Role Of Optical Coherence Tomography Research Articles

Ophthalmic manifestations of inherited neurodegenerative disorders.

Ophthalmic findings are common features of neurodegenerative disorders and, in addition to being clinically important, have emerged as potentially useful biomarkers of disease progression in several conditions. Clinically, these visual system abnormalities can be a clue to diagnosis, as well as being a prominent cause of disability in affected patients. In this Review, we describe the various afferent visual system and other ophthalmic features of inherited neurodegenerative disorders, including the muscular dystrophies, Friedreich ataxia, the spinocerebellar ataxias, hereditary spastic paraplegia, Charcot-Marie-Tooth disease, and other conditions. We focus on the expanding role of optical coherence tomography in diagnostic imaging of the retina and optic nerve head, and the possible use of ophthalmic findings as biomarkers of disease severity in hereditary neurodegenerative disorders. In addition, we discuss the ophthalmic manifestations and treatment implications of mitochondrial dysfunction, which is a feature of many inherited neurodegenerative diseases.

Invisible by angiography: the role of optical coherence tomography

Limited resolution and the ‘luminographical’ nature of invasive angiography can lead to misdiagnosis. Multidetector computed tomography and intravascular imaging tools can play a complementary role to angiography. A 63-year-old male, ten months after coronary artery bypass grafting for significant left main (LM) stenosis (Fig. 1A), was referred for control angiography due to recurrent angina. This revealed that all grafts were occluded. Thus, angiographically successful percutaneous coronary intervention (PCI) of the LM bifurcation and PCI of proximal segment of the left circumflex artery (LCx) was carried out. A 3.5 × 12 mm everolimus eluting stent (EES) was implanted to the mid-LCx. Next, a 3.0 × 28 mm EES was inserted across the distal LM segment and proximal left ascending artery (LAD) segment. A third 3.5 × 16 mm EES was implanted from the LM to the LCx in a Culotte-like fashion. Final kissing balloon (KB) post-dilatation was performed. Neither the first control angiography done two months after LM PCI, nor the next one at 12 month follow-up, revealed any suspicious restenotic lesions (Fig. 1B). However, computed tomography angiography (CTA) strongly suggested floating stent struts in the LM (Fig. 1C, D). Thus, optical coherence tomography (OCT) was performed (Fig. 2), which showed a short, ring-like lesion at the LAD ostium with the presence of a very few malapposed stent struts and neointimal proliferation outside the malaposed struts (Fig. 2D–F). Complex balloon angioplasty followed by KB post-dilatation was carried out. Final OCT showed apposed struts in the LM and torn restenotic ring with improvement in the minimal lumen area at the LAD ostium (Fig. 3C, D). However, a small tissue prolapse was still present in the LAD (Fig. 3A, B). No additional stent was implanted to cover the remaining flap. Bifurcation stenting is expected to induce greater stent deformity and malapposition. Culotte-like stenting can leave many malapposed struts in the flow divider region, despite consistent KB post-dilatation. It may be that a malapposed strut together with the tissue injury could have triggered the formation of such an unusual restenotic lesion. This case emphasises the crucial role of intravascular technique guidance for LM PCI, which was not used in the first procedure. Secondly, little is known about the clinical relevance of OCT detected tissue dissection, as in this case at the end of the re-PCI. Covering the short floating flap (which does not compromise significantly the LAD lumen), in our case with an additional layer of stent, is controversial.

Optical coherence tomography as a prognostic tool for visual improvement after management of diabetic macular edema

Objectives The aim of the study was to evaluate the role of optical coherence tomography (OCT) as a prognostic tool for visual improvement after management of diabetic macular edema (DME). Background OCT provides an easy quantitative assessment of the relationship between DME and visual acuity. Patients and methods Fifty eyes affected with DME were treated and followed up for 6 months. The main outcome measures were best corrected visual acuity (BCVA) and central macular thickness (CMT) in addition to photoreceptor integrity changes, which were measured using OCT at 1 month and 6 months after treatment. Result After treatment of DME, follow-up at 1 month revealed that the mean CMT was significantly higher among patients in the panretinal photocoagulation (PRP) + intravitreal triamcinolone acetonide (IVTA) + grid group compared with the patients in the grid + PRP group ( P = 0.001), focal + PRP group ( P = 0.01), and focal management group ( P = 0.008). The mean BCVA was significantly lower among patients in the grid + IVTA group compared with patients in the grid + PRP group ( P = 0.03), focal + PRP group ( P = 0.02), and focal treatment group ( P = 0.008). After 6 months of treatment, there was no significant difference between the mean values of CMT ( P = 0.46) or BCVA ( P = 0.07) with respect to different ways of management. With respect to the photoreceptor integrity at 1 month follow-up, the mean CMT was significantly lower in the intact ( P = 0.001) and disrupted ( P = 0.01) groups compared with that in the absent photoreceptor integrity group, whereas the mean BCVA was significantly higher in the intact group than in the absent ( P = 0.001) and disrupted ( P = 0.001) photoreceptor integrity groups. At 6 months, the mean CMT of the absent photoreceptor integrity group was significantly higher than that of the intact group ( P = 0.03), and the mean BCVA was significantly higher in the intact group than that in the disrupted photoreceptor integrity group ( P = 0.01). Conclusion CMT measured using OCT and the status of photoreceptor layer significantly provide an objective guideline for predicting the visual improvement in eyes with DME after treatment.

