Abstract
Purpose: :
To demonstrate quantitative measurement of choroidal blood flow by using synchronous measurement of 1-um high-penetration Doppler optical coherence tomography (OCT) and pulsation.
Methods: :
High-speed and high-resolution 1.0 um Doppler spectral-domain OCT imaging was applied for the in vivo human eye. This system operated at an axial resolution of 4.3 um, and detection speed of 47,000 axial scans/s. Thirty two sets of Doppler OCT volume were obtained continuously in the area of 2.0 mm by 2.0 mm (750 A-scan by 64 B-scan). Doppler frequency shift of choroidal artery at the same point was obtained from each volume set of the Doppler OCT. The Doppler shift frequency is then transformed to an absolute choroidal blood flow velocity by using the three-dimensional structural of the blood vessel obtained from structural OCT image. Pressure pulse of plethysmogram was recorded by a finger probe as the Doppler OCT measurement was performed. Doppler signals from each volume were divided into 7 phases of heart beat based on the plethysmogram data.
Results: :
Pulse curve of Doppler signals corresponding to single heart beat were detected. From this curve, a cyclic change of the choroidal blood velocities was quantitatively measured. Absolute choroidal blood flow velocities at peak systolic and end diastolic were 22.3 mm/s and 4.9 mm/s, respectively.
Conclusions: :
Quantitative data of choroidal blood flow velocities were obtained by Doppler OCT with plethysmogram. This measurement could provide fundamental data about regulation of choroidal blood flow in normal and pathological condition.
Keywords: choroid • blood supply • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)