Abstract WP1: High-Frequency Optical Coherence Tomography for Cerebrovascular Disease

Introduction: Optical coherence tomography (OCT) has played an important role in the diagnosis and treatment guidance in coronary artery disease. However, existing OCT systems are not suitable for routine neurovascular applications due to the size and tortuosity of the arteries. Hypothesis: We seek to demonstrate a prototype high-frequency OCT (HF-OCT) capable of high-resolution imaging in simulated cerebrovascular anatomy. Methods: A low-profile HF-OCT system was constructed with an image resolution approaching 10μm. Using an in vitro, patient-specific model of the circle of Willis with circulating porcine blood, we characterized the delivery of the device and ability to image in a tortuous path. Also, human cadaver intracranial atherosclerosis plaques were imaged with HF-OCT and assessed by an expert imager. Finally, neurovascular devices were implanted in 8 pigs (Fig 1) and HF-OCT imaging was compared with gold-standard DSA and CT. Results: In the phantom, optimal blood clearance was achieved through an intermediate catheter (5 Fr Navien) with infusion of contrast at 5 ml/s in the internal carotid and basilar artery, and 3 ml/sec in the MCA. The in vivo study demonstrated that both malapposition of devices or thrombus formation along the device surface could be reliably diagnosed among 3 reviewers (Fleiss’s kappa of 0.87 and 0.9, respectively). This agreement was superior to DSA and CT. Imaging in tortuous swine brachial showed in all cases imaging free of artifacts, uniform illumination and ability to visualize vessel wall layers. Plaque types including ‘lipid pools’, fibrotic, and calcific tissue from cadaver specimens of ICAD could be adequately depicted by HF-OCT. Conclusion: In vitro, in vivo and ex vivo characterization of a novel HF-OCT device has shown it is capable of imaging in the tortuous intracranial vascular anatomy. This technology has to potential to aid in the diagnosis of cerebrovascular disease and guide optimal endovascular treatment.

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Optimization of X-ray Investigations in Dentistry Using Optical Coherence Tomography

Sensors ◽

10.3390/s21134554 ◽

2021 ◽

Vol 21 (13) ◽

pp. 4554

Author(s):

Ralph-Alexandru Erdelyi ◽

Virgil-Florin Duma ◽

Cosmin Sinescu ◽

George Mihai Dobre ◽

Adrian Bradu ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Radiation Dose ◽

Imaging Techniques ◽

Image Resolution ◽

Optical Coherence ◽

X Rays ◽

High Quality ◽

X Ray

The most common imaging technique for dental diagnoses and treatment monitoring is X-ray imaging, which evolved from the first intraoral radiographs to high-quality three-dimensional (3D) Cone Beam Computed Tomography (CBCT). Other imaging techniques have shown potential, such as Optical Coherence Tomography (OCT). We have recently reported on the boundaries of these two types of techniques, regarding. the dental fields where each one is more appropriate or where they should be both used. The aim of the present study is to explore the unique capabilities of the OCT technique to optimize X-ray units imaging (i.e., in terms of image resolution, radiation dose, or contrast). Two types of commercially available and widely used X-ray units are considered. To adjust their parameters, a protocol is developed to employ OCT images of dental conditions that are documented on high (i.e., less than 10 μm) resolution OCT images (both B-scans/cross sections and 3D reconstructions) but are hardly identified on the 200 to 75 μm resolution panoramic or CBCT radiographs. The optimized calibration of the X-ray unit includes choosing appropriate values for the anode voltage and current intensity of the X-ray tube, as well as the patient’s positioning, in order to reach the highest possible X-rays resolution at a radiation dose that is safe for the patient. The optimization protocol is developed in vitro on OCT images of extracted teeth and is further applied in vivo for each type of dental investigation. Optimized radiographic results are compared with un-optimized previously performed radiographs. Also, we show that OCT can permit a rigorous comparison between two (types of) X-ray units. In conclusion, high-quality dental images are possible using low radiation doses if an optimized protocol, developed using OCT, is applied for each type of dental investigation. Also, there are situations when the X-ray technology has drawbacks for dental diagnosis or treatment assessment. In such situations, OCT proves capable to provide qualitative images.

