Petra P. Fang

Technical principles of OCT angiography

ZusammenfassungHintergrundDie OCT-Angiographie (OCT-A) ist eine neue klinische Untersuchungsmethode, die eine nichtinvasive dreidimensionale Darstellung der vaskulären Strukturen der Netzhaut und Aderhaut erlaubt. Technisch handelt es sich bei der OCT-A um eine Weiterentwicklung der optischen Kohärenztomographie (OCT). Durch leistungsfähigere Soft- und Hardware ermöglicht die OCT-A neben morphologischen Analysen auch eine dreidimensionale retinale und choroidale Perfusionsanalyse. Wir erläutern die Grundlagen sowie die Anwendung der OCT-A im Vergleich mit anderen nichtinvasiven Untersuchungsverfahren der retinalen und choroidalen Blutzirkulation.MethodenDer Arbeit liegen eine selektive Literaturrecherche und die Auswertung eigener Daten zugrunde.ErgebnisseVorteile der OCT-A bestehen in der einfachen Anwendung, die keiner Mydriasis oder intravenösen Fluoreszenzfarbstoffverabreichung bedarf. Sie gestattet eine exakte tiefensensitive Lokalisation vaskulärer Veränderungen. Bei retinalen Pathologien können Diskrepanzen zwischen softwareassistierter automatischer Segmentierung und realen Netzhautschichten bestehen, die bei der klinischen Interpretation zu beachten sind.SchlussfolgerungDie OCT-A ist von allen nichtinvasiven Perfusionsanalysen die einzige, die bereits in den klinischen Alltag implementiert werden kann. Mit diesem neuen bildgebenden Untersuchungsverfahren können vaskuläre retinale und choroidale Veränderungen tiefenselektiv und ohne Maskierungseffekt durch Pooling- oder Stainingphänomene detektiert werden.AbstractBackgroundOptical coherence tomography angiography (OCT-A) is a new diagnostic non-invasive method by which the vascular structures of the retina and choroid can be visualized three-dimensionally without need for using fluorescence dyes. The technology of OCT-A is an advancement of the OCT. By means of more powerful software and hardware used for OCT-A not only morphological but also retinal and choroidal vascular perfusion analyses can be performed. In this article, the principles and applications of OCT-A are discussed and compared to other non-invasive diagnostic devices for visualization of the retinal and choroidal blood circulation.MethodsThis article is based on a selective literature review and analyses of own data.ResultsThe advantages of OCT-A include easy application without the need for mydriasis or intravenous injection of fluorescence dyes and also the exact three-dimensional localization of vascular changes. In the case of retinal pathologies there is a considerable difference between software-assisted automatic segmentation and the real architecture of the retina, which must be taken into consideration in the clinical interpretation.ConclusionOf all noninvasive devices for visualization of the retinal and choroidal circulation, OCT-A is the only one which can already be implemented into the clinical routine. With this novel imaging device retinal and choroidal alterations can be visualized in a depth- selective manner and without masking affects, such as pooling or staining phenomena.BACKGROUND Optical coherence tomography angiography (OCT-A) is a new diagnostic non-invasive method by which the vascular structures of the retina and choroid can be visualized three-dimensionally without need for using fluorescence dyes. The technology of OCT-A is an advancement of the OCT. By means of more powerful software and hardware used for OCT-A not only morphological but also retinal and choroidal vascular perfusion analyses can be performed. In this article, the principles and applications of OCT-A are discussed and compared to other non-invasive diagnostic devices for visualization of the retinal and choroidal blood circulation. METHODS This article is based on a selective literature review and analyses of own data. RESULTS The advantages of OCT-A include easy application without the need for mydriasis or intravenous injection of fluorescence dyes and also the exact three-dimensional localization of vascular changes. In the case of retinal pathologies there is a considerable difference between software-assisted automatic segmentation and the real architecture of the retina, which must be taken into consideration in the clinical interpretation. CONCLUSION Of all noninvasive devices for visualization of the retinal and choroidal circulation, OCT-A is the only one which can already be implemented into the clinical routine. With this novel imaging device retinal and choroidal alterations can be visualized in a depth- selective manner and without masking affects, such as pooling or staining phenomena.

