cross-section. Patients and methods Twenty eyes diagnosed with primary open angle glaucoma were included in the study. All patients were subjected to complete ocular examination, VF examination by standard automated perimetry (SAP), and OCT assessment of the retinal nerve fiber layer in the primary visit. Follow-up periods were 3 and 6 months by SAP and OCT assessment of the retinal nerve fiber. Results The follow-up period was 6 months. SAP was nearly similar to OCT in detecting progression: eight (40%) eyes compared with 10 (50%) eyes by OCT. OCT was better because of its ability to detect early any progression before functional affection, but the difference between them is not significant. Conclusion OCT was able to detect more progression compared with VF. In addition, it detected progression earlier compared with VF. OCT proved the ability to detect any structural changes before corresponding functional defects can be detected.

Retinal nerve fiber layer atrophy in patients with multiple sclerosis: Longitudinal 5 years study

PurposeTo evaluate changes in the retinal nerve fiber layer (RNFL) thicknesses in multilple sclerosis (MS) patients compared with healthy subjects during 5 years of follow up. To compare ability of optical coherence tomography (OCT) and visual field test to detect axonal damage.MethodsFifty eyes of 50 MS patients and 50 eyes of 50 healthy controls were included. All of them underwent measurements of best corrected visual acuity (BCVA) refractive defect, color vision, visual field, and OCT (Spectralis OCT). All of them were annual re‐evaluated during 5 years. Change in both groups (MS patients and healthy controls) were evaluated and compared using paired T Student′s test.ResultsWe found decrease in all RNFL thicknesses during the 5 years follow‐up in both groups (patients and controls), and the changes were significant higher in MS group (T Student′s, p ≤ 0.05). No differences were found between patients and controls in visual functional tests (BCVA, color vision test and visual field). Higher change was found in inferior quadrant (113.67 in baseline and 105.39 μm in 5 years visit in MS group, p < 0.001). Correlations between structural and functional tests were found, but not between the changes in both tests during the 5 years follow up.ConclusionsMS progression causes axonal damage that can be detected by OCT but not by visual functional tests.

Optical Coherence Tomography as a Tool for In Vivo Staging and Grading of Upper Urinary Tract Urothelial Carcinoma: A Study of Diagnostic Accuracy

Biopsies and cytology are cornerstones in the diagnosis of upper urinary tract urothelial carcinoma. However, a high rate of nondiagnostic biopsies, tumor upgrading and tumor up staging after nephroureterectomy has been observed. In this prospective invivo study we evaluated the diagnostic accuracy of optical coherence tomography for the grading and staging of upper tract urothelial carcinoma. A total of 26 patients underwent diagnostic ureterorenoscopy including biopsies and optical coherence tomography, followed by nephroureterectomy or segmental ureter resection. The sensitivity, specificity, negative predictive value and positive predictive value of upper tract urothelial carcinoma grading and staging by optical coherence tomography were evaluated according to the STARD (Standards for Reporting of Diagnostic Accuracy) initiative and the second stage (2a and 2b) of the IDEAL model. For tumor staging a 2×2 table for sensitivity and specificity was calculated. For tumor grading the Wilcoxon rank sum test was used to test μoct in low and high grade lesions followed by ROC analysis for sensitivity and specificity. In 83% the staging of lesions was in accordance with final histopathology. Sensitivity and specificity analysis for tumor invasion was 100% and 92%, respectively. Tumor size greater than 2 mm and inflammation were risks for false-positives. For low and high grade lesions median μoct was 2.1 and 3.0mm-1, respectively (p <0.01). ROC analysis showed a sensitivity of 87% and a specificity of 90% using a μoct cutoff of 2.4 mm-1. This report describes optical coherence tomography as a real-time, intraoperatively diagnostic modality in the diagnostic evaluation of upper tract urothelial carcinoma. We confirmed the ability of optical coherence tomography to visualize, grade and stage urothelial carcinoma in the upper urinary tract.

