Marco Lupidi

OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY VERSUS TRADITIONAL MULTIMODAL IMAGING IN ASSESSING THE ACTIVITY OF EXUDATIVE AGE-RELATED MACULAR DEGENERATION: A New Diagnostic Challenge.

Purpose: To compare optical coherence tomography angiography (OCTA) with traditional multimodal imaging in patients with exudative age-related macular degeneration in terms of guiding the treatment decision. Methods: Prospective case series of 80 eyes of 73 consecutive patients with exudative age-related macular degeneration (39 women, mean age: 79.4 ± 5.3 years) diagnosed with different types of choroidal neovascularization (CNV) (58 Type I, 2 Type II, 6 mixed Type I and II, 3 retinal angiomatous proliferation, and 11 age-related macular degeneration-related polyps). The data obtained from traditional multimodal imaging, based on fluorescein angiography, indocyanine green angiography, and OCT were used to assess the need for treatment, those obtained from OCTA to identify two different patterns of CNV. Traditional multimodal imaging and OCTA findings were then compared with evaluate possible correspondence between treatment decision and CNV aspect on OCTA. Results: A CNV lesion was identified as Group A (requiring treatment) in 58 eyes (72.5%) in traditional multimodal imaging. On OCTA in 59 eyes (73.7%), the lesion was defined as Pattern I and the remaining 21 (26.3%) as Pattern II. There was 94.9% correspondence between the Pattern I CNV on OCTA and the cases Group A on conventional multimodal imaging. It was also computed 90.5% correspondence between Pattern II CNV on OCTA and the Group B (not requiring treatment) cases on conventional multimodal imaging. There was high (P < 0.05) interobserver agreement both for treatment decision in conventional multimodal and for Patterns (I or II) defining on OCTA imaging analysis. Conclusion: This study demonstrates a high level of correspondence, in patients with exudative age-related macular degeneration, between different CNV patterns identified on OCTA and treatment decisions established on conventional multimodal imaging. Although fluorescein angiography remains the gold standard for determining the presence of leakage, and OCT shows fluid accumulation and its variations, OCTA may now offer noninvasive monitoring of the CNV, aiding for each treatment decision during the follow-up.

Optical Coherence Tomography Angiography in Retinal Vein Occlusion: Evaluation of Superficial and Deep Capillary Plexa.

PURPOSE To evaluate the optical coherence tomography angiography (OCT angiography) appearance of the superficial and deep capillary plexa in eyes with retinal vein occlusion (RVO) and to compare these findings with those of fluorescein angiography (FA) and spectral-domain optical coherence tomography (SD OCT). DESIGN Retrospective observational case series. METHODS Patients presenting with RVO to Creteil University Eye Clinic were retrospectively evaluated. All patients had undergone a comprehensive ophthalmic examination including FA, SD OCT, and OCT angiography. RESULTS There were 54 (31 male, 57%) RVO patients with a mean age of 70 years. The perifoveal capillary arcade was visible in 52 of 54 eyes (96%) on OCT angiography and in 45 eyes (83%) on FA; this arcade was disrupted in 48 eyes (92%) and 39 eyes (72%) on OCT angiography and FA, respectively (P = .002). Perifoveal capillary arcade disruption was correlated with peripheral retinal ischemia (P = .025). Intraretinal cystoid spaces were observed in 34 eyes (68%) using FA, in 40 eyes (76%) using SD OCT, and in 49 eyes (90%) using OCT angiography (P = .008 for OCT angiography vs SD OCT and P = .001 for OCT angiography vs FA). Retinal capillary network abnormalities were observed in all patients in both superficial capillary plexus and deep capillary plexus on OCT angiography. Nonperfusion grayish areas were more frequent in the deep capillary plexus (43 eyes, 84%) than in the superficial capillary plexus (30 eyes, 59%, P < .001). CONCLUSION OCT angiography can simultaneously evaluate both macular perfusion and edema. For the first time, an imaging technique enables the evaluation of the deep capillary plexus, which appears to be more severely affected than the superficial capillary plexus in RVO.