Technische Grundlagen der OCT-Angiographie

ZusammenfassungHintergrundDie OCT-Angiographie (OCT-A) ist eine neue klinische Untersuchungsmethode, die eine nichtinvasive dreidimensionale Darstellung der vaskulären Strukturen der Netzhaut und Aderhaut erlaubt. Technisch handelt es sich bei der OCT-A um eine Weiterentwicklung der optischen Kohärenztomographie (OCT). Durch leistungsfähigere Soft- und Hardware ermöglicht die OCT-A neben morphologischen Analysen auch eine dreidimensionale retinale und choroidale Perfusionsanalyse. Wir erläutern die Grundlagen sowie die Anwendung der OCT-A im Vergleich mit anderen nichtinvasiven Untersuchungsverfahren der retinalen und choroidalen Blutzirkulation.MethodenDer Arbeit liegen eine selektive Literaturrecherche und die Auswertung eigener Daten zugrunde.ErgebnisseVorteile der OCT-A bestehen in der einfachen Anwendung, die keiner Mydriasis oder intravenösen Fluoreszenzfarbstoffverabreichung bedarf. Sie gestattet eine exakte tiefensensitive Lokalisation vaskulärer Veränderungen. Bei retinalen Pathologien können Diskrepanzen zwischen softwareassistierter automatischer Segmentierung und realen Netzhautschichten bestehen, die bei der klinischen Interpretation zu beachten sind.SchlussfolgerungDie OCT-A ist von allen nichtinvasiven Perfusionsanalysen die einzige, die bereits in den klinischen Alltag implementiert werden kann. Mit diesem neuen bildgebenden Untersuchungsverfahren können vaskuläre retinale und choroidale Veränderungen tiefenselektiv und ohne Maskierungseffekt durch Pooling- oder Stainingphänomene detektiert werden.AbstractBackgroundOptical coherence tomography angiography (OCT-A) is a new diagnostic non-invasive method by which the vascular structures of the retina and choroid can be visualized three-dimensionally without need for using fluorescence dyes. The technology of OCT-A is an advancement of the OCT. By means of more powerful software and hardware used for OCT-A not only morphological but also retinal and choroidal vascular perfusion analyses can be performed. In this article, the principles and applications of OCT-A are discussed and compared to other non-invasive diagnostic devices for visualization of the retinal and choroidal blood circulation.MethodsThis article is based on a selective literature review and analyses of own data.ResultsThe advantages of OCT-A include easy application without the need for mydriasis or intravenous injection of fluorescence dyes and also the exact three-dimensional localization of vascular changes. In the case of retinal pathologies there is a considerable difference between software-assisted automatic segmentation and the real architecture of the retina, which must be taken into consideration in the clinical interpretation.ConclusionOf all noninvasive devices for visualization of the retinal and choroidal circulation, OCT-A is the only one which can already be implemented into the clinical routine. With this novel imaging device retinal and choroidal alterations can be visualized in a depth- selective manner and without masking affects, such as pooling or staining phenomena.BACKGROUND Optical coherence tomography angiography (OCT-A) is a new diagnostic non-invasive method by which the vascular structures of the retina and choroid can be visualized three-dimensionally without need for using fluorescence dyes. The technology of OCT-A is an advancement of the OCT. By means of more powerful software and hardware used for OCT-A not only morphological but also retinal and choroidal vascular perfusion analyses can be performed. In this article, the principles and applications of OCT-A are discussed and compared to other non-invasive diagnostic devices for visualization of the retinal and choroidal blood circulation. METHODS This article is based on a selective literature review and analyses of own data. RESULTS The advantages of OCT-A include easy application without the need for mydriasis or intravenous injection of fluorescence dyes and also the exact three-dimensional localization of vascular changes. In the case of retinal pathologies there is a considerable difference between software-assisted automatic segmentation and the real architecture of the retina, which must be taken into consideration in the clinical interpretation. CONCLUSION Of all noninvasive devices for visualization of the retinal and choroidal circulation, OCT-A is the only one which can already be implemented into the clinical routine. With this novel imaging device retinal and choroidal alterations can be visualized in a depth- selective manner and without masking affects, such as pooling or staining phenomena.

