Optical Coherence Tomography Angiography – A General View

2016 ◽  
Vol 10 (01) ◽  
pp. 39 ◽  
Author(s):  
Burak Turgut ◽  

Optical coherence tomography angiography (OCTA) is a non-invasive angiography type without a contrast agent, which provides a detailed assessment of the retinal and choroidal vasculature and visualisation of blood flow by detecting motions of erythrocytes, using serial optical coherence tomography B-scans. OCTA has been thoroughly investigated during imaging of the microvasculature in various retinal and choroidal vascular and tumoural diseases that affect the central macula. It has some important advantages and some acceptable disadvantages.

Optical coherence tomography angiography (OCTA) is a new imaging method providing the assessment of retinal and choroidal vasculature without a contrast agent. In this angiography type, the vascular networks have been visualized in detail though detecting motion contrast of erythrocytes in the vessel, using serial optical coherence tomography B-scans. Currently, OCTA findings of many retinal diseases have been reported.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Rui Hua ◽  
Hailin Wang

Optical coherence tomography angiography (OCTA) based on mathematical processing of sequentially acquired structural OCT images has been applied widely in both retinal and choroidal research and may have advantages over traditional angiography. Images obtained by OCTA are rendered under the assumption that the only moving entity in the retina is blood flow. Optical phenomena and image processing algorithms may create imaging artefacts. Therefore, OCTA images require careful interpretation. This review discusses the dark signals seen in the choroidal vasculature on OCTA using multiple factor analysis. For accurate and comprehensive interpretation of the choroidal vasculature, we recommend simultaneous consideration of the laser light penetration depth and masking effect of retinal pigment epithelium, the orientation of vessels in relation to the scanning lasers and blood flow, the range of regional detectable velocity of blood flow, atrophic tissues in the periphery, and absorption of superior vessels on the scanning laser.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jang Ryul Park ◽  
ByungKun Lee ◽  
Min Ji Lee ◽  
Kyuseok Kim ◽  
Wang-Yuhl Oh

AbstractWe developed a method to measure the relative blood flow speed using optical coherence tomography angiography (OCTA) in retina and choroid, and investigated the feasibility of this method for assessing microcirculatory function in rat models of sepsis and hemorrhagic shock. Two sepsis models, 6-h severe sepsis without treatment and 30-h moderate sepsis maintaining mean arterial pressure, and volume controlled hemorrhagic shock and fluid resuscitation model were used to see the change of microcirculation. The blood flow index (BFI), which was calculated from the OCTA images to represent the average relative blood flow, was decreasing during the 6-h severe sepsis model. Its change is in parallel with the mean arterial blood pressure (MAP) and blood lactate levels. In the 30-h moderate sepsis model, the BFI was decreased while maintaining MAP, and lactate was increased. In the hemorrhagic shock model, the change of BFI is in line with MAP and lactate levels. In all models, BFI change is more sensitive in choroid than in retina. This study presents the OCTA-based retinal and choroidal microcirculatory blood flow monitoring method and shows its utility for assessment of critical illness.


2021 ◽  
Vol 8 ◽  
Author(s):  
Zheng Zhang ◽  
Yue Qi ◽  
Wenbin Wei ◽  
Zi-Bing Jin ◽  
Wen Wang ◽  
...  

Purpose: This work aimed to study the effect of posterior scleral reinforcement (PSR) on choroidal thickness (CT) and blood flow.Methods: This study included 25 eyes of 24 patients with high myopia ( ≤ -6.0 dioptres or axial length ≥ 26.0 mm) who underwent PSR surgery. All patients completed the 1-month follow-up visit. Myopic macular degeneration (MMD) was graded according to the International Meta-Analysis for Pathologic Myopia (META-PM) classification based on color fundus photographs. Swept-source optical coherence tomography angiography (SSOCTA) was performed to investigate CT, choroidal perfusion area (CPA), and choriocapillaris perfusion area (CCPA) change following PSR surgery.Results: The distribution of MMD categories was 9 (36.0%) in category 1, 10 (40.0%) in category 2, and 6 (24.0%) in category 3 or 4. MMD severity was strongly correlated with CT (all P < 0.01) and CPA (all P < 0.04). Postoperative CT at each sector increased significantly at 1 week's follow-up, compared to preoperative measures (all P < 0.05). Postoperative CPA at subfoveal, superior, inferior, and nasal sectors also increased significantly 1 week after PSR surgery (all P < 0.05). Moreover, the increased CT, CPA, and CCPA remain after PSR surgery at 1 month's follow-up, but the difference was not statistically significant.Conclusions: We demonstrated that the CT and choroidal blood flow increased significantly in patients with high myopia who underwent PSR surgery in a short period of time. In addition, the CT and CPA were independently associated with MMD. However, whether the transient improvement of the choroidal circulation could prevent long-term progression of high myopia warrants further study in the future.


