Effective bidirectional scanning pattern for optical coherence tomography angiography

We report a novel design and operation of a highly integrated miniature handheld OCT probe, with high-speed angiography function that can be used in clinical settings for young children and infants, providing rapid, non-invasive structural and angiographic imaging of the retina and choroid. The imaging system is operated at 200 kHz, with 3D OCT and OCTA scan time of 0.8 and 3.2 seconds, respectively, and the scanning angle on the pupil is ± 36°, covering the full perifoveal region. Operator assisting features of the direct-view iris camera and on-probe display are integrated into the hand-held probe, and the fixation target can display animations to attract the attention of young subjects. Compared to conventional OCT systems, the high-speed hand-held OCT system significantly improves the operator's experience and scanning efficiency, which is important for imaging infants. Imaging results indicate a significant reduction in total time consumption in pediatric ophthalmic imaging sessions, as well as the image quality of OCT angiography.

Section: Scanning Protocolmentioning

confidence: 99%

Development of a clinical prototype of a miniature hand-held optical coherence tomography probe for prematurity and pediatric ophthalmic imaging

Song

Zhou

et al. 2019

“…A bidirectional scanning protocol (Fig. 2) using a triangular function on the fast-axis has been developed recently on a 200-kHz SS-OCT system [20]. The forward scanning and the backward scanning are consecutively acquired without the use of fly-back scans.…”

Section: Bidirectional Scanning Protocols Opts Out Of Fly-back Timementioning

confidence: 99%

“…Many previous research works have demonstrated different scanning methods to decrease noise [19], increase efficiency [20,21] or increase the velocity ranging in OCT applications [22,23]. Recently, a pilot version of HDR-OCTA, variable inter-scan time analysis (VISTA), demonstrated sufficient sensitivity to detect flow impairment before the onset of capillary dropout [16].…”

Section: Introductionmentioning

confidence: 99%

“…However, this prior work was based on an inefficient OCT scanning protocol that had to achieve the optimal duty cycle by including an unnecessary fly-back at every Bscan across the fast scanning priority axis, and an additional superfluous cross-sectional Bscan. A novel fly-backless bidirectional scanning pattern has been introduced by Ju, et al which can increase scanning efficiency [20]. Based in part on this, for HDR-OCTA we have devised a bidirectional, interleaved scanning protocol can achieve an optimal scanning duty cycle and obtain three different inter-B-scan intervals with only three repetitions as opposed with the method used in previous work [11] could form two intervals with three repetitions.…”

Section: Introductionmentioning

confidence: 99%

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High dynamic range optical coherence tomography angiography (HDR-OCTA)

Wei

Hormel

et al. 2019

Self Cite

The dynamic range of current optical coherence tomography (OCT) angiography (OCTA) images is limited by the fixed scanning intervals. High speed OCT devices introduce the possibility of extending the flow signal dynamic range. In this study, we created a novel scanning pattern for achieving high dynamic range (HDR)-OCTA with a superior scanning efficiency. We implemented a bidirectional, interleaved scanning pattern that is sensitive to different flow speeds by adjustable adjacent inter-scan time intervals. We found that an improved flow dynamic range can be achieved by generating 3 different B-scan time intervals using 3 repetitions.

“…In this paper, to minimize the impact of motion artifact in handheld QME, we demonstrate a custom bidirectional scan pattern, capable of scanning a 6 × 6 × 1 mm volume of tissue in 3.4 seconds. Recently, a bidirectional triangular scan pattern using galvanometer-based scanners has been developed in OCT angiography [27]. In our method, we use the MEMS mirror with a similar bidirectional scan pattern which comprises two regions: a linear scan region where B-scans are acquired, and a sinusoidal turn-around region where the scanning direction of the beam is reversed whilst avoiding the resonant behavior of the MEMS mirror.…”

Section: Introductionmentioning

confidence: 99%

Handheld probe for quantitative micro-elastography

Fang¹,

Krajancich²,

Chin³

et al. 2019

Optical coherence elastography (OCE) has been proposed for a range of clinical applications. However, the majority of these studies have been performed using bulky, labbased imaging systems. A compact, handheld imaging probe would accelerate clinical translation, however, to date, this had been inhibited by the slow scan rates of compact devices and the motion artifact induced by the user's hand. In this paper, we present a proofof-concept, handheld quantitative micro-elastography (QME) probe capable of scanning a 6 × 6 × 1 mm volume of tissue in 3.4 seconds. This handheld probe is enabled by a novel QME acquisition protocol that incorporates a custom bidirectional scan pattern driving a microelectromechanical system (MEMS) scanner, synchronized with the sample deformation induced by an annular PZT actuator. The custom scan pattern reduces the total acquisition time and the time difference between B-scans used to generate displacement maps, minimizing the impact of motion artifact. We test the feasibility of the handheld QME probe on a tissue-mimicking silicone phantom, demonstrating comparable image quality to a benchmounted setup. In addition, we present the first handheld QME scans performed on human breast tissue specimens. For each specimen, quantitative micro-elastograms are co-registered with, and validated by, histology, demonstrating the ability to distinguish stiff cancerous tissue from surrounding soft benign tissue.