Optical coherence tomography angiography during follow-up: qualitative and quantitative analysis of mixed type I and II choroidal neovascularization after vascular endothelial growth factor trap therapy.

Purpose: To report the optical coherence tomography angiography (OCT-A) findings in an exudative age-related macular degeneration (AMD) patient presenting mixed type I and II choroidal neovascularization (CNV) during follow-up after intravitreal vascular endothelial growth factor (VEGF) trap treatment. Methods: The clinical assessment included both traditional multimodal imaging, based on fluorescein angiography (FA), indocyanine green angiography (ICGA) and B-scan OCT, and OCT-A at baseline and follow-up. OCT-A images were obtained using a Spectralis OCT-A prototype able to acquire 70,000 A-scans per second, with a resolution of 7 µm axially and 14 µm laterally. An amplitude decorrelation algorithm developed by Heidelberg Engineering was applied to a volume scan, on a 15 × 5° area, which was composed of 131 B-scans (35 frames per scan) at a distance of 11 µm each. The borders of type I and type II CNV were manually outlined and then the areas were analyzed using the provided automated software before and after treatment. Results: The qualitative approach revealed a substantial decrease in the visibility of tiny branching vessels and anastomoses both in type I and type II components of the neovascular complex, associated with persistence of a clear hyperintense signal coming from the larger trunks, which remained well-perfused. Quantitative analysis confirmed a reduction of the lesion area after VEGF trap treatment: the type II component decreased from 0.25 to 0.19 mm2, while the type I component decreased from 2.03 to 1.80 mm2. Conclusions: Our study qualitatively and quantitatively demonstrated the response of a mixed type I-II CNV to intravitreal VEGF trap therapy. Although FA remains the gold standard for determining the presence of leakage and OCT easily shows fluid accumulation and its variations, OCT-A offers noninvasive monitoring of the retinal and choriocapillaris microvasculature in patients with CNV, aiding in diagnosis and treatment decisions during follow-up.

Automated Quantitative Analysis of Retinal Microvasculature in Normal Eyes on Optical Coherence Tomography Angiography

PURPOSE To describe a new automated quantitative technique for displaying and analyzing macular vascular perfusion using optical coherence tomography angiography (OCT-A) and to determine a normative data set, which might be used as reference in identifying progressive changes due to different retinal vascular diseases. DESIGN Reliability study. METHODS A retrospective review of 47 eyes of 47 consecutive healthy subjects imaged with a spectral-domain OCT-A device was performed in a single institution. Full-spectrum amplitude-decorrelation angiography generated OCT angiograms of the retinal superficial and deep capillary plexuses. A fully automated custom-built software was used to provide quantitative data on the foveal avascular zone (FAZ) features and the total vascular and avascular surfaces. A comparative analysis between central macular thickness (and volume) and FAZ metrics was performed. Repeatability and reproducibility were also assessed in order to establish the feasibility and reliability of the method. RESULTS The comparative analysis between the superficial capillary plexus and the deep capillary plexus revealed a statistically significant difference (P < .05) in terms of FAZ perimeter, surface, and major axis and a not statistically significant difference (P > .05) when considering total vascular and avascular surfaces. A linear correlation was demonstrated between central macular thickness (and volume) and the FAZ surface. Coefficients of repeatability and reproducibility were less than 0.4, thus demonstrating high intraobserver repeatability and interobserver reproducibility for all the examined data. CONCLUSIONS A quantitative approach on retinal vascular perfusion, which is visible on Spectralis OCT angiography, may offer an objective and reliable method for monitoring disease progression in several retinal vascular diseases.

