No diagnostic method is currently available to visualize and measure the airway smooth muscle (ASM) within a living patient. Endoscopic Polarization Sensitive Optical Coherence Tomography (PS-OCT) might enable quantification of ASM mass in vivo, by assessing tissue birefringence. We performed in vivo PS-OCT on patients (n=17) with airway diseases (asthma and interstitial lung disease) and one healthy volunteer. An in-house built distal scanning catheter (1.35 mm) was used to circumferentially scan the airways at 52 fps B-scan rate. We demonstrated PS-OCT to be a minimally invasive technique to assess ASM thickness in diseased airways relative to healthy subjects.
Many quantum entanglement generation protocols require phase stabilization between the nodes. For color centers that are embedded in a solid immersion lens (SIL) often a reflection from the SIL’s surface is input to an interferometer where it is mixed with a reference beam. However, the beam reflected beam by the SIL does not travel colinear with the photons that are emitted by the color center, which ultimately leads to a reduction of the interferometer’s signal-to-noise ratio (SNR). Additionally, imperfections of the SIL surface introduce aberrations into the reflected light, thereby further reducing the SNR. Through several design-iterations and extensive experience realizing phase stabilization on many different SIL’s we have come to an approach that significantly improves the SNR and enhances the operability of the quantum node. In this paper we report on our optical design and provide useful guidelines for the operation thereof.
Currently, no diagnostic method exists to visualize and measure the airway smooth muscle (ASM) in vivo. Endoscopic Polarization Sensitive Optical Coherence Tomography (PS-OCT) has the potential to detect and quantify the ASM, by assessing tissue birefringence. We performed in vivo PS-OCT in patients (n=17) with airway diseases (asthma and interstitial lung disease) and one healthy volunteer. PS-OCT images were acquired with an in-house built distal scanning catheter (1.35mm), which allowed circumferential scan of the airways at 52 fps B-scan rate. We demonstrated PS-OCT to be a minimally invasive technique to assess ASM thickness in diseased airways relative to healthy subjects.
Asthma is an inflammatory disease, causing thickening of the Airway Smooth Muscle (ASM). No current method exists to directly measure ASM within a living patient. Endoscopic Polarization Sensitive Optical Coherence Tomography (PS-OCT) might enable quantification of ASM mass in vivo, by assessing tissue birefringence. We performed in vivo PS-OCT on severe asthma patients and healthy volunteers, with an in-house built distal scanning catheter (1.35 mm), to circumferentially scan the airways at 52 fps B-scan rate. We provided the first comparison of in vivo PS-OCT images between asthma and healthy subjects and demonstrated the ability of PS-OCT to assess ASM content.
Interstitial lung disease (ILD) is a group of lung conditions, characterized by inflammation and pulmonary fibrosis. High-resolution computed tomography (HRCT), is often insufficient to detect fibrosis, and acquisition of lung biopsies is needed. Polarization-sensitive optical coherence tomography (PS-OCT) provides high-resolution images of the airways and fibrotic tissue-specific contrast by assessing tissue birefringence in a minimally invasive way. We developed a distal scanning endoscope and performed in-vivo PS-OCT measurements by advancing the endoscope in the lungs of 16 ILD patients undergoing biopsy acquisition and in 3 asthma patients included as non-fibrotic controls. Fibrosis was quantified in the acquired PS-OCT images, in HRCT, and in biopsies. Results show excellent correlation of PS-OCT detected fibrosis with histologically confirmed fibrosis, while HRCT only showed a poor-moderate correlation with histology for fibrosis quantification.
Asthma is a chronic inflammatory disease associated with thickening of the airway smooth muscle (ASM).
Currently, there is no imaging modality available to assess ASM mass in vivo, other than invasive biopsies.
Polarization Sensitive Optical Coherence Tomography (PS-OCT) might enable minimally invasive in vivo quantification of ASM mass, by providing birefringent tissue-specific contrast.
We performed in vivo PS-OCT in three asthma patients who underwent bronchial thermoplasty (BT), an endoscopic treatment which induces ASM reduction. We found an excellent correlation between ASM content in PS-OCT images and biopsies. Moreover, PS-OCT was able to detect a reduction in the ASM content after BT.
Endobronchial polarization sensitive optical coherence tomography (PS-OCT) provides high-resolution images and can detect tissue birefringence. Using collagen birefringent properties, we postulated that PS-OCT can detect and quantify pulmonary fibrosis in interstitial lung disease (ILD) patients. In this study, we demonstrated PS-OCT in 19 patients (16 ILD and 3 non-fibrotic controls). In-vivo PS-OCT was performed by advancing a distal scanning endoscope through the working channel of a bronchoscope to the lung periphery of the patients. Results show that PS-OCT is feasible, safe, and can quantify pulmonary fibrosis, thereby has potential as minimally invasive diagnostic tool to detect fibrotic progression in ILD.
