Accurate guidance of the epidural needle is important for ensuring the safety and efficacy of epidural anesthesia. Within this study, we proposed an endoscopic system built on polarization-sensitive optical coherence tomography (PS-OCT). To evaluate its viability, we performed experiments on ex-vivo human epidural specimens. Throughout the experimental process, we captured and analyzed various layers of spinal tissue that the epidural needle goes through during the surgery, including subcutaneous fat, supraspinous ligament, interspinous ligament, ligamentum flavum, epidural space, dura, and the spinal cord. Each of these tissue layers had distinctive OCT imaging patterns. Furthermore, we employed deep learning techniques for automated tissue recognition.
The proper guidance of the epidural needle is crucial for safe and effective epidural anesthesia. In this research, we developed an innovative endoscopic system based on polarization-sensitive optical coherence tomography (PS-OCT). To assess its feasibility, we conducted experiments using ex vivo human epidural specimens. During the experiments, we imaged and analyzed different spinal tissue layers that the epidural needle passes through, including subcutaneous fat, supraspinous and interspinous ligament, ligamentum flavum, epidural space, dura, and spinal cord. Each of these tissue layers exhibited distinct imaging patterns. In addition, we used deep learning for automatic tissue recognition.
Lung transplantation is the last therapy option for patients with advanced lung diseases but the shortage of donor lungs currently is a large challenge. We used a polarization-sensitive optical coherence tomography (PS-OCT) system to obtain the distribution and quantification of alveolus and fibrous tissues. Our results showed that the distribution of alveolus and fibrosis was various at different locations on the lung. PS-OCT was able to provide effective quantifications of the alveolus density and size, and the fibrous tissues verified by the histology results. PS-OCT could serve as a promising tool for assessing the quality of donor lungs.
Kidney transplantation faces a worldwide shortage due to the lack of reliable assessment for screening qualified donor kidneys for transplantation. We evaluated the feasibility of using polarization-sensitive optical coherence tomography (PS-OCT) to provide a score map covering the entire surface of a kidney to evaluate the pre-transplantation kidney quality. Multiple histology staining and two-photon microscopy (TPM) were used to provide verification standards for microstructures, tissue distributions, and fibrosis in PS-OCT imaging. Our results indicated that PS-OCT was a reliable method for noninvasively imaging kidney microstructure and fibrosis matching the pretransplant scoring system for assessing the quality of pre-transplantation kidneys.
Early and accurate detection of renal tumor malignancy remains a critical challenge in clinical cancer diagnosis and treatment. Unfortunately, a third of all patients aren’t diagnosed until they have advanced disease. Percutaneous renal biopsy (PRB) followed by histopathology is the most commonly used surgical procedure for early kidney detection and diagnosis. However, PRB is challenging in precisely recognizing the tumor tissue and avoiding renal hemorrhage. In this project, we developed an endoscopic polarization-sensitive optical coherence tomography (PS-OCT) probe for PRB guidance. Deep-learning method was used to automate the tumor recognition procedure.
Percutaneous nephrostomy (PCN) is a minimally invasive procedure used in kidney surgery. PCN needle placement is of great importance for the following successful renal surgery. In this study, we designed and built an endoscopic polarization-sensitive optical coherence tomography (PS-OCT) system for the PCN needle guidance. Compared to traditional OCT, PS-OCT will allow more accurate differentiation of the renal tissue types in front of the needle. In the experiment, we imaged different renal tissues from human kidneys using the PS-OCT endoscope. Furthermore, deep learning methods were applied for automatic recognition of different tissue types.
Common two-dimensional (2D) models are ineffective in mimicking solid tumors. Additionally, fibrotic stroma is one of the major characteristics of pancreatic tumors and it is often missing in in vitro models. Therefore, there is a need for a better in vitro model to accurately mimic the characteristics of tumor and to detect the progression of fibrosis within the tumor model. Here, we utilized polarization-sensitive optical coherence tomography (PS-OCT) to longitudinally detect the collagen progression within multicellular pancreatic tumor spheroids in vitro. Spheroids were scanned by PS-OCT every two days, and progression of fibrosis within the spheroids were detected.
