Polarization-sensitive optical coherence tomography (PS-OCT) is used to investigate changes in fiber structures in the eyes of myopia, wet age-related macular degeneration (wAMD), and glaucoma patients. A depth-multiplexed fiber-based PS-OCT system is used to extract local optic axis orientations of birefringent structures in the eye locally in 3D in vivo. For healthy volunteers, birefringent structures include the retinal nerves, Henle’s fiber layer, and sclera. Scleral collagen architecture is observed to be altered in myopia patients. In wAMD patients fibrosis orientation and volume can be extracted using this technique.
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.
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.
Polarization sensitive optical coherence tomography (PS-OCT) has been used to visualize the orientation of the nerves in the retinal nerve fiber layer (RNFL) and to visualize depolarization in retinas of healthy volunteers and age-related macular degeneration (AMD) patients. Optic axis orientation images clearly visualize the nerve fibers leaving the optic nerve head (ONH) in all radial directions in healthy volunteers. Depolarization images show depolarization of the RPE and for some cases, highlight another depolarizing layer at the boundary of the choroid and sclera.
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.
A depth-multiplexed fiber-based PS-OCT system is used to extract local polarization information of retinas of age-related macular degeneration (AMD) patients in different stages. In the end stage of wet AMD, retinal structures are replaced with fibrous tissue which leads to irreversible loss of vision. Accurate imaging and evaluation of the lesions is important for reliable diagnosis and treatment of AMD. However, no imaging techniques exist which can clearly distinguish a fibrotic lesion from non-fibrotic neovascular tissue which is still active.
With PS-OCT fibrous tissue in the retina of AMD patients can be detected and quantified using its birefringent properties. Images from previous research often show cumulative phase retardation, where the polarization state of every pixel is compared to the polarization state at the surface of the retina. However, a quantity which is linearly related to the amount of birefringent tissue is more desirable for clinical interpretations. In the presented research, a new method is used to obtain depth-resolved local birefringence images which has only been used on breast tissue before. In this method, the birefringent quantities (linear phase retardation) are extracted from the differential Mueller matrix.
In the images of retinas from AMD patients, fibrotic lesion areas can be recognized and separated from non-fibrotic areas. An improvement to localize birefingence in depth while maintaining similar image quality is demonstrated. This provides new possibilities for clinical research to monitor the development of AMD and to assess the response to treatment.
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