Surgical Treatment of Recurrent Previously Coiled and/or Stent-Coiled Intracerebral Aneurysms: A Single-Center Experience in a Series of 75 Patients.

BACKGROUND: Endovascular treated cerebral aneurysms have a greater recurrence rate compared with microsurgical clip ligation. Despite recent endovascular advances, microsurgical clip ligation might be the treatment of choice for certain previously endovascular treated recurrent aneurysms. We report on our single-center experience with 76 previously coiled and/or stent-coiled aneurysms. OBJECTIVE: To analyze the surgical and radiologic outcome after clipping of previous endovascular treated recurrent cerebral aneurysms. METHODS: Patients were retrospectively identified. Demographic data, aneurysm size, location, perioperative coil extraction, occlusion rate, and complication rate were recorded. Patients were divided into a previously coiled-only group (COG) and a previously stent-assisted coiled group (SAC). RESULTS: Seventy-five patients with 76 aneurysms were included. Sixty-nine patients were included in the COG, 7 patients in the SAC group. Complete or acceptable near-complete occlusion was obtained in 95% of patients in the COG and 57% in the SAC group. Two patients in the COG (2.9%) died postoperatively of a major stroke. One patient died of rehemorrhage after wrapping of an aneurysm. Minor complications occurred in 8.7%. In the SAC group, the mortality was 0%, with 1 major stroke (14.2%), 1 minor stroke (14.2%), and 1 cranial nerve palsy (14.2%). Intraoperative coil extraction and previous stent-assisted coiling were significant predictors of complication rate (P = 0.025 and P = 0.0036 respectively). Previous stent-assisted coiling was a significant predictor of incomplete occlusion (P = 0.036). CONCLUSIONS: Microsurgical clipping of previously endovascular treated recurrent aneurysms is an effective treatment with high obliteration rates. Previously stent-assisted coiling and intraoperative coil extraction are predictors of worse outcome and incomplete occlusion.

Atlantoaxial fixation using C1 posterior arch screws: feasibility study, morphometric data, and biomechanical analysis.

OBJECTIVEC1-2 is a highly mobile complex that presents unique surgical challenges to achieving biomechanical rigidity and fusion. Posterior wiring methods have been largely replaced with segmental constructs using the C1 lateral mass, C1 pedicle, C2 pars, and C2 pedicle. Modifications to reduce surgical morbidity led to the development of C2 laminar screws. The C1 posterior arch has been utilized mostly as a salvage technique, but recent data indicate that this method provides significant rigidity in flexion-extension and axial rotation. The authors performed biomechanical testing of a C1 posterior arch screw (PAS)/C2 pars screw construct, collected morphometric data from a population of 150 CT scans, and performed a feasibility study of a freehand C1 PAS technique in 45 cadaveric specimens.METHODSCervical spine CT scans from 150 patients were analyzed to determine the average C1 posterior tubercle thickness and size of C1 posterior arches. Eight cadavers were used to compare biomechanical stability of intact specimens, C1 lateral mass/C2 pars screw, and C1 PAS/C2 pars screw constructs. Paired comparisons were made using repeated-measures ANOVA and Holm-Sidak tests. Forty-five cadaveric specimens were used to demonstrate the feasibility and safety of the C1 PAS freehand technique.RESULTSMorphometric data showed the average craniocaudal thickness of the C1 posterior tubercle was 12.3 ± 1.94 mm. Eight percent (12/150) of cases showed thin posterior tubercles or midline defects. Average posterior arch thickness was 6.1 ± 1.1 mm and right and left average posterior arch length was 28.7 mm ± 2.53 mm and 28.9 ± 2.29 mm, respectively. Biomechanical testing demonstrated C1 lateral mass/C2 pars and C1 PAS/C2 pars constructs significantly reduced motion in flexion-extension and axial rotation compared with intact specimens (p < 0.05). The C1 lateral mass/C2 pars screw construct provided significant rigidity in lateral bending (p < 0.05). There was no statistically significant difference between the two constructs in flexion-extension, lateral bending, or axial rotation. Of the C1 posterior arches, 91.3% were successfully cannulated using a freehand technique with a low incidence of cortical breach (4.4%).CONCLUSIONSThis biomechanical analysis indicates equivalent stability of the C1 PAS/C2 pars screw construct compared with a traditional C1 lateral mass/C2 pars screw construct. Both provide significant rigidity in flexion-extension and axial rotation. Feasibility testing in 45 cadaveric specimens indicates a high degree of accuracy with low incidence of cortical breach. These findings are supported by a separate radiographic morphometric analysis.