Esophageal cancer has a low survival rate, which is significantly improved through early detection, as well as monitoring of a common pre-cursor, Barrett’s esophagus. Optical Coherence Tomography is a low coherence interferometry technique which produces three-dimensional depth scans of tissues. OCT provides morphology but lacks in molecular specificity, and can thus be combined with targeted Near Infrared Fluorescence imaging. The viability of this dual-modality technique for use in detecting BE and esophageal cancer is assessed using topically and intravenously administered Bevacizumab in combination with an OCT-NIRF system, to produce ex vivo tissue scans, which are then histology matched.
Polarization-sensitive optical coherence tomography has been used to image two healthy and four diseased lungs ex vivo together with histology. Differences between lungs were found in alveoli size and airway smooth muscle thickness.
We performed in-vivo PS-OCT in three asthma patients who underwent bronchial thermoplasty (BT). PS-OCT qualified as minimally invasive technique to visualize airway smooth muscle (ASM) and showed its reduction after BT.
We present a motorized distal scanning endoscope with an outer diameter of 1.35 mm and 52 fps rotation speed for in vivo imaging in the peripheral airways of lungs [1]. Lung segments of an asthma patient pre and post bronchial thermoplasty (BT) treatment were imaged [2]. Optical coherence tomography (OCT) intensity images, attenuation coefficient (AC) images and polarization sensitive OCT (PS-OCT) images showing both birefringence, optic axis uniformity (OAxU) and optic axis (OA) orientation were extracted from the acquired data. PS-OCT endoscopy visualized airway smooth muscle layer thickness and location pre and post BT treatment as means to predict its effectiveness.
Imaging the heterogeneity of the tumor microenvironment is thought to be valuable for assessing the efficacy of a cancer therapy. However, due to the insufficient resolution of clinically available molecular imaging tools such as positron emission tomography, this feat is currently not achievable. Here, we demonstrate that revealing the TME is possible with immuno-near-infrared-fluorescence (Immuno-NIRF) imaging. Moreover, we combined immuno-NIRF with optical coherence tomography (OCT) to provide structural context to the molecular images. The combination of the two techniques may represent a novel tool in the operating room for assessing development or early diagnosis of tumors.
Polarization-sensitive optical coherence tomography (PS-OCT) has been used to extract polarization properties of four different diseased lungs ex vivo, including fibrotic sarcoidosis (FS), chronic obstructive pulmonary disease (COPD), fibrotic extrinsic allergic alveolitis (fibrotic EAA) and cystic fibrosis (CF). An increase in alveoli size has been observed in COPD lungs. Furthermore, an increase in birefringence signal was observed for FS and fibrotic EAA. In CF, a few areas with thick patches of birefringence occurred. The results show potential of in vivo assessment of lung fibrosis. Histology slides of all lungs were acquired, and will be used to further interpret the results.
We present a motorized distal scanning endoscope with an outer diameter of 1.35 mm and 52 fps rotation speed for in vivo imaging in the peripheral airways of lungs. Three lung segments of an asthma patient pre and post bronchial thermoplasty (BT) treatment were imaged. Optical coherence tomography (OCT) intensity images, attenuation coefficient (AC) images and polarization sensitive OCT (PS-OCT) images showing both birefringence, optic axis uniformity (OAxU) and optic axis (OA) orientation were extracted from the acquired data. PS-OCT endoscopy visualized airway smooth muscle layer thickness and location pre and post BT treatment as means to predict its effectiveness.
Early detection of cancer lesions is a critical factor for improving disease prognosis. Detection rates might be improved by catheter based optical coherence tomography (OCT), which enables three dimensional high-resolution images acquisition of organ surfaces and luminal walls. However, OCT lacks in specificity; this limitation can be overcome combining it with targeted fluorescence. To this end, we developed a miniature motorized endoscopic probe with an outer diameter of 1.35mm and a rotation speed of 3,200rpm. Combining near-infrared fluorescence (NIRF) imaging with our OCT system we were able to specifically locate a cell-type by targeting its membrane receptors with fluorescently labelled monoclonal antibodies (mAbs). Exploiting double clad fiber (DCF) coupler technology the OCT and NIRF excitation signals were delivered to the endoscope tip through its single mode core, while the emitted fluorescence signal was efficiently collected by the DCF inner cladding. The catheter was demonstrated to acquire in situ images in a xenograft mouse model of human colorectal cancer, by metabolized mAb labelled with a near-infrared fluorophore (IRDye800CW). While circumferentially scanning the sample with the endoscope, the NIRF signal served as navigation tool to identify the tumour location; once a suspicious region was identified, B-scans and NIRF were acquired. NIRF and OCT images proved to complement each other by revealing molecular contrast within the surrounding tissue architectural context. Moreover, high degree of heterogeneity in the malignant tissue was revealed by the NIRF images. The excellent contrast provided by endoscopic immuno-NIRF-OCT demonstrated its potential to reduce erroneous sampling of tissue.
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