OHSU # 2837 — Self-tracking real-time high-resolution wide-field OCT angiography (OCTA)
Optical coherence tomographic angiography (OCTA) provides superior resolution and volumetric data compared to fluorescein angiography, but this 3D technology requires motion artifact compensation caused by movements during the scan. Oregon Health & Science University researchers have developed a method to suppress motion artifacts caused by eye motion and blinking in real-time during OCTA scans without requiring any additional hardware.
OCTA provides high-resolution angiographic data by measuring inherent motion contrast between successive OCT images; however, this method is highly susceptible to artifacts caused by movement of the patient during the scan. Post-processing removal of these artifacts involves some information loss, and while instrumental changes can be effective they require costly hardware installation. The laboratory of Dr. Yali Jia has developed a motion artifact correction method that includes a motion strength index (MSI) to indicate the motion, a cross-scanning pattern for imaging position alignment and a tracking algorithm to rescan the artifact areas in real-time. Testing of 14 healthy eyes found that the tracking algorithm was highly effective at detecting and correcting motion artifacts as demonstrated by a 100% reduction in blink artifacts and a 91% reduction in eye movement artifacts. Testing in patients with diabetic retinopathy found the tracking algorithm provided high OCTA scan resolution and the ability to show retinal capillaries and detect areas of non-perfusion and other vascular pathologies, indicating that this system could be useful in clinical applications (see Figure). All test scans utilizing the tracking algorithm were completed in less than a minute and the imaging subjects can freely blink in a comfortable condition. With this unique tracking engaged, OCTA scan yield rate can be significantly increased. In conclusion, this motion tracking and correction algorithm dramatically reduces movement artifacts, without requiring third-party hardware or significant increases in scan time, thereby providing increased resolution and utility for OCTA scanning.
Wei et al., “High-resolution wide-field OCT angiography with a self-navigation method to correct microsaccades and blinks.” Biomedial Optics Express 11(2020):3234-3245.
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