NON-INVASIVE DIAGNOSTICS OF NON-TUMOR DISORDERS WITH OPTICAL COHERENCE TOMOGRAPHY

Introduction: The distinctive features of modern inflammatory diseases are their indolent course and predisposition to chronicity. Chronic inflammation is the basis for the development of serious disorders, including autoimmune and oncologic ones, and a cause of major functional abnormalities of the human body. Diagnostics of chronic inflammation is associated with a number of problems which originate from a variety of clinical phenotypes and morphological forms, on the one hand, and from the rising prevalence of their latent course, on the other. In its turn, an adequate treatment choice may be based on understanding and accurate detection of etiological and morphological types of the disease. In this connection, development of novel diagnostic techniques, such as optical coherence tomography (OCT), is of utmost importance. Aim: To demonstrate feasibility of OCT in detection of morphological abnormalities associated with chronic inflammatory disorders of various localizations. Materials and methods: OCT diagnostics was performed in addition to standard diagnostic procedures in 225 patients with chronic inflammatory disorders of various localizations, such as chronic recurrent rhinitis, chronic latent salpingitis and chronic endometritis. For OCT, an “OCT-1300U” system was used, with central wavelength of 1280 nm, spatial resolution of 15–20 μm, image acquisition rate of 8 frames per second, imaging depth of 1.4 mm and a probe diameter of 2.4 mm. The following techniques of quantitative processing were used for processing of the OCT images. Quantitative characterization of histograms and image texture was performed with further determination of values typical for various images groups corresponding to particular states of biological tissues. Neural network was also employed with histograms and 2D Fourier transforms of the images as input data. Results: OCT laparoscopy allowed to obtain three types of OCT images of fallopian tubes with features typical for healthy and inflammatory states. Presence of heterogeneity in the structure of an OCT image indicated heterogeneity in the muscle layer of the fallopian tube, which allowed for a conclusion on chronic salpingitis. With OCT hysteroscopy we demonstrated the ability of OCT to visualize pathomorphologic features of chronic endometritis. The diagnostic data obtained by OCT-rhinoscopy allowed to draw preliminary conclusions on the OCT ability to detect specific features of various types of chronic rhinitis. Numerical processing of diagnostic OCT images resulted in their higher objectivity and an improvement of diagnostic accuracy of the technique. Conclusion: OCT is able to detect morphological changes induced by a chronic inflammatory process. OCT criteria were shown to be universal for various organs. We demonstrated the possibility of non-invasive diagnostics of pathomorphologic forms of disease, showed some challenges in the development of OCT for diagnostics of non-tumor disorders and ways to overcome them are proposed, in particular, the use of image numerical processing. Further studies seem to be justified.

Optical Coherence Tomography of the Aging Kidney.

The aging kidney exhibits a progressive decline in renal function with characteristic histopathologic changes and is a risk factor for renal transplant. However, the degree to which the kidney exhibits this decline depends on several factors that vary from one individual to the next. Optical coherence tomography is an evolving noninvasive imaging technology that has recently been used to evaluate acute tubular necrosis of living-human donor kidneys before their transplant. With the increasing use of kidneys from older individuals, it is important to determine whether optical coherence tomography also can distinguish the histopathology associated with aging. In this investigation, we used Munich-Wistar rats to evaluate the ability of optical coherence tomography to detect histopathologic changes associated with aging. Optical coherence tomography observations were correlated with renal function and conventional light microscopic evaluation of these same kidneys. With the onset of severe proteinuria at 10 to 12 months of age, optical coherence tomography revealed tubular necrosis/atrophy, interstitial fibrosis, tubular dilation, and glomerulosclerosis. With a further deterioration in kidney function at 16 to 18 months of age (as indicated by rising creatinine levels), optical coherence tomography revealed more extensive interstitial fibrosis and tubular atrophy, increased tubular dilation with cyst formation and more sclerotic glomeruli. The foregoing observations suggest that optical coherence tomography can be used to detect the histopathology of progressive nephropathy associated with aging.