Persistent visual loss in dengue fever due to outer retinal damage

An 18-year-old woman presented with persistent vision loss and a central scotoma in both eyes since the beginning of an episode of dengue fever 3 weeks previously. Best corrected visual acuity (BCVA) was 20/50 in the right eye and 1/20 in the left eye. Pupillary reaction and intraocular pressure were unremarkable in both eyes. No intraocular inflammation was present in the anterior chamber or the vitreous. Ophthalmoscopy of both eyes revealed darkish red lesions at the posterior pole, which were more extensive in the left eye (Fig.1a,b). No optic disc swelling, retinal haemorrhages or signs of vasculitis were present on funduscopy or fluorescein angiography. Corresponding to the retinal lesions, a mild hypofluorescence was observed in the late phase of indocyanine green angiography, and a disruption of the outer neurosensory retina involving the outer limiting membrane, the myoid and ellipsoid zone as well as the outer segments of the photoreceptors was present on optical coherence tomography (OCT, Fig. 1c,d). Central and paracentral scotomas were present on mesopic funduscontrolled perimetry (Fig. 2a,f ). The mean deviation was −5.43 decibel (dB) for the right eye and −10.07 dB for the left eye. Serological testing identified high antibody titres for dengue virus and was negative for all other tested viruses including Zika virus and human T-lymphotropic virus. As there is no specific antiviral therapy for dengue fever, oral steroids at a dose of 0.5 mg/kg were started and tapered over the course of 2 months, during which the patient was followed up regularly. Figure 2. Top optical coherence tomography scan and infra-red reflectance image at the initial presentation. Bottom left, restoration of optical coherence tomography layers after 1 week after the onset of his symptoms. Right, development of cystoid macular oedema 2 weeks after presentation.

OCT Angiography–Based Detection and Quantification of the Neovascular Network in Exudative AMD

Purpose To investigate the potential of optical coherence tomography (OCT) angiography to detect and quantify the neovascular network in exudative AMD. Methods Treatment-naïve eyes that were diagnosed with exudative AMD were prospectively examined by OCT angiography (OCT-A). The extent of the neovascular network was measured by three independent readers. Interclass-correlation coefficient and area overlap coefficients (OC) were calculated to assess locally precise agreement between measurements. As a reference for interreader agreement, the extent of the neovascular network was further measured on fluorescein angiography (FA) images. Results A total of 31 eyes (27 patients, mean age 82.5 years, 15 female) were included in the study. Neovascularization subtype was classified as type I in 5, type II in 11, type III in 9, and mixed in 6 eyes, respectively. Interreader agreement for measurements of the neovascular network was 0.884 for OCT-A and 0.636 for FA. Overlap coefficient was 0.705 (interquartile [IQR]: 0.450-0.76) for OCT-A and 0.704 (IQR: 0.673-0.750) for FA, respectively. Area agreement was weaker in type III and mixed lesions. Conclusions Optical coherence tomography angiography-based measurements of the new vessel complex in neovascular AMD are feasible with interreader agreement comparable with the values obtained for FA. The results underscore the potential of OCT-A as a noninvasive diagnostic tool in neovascular AMD. Yet, further studies will be required to reveal the origin of poor agreement observed in single eyes and to advance OCT-A toward dependable use (e.g., in a reading center context).

Longitudinal Analysis of Drusen Volume in Intermediate Age-Related Macular Degeneration Using Two Spectral-Domain Optical Coherence Tomography Scan Patterns

Purpose: To evaluate two different spectral-domain optical coherence tomography (SD-OCT) scan patterns in eyes with intermediate age-related macular degeneration (AMD) for the longitudinal assessment of drusen volume. Methods: The data of 38 eyes of 38 AMD patients (age 69.97 ± 6.08 years) were included. The longitudinal drusen volume over 4 years was analyzed by annual SD-OCT raster scanning (field size 20 × 15°). Two raster scan patterns (A/B) differed in the distance between neighboring B-scans (240 vs. 30 µm) and in the number of averaged frames (4 vs. 15). Results: The mean drusen volume at baseline was 0.213 ± 0.100 mm3 (pattern A) and 0.219 ± 0.103 mm3 (pattern B) (p = 0.937). Linear mixed-effect models showed no significant difference for the change within 4 years for both pattern A (p = 0.8) and pattern B (p = 0.8). Conclusions: The results indicate that the performance of interpolation algorithms may be sufficient to balance for less dense raster scanning with regard to quantification of longitudinal drusen volume, which can be used as a surrogate marker for AMD progression in future clinical trials.