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Comparison of optical coherence tomography and high frequency ultrasound imaging in mice for the assessment of skin morphology and intradermal volumes

Scientific Reports ◽

10.1038/s41598-019-50104-4 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Kornelia Schuetzenberger ◽

Martin Pfister ◽

Alina Messner ◽

Vanessa Froehlich ◽

Gerhard Garhoefer ◽

...

Keyword(s):

Optical Coherence Tomography ◽

High Frequency ◽

Ex Vivo ◽

Clinical Settings ◽

Optical Coherence ◽

High Frequency Ultrasound ◽

Skin Morphology ◽

Frequency Ultrasound ◽

Good Agreement

Abstract Optical coherence tomography (OCT) and high-frequency ultrasound (HFUS), two established imaging modalities in the field of dermatology, were evaluated and compared regarding their applicability for visualization of skin tissue morphology and quantification of murine intradermal structures. The accuracy and reproducibility of both methods were assessed ex vivo and in vivo using a standardized model for intradermal volumes based on injected soft tissue fillers. OCT revealed greater detail in skin morphology, allowing for detection of single layers due to the superior resolution. Volumetric data measured by OCT (7.9 ± 0.3 μl) and HFUS (7.7 ± 0.5 μl) were in good agreement and revealed a high accuracy when compared to the injected volume of 7.98 ± 0.8 µl. In vivo, OCT provided a higher precision (relative SD: 26% OCT vs. 42% HFUS) for the quantification of intradermal structures, whereas HFUS offered increased penetration depth enabling the visualization of deeper structures. A combination of both imaging technologies might be valuable for tumor assessments or other dermal pathologies in clinical settings.

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High frequency optical coherence tomography assessment of homogenous neck coverage by intrasaccular devices predicts successful aneurysm occlusion

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2019-014843 ◽

2019 ◽

Vol 11 (11) ◽

pp. 1150-1154 ◽

Cited By ~ 7

Author(s):

Robert M King ◽

Miklos Marosfoi ◽

Jildaz Caroff ◽

Giovanni J Ughi ◽

Dale M Groth ◽

...

Keyword(s):

Optical Coherence Tomography ◽

High Frequency ◽

Thrombus Formation ◽

Optical Coherence ◽

Aneurysm Neck ◽

Coverage Gap ◽

Aneurysm Embolization ◽

Aneurysm Occlusion ◽

Automated Image Processing

BackgroundHigh frequency optical coherence tomography (HF-OCT) is a novel intravascular imaging technology developed for use in the cerebral vasculature. We hypothesize that HF-OCT characterization of intrasaccular device neck coverage can prognosticate exclusion of the aneurysm from the circulation.MethodsBifurcation and sidewall aneurysms were made in six dogs. Seven aneurysms were treated with next generation intrasaccular devices (NGID) and four with traditional platinum coils. HF-OCT was performed to interrogate gaps in the neck coverage, coil herniation, or acute thrombus formation. Animals were re-imaged at 7, 30, 90, and 180 days following aneurysm embolization. An automated image processing method segmented the devices at the neck of the aneurysm and quantified neck coverage. The largest coverage gap was used to predict aneurysm occlusion at 180 days.ResultsNo difference was found in occlusion rates between the coil and NGID groups (P=0.45). Successful segmentation of the NGID construct was achieved in all cases. A coverage gap >1 mm2 was found to predict failed aneurysm occlusion (P=0.047). This threshold was able to predict all cases of failed occlusion. The average number of devices needed to treat the aneurysm was lower in the NGID group (1.9 vs 6.75, P=0.009). HF-OCT showed strong agreement with scanning electron microscopy (bias 0.0024 mm2 (95% CI −0.0279, 0.0327)).ConclusionsHF-OCT enables precise and accurate measurement of coverage gaps at the neck of aneurysms treated with intrasaccular devices in vivo. We provide in vivo evidence that uniform aneurysm neck coverage by intrasaccular devices is critical for aneurysm occlusion.