Tissue characterization using optical coherence tomography and cone beam computed tomography: a comparative pilot study

To evaluate the ability of optical coherence tomography (OCT) in differentiating human oral tissues in comparison with cone beam computed tomography. In this study, we imaged four types of tissues exvivo: human enamel, human cortical bone, human trabecular bone, and fatty tissue plus water and air by using OCT (Axsun Inc., Billerica, MA). We then developed a method for qualitative and quantitative analyses of the human specimens. The same types of tissues were also imaged using cone beam computed tomography, and gray-scale values were measured. The qualitative indices (intensity profile, contour plot, and histogram) for OCT images were able to provide information regarding surface characteristics as well as changes in tissue properties at different interfaces. The quantitative index (pixel intensity values) was also able to render information regarding the distribution and density of the pixels in different samples. A similar pattern was observed in the pixel intensity values and gray-scale values in both imaging modalities. Within the limitations of this exvivo pilot study, OCT can reliably differentiate between a range of hard and soft tissues.

System of label-free three-dimensional optical coherence tomography angiography with high sensitivity and motion contrast and its applications in brain science

Combining three-dimensional (3D) imaging ability of optical coherence tomography (OCT) with movement recognition ability of dynamic scattering technique, label-free 3D OCT angiography can be realized, which has a wide range of applications in basic science research and clinical diagnosis. At no expense of line scanning speed, the scale of capillaries can be detected by improving the sensitivity through the interframe analysis. However, there exists a certain residual overlap between dynamic flow signals and static tissue beds due to a series of reasons, thus making it difficult to completely distinguish dynamic flow signals from static tissue beds. Thus, when it comes to threshold segmentation for the blood flow signal extraction, classification error rate is inevitable, resulting in the decrease of the motion contrast of angiogram. In order to reduce classification error rate between static tissue beds and dynamic flow signals for high motion-contrast angiography, we propose a method of component compounding in wavelet domain. Three main steps are needed for this method. Firstly, on the basis of two-dimensional (2D) discrete static wavelet transform, a frame image can be decomposed into multiple levels. Each level has four components, i.e., approximation component, horizontal detail component, vertical detail component and diagonal detail component. Different decomposition levels and types of wavelet can be selected according to the demand. Secondly, the algorithm of inverse iteration compounding is used, which contains the arithmetic mean and the geometric mean of the components of adjacent decomposition levels. The adopted order for inverse iteration compounding is from the last level to the first one. The weight of the arithmetic mean to the geometric mean is one to one. In this way, four compounding components can be obtained. Thirdly, a new frame image with higher motion contrast can be obtained by using 2D discrete static wavelet inverse transform of the four compounding components. Both flow phantom and live animal experiments are performed. The results show that classification error rate decreases by 83% and 71% respectively after component compounding in wavelet domain. Besides, the angiogram has an improved motion contrast and a better vessel connectivity, which may contribute to better and wider applications of OCT angiography. Furthermore, based on the developed system, the preliminary imaging studies on the model of local stroke are conducted. In this experiment, we record the 3D data of SD mouse brain before and after the local stroke and on the tenth day. As a consequence, a clear presentation for the whole process of stroke model formation, vessel damage and vessel recovery is achieved, which may be beneficial to studying the mechanism of local stroke model.

Quantitative assessment of oral microstructural and microvascular changes in late oral radiation toxicity, using noninvasive in-vivo optical coherence tomography

Abstract Background and objectives: About half of the head and neck cancer patients treated with radiotherapy suffer from late radiation effects months to years after the treatment. The most common diagnosis and monitoring methods for such oral toxicities are based on surface examination of the oral tissue, which is subjective. Therefore, subsurface imaging and image quantification tools can be highly useful for monitoring these late effects as these approaches are more robust and objective. In this study, we demonstrate the ability of optical coherence tomography (OCT) technology and its newly developed quantitative imaging platform to reveal subsurface microstructural and microvascular changes in late oral radiation toxicity patients, not detectable by available clinical tools. Materials and methods: Fifteen patients exhibiting late oral radiation toxicity, and five healthy age-matched volunteers were imaged with OCT in a clinical pilot study. Image assessment methods, developed in-house, were used to extract four quantitative metrics of potential clinical importance from the acquired microstructural and microvascular oral OCT images. Results: The statistically significant differences in the patients compared to healthy volunteers were: lower epithelium to lamina propria thickness (indicating epithelial atrophy and/or fibrosis of lamina propria), smaller vessel diameter (indicating vessel lumen narrowing), and higher blood velocity. The observed in-vivo morphological changes correlated well with reported histology findings. No significant changes were observed in vessel tortuosity between the cohorts. Conclusion: The quantitative metrics extracted from the OCT images demonstrated significant microstructural and microvascular differences between the two cohorts. Potentially, OCT and its newly developed image analysis platform can be used as a noninvasive in-vivo subsurface tool for “shedding light” on late oral radiation toxicity, for example in palliative treatment efficacy monitoring.