2020 ◽  
Author(s):  
Juejun Liu ◽  
Changzheng Chen ◽  
Lu Li ◽  
Yishuang Xu ◽  
Zuohuizi Yi ◽  
...  

Abstract Background: Optical coherence tomography angiography (OCTA) is a newly developed imaging quantitative technique for analysis of choriocapillaris (CC) flow changes, thereby exploring the pathological mechanism of chronic central serous chorioretinopathy (CCSC) and the therapeutic effects of photodynamic therapy (PDT). In this study, we sought to quantify the blood flow changes in CC of CCSC patients receiving half-dose PDT using OCTA.Methods: A total of 28 affected eyes and 24 unaffected eyes of 26 CCSC patients receiving half-dose PDT, and 40 eyes of 20 healthy gender- and age-matched subjects were retrospectively enrolled in this study. The proportion of total areas of flow signal voids (FSV, %) in CC level of OCTA was assessed in both eyes of the CCSC patients at baseline and repeated in multiple sections at 1-week, 1-month, 3-month and 6-month intervals after PDT. In addition, the CC patterns in response to PDT at early stage and the subsequent morphologic changes were qualitatively documented using OCTA.Results: For affected eyes, FSV at 6-m follow-up was significantly lower than that at 1-m follow-up (p=0.036). When compared to normal control eyes, FSV in affected eyes was significantly higher at 1-m, 3-m and 6-m follow-up (p<0.05 for all), and FSV in unaffected eyes was significantly higher at baseline, 1-w, 1-m and 3-m follow-up (p<0.05 for all). Three CC patterns of early response to PDT were identified, including signs of recovery with more even flow signals, transient appearance of worse ischemia and secondary neovascularization within CC level.Conclusion: Abnormal CC flow attenuation remains in completely resolved eyes of CCSC patients treated with half-dose PDT.


2017 ◽  
Vol 2017 ◽  
pp. 1-4
Author(s):  
Victor M. Villegas ◽  
Jaclyn L. Kovach

Optical coherence tomography angiography (OCTA) is a recently established noninvasive technology for evaluation of the retinal and choroidal vasculature. The literature regarding the findings in macular telangiectasia type 2 (MacTel2) is scarce. We report the OCTA findings associated with a subject with MacTel2 and secondary subretinal neovascularization (SNV). The commercially available Cirrus 5000 with AngioPlex (Zeiss, Jena, Germany) was used, without any subsequent image modification or processing. Subretinal neovascularization was detectable with OCTA at the level of the outer retina and choriocapillaris. Microvascular abnormalities associated with MacTel2 were present mostly in the deep capillary plexus of the retina temporally.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Juejun Liu ◽  
Changzheng Chen ◽  
Lu Li ◽  
Yishuang Xu ◽  
Zuohuizi Yi ◽  
...  

Abstract Background Optical coherence tomography angiography (OCTA) is a newly developed imaging quantitative technique for analysis of choriocapillaris (CC) flow changes, thereby exploring the pathological mechanism of chronic central serous chorioretinopathy (CCSC) and the therapeutic effects of photodynamic therapy (PDT). In this study, we sought to quantify the blood flow changes in CC of CCSC patients receiving half-dose PDT using OCTA. Methods A total of 28 affected eyes and 24 unaffected eyes of 26 CCSC patients receiving half-dose PDT, and 40 eyes of 20 healthy gender- and age-matched subjects were retrospectively enrolled in this study. The proportion of total areas of flow signal voids (FSV, %) in CC level of OCTA was assessed in both eyes of the CCSC patients at baseline and repeated in multiple sections at 1-week, 1-month, 3-month and 6-month intervals after PDT. In addition, the CC patterns in response to PDT at early stage and the subsequent morphologic changes were qualitatively documented using OCTA. Results For affected eyes, FSV at 6-m follow-up was significantly lower than that at 1-m follow-up (p = 0.036). When compared to normal control eyes, FSV in affected eyes was significantly higher at 1-m, 3-m and 6-m follow-up (p < 0.05 for all), and FSV in unaffected eyes was significantly higher at baseline, 1-w, 1-m and 3-m follow-up (p < 0.05 for all). Three CC patterns of early response to PDT were identified, including signs of recovery with more even flow signals, transient appearance of worse ischemia and secondary neovascularization within CC level. Conclusion Abnormal CC flow attenuation remains in completely resolved eyes of CCSC patients treated with half-dose PDT.


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