Toward a Specific Classification of Polypoidal Choroidal Vasculopathy: Idiopathic Disease or Subtype of Age-Related Macular Degeneration

PURPOSE To suggest a clinical distinction between idiopathic polypoidal choroidal vasculopathy (PCV) and secondary polyps associated with neovascular age-related macular degeneration (NV-AMD). METHODS The study was a retrospective case series of 52 eyes of 52 consecutive patients (31 females and 21 males) diagnosed with PCV. Initial diagnosis was based on scanning laser ophthalmoscope-indocyanine green angiography (SLO-ICGA) in association with fluorescein angiography (FA) and optical coherence tomography (OCT). All the data and images were analyzed in a masked fashion by four experienced examiners in two different sessions: the first, to classify patients into the two hypothesized groups (idiopathic polyps or NV-AMD-related polyps); the second, following a predetermined scheme, to describe objective features. The results obtained in each session underwent a cross multivariate analysis to identify statistically significant differences (P ≤ 0.05) between the two groups. RESULTS The two groups were clinically different on the basis of FA (leakage origin [P = 0.001] and presence of drusen [P = 0.001]), ICGA (evidence of choroidal neovascularization [CNV; P = 0.001] and/or branching vascular network [BVN; P = 0.001]), OCT imaging (type of pigmented epithelium detachment [P = 0.001], presence of BVN [P = 0.001], and subfoveal choroidal thickness [P = 0.001]). Further significant differences were observed according to the location of lesion (uni- or multifocal) (P = 0.001), type of CNV (P = 0.001), and best-corrected visual acuity (P = 0.001). CONCLUSIONS Our study demonstrated clinical and statistically significant differences between idiopathic PCV and NV-AMD-related polyps that could be considered as distinct entities. Although they share some similarities, mainly the sub-RPE location, the ability to identify a specific clinical pattern suggests a more specific therapeutic approach for these two entities.

Ocular penetration of topical antibiotics: study on the penetration of chloramphenicol, tobramycin and netilmicin into the anterior chamber after topical administration

To compare penetration in the aqueous humour of topically applied antibiotics.

Heidelberg Spectralis Optical Coherence Tomography Angiography: Technical Aspects

Optical coherence tomography angiography (OCT-A) is a promising new method for visualizing the retinal vasculature and choroidal vascular layers in the macular area and provides depth-resolved functional information on blood flow in these vessels. OCT-A is based on the concept that in a static eye the only moving structure in the fundus of the eye is blood flowing through the vessels. Contrast is generated based on the difference between moving cells in the vasculature and the static surrounding tissue. Artifacts can arise due to scan positioning errors caused by normal ocular microsaccades. In order to avoid artifacts, a sequence of OCT B-scans in the exact same retinal location must be taken to detect flow. Active eye-tracking (TruTrack™) using the simultaneous acquisition of fundus and optical coherence tomography (OCT) images presents a very reliable method of acquiring OCT volume scans without motion artifacts and helps significantly improve signal-to-noise ratio. This system also allows the use of a full spectrum amplitude decorrelation algorithm that produces clear differentiation between blood flow and static tissue without sacrificing the axial resolution of OCT images. Accuracy in layer segmentation, which requires high-resolution OCT B-scans, is crucial for producing reliable OCT-A images. This can be achieved through automated or manual layer segmentation. During OCT scan acquisition, the effect of axial motion (e.g. a patient moving towards the camera) is compensated for by geometric alignment of successive B-scans before analyzing temporal changes.

