F. Scholz

[Optical coherence tomography for macular edema. Classification, quantitative assessment, and rational usage in the clinical practice].

Optical coherence tomography (OCT) allows for morphological assessment of macular edema of various origins by producing two-dimensional images of the retina. In addition, retinal thickness can be measured quantitatively. In diabetic maculopathy, damage of the blood-retinal barrier can be indirectly assessed by locating the intraretinal fluid accumulation and the progress of maculopathy from diffuse to cystoid edema and even rupture of the retinal structure can be described as well as the formation of neurosensory retinal detachment with subretinal fluid. Increase of retinal thickness correlates with decrease in visual acuity. Detailed interpretation of OCT images can replace fluorescein angiography in certain cases, as has been shown for uveitis. In order to obtain correct classification of macular disease in routine clinical use, all images have to be completely assessed and compared to previous investigations and to the measurements of the fellow eye. More accurate normal values of retinal thickness and volume can be expected in the future. The importance of OCT in routine clinical assessment of macular edema will most probably continue to grow.ZusammenfassungDie optische Kohärenztomographie (OCT) ermöglicht die morphologische Beurteilung von Makulaödemen verschiedener Ursache im zweidimensionalen Schnittbild in vivo. Darüber hinaus kann eine quantitative Beurteilung durch die Messung der Netzhautdicke durchgeführt werden. Bei der diabetischen Makulopathie lässt sich die Schädigung der Blut-Retina-Schranke indirekt an der Lokalisation der intraretinalen Flüssigkeit nachweisen und die Entwicklung der Makulopathie über das diffuse und zystoide Ödem bis hin zur Ruptur der Netzhaut ebenso beschreiben, wie die Abhebung der neurosensorischen Netzhaut. Es besteht ein Zusammenhang zwischen der Zunahme der Netzhautdicke und der Visusminderung. Bei detaillierter Auswertung kann die OCT beispielsweise bei Uveitis die Fluoreszeinangiographie ersetzen. In der klinischen Routine muss zur Klassifizierung auf die vollständige Beurteilung aller verfügbaren Scans geachtet, der Seitenvergleich berücksichtigt und der Verlauf miteinbezogen werden. Für die Zukunft sind genauere Normwerte für die Netzhautdicken- und -volumenmessung zu erwarten. Die OCT wird in der Beurteilung des Makulaödems in der klinischen Routine weiter an Bedeutung gewinnen.AbstractOptical coherence tomography (OCT) allows for morphological assessment of macular edema of various origins by producing two-dimensional images of the retina. In addition, retinal thickness can be measured quantitatively. In diabetic maculopathy, damage of the blood-retinal barrier can be indirectly assessed by locating the intraretinal fluid accumulation and the progress of maculopathy from diffuse to cystoid edema and even rupture of the retinal structure can be described as well as the formation of neurosensory retinal detachment with subretinal fluid. Increase of retinal thickness correlates with decrease in visual acuity. Detailed interpretation of OCT images can replace fluorescein angiography in certain cases, as has been shown for uveitis. In order to obtain correct classification of macular disease in routine clinical use, all images have to be completely assessed and compared to previous investigations and to the measurements of the fellow eye. More accurate normal values of retinal thickness and volume can be expected in the future. The importance of OCT in routine clinical assessment of macular edema will most probably continue to grow.

[Optical coherence tomography for macula diagnostics. Review of methods and standardized application concentrating on diagnostic and therapy control of age-related macula degeneration].

BACKGROUND Optical coherence tomography (OCT) has gained increasing relevance for follow-up after the treatment of macular diseases especially after anti-VEGF therapy. Therefore it seemed reasonable to develop standardized evaluation strategies and OCT examination guidelines for Stratus OCT III. MATERIALS AND METHODS Basic guidelines for the Stratus OCT III examination of macular diseases were developed. The first part contains basic advice for the OCT examination with respect to the examiner, patients, image quality, movement artefacts, algorithms, archiving and interpretation of OCT images. The second part consists of the relevance and indications for OCT examination especially in age-related macular degeneration (AMD), subgroups of AMD and follow-up after treatment. The third part demonstrates a brief outlook on future developments, such as the digital integration method (DIM), which provides identical scan localization in follow-up and eliminates any movement artefacts. CONCLUSION The application of standardized routine scanning and analysis protocols in Stratus OCT III for macular diseases and follow-up examinations provides an optimized, time-saving and comparable use of OCT. Therefore, the relevance and quality of OCT is increased for routine use in outpatient departments, hospitals and also for clinical studies.