Automated registration of optical coherence tomography and dermoscopy in the assessment of sub-clinical spread in basal cell carcinoma

Optical coherence tomography (OCT) has been shown to be of clinical value in imaging basal cell carcinoma (BCC). A novel dual OCT-video imaging system, providing automated registration of OCT and dermoscopy, has been developed to assess the potential of OCT in measuring the degree of sub-clinical spread of BCC. Seventeen patients selected for Mohs micrographic surgery (MMS) for BCC were recruited to the study. The extent of BCC infiltration beyond a segment of the clinically assessed pre-surgical border was evaluated using OCT. Sufficiently accurate (<0.5 mm) registration of OCT and dermoscopy images was achieved in 9 patients. The location of the OCT-assessed BCC border was also compared with that of the final surgical defect. Infiltration of BCC across the clinical border ranged from 0 mm to >2.5 mm. In addition, the OCT border lay between 0.5 mm and 2.0 mm inside the final MMS defect in those cases where this could be assessed. In one case, where the final MMS defect was over 17 mm from the clinical border, OCT showed >2.5 mm infiltration across the clinical border at the FOV limit. These results provide evidence that OCT allows more accurate assessment of sub-clinical spread of BCC than clinical observation alone. Such a capability may have clinical value in reducing the number of surgical stages in MMS for BCC. There may also be a role for OCT in aiding the selection of patients most suitable for MMS.

Role of optical coherence tomography in posterior segment eye disorders: A review of two cases

Optical Coherence Tomography produces high resolution tomographic in in vivo imaging of biological tissues. The study reviews OCT images of two patients with varied retinal pathologies to determine its usefulness in aiding evaluation and management of retinal diseases. The patients were imaged using OCT conventional fundus photography and angiography. A case each of premacular haemorrhage and idiopathic polypoidal choroidal vasculopathy, are presented highlighting the merits of OCT. OCT establishes the accurate diagnosis of retinal diseases and in monitoring response to therapy. It is complementary to clinical techniques of direct and indirect ophthalmoscopy, conventional fundus photography, fluorescein and indocyanine green angiography thus should be made readily available for use in the evaluation of retinal disorders to enhance their management.

Role of Optical Coherence Tomography as a Diagnostic Tool in Macular Diseases

Back ground: Optimal coherence tomography (OCT) is a non contactnon invasive newer diagnostic tool that can perform tomography cross sectional imaging of biological tissues with <10 micron axial resolution using light waves near infrared beam. Methodology: Hospital based study conducted on 50 patients having macular diseases who attended DR RSPR Govt. regional eye hospital, Visakhapatnam. Each patient underwent a complete ophthalmic examination including best corrected visual acuity slit lamp biomicroscopy, IOP recording and fundus evaluation by indirect Opthalmoscopy with+90 D lens. In addition fundus photographs were taken. Routine blood examination and urine examination were done. Then the patients were subjected to evaluation of posterior segment by OCT. Results: Of the 50 cases on whom the OCT was done, majority (32%) were diabetic macular Oedema, followed by central serous Retinopathy (24%) and Epiretinal membrane was seen in 10% cases. Among the study participants, 7 patients presented with macular holes. Two patients had full thickness macular holes and five patients had lamellar holes. Conclusion: Diagnosis is confirmed by OCT gives additional information regarding pathological presentation, so help in the management.It may beneficially impact the visual disability by diagnosing a disease at an earlier stage.

