分频幅去相干血管成像

相干光断层扫描血管成像(optical coherence tomography angiography,OCTA)通过比较同一位置的不同扫描,去除不变的结构,即可在不使用造影剂的情况下观察到有红细胞流动的视网膜和脉络膜血管结构.目前,一种新的运算方法——分频幅去相干血管成像(split-spectrum amplitude decorrelation angiography,SSADA)的应用,大大改善了OCTA的信噪比.与其他OCTA不同的是,SSADA OCT可获取与OCT光波平行或垂直的血流信号,不依赖多普勒角,并且图像噪音、组织运动等噪音较小.目前SSADA OCT已越来越多地应用于多种眼部疾病中,如脉络膜新生血管性疾病、糖尿病视网膜病变,视网膜血管阻塞等,在这些疾病的诊断、随访中均有重要意义.

Optical coherence tomography angiography with split-spectrum amplitude decorrelation angiography

Optical coherence tomography angiography (OCTA) is a new method of analysis based on high-resolution imaging techniques whereby the retinal and choroidal circulation can be visualized without the need to injecting any contrast agent.OCTA operates on the principle that,all other elements remaining the same,the only difference between sequentially obtained OCT cross-sectional scans in a particular eye is attributed to motion of erythrocytes within the retinal and choroidal vasculature.Recently,a new algorithm——split-spectrum amplitude decorrelation angiography (SSADA) has been used in OCTA.It can identify movement orthogonal or transversal to the OCT beam,quantifying flow independent of the Doppler angle.An additional advantage of the amplitude-based technology,in comparison with the phase-based,is that the latter is more significantly degraded by image noise and background tissue motion.OCTA with SSADA has been widely used in various kinds of ocular diseases,such as choroidal neovascularization,diabetic retinopathy and retinal vascular occlusions and it is very important in the diagnosis and follow up in those diseases.