Die digitale Integrationsmethode (DIM): Ein neues Verfahren zur präzisen Korrelation von OCT und Fluoreszenzangiographie

ZusammenfassungDie neue digitale Integrationsmethode (DIM) erlaubt erstmals die anatomisch exakte Integration der OCT-Scanlage in das Fluoreszenzangiographiebild (FLA) mit Hilfe von Referenzmarkern an Gefäßgabelungen. Somit ist eine präzise Korrelation von angiographischen und morphologischen Pathologien möglich und führt zu gegenseitigem besseren Verständnis. Am meisten haben die Erkrankungen profitiert, die in der Angiographie unklare Phänomene zeigen und mit deren präziser Korrelation im OCT zusätzliche Information gewonnen werden kann wie z. B. bei den Leckagen unklarer Herkunft, wo das OCT topographisch das Areal einer serösen RPE-Abhebung (RPE) markieren kann. Bisher war nicht wirklich klar, ob die wichtigsten Makulastrukturpathologien von FLA und OCT dieselbe Region tatsächlich erfasst haben. Dies war besonders dann von Relevanz, wenn unterschiedliche Personen die Untersuchung durchführen oder auch beurteilen. Dieses Problem kann nunmehr durch die neue digitale Integrationsmethode (DIM) als weitgehend gelöst gelten. Dies ist zudem die eigentliche Voraussetzung für Verlaufskontrollen mittels OCT. Durch die objektive, zuverlässige und präzise gegenseitige Korrelation der OCT- und FLA-Befunde ist es nun erstmals möglich auch bei Verlaufskontrollen sicher dieselbe Scanlokalisation einzustellen. Für Verlaufskontrollen in Studien mit dem OCT sollte die digitale Integrationsmethode (DIM) auch als qualitätssichern de Maßnahme gefordert werden, um die Aussagekraft der Ergebnisse zu erhöhen.SummaryThe new integration method (DIM) provides for the first time the anatomically precise integration of the OCT-scan position into the angiogram (fluorescein angiography, FLA), using reference marker at corresponding vessel crossings. Therefore an exact correlation of angiographic and morphological pathological findings is possible und leads to a better understanding of OCT and FLA. Occult findings in FLA were the patient group which profited most. Occult leakages could gain additional information using DIM such as serous detachment of the retinal pigment epithelium (RPE) in a topography. So far it was unclear wether the same localization in the lesion was examined by FLA and OCT especially when different staff were performing and interpreting the examination. Using DIM this problem could be solved using objective markers. This technique is the requirement for follow-up examinations by OCT. Using DIM for an objective, reliable and precise correlation of OCT and FLA-findings it is now possible to provide the identical scan-position in follow-up. Therefore for follow-up in clinical studies it is mandatory to use DIM to improve the evidence-based statement of OCT and the quality of the study.

OCT in macular holes

ZusammenfassungNach der traditionellen Stadieneinteilung von Makulaforamina (MF) nach Gass ergeben sich durch das OCT zusätzliche und genauere morphologische Kenntnisse von Makulaforamen. Als primärer Pathomechanismus der Makulaforamenentstehung wird eine perifoveale GK-Abhebung mit anteriorer fovealer Glaskörpertraktion angenommen. Bei persistierender Traktion kann diese zur foveolären Dehiszenz führen. Eine mögliche Erklärung für die intraretinale Zystenbildung ist die Hydratation der Fovea durch Glaskörperflüssigkeit. Aufgrund zusätzlicher Befunde aus dem OCT ist eine Klassifikation von MF möglich. Das OCT bei MF ist eine wertvolle Hilfe für die Differenzialdiagnose (Pseudomakulaforamen — echtes MF), präzise Stadieneinteilung, Therapieentscheidung, Erfolgskontrolle nach Makulachirurgie und als Prognoseindikator.AbstractThe traditional Gass classification of macular holes can now be supplemented by additional and more detailed morphologic information obtained with optical coherence tomography (OCT). The perifoveal vitreous detachment and subsequent anterior foveal traction is considered to be the primary pathomechanism of macular hole formation. In cases of persistent traction on the fovea it may lead to foveal dehiscence. A possible explanation for intraretinal cyst formation may be secondary vitreous body fluid accumulation within the retina. A classification of macular holes based on additional information from OCT images is possible. Thus, OCT is a valuable tool for differential diagnosis of a pseudo macular hole versus macular hole, precise stage classification, therapy decision making process, outcome control after macular surgery, and prognosis prediction.