OCT-BASED INTERPRETATION OF THE VITREOMACULAR INTERFACE AND INDICATIONS FOR PHARMACOLOGIC VITREOLYSIS

To review the role of optical coherence tomography (OCT) in diagnosis and management of vitreomacular disease and the impact of OCT on potential uses of ocriplasmin, a new pharmacologic vitreolysis agent recently approved by the U.S. Food and Drug Administration for the treatment of symptomatic vitreomacular adhesion. Analysis of current literature regarding OCT in diagnosis and management of vitreomacular interface disease. Posterior vitreous detachment is typically a nonpathologic age-related event. Anomalous posterior vitreous detachment emerges when the vitreous cortex fails to cleanly detach from the macula, optic nerve, or other adherent sites. Focal vitreomacular adhesion is a nonpathologic anatomical designation associated with perifoveal posterior vitreous detachment but normal retinal morphology on OCT. Vitreomacular traction is a pathologic consequence of persistent vitreous attachment with structural disturbance of the macular retina visible on OCT. Full-thickness macular holes are foveal defects continuous through all retinal layers to the retinal pigment epithelium. Vitreomacular traction and macular hole with focal vitreomacular adhesion are indications for pharmacologic vitreolysis. Noninvasive high-resolution OCT imaging has transformed the understanding of vitreomacular interface disease. Careful evaluation of the vitreomacular interface with OCT has increased in importance with the introduction of ocriplasmin for vitreomacular adhesion associated with symptomatic anatomical retinal changes.

Optical coherence tomography following percutaneous coronary intervention with Excimer laser coronary atherectomy

The indications for Excimer laser coronary atherectomy (ELCA) have been refined in modern interventional practice. With the expanding role for optical coherence tomography (OCT) providing high-resolution intra-coronary imaging, this article examines the appearance of the coronary lumen after ELCA. Each indication for ELCA is discussed and illustrated with a clinical case, followed by detailed analysis of the OCT imaging pre and post ELCA. The aim of the article is to provide information to interventional cardiologists to facilitate decision making during PCI, when ELCA has been used as part of the interventional strategy.

Idiopathic intracranial hypertension; research progress and emerging themes

Idiopathic intracranial hypertension (IIH) is a condition characterised by increased intracranial pressure of unknown cause predominantly seen in obese women of childbearing age and associated with a history of recent weight gain. The aetiology is poorly understood and there are no evidence-based guidelines on the management of the disease. We aim to provide a review of the recent literature outlining the latest advances in this field over the past few years. Areas of emerging interest related to the pathophysiology of IIH will be discussed, such as the role of obesity, adipose tissue and 11β-hydroxysteroid dehydrogenase type 1. We consider the latest research on the role of venous sinus stenosis in IIH and ex vivo advances into cerebrospinal fluid drainage via the arachnoid granulation tissue. The latest techniques for optic nerve head evaluation and the role of optical coherence tomography will be summarised. Finally, we will discuss recent advances in the management of IIH, including weight loss, and medical and surgical treatment strategies.

Macular segmentation in Neuro-Ophthalmology: Descriptive or predictive?

Optical coherence tomography (OCT) has become essential to evaluate axonal/neuronal integrity, to assess disease progression in the afferent visual pathway and to predict visual recovery after surgery in compressive optic neuropathies. Besides that OCT testing is considered a powerful biomarker of neurodegeneration and a promising outcome measure for neuroprotective trials in multiple sclerosis (MS).Currently, spectral-domain OCT (SD-OCT) technology allows quantification of retinal individual layers. The Ganglion Cell layer (GCL) investigation has become one of the most useful tools from a neuro-ophthalmic perspective. It has a high correlation with perimetry, is predictive of future progression and is a highly sensitive, specific of several neuro-ophthalmic pathologies. Moreover the superior correlation with clinical measures compared to peripapillary retinal nerve fiber layer (pRNFL) suggests that GCL analysis might be a better approach to examine MS neurodegeneration.In disorders with optic disk edema, such as ischemic optic neuropathy, papillitis and papilledema, reduction in RNFL thickness caused by axonal atrophy is difficult to distinguish from a swelling resolution. In this setting, and in buried optic nerve head drusen (ONHD), GCL analysis may provide more accurate information than RNFL analysis and it might be an early structural indicator of irreversible neuronal loss.Enhanced depth imaging OCT (EDI-OCT) provides in vivo detail of ONHD, allowing to evaluate and quantify the drusen dimensions.OCT is improving our knowledge in hereditary optic neuropathies. Furthermore, there is growing evidence about the role of OCT as an adjunctive biomarker of disorders such as Alzheimer and Parkinson’s disease.

