4/23/2019 1 Introduction to OCT-Angiography Gary Michalec, CRA Sr. Regional Strategic Clinical Manager North America ZEISS Ophthalmic Devices Carl Zeiss Meditec, Inc. 4/23/2019 What we’ll be covering OCT Technology Past, Present and Future OCT Angiography Advantages and Disadvantages Clinical Cases 4/23/2019 How Did We Get From Here… 4/23/2019 …to here ? 4/23/2019 Puliafito,C. 4/23/2019 2 mm 2 mm 1024 128-512 200-4096 Groups of A‐scans form to make the B‐scan 4/23/2019
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4/23/2019
1
Introduction to OCT-Angiography
Gary Michalec, CRA
Sr. Regional Strategic Clinical Manager
North America
ZEISS Ophthalmic Devices
Carl Zeiss Meditec, Inc.
4/23/2019
What we’ll be covering
OCT Technology
Past, Present and Future
OCT Angiography
Advantages and Disadvantages
Clinical Cases
4/23/2019
How Did We Get From Here…
4/23/2019
…to here ?
4/23/2019
Puliafito,C.
4/23/2019
2 mm 2 mm1024
128-512 200-4096
Groups of A‐scans form to make the B‐scan
4/23/2019
4/23/2019
2
Time Domain OCT• In TD‐OCT the depth information has to be subsequently probed by mechanically adjusting the length of the reference arm.
• This required motion limits the speed of the acquisition of an A‐Scan, (e.g. the STRATUS has a 400 Hz A‐Scan rate).
*Reference arm is mechanically adjusted to scan depth of eye
400‐500 A‐scans per second
Mechanical motion limits speed and precision of the acquisition
“outdated technology” slow and less precise
4/23/2019
Spectral Domain OCTHowever, instead of changing the length of the reference arm, it is equivalent to use a different wavelength of the light
When broadband laser diodes became available, SD‐OCT could use the different wavelengths to simultaneously obtain the depth information
Wide‐band source provides speed, but spectrometer causes signal loss w/depth, detector tech limits speed
27,000 A‐scans and up
“mature technology” speed/depth limitations
4/23/2019
TD vs. SD Comparison
4/23/2019
Swept Source OCTAdvances in the telecom industry provide narrow‐band lasers, where the wave‐length can be electronically tuned
Corresponding detectors are very sensitive with low noise.
Lack of a spectrometer allows improved imaging of deeper /wider structures
100,000 A‐scans and up
“developing technology” improvements vs. cost ?
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OCT Angiography• Algorithm detects red blood cells moving through vessels• Eye tracking, reduces motion artifact, negates blinks, and ensures precise
scan location on follow‐up scans
4/23/2019
• 245 B-Scans (cuts)• Each Repeated 4x
tracking
3 mm X 3 mm Angio
Total = 240,000 A‐scans, ~ 5.0 secs
• 245 axial A-Scans per B-Scan, e 1024 voxels deep
OCT Angiography
4/23/2019
4/23/2019
3
OCTA vs FA
4/23/2019
Conventional IVFA shows dynamic phases of staining, leakage and pooling, OCTA does not.
4/23/2019
OCT‐A shows movement of red blood cells
Imagecaptured is equivalent to mid‐phase of FA
4/23/2019
• No NEEDLES, Less TIME, Less Complicated ‐ ‐ ‐ Lowered Risk• Single Scan ‐ in a few seconds