Optische Kohärenztomographie in der Makuladiagnostik

BACKGROUND Optical coherence tomography (OCT) has gained increasing relevance for follow-up after the treatment of macular diseases especially after anti-VEGF therapy. Therefore it seemed reasonable to develop standardized evaluation strategies and OCT examination guidelines for Stratus OCT III. MATERIALS AND METHODS Basic guidelines for the Stratus OCT III examination of macular diseases were developed. The first part contains basic advice for the OCT examination with respect to the examiner, patients, image quality, movement artefacts, algorithms, archiving and interpretation of OCT images. The second part consists of the relevance and indications for OCT examination especially in age-related macular degeneration (AMD), subgroups of AMD and follow-up after treatment. The third part demonstrates a brief outlook on future developments, such as the digital integration method (DIM), which provides identical scan localization in follow-up and eliminates any movement artefacts. CONCLUSION The application of standardized routine scanning and analysis protocols in Stratus OCT III for macular diseases and follow-up examinations provides an optimized, time-saving and comparable use of OCT. Therefore, the relevance and quality of OCT is increased for routine use in outpatient departments, hospitals and also for clinical studies.

OCT bei Makulaforamen

ZusammenfassungNach der traditionellen Stadieneinteilung von Makulaforamina (MF) nach Gass ergeben sich durch das OCT zusätzliche und genauere morphologische Kenntnisse von Makulaforamen. Als primärer Pathomechanismus der Makulaforamenentstehung wird eine perifoveale GK-Abhebung mit anteriorer fovealer Glaskörpertraktion angenommen. Bei persistierender Traktion kann diese zur foveolären Dehiszenz führen. Eine mögliche Erklärung für die intraretinale Zystenbildung ist die Hydratation der Fovea durch Glaskörperflüssigkeit. Aufgrund zusätzlicher Befunde aus dem OCT ist eine Klassifikation von MF möglich. Das OCT bei MF ist eine wertvolle Hilfe für die Differenzialdiagnose (Pseudomakulaforamen — echtes MF), präzise Stadieneinteilung, Therapieentscheidung, Erfolgskontrolle nach Makulachirurgie und als Prognoseindikator.AbstractThe traditional Gass classification of macular holes can now be supplemented by additional and more detailed morphologic information obtained with optical coherence tomography (OCT). The perifoveal vitreous detachment and subsequent anterior foveal traction is considered to be the primary pathomechanism of macular hole formation. In cases of persistent traction on the fovea it may lead to foveal dehiscence. A possible explanation for intraretinal cyst formation may be secondary vitreous body fluid accumulation within the retina. A classification of macular holes based on additional information from OCT images is possible. Thus, OCT is a valuable tool for differential diagnosis of a pseudo macular hole versus macular hole, precise stage classification, therapy decision making process, outcome control after macular surgery, and prognosis prediction.