Optical coherence tomography as a progression marker in mild cognitive impairment and Alzheimer´s disease

AbstractPurpose To study the role of optical coherence tomography (OCT) as a progression marker in patients with mild cognitive impairment (MCI) and Alzheimer’s disease (AD).Methods We studied 36 eyes of 18 patients meeting criteria for AD (6 patients with mild AD, 7 patients with moderate AD and 5 patients with severe AD), and 21 eyes of 42 patients meeting criteria for MCI. In these two groups, we evaluated cognitive impairment through the Mini‐Mental State Examination (MMSE), the verbal fluency test (VFT) and the clock test (CT) and we measured peripapillary retinal nerve fiber layer (RNFL) thickness, and macular volume and thickness using OCT.Results There is a significant correlation between the decrease in peripapillary RNFL thickness, macular volume and macular thickness and the severity of the cognitive impairment measured by the three neuro‐psychological tests (p=0.00).Conclusion The reduction in peripapillary and macular thickness and macular volume is related to the severity of cognitive impairment. Thus, OCT can be used for the diagnosis of AD and MCI (especially in the diagnosis of early‐ stage AD), as well as to evaluate cognitive impairment progression.

Macula en dôme : aspects échographique et tomographique

The purpose of our work is to demonstrate the role of optical coherence tomography and ocular ultrasound in the diagnosis of the dome-shaped macula in high myopia.We report the case of a patient with high myopia who presented with a decrease in visual acuity and metamorphopsia in the left eye. She underwent visual acuity measurement, biomicroscopic examination and measurement of axial length. B-mode ultrasound and optical coherence tomography showed a projection of the macula in the convexity of the myopic staphyloma confirming the diagnosis of dome-shaped macula.Dome-shaped macula is a recently discovered entity, which may be responsible for a decrease in visual acuity in patients with high myopic posterior staphyloma. Ultrasound and optical coherence tomography are very helpful in making the diagnosis.

Optical coherence tomography for evaluation of coronary stents in vivo

Coronary optical coherence tomography (OCT) is a light-based imaging modality that emits light in the near-infrared range. Compared with intravascular ultrasound, OCT has an extraordinarily high resolution (nearly tenfold higher), with an axial resolution in the range of 12–15 µm and a lateral resolution of 20–40 µm. The main drawback of OCT is its relatively low penetration power, especially into lipid-rich atherosclerotic tissue. Second-generation OCT systems, known as frequency domain OCT, are now widely available in many catheter laboratories. The hallmark of OCT is its outstanding ability to depict superficial vessel wall structures with high accuracy. In this regard, OCT was used to evaluate stent expansion and stent strut apposition both early and late following stent deployment, as well as neointimal coverage over struts at long-term follow-up. It has discriminated the differences in strut malapposition and strut neointimal coverage among different stent designs and in various strut subsets. Similarly, OCT delineated many forms of vessel wall injury following percutaneous coronary intervention, such as dissections, thrombosis and tissue protrusion between struts. Recently, OCT was used to study the biodegradation of bioresorbable vascular scaffolds. This review focuses on the role of OCT in the in vivo evaluation of coronary stents.

Role of optical coherence tomography for flexor tendon imaging in a rabbit model

Optical coherence tomography (OCT) was used to monitor various flexor tendon states including tendon at rest, normal tendons during loading, tendon microstructural damage post loading, and healing tendons at 0, 3, and 8 weeks time points.Potential uses include assessing microstructural damage, monitoring the quality of suture repair, and tendon healing. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:990–995, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27514

Optical coherence tomography and fundus autofluorescence imaging in uveitis

The current role of optical coherence tomography (OCT) and fundus autofluorescence (FAF) imaging in the diagnosis and management of uveitis is summarized in this article. OCT can be useful to detect and monitor cystoid macular edema and epiretinal membrane, two findings that are very common in intermediate, posterior and pan-uveitis. Both OCT and FAF demonstrate unique findings in several forms of posterior uveitis including birdshot chorioretinopathy, multiple evanescent white dot syndrome, acute posterior multifocal placoid pigment epitheliopathy, acute zonal occult outer retinopathy, multifocal choroiditis and Vogt–Koyanagi–Harada disease. Advances in OCT have allowed detection of alterations in retinal microstructure (spectral-domain OCT) as well as variations in choroidal thickness (enhanced-depth imaging OCT). With new advances in imaging, OCT and FAF have been shown to be helpful in understanding the pathophysiology of and differentiating between various forms of uveitis. Both imaging techniques may be helpful in monitoring patients with uveitis over time.