Microscope-Integrated Intraoperative Ultrahigh-Speed Swept-Source Optical Coherence Tomography for Widefield Retinal and Anterior Segment Imaging.

BACKGROUND AND OBJECTIVE: To demonstrate the feasibility of retinal and anterior segment intraoperative widefield imaging using an ultrahigh-speed, swept-source optical coherence tomography (SS-OCT) surgical microscope attachment. PATIENTS AND METHODS: A prototype post-objective SS-OCT using a 1,050-nm wavelength, 400 kHz A-scan rate, vertical cavity surface-emitting laser (VCSEL) light source was integrated to a commercial ophthalmic surgical microscope after the objective. Each widefield OCT data set was acquired in 3 seconds (1,000 × 1,000 A-scans, 12 × 12 mm2 for retina and 10 × 10 mm2 for anterior segment). RESULTS: Intraoperative SS-OCT was performed in 20 eyes of 20 patients. In six of seven membrane peels and five of seven rhegmatogenous retinal detachment repair surgeries, widefield retinal imaging enabled evaluation pre- and postoperatively. In all seven cataract cases, anterior imaging evaluated the integrity of the posterior lens capsule. CONCLUSIONS: Ultrahigh-speed SS-OCT enables widefield intraoperative viewing in the posterior and anterior eye. Widefield imaging visualizes ocular structures and pathology without requiring OCT realignment. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:94-102.].

Assessment of the radiofrequency ablation dynamics of esophageal tissue with optical coherence tomography.

Radiofrequency ablation (RFA) is widely used for the eradication of dysplasia and the treatment of early stage esophageal carcinoma in patients with Barrett's esophagus (BE). However, there are several factors, such as variation of BE epithelium (EP) thickness among individual patients and varying RFA catheter-tissue contact, which may compromise RFA efficacy. We used a high-speed optical coherence tomography (OCT) system to identify and monitor changes in the esophageal tissue architecture from RFA. Two different OCT imaging/RFA application protocols were performed using an

Direct Versus Indirect Bypass for Moyamoya Disease.

Moyamoya disease is a progressive occlusive vasculopathy that involves the supraclinoid internal carotid arteries and Circle of Willis, and results in the formation of collateral vessels at the skull base. The progressive nature of this disease leads to cerebral ischemia and sometimes intracerebral hemorrhage. The treatment of moyamoya disease is mainly surgical revascularization, using revascularization techniques that include direct, indirect, and combined strategies. Here we discuss the available options for revascularization as well as our opinions regarding the surgical management of patients with moyamoya disease.

Thick Prelaminar Tissue Decreases Lamina Cribrosa Visibility.

Purpose: Evaluation of the effect of prelaminar tissue thickness on visualization of the lamina cribrosa (LC) using optical coherence tomography (OCT). Methods: The optic nerve head (ONH) region was scanned using OCT. The quality of visible LC microstructure was assessed subjectively using a grading system and objectively by analyzing the signal intensity of each scan's superpixel components. Manual delineations were made separately and in 3-dimensions quantifying prelaminar tissue thickness, analyzable regions of LC microstructure, and regions with a visible anterior LC (ALC) boundary. A linear mixed effect model quantified the association between tissue thickness and LC visualization. Results: A total of 17 healthy, 27 glaucoma suspect, and 47 glaucomatous eyes were included. Scans with thicker average prelaminar tissue measurements received worse grading scores (P = 0.007), and superpixels with low signal intensity were associated significantly with regions beneath thick prelaminar tissue (P < 0.05). The average prelaminar tissue thickness in regions of scans where the LC was analyzable (214 µm) was significantly thinner than in regions where the LC was not analyzable (569 µm; P < 0.001). Healthy eyes had significantly thicker average prelaminar tissue measurements than glaucoma or glaucoma suspect eyes (both P < 0.001), and glaucoma suspect eyes had significantly thicker average prelaminar tissue measurements than glaucoma eyes (P = 0.008). Significantly more of the ALC boundary was visible in glaucoma eyes (63% of ONH) than in healthy eyes (41%; P = 0.005). Conclusions: Thick prelaminar tissue was associated with impaired visualization of the LC. Healthy subjects generally had thicker prelaminar tissue, which potentially could create a selection bias against healthy eyes when comparing LC structures.