Microvascular Abnormalities on Optical Coherence Tomography Angiography in Macular Edema Associated With Branch Retinal Vein Occlusion

To determine the ability of optical coherence tomography (OCT) angiography to image the microvascular structures compared with fluorescein angiography (FA) in patients with macular edema associated with branch retinal vein occlusion (BRVO). Retrospective, observational, consecutive case series. Twenty-eight eyes of 27 patients (14 men, 13 women; mean age, 68.4 years) with macular edema associated with BRVO were enrolled. Simultaneous OCT angiography and FA were performed in all patients to evaluate the microvascular abnormalities and nonperfused areas. OCT angiography detected nonperfused areas in 28 eyes and FA in 18 eyes. The respective findings of superficial capillary telangiectasias by OCT angiography and FA were 13 and 11 eyes, for deep capillary telangiectasias 28 eyes and 11 eyes, for collateral vessels 18 eyes and 16 eyes, and for microaneurysms 13 eyes and 14 eyes. OCT angiography facilitated differential layer analysis of microaneurysms and collaterals as well as capillary telangiectasias in the retina. OCT angiography can visualize microvascular abnormalities equally well or better than FA in eyes with BRVO. Multimodal imaging using OCT angiography and FA can be a powerful tool to evaluate the pathology in BRVO.

Retinal Nerve Fiber Layer Thickness Changes in Migraine: A Meta-Analysis of Case–Control Studies

Background: The neurovascular dysfunction appears to be related to the development of migraines and it could be possible that hypoperfusion might also involve other areas besides brain, including the retina. Numerous studies have analyzed the ability of optical coherence tomography (OCT) to detect retinal nerve fiber layer (RNFL) thickness abnormalities and changes in migraine, but the results have not always been consistent. Therefore, we carried out a meta-analysis to evaluate the RNFL thickness measured with OCT in migraine.Methods: Case–control studies were selected through an electronic search of the Cochrane Controlled Trials Register, PUBMED and EMBASE. For the continuous outcomes, we calculated the weighted mean difference (WMD) and 95% confidence interval (CI). The statistical analysis was performed by RevMan 5.0 software.Results: Six case–control studies were included in the present meta-analysis, containing a total of 432 eyes in migraine patients and 288 eyes in healthy controls. The results of our study showed that there was a significant reduction in average RNFL thickness in patients with migraine compared to healthy controls (WMD = −3.67, 95% CI: −6.84 to −0.49, p = 0.02). Additionally, differences of RNFL thickness in superior quadrant (WMD = −9.23, 95% CI: −15.63 to −2.82, p = 0.005), inferior quadrant (WMD = −3.47, 95% CI: −6.73 to −0.22, p = 0.04), nasal quadrant (WMD = −3.86, 95% CI: −7.10 to −0.61, p = 0.02) and temporal quadrant (WMD = −3.10, 95% CI: −5.05 to −1.15, p = 0.002) were all significant between the two groups.Conclusions: Our meta-analysis found that RNFL thickness in the migraine patients was thinner than that in the healthy control group. Given the limited sample size, further investigations are needed to validate these findings.

Quantitative optical coherence tomography angiography of vascular abnormalities in the living human eye

Retinal vascular diseases are important causes of vision loss. A detailed evaluation of the vascular abnormalities facilitates diagnosis and treatment in these diseases. Optical coherence tomography (OCT) angiography using the highly efficient split-spectrum amplitude decorrelation angiography algorithm offers an alternative to conventional dye-based retinal angiography. OCT angiography has several advantages, including 3D visualization of retinal and choroidal circulations (including the choriocapillaris) and avoidance of dye injection-related complications. Results from six illustrative cases are reported. In diabetic retinopathy, OCT angiography can detect neovascularization and quantify ischemia. In age-related macular degeneration, choroidal neovascularization can be observed without the obscuration of details caused by dye leakage in conventional angiography. Choriocapillaris dysfunction can be detected in the nonneovascular form of the disease, furthering our understanding of pathogenesis. In choroideremia, OCT's ability to show choroidal and retinal vascular dysfunction separately may be valuable in predicting progression and assessing treatment response. OCT angiography shows promise as a noninvasive alternative to dye-based angiography for highly detailed, in vivo, 3D, quantitative evaluation of retinal vascular abnormalities.

