Abstract
Purpose:
To analyse high resolution images of arteriovenous (AV) crossings.
Methods:
Retrospective study. Sixty AV crossings from 50 subjects 13 to 75 years old were imaged using a flood imaging AO fundus camera (rtx1, ImagineEyes, Orsay, France).
Results:
We observed new semiological aspects such as perivascular hyperreflectivity which was more marked around arterioles than venules. The loss of transparency of arteries, characterized by the absence of visibility of the underlying vein through the artery, was more frequent in patients older than 50 years. The arterial wall could be observed on both sides of the AV crossing in 42 cases. Measurement of the wall-to-lumen ratio (WLR) showed that there was no detectable parietal abnormality at the level of AV crossing, even in the presence of AV nicking. Venous nickings were also found were arteries and veins were in close proximity yet without overlapping (n=11); in 2 cases of venous pre-occlusion occurring in these situation, it could be shown that the arterial wall was not in physical contact with the vein.
Conclusions:
AO imaging is of interest for the exploration of retinal vascular pathologies due to ageing. Venous obstruction in pathological AV crossing is not necessarily due to arterial compression, since similar modifications are found where it can be unequivocally demonstrated that arteries and veins are not in contact. Our data suggest the role of a paravascular structure in the pathogenesis of pathological AV crossings.
Keywords: 749 vascular occlusion/vascular occlusive disease •
550 imaging/image analysis: clinical