Relief of Cervicogenic Headaches after Single-Level and Multilevel Anterior Cervical Diskectomy: A 5-Year Post Hoc Analysis.

STUDY DESIGN: Prospective study. OBJECTIVE: Because single-level disk arthroplasty or arthrodesis in the lower subaxial spine improves headaches after surgery, we studied whether this effect may be better appreciated after two-level arthroplasty. METHODS: We performed an independent post hoc analysis of two concurrent prospective randomized investigational device exemption trials for cervical spondylosis, one for single-level treatment and the other for two adjacent-level treatments. RESULTS: For the one-level study, baseline mean headache scores significantly improved at 60 months for both the cervical disk arthroplasty (CDA) and anterior cervical diskectomy and fusion (ACDF) groups (p < 0.0001). However, mean improvement in headache scores was not statistically different between the investigational and control groups from 6 months through 60 months. For the two-level study, baseline mean headache scores significantly improved at 60 months for both the CDA and ACDF groups (p < 0.0001). The CDA group demonstrated greater improvement from baseline at all points; this difference was statistically significant at 6, 12, 24, 36, and 48 months but not at 18 and 60 months. CONCLUSION: Both CDA and ACDF at either one or two levels are associated with sustained headache relief from baseline. Patients undergoing two-level arthroplasty had significantly greater improvement in headache at all points except for at 18 and 60 months. This difference in improvement was not observed in patients undergoing single-level arthroplasty. The mechanism of greater headache relief after two-level arthroplasty remains unclear.

Diagnosing an atypical site of giant cell arteritis with magnetic resonance angiography: a case report.

BACKGROUND: Giant cell arteritis typically involves the temporal arteries, but can involve other cranial arteries. Temporal artery biopsy is the mainstay for the diagnosis of giant cell arteritis; however, biopsy may be problematic if giant cell arteritis involves other cranial arteries that are inaccessible for sampling. In these situations, magnetic resonance angiography is a useful, non-invasive adjunctive method in the diagnosis of giant cell arteritis. In this case report, we describe a case of giant cell arteritis involving only the occipital artery which was revealed by magnetic resonance angiography. CASE PRESENTATION: A 67-year-old Caucasian man was admitted to our hospital with a 4-week history of malaise, fever, and mild occipital headaches. There were no other positive findings on physical examination. Laboratory studies were remarkable for normocytic anemia, raised inflammatory markers, and mildly deranged liver function tests. To exclude intracranial pathology, he underwent a cranial magnetic resonance imaging with gadolinium, which demonstrated a thickened wall and mural enhancement of his right occipital artery, consistent with giant cell arteritis. His temporal arteries were normal. His occipital arteries were not accessible for biopsy and he was commenced on high-dose prednisolone (60 mg daily). His symptoms resolved completely after a week of glucocorticoid steroid treatment and he was well on 5 mg of prednisolone once a day on follow-up. CONCLUSION: While magnetic resonance angiography may not replace the need for biopsy, it may have a diagnostic role in suspected giant cell arteritis, such as when the involved arteries are inaccessible for biopsy.

Three-Dimensional Enhanced Imaging of Vitreoretinal Interface in Diabetic Retinopathy Using Swept-Source Optical Coherence Tomography.