Application value of optical coherence tomography in predicting visual outcome after vitrectomy for idiopathic macular epiretinal membrane

Background Idiopathic macular epiretinal membrane (IMEM) shows a high incidence and affects visual function of patients.The primary management of IMEM is vitrectomy, but the study on prediction of visual acuity after operation by optical coherence tomography (OCT) is seldom. Objective This study was to evaluate the predicting ability of OCT for preoperative visual outcome for IMEM patients who received vitrectomy. Methods The clinical data of IMEM patients with vitrectomy from March 2009 to May 2013 were retrospectively analyzed in People's Hospital Peking University.Forty-nine eyes of 48 cases were divided into continuous group (19 eyes of 18 cases) and discontinuous group (31 eyes of 31 cases) based on whether the extraretinal layers were intact on OCT, including retinal pigment epithelium (RPE), inner and outer segment of photoreceptors (IS/OS) and external limiting membrane (ELM).Central foveal thickness (CFT) by high-resolution spectral-domain OCT and best corrected visual acuity (BCVA) (LogMAR) before surgery and 12 weeks after surgery were recorded and compared between the two groups, and the correlations of shift of CFT with the shift of LogMAR vision was analyzed by unitary linear regression to evaluate the value of OCT in predicting postoperative vision.Writen informed consent was obtained from each patient prior to any medical operation.Written informed consent was obtained from each patient before surgery. Results In 12 weeks after operation, reflective strips of RPE layer, IS/OS and ELM layer were intact in 18 eyes of the continuous group after vitrectomy.The number of eyes with discontinuous strip in RPE layer decreased to 1 eye after operation from 6 eyes before operation, and the number of eyes with IS/OS reflective strip discontinue decreased to 19 eyes after operation from 29 eyes before operation, and that with ELM layer discontinue decreased to 15 eyes after operation from before operation in the discontinuous group.The improvement of LogMAR BCVA was increased with the decline of CFT values with a negative correlation between them (R2=0.298, B=0.001, P=0.000), and postoperative LogMAR visual acuity improved 1 line whenever CFT reduced by 100 μm.LogMAR BCVA was 0.4±0.19 before surgery and 0.36±0.21after surgery in the continuous group, showing a insignificant difference between them (t=0.876, P=0.393).In the discontinuous group, the postoperative logMAR BCVA was significantly higher after operation (0.46±0.26) than 0.82±0.41 after operation (t=6.206, P=0.000).The increase value of LogMAR after vitrectomy was 0.3 in the discontinuous group, which was superior to 0.0 of the continuous group. Conclusions The continuity of extraretinal layers and CFT by OCT are closely associated with the improvement of vision after vitrectomy in the eyes with IMEM. Postoperative vision is better in IMEM eye with continuous retinal reflective strips before operation, and majority of IMEM eyes can improve vision after operation. Preoperative OCT seems to be an important diagnostic tool for the selection of patients who benefit or not from surgery to certain extent. Key words: Computerized tomography; Optical coherence tomography; Visual outcome; Prognosis; Idiopathic macular epiretinal membranes; Vitrectomy

Application of optical coherence tomography to identify pulp exposure during access cavity preparation using an Er:YAG laser.

The study aimed to evaluate the ability of optical coherence tomography (OCT) to guide and identify pulp exposure using an erbium: yttrium-aluminum-garnet (Er:YAG) laser. The Er:YAG laser has been proven to be effective in ablating dental hard tissue and offers advantages, as there is none of the vibration and noise you get with conventional methods, but it has limitations in relation to the tactile feedback that would aid in identification of entry into the pulp chamber. Based on depth-resolved optical reflectivity, OCT technology has been developed to provide high-resolution, cross-sectional images of the internal structure of biological tissues. The pulp chambers of 20 human mandibular incisors were examined, and the average thickness of hard tissue covering the pulp chamber was assessed using micro-computed tomography (micro-CT) images. An Er:YAG laser was used to gradually penetrate the hard tissue over the pulp chamber under microscopic guidance. The preparation was constantly imaged using a swept-source OCT at 10 sec intervals until a pulp chamber exposure was identified using the technology. The pulp exposure was re-examined under the microscope and compared with micro-CT images for verification. The pulp exposures of 20 incisors were all verified microscopically and with micro-CT images. The thickness of hard tissue penetrated by the laser ranged from 0.44 to 1.69 mm. Swept-source OCT is a useful tool for identifying pulp exposure during access opening with the Er: YAG laser.

