A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Angiography of the retina and the choroid with phase-resolved OCT using interval-optimized backstitched B-scans
Tekijät: Braaf B, Vermeer KA, Vienola KV, de Boer JF
Kustantaja: Optica Publishing Group
Julkaisuvuosi: 2012
Journal: Optics Express
Tietokannassa oleva lehden nimi: OPTICS EXPRESS
Lehden akronyymi: OPT EXPRESS
Vuosikerta: 20
Numero: 18
Aloitussivu: 20516
Lopetussivu: 20534
Sivujen määrä: 19
ISSN: 1094-4087
DOI: https://doi.org/10.1364/OE.20.020516
Verkko-osoite: https://opg.optica.org/oe/fulltext.cfm?uri=oe-20-18-20516
Tiivistelmä
In conventional phase-resolved OCT blood flow is detected from phase changes between successive A-scans. Especially in high-speed OCT systems this results in a short evaluation time interval. This method is therefore often unable to visualize complete vascular networks since low flow velocities cause insufficient phase changes. This problem was solved by comparing B-scans instead of successive A-scans to enlarge the time interval. In this paper a detailed phase-noise analysis of our OCT system is presented in order to calculate the optimal time intervals for visualization of the vasculature of the human retina and choroid. High-resolution images of the vasculature of a healthy volunteer taken with various time intervals are presented to confirm this analysis. The imaging was performed with a backstitched B-scan in which pairs of small repeated B-scans are stitched together to independently control the time interval and the imaged lateral field size. A time interval of >= 2.5 ms was found effective to image the retinal vasculature down to the capillary level. The higher flow velocities of the choroid allowed a time interval of 0.64 ms to reveal its dense vasculature. Finally we analyzed depth-resolved histograms of volumetric phase-difference data to assess changes in amount of blood flow with depth. This analysis indicated different flow regimes in the retina and the choroid. (C) 2012 Optical Society of America
In conventional phase-resolved OCT blood flow is detected from phase changes between successive A-scans. Especially in high-speed OCT systems this results in a short evaluation time interval. This method is therefore often unable to visualize complete vascular networks since low flow velocities cause insufficient phase changes. This problem was solved by comparing B-scans instead of successive A-scans to enlarge the time interval. In this paper a detailed phase-noise analysis of our OCT system is presented in order to calculate the optimal time intervals for visualization of the vasculature of the human retina and choroid. High-resolution images of the vasculature of a healthy volunteer taken with various time intervals are presented to confirm this analysis. The imaging was performed with a backstitched B-scan in which pairs of small repeated B-scans are stitched together to independently control the time interval and the imaged lateral field size. A time interval of >= 2.5 ms was found effective to image the retinal vasculature down to the capillary level. The higher flow velocities of the choroid allowed a time interval of 0.64 ms to reveal its dense vasculature. Finally we analyzed depth-resolved histograms of volumetric phase-difference data to assess changes in amount of blood flow with depth. This analysis indicated different flow regimes in the retina and the choroid. (C) 2012 Optical Society of America
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