PURPOSE: To analyze the vitreoretinal interface in diabetic eyes using 3-dimensional wide-field volumes acquired using high-speed, long-wavelength swept-source optical coherence tomography (SSOCT). DESIGN: Prospective cross-sectional study. METHODS: Fifty-six diabetic patients (88 eyes) and 11 healthy nondiabetic controls (22 eyes) were recruited. Up to 8 SSOCT volumes were acquired for each eye. A registration algorithm removed motion artifacts and merged multiple SSOCT volumes to improve signal. Vitreous visualization was enhanced using vitreous windowing method. RESULTS: Of 88 diabetic eyes, 20 eyes had no retinopathy, 21 eyes had nonproliferative diabetic retinopathy (NPDR) without macular edema, 20 eyes had proliferative diabetic retinopathy (PDR) without macular edema, and 27 eyes had diabetic macular edema (DME) with either NPDR or PDR. Thick posterior hyaloid relative to healthy nondiabetic controls was observed in 0 of 20 (0%) diabetic eyes without retinopathy, 4 of 21 (19%) eyes with NPDR, 11 of 20 (55%) eyes with PDR, and 11 of 27 (41%) eyes with DME (P = .0001). Vitreoschisis was observed in 6 of 22 (27%) healthy nondiabetic eyes, 9 of 20 (45%) diabetic eyes without retinopathy, 10 of 21 (48%) eyes with NPDR, 13 of 20 (65%) eyes with PDR, and 17 of 27 (63%) eyes with DME (P = .007). While no healthy nondiabetic controls and diabetic eyes without retinopathy had adhesions/pegs between detached posterior hyaloid and retina, 1 of 21 (4%), 11 of 20 (55%), and 11 of 27 (41%) eyes with NPDR, PDR, and DME, respectively, demonstrated this feature (P = .0001). CONCLUSION: SSOCT with motion-correction and vitreous windowing provides wide-field 3-dimensional information of vitreoretinal interface in diabetic eyes. This may be useful in assessing progression of retinopathy, planning diabetic vitreous surgery, and predicting treatment outcomes.

Dysphagia Secondary to Anterior Osteophytes of the Cervical Spine.

Study Design Retrospective case series. Objective Diffuse idiopathic skeletal hyperostosis (DISH) or Forestier disease involves hyperostosis of the spinal column. Hyperostosis involving the anterior margin of the cervical vertebrae can cause dysphonia, dyspnea, and/or dysphagia. However, the natural history pertaining to the risk factors remain unknown. We present the surgical management of two cases of dysphagia secondary to cervical hyperostosis and discuss the etiology and management of DISH based on the literature review. Methods This is a retrospective review of two patients with DISH and anterior cervical osteophytes. We reviewed the preoperative and postoperative images and clinical history. Results Two patients underwent anterior cervical osteophytectomies due to severe dysphagia. At more than a year follow-up, both patients noted improvement in swallowing as well as their associated pain. Conclusion The surgical removal of cervical osteophytes can be highly successful in treating dysphagia if refractory to prolonged conservative therapy.

Contrast encephalopathy after coiling in the setting of obstructive sleep apnoea.

Obstructive sleep apnoea (OSA) is increasingly recognised as a source of perioperative morbidity and mortality. We describe a patient with severe OSA who developed transient contrast encephalopathy after elective coiling of an anterior communicating artery aneurysm. Contrast extravasation led to cerebral oedema, seizures and delirium, which eventually completely resolved. OSA is known to be associated with a proinflammatory state that leads to hypertension, impaired endothelial repair capacity and endothelial dysfunction. Further studies are needed to clarify whether OSA increases the risk of endovascular procedures.

Intradural extramedullary capillary hemangioma of the cauda equina: Case report and literature review.