Repeatability and Reproducibility of Retinal Thickness Measurements in Diabetic Patients with Spectral Domain Optical Coherence Tomography

ABSTRACT Background: To determine the repeatability and reproducibility of optical coherence tomography (OCT) Spectralis retinal thickness measurements in diabetic patients with clinically significant macular edema (CSME). Methods: Twelve eyes of 12 volunteers (without macular pathology – control group) and 21 eyes of 21 diabetic patients with CSME were included in the study. Reproducibility, repeatability, intraclass correlation coefficients (ICCs) and intrasession correlation coefficients were tested with 20 × 15 degree raster scans consisting of 19 high-resolution line scans that were repeated three times by two experienced examiners. Results: In the control group, examining all regions, coefficient of repeatability was less than 1.1%, while coefficient of reproducibility was less than 2.2%. In diabetic patients, examining all regions, coefficient of repeatability was less than 2.6%, while coefficient of reproducibility was less than 2.4%. ICCs were, respectively, greater than or equal to 0.98 in the control group and 0.99 in diabetic patients. Intrasession coefficients of variation were less than 0.4% in the control group and less than 0.5% in diabetic patients. Conclusion: Retinal thickness measurements are repeatable and reproducible with OCT Spectralis in both the control group and diabetic patients. The results indicate that a change in central subfield thickness exceeding 12 µm and 3% in the diabetic patients is likely to be real.

Optical Coherence Tomography Angiography of a Choroidal Neovascularization in Adult Onset Foveomacular Vitelliform Dystrophy: Pearls and Pitfalls.

PURPOSE The purpose of this study was to determine the sensitivity and specificity of optical coherence tomography angiography (OCT-A) in detecting choroidal neovascularization (CNV)-complicating adult onset foveomacular vitelliform dystrophy (AOFVD) and to highlight the possible pitfalls related to the heterogeneous spectrum of acquired vitelliform maculopathies. METHODS Twenty-five eyes of 22 consecutive AOFVD patients with suspected CNV were enrolled. Conventional multimodal imaging findings, based on fluorescein angiography (FA), indocyanine green angiography (ICGA) and B-Scan OCT, were used as a basis and were compared with those obtained from OCT-A to define its sensitivity and specificity for detecting CNV in the case of AOFVD. A qualitative and quantitative analysis of the CNV appearance and of the associated OCT-A findings were also performed with the aim of defining features and elucidating possible diagnostic pitfalls. RESULTS Conventional multimodal imaging allowed diagnosis of a CNV in 5 of 25 eyes (20%), whereas a CNV lesion was clearly observed on OCT-A in 4 of 25 cases (16%). The sensitivity and specificity of CNV detection by OCT-A in cases of AOFVD was 4 of 5 cases (80%) and 20 of 20 cases (100%), respectively. Optical coherence tomography angiography in 10 cases (40%) showed a focal hyperintense signal, without vascular aspects, at the level of the outer nuclear layer or immediately above the subretinal material accumulation. CONCLUSIONS Our study demonstrates the capability of OCT-A to allow diagnosis of the presence of a CNV in AOFVD patients. Although FA remains the gold standard for determining the presence of a neovascular network, OCT-A offers noninvasive monitoring of the retinal and choroidal microvasculature, aiding in diagnosis and treatment decisions during follow-up.

Image Analysis of Optical Coherence Tomography Angiography

Optical coherence tomography (OCT) angiography (OCT-A) is a transformative approach in imaging ocular vessels based on flow rather than simple reflectance intensity. It is therefore a functional extension of OCT that can be used to visualize microvasculature by detecting motion contrast from flowing blood. As OCT-A is a depth-resolved examination, it needs careful axial segmentation in order to preserve important data on perfused structures and to avoid the risk of generating superimposed images, which are typical of dye angiographies. An automated segmentation algorithm for both retinal and choroidal layers is provided by the majority of different OCT-A devices. In the case of accentuated macular retinal/choroidal disruptions causing potential segmentation errors, specific manual correction allows one to modify the shape and the localization of each layer. In the case of manual segmentation, the thickness of every C-scan may be modified in order to provide a constant thickness of tissue slices at different retinal or choroidal levels. OCT projection artifacts also occur from superficial retinal vessels, which can be seen in deeper retinal layers, or retinal and choroidal vessels, which can even be seen in the scleral tissue. These projection artifacts are almost always present and are visible in any layer that is located below the perfused vasculature.