OCT bei Makulaödem

Optical coherence tomography (OCT) allows for morphological assessment of macular edema of various origins by producing two-dimensional images of the retina. In addition, retinal thickness can be measured quantitatively. In diabetic maculopathy, damage of the blood-retinal barrier can be indirectly assessed by locating the intraretinal fluid accumulation and the progress of maculopathy from diffuse to cystoid edema and even rupture of the retinal structure can be described as well as the formation of neurosensory retinal detachment with subretinal fluid. Increase of retinal thickness correlates with decrease in visual acuity. Detailed interpretation of OCT images can replace fluorescein angiography in certain cases, as has been shown for uveitis. In order to obtain correct classification of macular disease in routine clinical use, all images have to be completely assessed and compared to previous investigations and to the measurements of the fellow eye. More accurate normal values of retinal thickness and volume can be expected in the future. The importance of OCT in routine clinical assessment of macular edema will most probably continue to grow.ZusammenfassungDie optische Kohärenztomographie (OCT) ermöglicht die morphologische Beurteilung von Makulaödemen verschiedener Ursache im zweidimensionalen Schnittbild in vivo. Darüber hinaus kann eine quantitative Beurteilung durch die Messung der Netzhautdicke durchgeführt werden. Bei der diabetischen Makulopathie lässt sich die Schädigung der Blut-Retina-Schranke indirekt an der Lokalisation der intraretinalen Flüssigkeit nachweisen und die Entwicklung der Makulopathie über das diffuse und zystoide Ödem bis hin zur Ruptur der Netzhaut ebenso beschreiben, wie die Abhebung der neurosensorischen Netzhaut. Es besteht ein Zusammenhang zwischen der Zunahme der Netzhautdicke und der Visusminderung. Bei detaillierter Auswertung kann die OCT beispielsweise bei Uveitis die Fluoreszeinangiographie ersetzen. In der klinischen Routine muss zur Klassifizierung auf die vollständige Beurteilung aller verfügbaren Scans geachtet, der Seitenvergleich berücksichtigt und der Verlauf miteinbezogen werden. Für die Zukunft sind genauere Normwerte für die Netzhautdicken- und -volumenmessung zu erwarten. Die OCT wird in der Beurteilung des Makulaödems in der klinischen Routine weiter an Bedeutung gewinnen.AbstractOptical coherence tomography (OCT) allows for morphological assessment of macular edema of various origins by producing two-dimensional images of the retina. In addition, retinal thickness can be measured quantitatively. In diabetic maculopathy, damage of the blood-retinal barrier can be indirectly assessed by locating the intraretinal fluid accumulation and the progress of maculopathy from diffuse to cystoid edema and even rupture of the retinal structure can be described as well as the formation of neurosensory retinal detachment with subretinal fluid. Increase of retinal thickness correlates with decrease in visual acuity. Detailed interpretation of OCT images can replace fluorescein angiography in certain cases, as has been shown for uveitis. In order to obtain correct classification of macular disease in routine clinical use, all images have to be completely assessed and compared to previous investigations and to the measurements of the fellow eye. More accurate normal values of retinal thickness and volume can be expected in the future. The importance of OCT in routine clinical assessment of macular edema will most probably continue to grow.

Die neue OCT-Generation lässt tiefer blicken

BACKGROUND Until now depiction of the choroid using time domain optical coherence tomography (OCT) (Stratus III) was barely possible. Visualization of choroidal perfusion was carried out using indocyanine green angiography (ICGA). The spectral-domain OCT, such as Cirrus OCT (C-OCT) is able to image the choroid better because it offers higher resolution, increased penetration depth of the scan beam and faster acquisition of A-scan data. The aim of the study was to evaluate the potential of choroidal imaging in patients suffering from macular disease. METHODS The advanced visualization tool of C-OCT was primarily used and converted to a z-axis topography. Because of a special algorithm developed by our team, targeted imaging of the choroidal vessels was possible through the scanned two dimensional retinal areas. This image offers an extended image of choroidal vessels (large and small vessels) in several levels. In total 20 patients eyes (n = 15 with various macular diseases and n = 5 normal conditions) who underwent C-OCT and ICG angiography (HRA 2) were chosen to participate in this special algorithm. A precise correlation of ICG and choroid OCT in a semitransparent manner was carried out. RESULTS The first prototype of the recognition software prototype produced clear imaging of the choroid in 100% of cases but only in 55% in the macular region depending on the extent of macular disease. Limitations were low signal intensity and penetration depth as well as a poorly defined retinal pigment epithelium (RPE) and choriocapillaris especially in macular diseases of the RPE layer. After a black and white conversion in OCT using the software it was possible in all cases to integrate the choroidal OCT with the ICG angiogram in a semitransparent manner. This confirms that the choroidal vessels in C-OCT correlated identically with the ICG angiography. In contrast to the ICG where the contrast agent in the vessel emits a signal, the choroidal vessels are visible due to different reflectivity in the merging tissue. CONCLUSIONS These investigations showed that non-invasive topographic imaging of the choroid using spectral domain OCT, such as Cirrus OCT is now possible. Distinguishability of smaller vessels was excellent. The ICG (perfusion) and C-OCT (morphology) methods are two very different vessel imaging techniques. The integration of both methods is possible. The clinical relevance of the new image information still has to be researched.

[The new OCT generation offers deep insights: imaging of the choroid using the Cirrus OCT].