BACKGROUND: Capillary hemangiomas are benign vascular tumors that rarely occur in the neuraxis. When encountered in the spine, prompt diagnosis and complete resection is crucial. On rare instances, these lesions can acutely hemorrhage, leading to sudden neurological decline. To date, there are only 16 reported cases of intradural capillary hemangiomas in the cauda equina. CASE DESCRIPTION: We report a case of an intradural extramedullary cauda equina capillary hemangioma that resulted in back pain and lower extremity motor deficit. Initial magnetic resonance (MR) imaging demonstrated a bilobular intradural L3-4 cauda equina lesion. The lesion was isointense on T1-weighted imaging, mildly hyperintense on T2-weighted images and avidly enhancing after gadolinium administration. Pathology confirmed the diagnosis of capillary hemangioma. CONCLUSION: Early diagnosis and treatment of this patient resulted in complete resection of the tumor and return of lower extremity motor function. Capillary hemangiomas should be considered in the differential diagnosis of cauda equina lesions. En bloc resection of these lesions is the mainstay of treatment.

Cardiac-Gated En Face Doppler Measurement of Retinal Blood Flow Using Swept-Source Optical Coherence Tomography at 100,000 Axial Scans per Second.

PURPOSE: To develop and demonstrate a cardiac gating method for repeatable in vivo measurement of total retinal blood flow (TRBF) in humans using en face Doppler optical coherence tomography (OCT) at commercially available imaging speeds. METHODS: A prototype swept-source OCT system operating at 100-kHz axial scan rate was developed and interfaced with a pulse oximeter. Using the plethysmogram measured from the earlobe, Doppler OCT imaging of a 1.5- × 2-mm area at the optic disc at 1.8 volumes/s was synchronized to cardiac cycle to improve sampling of pulsatile blood flow. Postprocessing algorithms were developed to achieve fully automatic calculation of TRBF. We evaluated the repeatability of en face Doppler OCT measurement of TRBF in 10 healthy young subjects using three methods: measurement at 100 kHz with asynchronous acquisition, measurement at 100 kHz with cardiac-gated acquisition, and a control measurement using a 400-kHz instrument with asynchronous acquisition. RESULTS: The median intrasubject coefficients of variation (COV) of the three methods were 8.0%, 4.9%, and 6.1%, respectively. All three methods correlated well, without a significant bias. Mean TRBF measured at 100 kHz with cardiac-gated acquisition was 40.5 ± 8.2 µL/min, and the range was from 26.6 to 55.8 µL/min. CONCLUSIONS: Cardiac-gated en face Doppler OCT can achieve smaller measurement variability than previously reported methods. Although further validation in older subjects and diseased subjects is required, precise measurement of TRBF using cardiac-gated en face Doppler OCT at commercially available imaging speeds should be feasible.

High-speed ultrahigh-resolution OCT of Bruch's membrane in membranoproliferative glomerulonephritis type 2.

Membranoproliferative glomerulonephritis (MPGN) type 2 is characterized by electron-dense deposits in the glomerular basement membrane and drusen-like deposits in Bruch's membrane. Over time, atrophic changes in the retina and retinal pigment epithelium occur, which can progress to choroidal neovascularization (CNV). This report describes a patient with MPGN type 2 who developed progressive loss of vision secondary to CNV. High-speed ultrahigh-resolution optical coherence tomography (UHR-OCT) showed an irregular Bruch's membrane that measured 10 µm beneath the foveal center. High-speed UHR-OCT can potentially be used to analyze Bruch's membrane in secondary ocular manifestations of diseases such as MPGN type 2 and primary retinal diseases such as age-related macular degeneration.

Spectral-domain and swept-source OCT imaging of asteroid hyalosis: a case report.

A 72-year-old man with diabetes was referred to the retina clinic for diabetic retinopathy. Detailed funduscopic examination of the left eye was limited by prominent asteroid hyalosis. Spectral-domain (SD) and swept-source (SS) optical coherence tomography (OCT) were utilized to examine the vitreous, vitreoretinal interface, and the morphology of the retina. Asteroid hyalosis induced artifacts of the OCT images, which resolved when the appropriate imaging protocols were applied. SS-OCT may show superior diagnostic and preoperative capabilities when compared to SD-OCT in the settings of asteroid hyalosis-induced media opacity.

