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The use of distal scanning micro-motor OCT probes dramatically reduces NURD associated with mechanical friction in the probe. It is further exacerbated by physiological motion of the tissue lumen and bending of the imaging catheter. In proximal scanning systems, NURD is typically caused by the mechanical friction between the catheter torque coil and surrounding sheath. The second type of distortion, circumferential distortion, is sometimes referred to as non-uniform rotational distortion (NURD) and is caused by variations in the circumferential scan position or speed. However, in catheter/endoscopic OCT, this motion is usually small, because the probe is in contact with the tissue. Radial distortion is often caused by changes in the distance between the tissue lumen and scanning probe, leading to variation in the axial position of the tissue and also the spatial sampling pitch. There are different types of motion distortion in side-viewing OCT probes including: radial, circumferential, and longitudinal distortion. In this paper, we limit our attention to motion distortion associated with side-viewing probes. The circumferential scanning is combined with a pullback retraction of the optical assembly to perform a helical scan and acquire volumetric data. Conversely, distal scanning probes use micro-motors at their tip for circumferential beam scanning. Proximal scanning probes use a fiber optic rotary joint to transmit the rotation from a proximal motor to the distal end of the probe. Side-viewing probes are more popular for imaging luminal organs and can be further divided based on the type of scanning mechanism (proximal or distal). Depending on the optical beam scanning direction relative to the longitudinal axis of the probe, catheter OCT probes can be divided into either forward-viewing, scanning the beam in front of the probe, or side-viewing, scanning the beam perpendicular to the longitudinal axis. The imaging probe can be miniaturized so that it can be introduced through instrument channels of endoscopes and image areas of interest under endoscopic guidance.
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These scanning probes consist of micro-optics to deflect and focus light onto the tissue and beam scanning mechanisms which can acquire cross sectional or volumetric OCT data. Since the development of the first catheter-based OCT probe more than 20 years ago, many variations of scanning probes have been developed. IntroductionĬatheter/endoscope-based optical coherence tomography (OCT) is a powerful imaging modality capable of capturing depth-resolved tissue features in luminal organs. © 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement 1. Results are presented on synthetic images and clinical OCT images of the human esophagus. Finally, the OCT volume is resampled and motion corrected. Then longitudinal motion distortion is estimated and corrected using diversity of image features along the catheter pullback direction. The circumferential motion distortion is estimated and corrected using the en face image. This paper presents a novel image processing method to estimate and correct motion distortion in both the circumferential and longitudinal directions using a single en face image from a volumetric data set. However motion distortion remains a challenge because catheter/endoscope OCT imaging involves both circumferential and longitudinal scanning of tissue. Increases in OCT speed have reduced motion artifacts by enabling acquisition faster than or comparable to the time scales of physiological motion. Note: Author names will be searched in the keywords field, also, but that may find papers where the person is mentioned, rather than papers they authored.Ĭatheter/endoscope-based optical coherence tomography (OCT) is a powerful modality that visualizes structural information in luminal organs.Use a comma to separate multiple people: J Smith, RL Jones, Macarthur.Use these formats for best results: Smith or J Smith.For best results, use the separate Authors field to search for author names.Use quotation marks " " around specific phrases where you want the entire phrase only.Question mark (?) - Example: "gr?y" retrieves documents containing "grey" or "gray".Asterisk ( * ) - Example: "elect*" retrieves documents containing "electron," "electronic," and "electricity".Improve efficiency in your search by using wildcards.Example: (photons AND downconversion) - pump.Example: (diode OR solid-state) AND laser.Note the Boolean sign must be in upper-case. Separate search groups with parentheses and Booleans.Keep it simple - don't use too many different parameters.