Retinal nerve fiber layer thickness changes in Parkinson disease: a meta-analysis.

BackgroundParkinson disease (PD) is a neurodegenerative process that leads to a selective loss of dopaminergic neurons, mainly in the basal ganglia of the brain. Numerous studies have analyzed the ability of optical coherence tomography (OCT) to detect retinal nerve fiber layer (RNFL) thickness abnormalities and changes in PD, but the results have not always been consistent. Therefore, we carried out a meta-analysis to evaluate the RNFL thickness measured with OCT in PD.Methods and FindingsCase-control studies were selected through an electronic search of the Cochrane Controlled Trials Register, PUBMED and EMBASE. For the continuous outcomes, we calculated the weighted mean difference (WMD) and 95% confidence interval (CI). The statistical analysis was performed by RevMan 5.0 software. Thirteen case-control studies were included in the present meta-analysis, containing a total of 644 eyes in PD patients and 604 eyes in healthy controls. The results of our study showed that there was a significant reduction in average RNFL thickness in patients with PD compared to healthy controls (WMD = −5.76, 95% CI: −8.99 to −2.53, P = 0.0005). Additionally, differences of RNFL thickness in superior quadrant (WMD = −4.44, 95% CI: −6.93 to −1.94, P = 0.0005), inferior quadrant (WMD = −7.56, 95% CI: −11.33 to −3.78, P<0.0001), nasal quadrant (WMD = −3.12, 95% CI: −5.63 to −0.61, P = 0.01) and temporal quadrant (WMD = −4.63, 95% CI: −7.20 to −2.06, P = 0.0004) were all significant between the two groups.ConclusionIn view of these results and the noninvasive nature of OCT technology, we surmise that OCT could be a useful tool for evaluating the progression of the Parkinson disease.Trial RegistrationClinicalTrials.gov NCT01928212

Optical coherence tomography in diagnosing inflammatory diseases of ENT

AbstractThe object of the study was to demonstrate the abilities of optical coherence tomography (OCT) technique in diagnostics of inflammatory processes in ear, nose, and throat (ENT). When used in diagnostics of the nose and pharynx, OCT facilitates differential diagnostics of rhinitis enabling differentiation between the normal state, two stages of allergic rhinitis, vasomotor and atrophic rhinitis and diagnostics of pharyngitis. This paper also demonstrates the ability of OCT to monitor changes in pharynx induced by cryotherapy. In diagnostics of the tympanic cavity the ability of OCT to differentiate between different stages of chronic otitis and retraction of the tympanic membrane is demonstrated. Finally a correlation is discussed between morphologic alterations induced by inflammatory processes and changes in diagnostic OCT images.

Artificial Neural Network Techniques to Improve the Ability of Optical Coherence Tomography to Detect Optic Neuritis

ABSTRACTPurpose: To analyze the ability of Spectralis optical coherence tomography (OCT) to detect multiple sclerosis (MS) and to distinguish MS eyes with antecedent optic neuritis (ON). To analyze the capability of artificial neural network (ANN) techniques to improve the diagnostic precision. Methods: MS patients and controls were enrolled (n = 217). OCT was used to determine the 768 retinal nerve fiber layer thicknesses. Sensitivity and specificity were evaluated to test the ability of OCT to discriminate between MS and healthy eyes, and between MS with and without antecedent ON using ANN. Results: Using ANN technique multilayer perceptrons, OCT could detect MS with a sensitivity of 89.3%, a specificity of 87.6%, and a diagnostic precision of 88.5%. Compared with the OCT-provided parameters, the ANN had a better sensitivity-specificity balance. Conclusions: ANN technique improves the capability of Spectralis OCT to detect MS disease and to distinguish MS eyes with or without antecedent ON.