Quantitative 3D-OCT motion correction with tilt and illumination correction, robust similarity measure and regularization.

Variability in illumination, signal quality, tilt and the amount of motion pose challenges for post-processing based 3D-OCT motion correction algorithms. We present an advanced 3D-OCT motion correction algorithm using image registration and orthogonal raster scan patterns aimed at addressing these challenges. An intensity similarity measure using the pseudo Huber norm and a regularization scheme based on a pseudo L0.5 norm are introduced. A two-stage registration approach was developed. In the first stage, only axial motion and axial tilt are coarsely corrected. This result is then used as the starting point for a second stage full optimization. In preprocessing, a bias field estimation based approach to correct illumination differences in the input volumes is employed. Quantitative evaluation was performed using a large set of data acquired from 73 healthy and glaucomatous eyes using SD-OCT systems. OCT volumes of both the optic nerve head and the macula region acquired with three independent orthogonal volume pairs for each location were used to assess reproducibility. The advanced motion correction algorithm using the techniques presented in this paper was compared to a basic algorithm corresponding to an earlier version and to performing no motion correction. Errors in segmentation-based measures such as layer positions, retinal and nerve fiber thickness, as well as the blood vessel pattern were evaluated. The quantitative results consistently show that reproducibility is improved considerably by using the advanced algorithm, which also significantly outperforms the basic algorithm. The mean of the mean absolute retinal thickness difference over all data was 9.9 um without motion correction, 7.1 um using the basic algorithm and 5.0 um using the advanced algorithm. Similarly, the blood vessel likelihood map error is reduced to 69% of the uncorrected error for the basic and to 47% of the uncorrected error for the advanced algorithm. These results demonstrate that our advanced motion correction algorithm has the potential to improve the reliability of quantitative measurements derived from 3D-OCT data substantially.

Enhanced vitreous imaging in healthy eyes using swept source optical coherence tomography.

PURPOSE: To describe enhanced vitreous imaging for visualization of anatomic features and microstructures within the posterior vitreous and vitreoretinal interface in healthy eyes using swept-source optical coherence tomography (SS-OCT). The study hypothesis was that long-wavelength, high-speed, volumetric SS-OCT with software registration motion correction and vitreous window display or high-dynamic-range (HDR) display improves detection sensitivity of posterior vitreous and vitreoretinal features compared to standard OCT logarithmic scale display. DESIGN: Observational prospective cross-sectional study. METHODS: Multiple wide-field three-dimensional SS-OCT scans (500×500A-scans over 12×12 mm2) were obtained using a prototype instrument in 22 eyes of 22 healthy volunteers. A registration motion-correction algorithm was applied to compensate motion and generate a single volumetric dataset. Each volumetric dataset was displayed in three forms: (1) standard logarithmic scale display, enhanced vitreous imaging using (2) vitreous window display and (3) HDR display. Each dataset was reviewed independently by three readers to identify features of the posterior vitreous and vitreoretinal interface. Detection sensitivities for these features were measured for each display method. RESULTS: Features observed included the bursa premacularis (BPM), area of Martegiani, Cloquet's/BPM septum, Bergmeister papilla, posterior cortical vitreous (hyaloid) detachment, papillomacular hyaloid detachment, hyaloid attachment to retinal vessel(s), and granular opacities within vitreous cortex, Cloquet's canal, and BPM. The detection sensitivity for these features was 75.0% (95%CI: 67.8%-81.1%) using standard logarithmic scale display, 80.6% (95%CI: 73.8%-86.0%) using HDR display, and 91.9% (95%CI: 86.6%-95.2%) using vitreous window display. CONCLUSIONS: SS-OCT provides non-invasive, volumetric and measurable in vivo visualization of the anatomic microstructural features of the posterior vitreous and vitreoretinal interface. The vitreous window display provides the highest sensitivity for posterior vitreous and vitreoretinal interface analysis when compared to HDR and standard OCT logarithmic scale display. Enhanced vitreous imaging with SS-OCT may help assess the natural history and treatment response in vitreoretinal interface diseases.