Technische Grundlagen der OCT-Angiographie@@@Technical principles of OCT angiography

ZusammenfassungHintergrundDie OCT-Angiographie (OCT-A) ist eine neue klinische Untersuchungsmethode, die eine nichtinvasive dreidimensionale Darstellung der vaskulären Strukturen der Netzhaut und Aderhaut erlaubt. Technisch handelt es sich bei der OCT-A um eine Weiterentwicklung der optischen Kohärenztomographie (OCT). Durch leistungsfähigere Soft- und Hardware ermöglicht die OCT-A neben morphologischen Analysen auch eine dreidimensionale retinale und choroidale Perfusionsanalyse. Wir erläutern die Grundlagen sowie die Anwendung der OCT-A im Vergleich mit anderen nichtinvasiven Untersuchungsverfahren der retinalen und choroidalen Blutzirkulation.MethodenDer Arbeit liegen eine selektive Literaturrecherche und die Auswertung eigener Daten zugrunde.ErgebnisseVorteile der OCT-A bestehen in der einfachen Anwendung, die keiner Mydriasis oder intravenösen Fluoreszenzfarbstoffverabreichung bedarf. Sie gestattet eine exakte tiefensensitive Lokalisation vaskulärer Veränderungen. Bei retinalen Pathologien können Diskrepanzen zwischen softwareassistierter automatischer Segmentierung und realen Netzhautschichten bestehen, die bei der klinischen Interpretation zu beachten sind.SchlussfolgerungDie OCT-A ist von allen nichtinvasiven Perfusionsanalysen die einzige, die bereits in den klinischen Alltag implementiert werden kann. Mit diesem neuen bildgebenden Untersuchungsverfahren können vaskuläre retinale und choroidale Veränderungen tiefenselektiv und ohne Maskierungseffekt durch Pooling- oder Stainingphänomene detektiert werden.AbstractBackgroundOptical coherence tomography angiography (OCT-A) is a new diagnostic non-invasive method by which the vascular structures of the retina and choroid can be visualized three-dimensionally without need for using fluorescence dyes. The technology of OCT-A is an advancement of the OCT. By means of more powerful software and hardware used for OCT-A not only morphological but also retinal and choroidal vascular perfusion analyses can be performed. In this article, the principles and applications of OCT-A are discussed and compared to other non-invasive diagnostic devices for visualization of the retinal and choroidal blood circulation.MethodsThis article is based on a selective literature review and analyses of own data.ResultsThe advantages of OCT-A include easy application without the need for mydriasis or intravenous injection of fluorescence dyes and also the exact three-dimensional localization of vascular changes. In the case of retinal pathologies there is a considerable difference between software-assisted automatic segmentation and the real architecture of the retina, which must be taken into consideration in the clinical interpretation.ConclusionOf all noninvasive devices for visualization of the retinal and choroidal circulation, OCT-A is the only one which can already be implemented into the clinical routine. With this novel imaging device retinal and choroidal alterations can be visualized in a depth- selective manner and without masking affects, such as pooling or staining phenomena.BACKGROUND Optical coherence tomography angiography (OCT-A) is a new diagnostic non-invasive method by which the vascular structures of the retina and choroid can be visualized three-dimensionally without need for using fluorescence dyes. The technology of OCT-A is an advancement of the OCT. By means of more powerful software and hardware used for OCT-A not only morphological but also retinal and choroidal vascular perfusion analyses can be performed. In this article, the principles and applications of OCT-A are discussed and compared to other non-invasive diagnostic devices for visualization of the retinal and choroidal blood circulation. METHODS This article is based on a selective literature review and analyses of own data. RESULTS The advantages of OCT-A include easy application without the need for mydriasis or intravenous injection of fluorescence dyes and also the exact three-dimensional localization of vascular changes. In the case of retinal pathologies there is a considerable difference between software-assisted automatic segmentation and the real architecture of the retina, which must be taken into consideration in the clinical interpretation. CONCLUSION Of all noninvasive devices for visualization of the retinal and choroidal circulation, OCT-A is the only one which can already be implemented into the clinical routine. With this novel imaging device retinal and choroidal alterations can be visualized in a depth- selective manner and without masking affects, such as pooling or staining phenomena.