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Detecting glucose-induced changes in in vitro and in vivo experiments with optical coherence tomography

Journal of Biomedical Optics ◽

10.1117/1.2904957 ◽

2008 ◽

Vol 13 (2) ◽

pp. 021111 ◽

Cited By ~ 24

Author(s):

Matti Kinnunen ◽

Risto Myllylä ◽

Seppo Vainio

Keyword(s):

Optical Coherence Tomography ◽

Optical Coherence ◽

In Vivo Experiments ◽

Induced Changes

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Assessing ex vivo dental biofilms and in vivo composite restorations using cross-polarization optical coherence tomography

10.1117/12.914598 ◽

2012 ◽

Cited By ~ 1

Author(s):

R. Jones ◽

C. Aparicio ◽

R. Chityala ◽

R. Chen ◽

A. Fok ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Ex Vivo ◽

Optical Coherence ◽

Cross Polarization ◽

Composite Restorations

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Polarization sensitive optical coherence tomography with single input for imaging depth-resolved collagen organizations

Light Science & Applications ◽

10.1038/s41377-021-00679-3 ◽

2021 ◽

Vol 10 (1) ◽

Author(s):

Peijun Tang ◽

Mitchell A. Kirby ◽

Nhan Le ◽

Yuandong Li ◽

Nicole Zeinstra ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Structural Integrity ◽

Ex Vivo ◽

Polarization State ◽

Transmission Model ◽

Optical Coherence ◽

Healthy Human ◽

Collagen Organization ◽

Single Input

AbstractCollagen organization plays an important role in maintaining structural integrity and determining tissue function. Polarization-sensitive optical coherence tomography (PSOCT) is a promising noninvasive three-dimensional imaging tool for mapping collagen organization in vivo. While PSOCT systems with multiple polarization inputs have demonstrated the ability to visualize depth-resolved collagen organization, systems, which use a single input polarization state have not yet demonstrated sufficient reconstruction quality. Herein we describe a PSOCT based polarization state transmission model that reveals the depth-dependent polarization state evolution of light backscattered within a birefringent sample. Based on this model, we propose a polarization state tracing method that relies on a discrete differential geometric analysis of the evolution of the polarization state in depth along the Poincare sphere for depth-resolved birefringent imaging using only one single input polarization state. We demonstrate the ability of this method to visualize depth-resolved myocardial architecture in both healthy and infarcted rodent hearts (ex vivo) and collagen structures responsible for skin tension lines at various anatomical locations on the face of a healthy human volunteer (in vivo).

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Imaging depth extension of optical coherence tomography in rabbit eyes using optical clearing agents

Experimental Biology and Medicine ◽

10.1177/1535370220949834 ◽

2020 ◽

Vol 245 (18) ◽

pp. 1629-1636

Author(s):

Ruiming Kong ◽

Wenjuan Wu ◽

Rui Qiu ◽

Lei Gao ◽

Fengxian Du ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Ex Vivo ◽

Light Attenuation ◽

Anterior Segment ◽

Posterior Segment ◽

Glycerol Solution ◽

Optical Coherence ◽

Optical Clearing ◽

Imaging Depth

Optical coherence tomography has become an indispensable diagnostic tool in ophthalmology for imaging the retina and the anterior segment of the eye. However, the imaging depth of optical coherence tomography is limited by light attenuation in tissues due to optical scattering and absorption. In this study of rabbit eye both ex vivo and in vivo, optical coherence tomography imaging depth of the anterior and posterior segments of the eye was extended by using optical clearing agents to reduce multiple scattering. The sclera, the iris, and the ciliary body were clearly visualized by direct application of glycerol at an incision on the conjunctiva, and the posterior boundary of sclera and even the deeper tissues were detected by submerging the posterior segment of eye in glycerol solution ex vivo or by retro-bulbar injection of glycerol in vivo. The ex vivo rabbit eyes recovered to their original state in 60 s after saline-wash treatment, and normal optical coherence tomography images of the posterior segment of the sample eyes proved the self-recovery of in vivo performance. Signal intensities of optical coherence tomography images obtained before and after glycerol treatment were compared to analysis of the effect of optical clearing. To the best of our knowledge, this is the first study for imaging depth extension of optical coherence tomography in both the anterior and posterior segments of eye by using optical clearing agents.

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