Optical coherence tomography angiography of optic nerve head and parafovea in multiple sclerosis.

AIMS: To investigate swept-source optical coherence tomography (OCT) angiography in the optic nerve head (ONH) and parafoveal regions in patients with multiple sclerosis (MS). METHODS: Fifty-two MS eyes and 21 healthy control (HC) eyes were included. There were two MS subgroups: 38 MS eyes without an optic neuritis (ON) history (MS -ON), and 14 MS eyes with an ON history (MS +ON). The OCT images were captured by high-speed 1050 nm swept-source OCT. The ONH flow index (FI) and parafoveal FI were quantified from OCT angiograms. RESULTS: The mean ONH FI was 0.160 ± 0.010 for the HC group, 0.156 ± 0.017 for the MS-ON group, and 0.140 ± 0.020 for the MS+ON group. The ONH FI of the MS+ON group was reduced by 12.5% compared to HC eyes (p=0.004). A higher percentage of MS+ON eyes had abnormal ONH FI compared to HC patients (43% vs 5%, p=0.01). Mean parafoveal FIs were 0.126 ± 0.007, 0.127 ± 0.010, and 0.129 ± 0.005 for the HC, MS-ON, and MS +ON groups, respectively, and did not differ significantly among them. The coefficient of variation (CV) of intravisit repeatability and intervisit reproducibility were 1.03% and 4.53% for ONH FI, and 1.65% and 3.55% for parafoveal FI. CONCLUSIONS: Based on OCT angiography, the FI measurement is feasible, highly repeatable and reproducible, and it is suitable for clinical measurement of ONH and parafoveal perfusion. The ONH FI may be useful in detecting damage from ON and quantifying its severity.

Quantitative optical coherence tomography angiography of choroidal neovascularization in age-related macular degeneration.

PURPOSE: To detect and quantify choroidal neovascularization (CNV) in patients with age-related macular degeneration (AMD) using optical coherence tomography (OCT) angiography. DESIGN: Observational, cross-sectional study. PARTICIPANTS: A total of 5 normal subjects and 5 subjects with neovascular AMD were included. METHODS: A total of 5 eyes with neovascular AMD and 5 normal age-matched controls were scanned by a high-speed (100 000 A-scans/seconds) 1050-nm wavelength swept-source OCT. The macular angiography scan covered a 3 × 3-mm area and comprised 200 × 200 × 8 A-scans acquired in 3.5 seconds. Flow was detected using the split-spectrum amplitude-decorrelation angiography (SSADA) algorithm. Motion artifacts were removed by 3-dimensional (3D) orthogonal registration and merging of 4 scans. The 3D angiography was segmented into 3 layers: inner retina (to show retinal vasculature), outer retina (to identify CNV), and choroid. En face maximum projection was used to obtain 2-dimensional angiograms from the 3 layers. The CNV area and flow index were computed from the en face OCT angiogram of the outer retinal layer. Flow (decorrelation) and structural data were combined in composite color angiograms for both en face and cross-sectional views. MAIN OUTCOME MEASURES: The CNV angiogram, CNV area, and CNV flow index. RESULTS: En face OCT angiograms of CNV showed sizes and locations that were confirmed by fluorescein angiography (FA). Optical coherence tomography angiography provided more distinct vascular network patterns that were less obscured by subretinal hemorrhage. The en face angiograms also showed areas of reduced choroidal flow adjacent to the CNV in all cases and significantly reduced retinal flow in 1 case. Cross-sectional angiograms were used to visualize CNV location relative to the retinal pigment epithelium and Bruch's layer and classify type I and type II CNV. A feeder vessel could be identified in 1 case. Higher flow indexes were associated with larger CNV and type II CNV. CONCLUSIONS: Optical coherence tomography angiography provides depth-resolved information and detailed images of CNV in neovascular AMD. Quantitative information regarding CNV flow and area can be obtained. Further studies are needed to assess the role of quantitative OCT angiography in the evaluation and treatment of neovascular AMD.