Retinal and choroidal intravascular spectral‐domain optical coherence tomography

Abstract

ABSTRACT.Purpose: To examine retinal and choroidal blood vessels using spectral-domain optical coherence tomography (SD-OCT). Methods: Retrospective case series. Results: Scans through retinal blood vessels in healthy subjects demonstrated vessel wall reflexes and a tri-layer profile of the blood column on longitudinal scans and a figure-of-eight configuration on cross-sectional scans. Intravascular reflectivity decreased with increasingly oblique angles of observation and was absent when blood flow was parallel to the line of sight. The high blood flow in the choroidal vessels in healthy subjects and the low flow in the retinal vessels in patients with ocular ischaemic syndrome and central retinal artery occlusion were both associated with lower reflectivity of the blood and an unstructured intravascular SD-OCT profile. Discussion: This qualitative in vivo study found a characteristically structured SD-OCT profile of the blood column in retinal vessels with normal blood flow. Both structure and total reflectivity faded when blood flow was lower or higher than normal or at oblique angles to the line of sight. In conclusion, SD-OCT scans of the vessels in the posterior pole of the eye may assist the clinical assessment of gross abnormalities of ocular blood flow, e.g. in carotid artery stenosis.Key words: blood flow imaging -central retinal artery occlusion -choroidal blood flow -in vivo -ocular ischemic syndrome -optical coherence tomography -red blood cell alignment -retinal blood flow -shear rate

Embolus characterization in branch retinal artery occlusion by optical coherence tomography

“…At its present stage of development, however, SD‐OCT can only be used to identify gross qualitative abnormalities of retinal blood flow such as severe hypoperfusion in the ocular ischaemic syndrome (Willerslev et al. ).…”

Spectral‐domain optical coherence tomography of retinal vessels in Waldenström's macroglobulinemia

“…The ordered signal is reduced or disappears when flow is turbulent, too high or too slow to induce order in the blood column or in cases of severe blood dyscrasia (Willerslev et al. , ). It cannot be ruled out, however, that the change in blood composition per se may change the optical reflectivity of the intravascular blood column, and new OCT methods that apply Doppler technology (Tayyari et al.…”

“…; Willerslev et al. ). The intravascular reflectivity pattern fades or disappears when blood flow is slow or turbulent and in vessels from patients with some types of severe blood dyscrasia.…”

“…Of relevance, optical coherence tomography (OCT) has enabled imaging of flow patterns in the streaming blood in the retinal vessels. Under normal conditions, there is ordered laminar flow in retinal trunk vessels, which is seen as a characteristic intravascular figure-of-8 on cross-sectional OCT scans, with retinal and choroidal structures posterior to the vessel being masked by a shadow effect (Muraoka et al 2013;Willerslev et al 2014). The intravascular reflectivity pattern fades or disappears when blood flow is slow or turbulent and in vessels from patients with some types of severe blood dyscrasia.…”

Optical coherence tomography‐based retinal vessel analysis for the evaluation of hypertensive vasculopathy

“…Second, the vessel shadow can be analysed assuming that the blood flow through the vessel lumen attenuates the OCT signal reflecting from deeper structures. Red blood cells physiologically take laminar blood flow within major retinal vessels (Cimalla et al 2011) and reflect the OCT beam (Willerslev et al 2014). We decided to use the vessel shadow width as a parameter of retinal vessel being better to separate from the neuronal retinal structures than the retinal vessels.…”