缺血型与非缺血型视网膜分支静脉阻塞患者黄斑区血流对比

目的　应用光学相干断层扫描血管成像（optical coherence tomography angiography，OCTA）观察缺血型和非缺血型视网膜分支静脉阻塞（branch retinal vein occlusion，BRVO）黄斑区深浅层视网膜血流密度、深浅层血流比（deep-superficial flow ratio，DSFR）及浅层黄斑中心凹无灌注区（foveal avascular zone，FAZ）面积的差异。方法　将临床确诊为颞侧BRVO患者45例45眼纳入研究，依据荧光素眼底血管造影（fundus fluorescein angiography，FFA）结果将患眼分为两组，其中缺血型BRVO 23例23眼（缺血组）、非缺血型BRVO 22例22眼（非缺血组）。另选取与其年龄、性别相匹配的健康22人（22眼）为对照组。对所有入选者均行OCTA检查，扫描以黄斑中心凹为中心3 mm×3 mm的范围，以设备自带软件自动识别并测量此区域内深浅层血流密度及浅层FAZ面积，再计算出DSFR。比较缺血组、非缺血组及对照组各区域内深浅层黄斑区血流密度、DSFR、FAZ面积的差异。结果　三组黄斑区浅层和深层总血流密度、最严重无灌注区DSFR及浅层FAZ面积缺血组分别为（39.82±5.01）%、（41.61±6.28）%、0.95±0.20、（0.30±0.10）mm²，非缺血组分别为（39.26±5.07）%、（42.48±5.77）%、1.11±0.23、（0.32±0.19）mm²，对照组分别为（49.00±2.72）%、（53.05±3.26）%、1.08±0.10、（0.32±0.13）mm²。与对照组相比，缺血组和非缺血组深浅层血流密度均明显降低，差异均有统计学意义（均为P<0.05），而浅层FAZ面积均无明显差异（均为P>0.05）。非缺血组DSFR与对照组无明显差异；而缺血组最严重无灌注区DSFR较非缺血组和对照组明显下降，差异均有统计学意义（均为P<0.05）。缺血组与非缺血组相比，深浅层血流密度及浅层FAZ均无明显差异（均为P>0.05）。结论　缺血型BRVO较非缺血型BRVO的黄斑区血流缺失更重，且深层较浅层更重；DSFR可作为BRVO血流改变异常新的生物标志物，可反映深浅层血管的相对损伤。

Observation of the macular vessels in ischemic and non-ischemic branch retinal vein occlusion using optical coherence tomography angiography

Objective　To observe the alterations of macular vascular density,deep-superficial flow ratio (DSFR) and the area of foveal avascular zone (FAZ) in ischemic and non-ischemic branch retinal vein occlusion (BRVO) eyes using optical coherence tomography angiography (OCTA).Methods　Forty-five patients (45 eyes) with temporal BRVO were enrolled in this study.According to the fundus fluorescein angiography (FFA) results,the eyes were divided into two groups:ischemic group (23 patients 23 eyes) and non-ischemic group (22 patients 22 eyes).Another 22 healthy subjects (22 eyes) with matched age and gender were selected as the control group.OCTA was performed on the all eyes.The scanning region in the macular area was 3 mm×3 mm.Macular vascular density and FAZ area in the superficial and deep retinal capillary plexus were measured in all eyes for calculating the DSFR.The values of macular vascular density,DSFR and FAZ area between ischemic,non-ischemic BRVO and the control eyes were compared.Results　The macular vascular density of superficial layer and deep layer,the DSFR of the most severe non-perfusion area and the area of FAZ was (39.82±5.01)%,(41.61±6.28)%,0.95±0.20 and (0.30±0.10)mm² in ischemic group,respectively,(39.26±5.07)%,(42.48±5.77)%,1.11±0.23,(0.32±0.19)mm² in non-ischemic group,respectively,(49.00±2.72)%,(53.05±3.26)%,1.08±0.10,(0.32±0.13)mm² in control group.The mean overall vascular density measured in the entire scan was lower in ischemic and non-ischemic BRVO eyes compared with the control eyes in both the superficial and deep capillary plexus ( all P＜0.05),while the FAZ area had no significant difference (both P>0.05).There was no significant difference in DSFR between the non-ischemic group and the control group,and the DSFR of the most severe non-perfusion area in the ischemic group was significantly lower than that in the non-ischemic group and control group (all P<0.05).There was no significant difference in macular vascular density of superficial layer and deep layer and FAZ area superficial layer between the ischemic group and the non-ischemic group (all P>0.05).Conclusion　The damage degree of macular flow in ischemic BRVO is more severe compared with ischemic BRVO,especially in the deep capillary.DSFR can be used as a new biomarker to assess vascular density change of BRVO,reflecting the relative damage of deep capillary plexus.