The Role of Optical Coherence Tomography in Clarifying the Mechanisms for Dobutamine Stress Echocardiography‐Induced Takotsubo Cardiomyopathy

Takotsubo cardiomyopathy is a clinical disorder characterized by a transient dilatation and akynesis or dyskinesis of the left ventricular (LV) apex, mimicking an anterior wall acute myocardial infarction in the absence of significant coronary artery disease (CAD). It typically occurs during an episode of severe emotional or physical stress. Recent reports suggested the potential of dobutamine stress echocardiography (DSE) in inducing the aforementioned syndrome. The transient dysfunction of the LV does not fit any known coronary distribution. Furthermore, there is no obstructive CAD demonstrated at angiography to account for the observed dysfunction. Consequently, the pathophysiology of this syndrome is still undetermined. Here, we report a case of DSE-induced Takotsubo cardiomyopathy in which high-resolution intracoronary imaging was utilized to exclude possible vessel alterations to help provide potential mechanistic explanations for the development of this condition.

Evidence Based Medicine: Why should we be practicing it all the time?

Evidence Based Medicine: Why should we be practicing it all the time?

Mechanisms of late stent-related myocardial infarction: insights from optical coherence tomography

This article focuses on optical coherence tomography findings in patients with late major cardiovascular events like myocardial infarction and/or stent thrombosis, following drug-eluting stent and bare-metal stent implantation. Uncovered stent struts and malapposition seem to play a critical role in drug-eluting stent-related late events. Neointimal features similar to native atherosclerosis are usually found in bare-metal stent-related late events, although there is increasing evidence that this may also happen with drug-eluting stents, but with a different chronology. The role of optical coherence tomography in exploring the mechanisms of such late events, and its potential role in percutaneous coronary intervention optimization guided by these presumed mechanisms, is further discussed.

Role of optical coherence tomography on corneal surface laser ablation.

This paper focuses on reviewing the roles of optical coherence tomography (OCT) on corneal surface laser ablation procedures. OCT is an optical imaging modality that uses low-coherence interferometry to provide noninvasive cross-sectional imaging of tissue microstructure in vivo. There are two types of OCTs, each with transverse and axial spatial resolutions of a few micrometers: the time-domain and the fourier-domain OCTs. Both have been increasingly used by refractive surgeons and have specific advantages. Which of the current imaging instruments is a better choice depends on the specific application. In laser in situ keratomileusis (LASIK) and in excimer laser phototherapeutic keratectomy (PTK), OCT can be used to assess corneal characteristics and guide treatment decisions. OCT accurately measures central corneal thickness, evaluates the regularity of LASIK flaps, and quantifies flap and residual stromal bed thickness. When evaluating the ablation depth accuracy by subtracting preoperative from postoperative measurements, OCT pachymetry correlates well with laser ablation settings. In addition, OCT can be used to provide precise information on the morphology and depth of corneal pathologic abnormalities, such as corneal degenerations, dystrophies, and opacities, correlating with histopathologic findings.

The Role of Optical Coherence Tomography in Coronary Intervention

Optical coherence tomography (OCT) is an optical analog of intravascular ultrasound (IVUS) that can be used to examine the coronary arteries and has 10-fold higher resolution than IVUS. Based on polarization properties, OCT can differentiate tissue characteristics (fibrous, calcified, or lipid-rich plaque) and identify thin-cap fibroatheroma. Because of the strong attenuation of light by blood, OCT systems required the removal of blood during OCT examinations. A recently developed frequency-domain OCT system has a faster frame rate and pullback speed, making the OCT procedure more user-friendly and not requiring proximal balloon occlusion. During percutaneous coronary intervention (PCI), OCT can provide detailed information (dissection, tissue prolapse, thrombi, and incomplete stent apposition [ISA]). At follow-up examinations after stent implantation, stent strut coverage and ISA can be assessed. Several OCT studies have demonstrated delayed neointimal coverage following drug-eluting stent (DES) implantation vs. bare metal stent (BMS) placement. While newer DESs promote more favorable vascular healing, the clinical implications remain unknown. Recent OCT studies have provided insights into restenotic tissue characteristics; DES restenotic morphologies differ from those with BMSs. OCT is a novel, promising imaging modality; with more in-depth assessments of its use, it may impact clinical outcomes in patients with symptomatic coronary artery disease.