Electropysiologic Evaluation of the Visual Pathway in Patients With Multiple Sclerosis

To evaluate the ability of visual evoked potentials and pattern electroretinograms (PERG) to detect subclinical axonal damage in patients during the early diagnostic stage of multiple sclerosis (MS). The authors also compared the ability of optical coherence tomography (OCT), PERG, and visual evoked potentials to detect axonal loss in MS patients and correlated the functional and structural properties of the retinal nerve fiber layer. Two hundred twenty-eight eyes of 114 subjects (57 MS patients and 57 age- and sex-matched healthy controls) were included. The visual pathway was evaluated based on functional and structural assessments. All patients underwent a complete ophthalmic examination that included assessment of visual acuity, ocular motility, intraocular pressure, visual field, papillary morphology, OCT, visual evoked potentials, and PERG. Visual evoked potentials (P100 latency and amplitude), PERG (N95 amplitude and N95/P50 ratio), and OCT parameters differed significantly between MS patients and healthy subjects. Moderate significant correlations were found between visual evoked potentials or PERG parameters and OCT measurements. Axonal damage in ganglion cells of the visual pathway can be detected based on structural measures provided by OCT in MS patients and by the N95 component and N95/P50 index of PERG, thus providing good correlation between function and structure.

Retina thickness measurements provide a sensitive and specific diagnostic tool in Parkinson’s disease

AbstractPurpose To test the diagnostic ability of optical coherence tomography (OCT) for the detection of Parkinson’s disease (PD). Retinal thickness depends in part on the retinal pigment epithelium, one of the principal tissues producing levodopa.Methods PD patients (n=111) and healthy subjects (n=200) were enrolled. The Axonal application of the Spectralis OCT was used to obtain the circumpapillary RNFL thickness and retinal measurements in each participant. Two linear discriminant functions (LDF) were developed, one using RNFL parameters and another LDF using retinal thickness. A validating set (120 eyes from healthy individuals and 66 eyes from PD patients) was used to test the performance of both LDFs in an independent population. Receiver operating characteristic (ROC) curves were plotted and compared between both LDFs and with the standard parameters provided by OCT. Sensitivity and specificity were used to evaluate diagnostic performance.Results The Retinal LDF combines only retinal parameters and provided the best performance: 31.1 + 0.02 x Temporal Outer ‐ 0.2 x Superior Outer + 0.16 x Nasal Outer ‐ 0.2 x Inferior Outer ‐ 0.06 x Superior Inner + 0.05 x Foveal thickness. The largest areas under ROC curve were 0.902 for Retinal LDF and 0.845 for RNFL LDF. At 95% fixed specificity, the Retinal LDF yielded the highest sensitivity values.Conclusion Measurements of retinal thickness obtained with Spectralis OCT had a very good ability to differentiate between healthy and PD individuals. Based on the area under the ROC curve, the Retinal LDF performed better than any single parameter or diagnostic test used for PD.

Criteria for pathology recognition in optical coherence tomography of fallopian tubes

An increase of infertility and chronic pelvic pains syndrome, a growing level of latent diseases of this group, as well as a stably high percentage (up to 25% for infertility and up to 60% for the chronic pelvic pains syndrome) of undetermined origin raises the requirement for novel introscopic diagnostic techniques. We demonstrate abilities of optical coherence tomography (OCT) as a complementary technique to laparoscopy in diagnostics of fallopian tubes pathologies. We have acquired OCT images of different parts of fallopian tubes in norm and with morphologically proven pathology. Based on comparative analysis of the OCT data and the results of histological studies, we have worked out the subjective OCT criteria for distinguishing between unaltered and pathologic tissues. The developed criteria are verified in blind recognition tests. Diagnostic efficacy of OCT diagnostics in the case ofpelvic inflammatory diseases has been statistically evaluated, and high diagnostic accuracy (88%) is shown. Basing of the subjective criteria, an attempt to develop independent criteria aimed for automated recognition of pathological states in fallopian tubes is undertaken. Enhanced diagnostic accuracy (96%) of the developed independent criteria is demonstrated.