Megahertz-rate optical coherence tomography angiography improves the contrast of the choriocapillaris and choroid in human retinal imaging

Justin V. Migacz, Iwona Gorczynska, Mehdi Azimipour, Ravi Jonnal, Robert Zawadzki, John S Werner

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Angiographic imaging of the human eye with optical coherence tomography (OCT) is becoming an increasingly important tool in the scientific investigation and clinical management of several blinding diseases, including age-related macular degeneration and diabetic retinopathy. We have observed that OCT angiography (OCTA) of the human choriocapillaris and choroid with a 1.64 MHz A-scan rate swept-source laser yields higher contrast images as compared to a slower rate system operating at 100 kHz. This result is unexpected because signal sensitivity is reduced when acquisition rates are increased, and the incident illumination power is kept constant. The contrast of angiography images generated by acquiring multiple sequential frames and calculating the variation caused by blood flow, however, appears to be improved significantly when lower-contrast images are taken more rapidly. To demonstrate that the acquisition rate plays a role in the quality improvement, we have imaged five healthy subjects with a narrow field of view (1.2 mm) OCTA imaging system using two separate swept-source lasers of different A-line rates and compared the results quantitatively using the radially-averaged power spectrum. The average improvement in the contrast is 23.0% (+/−7.6%). Although the underlying cause of this enhancement is not explicitly determined here, we speculate that the higher-speed system suppresses the noise contribution from eye motion in subjects and operates with an inter-scan time that better discriminates the flow velocities present in the choroid and choriocapillaris. Our result informs OCT system developers on the merits of ultrahigh-speed acquisition in functional imaging applications.

Original languageEnglish (US)
Pages (from-to)50-65
Number of pages16
JournalBiomedical Optics Express
Volume10
Issue number1
DOIs
StatePublished - Jan 1 2019

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Choroid
angiography
Optical Coherence Tomography
Angiography
tomography
Lasers
acquisition
image contrast
Macular Degeneration
Diabetic Retinopathy
Quality Improvement
Lighting
Noise
Healthy Volunteers
degeneration
photographic developers
blood flow
field of view
lasers
power spectra

ASJC Scopus subject areas

  • Biotechnology
  • Atomic and Molecular Physics, and Optics

Cite this

Megahertz-rate optical coherence tomography angiography improves the contrast of the choriocapillaris and choroid in human retinal imaging. / Migacz, Justin V.; Gorczynska, Iwona; Azimipour, Mehdi; Jonnal, Ravi; Zawadzki, Robert; Werner, John S.

In: Biomedical Optics Express, Vol. 10, No. 1, 01.01.2019, p. 50-65.

Research output: Contribution to journalArticle

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