BACKGROUND Until now depiction of the choroid using time domain optical coherence tomography (OCT) (Stratus III) was barely possible. Visualization of choroidal perfusion was carried out using indocyanine green angiography (ICGA). The spectral-domain OCT, such as Cirrus OCT (C-OCT) is able to image the choroid better because it offers higher resolution, increased penetration depth of the scan beam and faster acquisition of A-scan data. The aim of the study was to evaluate the potential of choroidal imaging in patients suffering from macular disease. METHODS The advanced visualization tool of C-OCT was primarily used and converted to a z-axis topography. Because of a special algorithm developed by our team, targeted imaging of the choroidal vessels was possible through the scanned two dimensional retinal areas. This image offers an extended image of choroidal vessels (large and small vessels) in several levels. In total 20 patients eyes (n = 15 with various macular diseases and n = 5 normal conditions) who underwent C-OCT and ICG angiography (HRA 2) were chosen to participate in this special algorithm. A precise correlation of ICG and choroid OCT in a semitransparent manner was carried out. RESULTS The first prototype of the recognition software prototype produced clear imaging of the choroid in 100% of cases but only in 55% in the macular region depending on the extent of macular disease. Limitations were low signal intensity and penetration depth as well as a poorly defined retinal pigment epithelium (RPE) and choriocapillaris especially in macular diseases of the RPE layer. After a black and white conversion in OCT using the software it was possible in all cases to integrate the choroidal OCT with the ICG angiogram in a semitransparent manner. This confirms that the choroidal vessels in C-OCT correlated identically with the ICG angiography. In contrast to the ICG where the contrast agent in the vessel emits a signal, the choroidal vessels are visible due to different reflectivity in the merging tissue. CONCLUSIONS These investigations showed that non-invasive topographic imaging of the choroid using spectral domain OCT, such as Cirrus OCT is now possible. Distinguishability of smaller vessels was excellent. The ICG (perfusion) and C-OCT (morphology) methods are two very different vessel imaging techniques. The integration of both methods is possible. The clinical relevance of the new image information still has to be researched.

Die neue OCT-Generation lässt tiefer blicken@@@The new OCT generation offers deep insights: Darstellung der Aderhaut mit dem Cirrus-OCT@@@Imaging of the choroid using the Cirrus OCT

BACKGROUND Until now depiction of the choroid using time domain optical coherence tomography (OCT) (Stratus III) was barely possible. Visualization of choroidal perfusion was carried out using indocyanine green angiography (ICGA). The spectral-domain OCT, such as Cirrus OCT (C-OCT) is able to image the choroid better because it offers higher resolution, increased penetration depth of the scan beam and faster acquisition of A-scan data. The aim of the study was to evaluate the potential of choroidal imaging in patients suffering from macular disease. METHODS The advanced visualization tool of C-OCT was primarily used and converted to a z-axis topography. Because of a special algorithm developed by our team, targeted imaging of the choroidal vessels was possible through the scanned two dimensional retinal areas. This image offers an extended image of choroidal vessels (large and small vessels) in several levels. In total 20 patients eyes (n = 15 with various macular diseases and n = 5 normal conditions) who underwent C-OCT and ICG angiography (HRA 2) were chosen to participate in this special algorithm. A precise correlation of ICG and choroid OCT in a semitransparent manner was carried out. RESULTS The first prototype of the recognition software prototype produced clear imaging of the choroid in 100% of cases but only in 55% in the macular region depending on the extent of macular disease. Limitations were low signal intensity and penetration depth as well as a poorly defined retinal pigment epithelium (RPE) and choriocapillaris especially in macular diseases of the RPE layer. After a black and white conversion in OCT using the software it was possible in all cases to integrate the choroidal OCT with the ICG angiogram in a semitransparent manner. This confirms that the choroidal vessels in C-OCT correlated identically with the ICG angiography. In contrast to the ICG where the contrast agent in the vessel emits a signal, the choroidal vessels are visible due to different reflectivity in the merging tissue. CONCLUSIONS These investigations showed that non-invasive topographic imaging of the choroid using spectral domain OCT, such as Cirrus OCT is now possible. Distinguishability of smaller vessels was excellent. The ICG (perfusion) and C-OCT (morphology) methods are two very different vessel imaging techniques. The integration of both methods is possible. The clinical relevance of the new image information still has to be researched.