KEYWORDS: Tumors, Optical coherence tomography, Blood vessels, Tissue optics, Surgery, Signal attenuation, Pancreatic cancer, Oncology, In vivo imaging, Cancer
We utilized optical coherence tomography (OCT) to monitor the longitudinal progression of the microenvironment and microvasculature of pancreatic tumors before and after the photothermal therapy-induced immunotherapy in vivo. The primary pancreatic tumors implanted on mouse legs and treated via the photothermal therapy-induced immunotherapy were observed every three days for 36 days. The intensity-based OCT structure, uniformity, texture, intrinsic optical attenuation contrast, and vascular structures were detected and analyzed. Our result demonstrated that the photothermal-induced immunotherapy could cause significant changes in the distribution of the tissue structure and vasculature within the microenvironment and microvasculature of the primary pancreatic tumors.
Guidance of epidural needle is important for the safe and efficient epidural anesthesia procedure. In this study, we built an endoscopic system based on polarization-sensitive optical coherence tomography (PS-OCT). We used pig backbones to test the feasibility of our PS-OCT endoscopic system. Different spinal tissue layers that epidural needle punctures through including subcutaneous fat, ligament, ligamentum flavum, epidural space and spinal cord were imaged and analyzed. They showed different imaging features on the PS-OCT imaging results. Furthermore, we applied deep-learning methods to classify those tissue types automatically to improve the recognition efficiency.
When the epidural needle is punctured into human body during epidural anesthesia surgery, the location of the needle tip is of great importance. In our study, we developed an OCT endoscopic system to help locate the needle tip in real time. Backbones from pigs were utilized to test our system. According to the tissue types that epidural needle punctures through, we imaged five different tissues (fat, ligament, flavum, epidural space and spinal cord). Furthermore, deep-learning methods were used to automatically distinguish the tissue types and predict the distance between the needle tip and the spinal cord. We achieved an average prediction accuracy of 96.65% in tissue classification, and an absolute percentage error at 3.05%±0.55% in distance measurement.
Near-infrared photoimmunotherapy (NIR-PIT) is an emerging cancer therapy based on conjugating monoclonal antibody (mAb) with a NIR phthalocyanine dye conjugate. Direct tumor necrosis and immunogenic cell death occur during NIR irradiation. We applied a multi-modal optical imaging approach including high-resolution optical coherence tomography (OCT) and high-sensitivity fluorescence mesoscopic tomography, to provide 3D tumor micro-structure and micro-distribution of mAb-IR700 in the tumor simultaneously during and after NIR-PIT in situ and in vivo. Moreover, label-free speckle variance algorithm combined OCT was applied to monitor the change of blood vessels and the alterations of the blood volume inside the blood vessels during and NIR-PIT treatment.
KEYWORDS: Tumors, Optical coherence tomography, Melanoma, Signal attenuation, Tissues, In vivo imaging, Angiography, Cancer, Tissue optics, Pancreatic cancer
Pancreatic tumors and melanoma are two types of cancers with high mortality. Monitoring the tumor microenvironment during growth plays an important role in studying the property of tumors. To study the progression of pancreatic tumors and melanoma in vivo, we propose to use optical coherence tomography (OCT) to monitor the tumor structure and angiogenesis in mouse in a longitudinal manner. Our results demonstrate that OCT is a promising tool to longitudinally monitor the change and progression of structure, tissue distribution, and microvasculature in pancreatic and melanoma tumor models. OCT can serve as a promising modality to provide structural and microvascular information for future anti-cancer treatment and drug development.
Percutaneous renal access remains the cornerstone initial step in varied clinical settings. For obtaining the best surgical outcome and minimizing patient morbidity, an appropriate access to the target calyx is needed. In our study, we built a forward-view endoscopic OCT system for PCN guidance. Pig kidneys were imaged to demonstrate the feasibility of the imaging system. Different parts of pig kidneys (cortex, medulla and renal pelvis) can be clearly differentiated. Furthermore, machine learning based computer aided diagnosis platform was developed to distinguish different tissue types automatically and the accuracy of recognition was as high as 90%.
Early and accurate detection of neoplastic changes remains a critical challenge in bladder cancer diagnosis and treatment. Using existing cystoscopy guided techniques, direct visualization of the tumor is limited to the surface of the bladder. Assessment of sub-surface three-dimensional (3D) tumor extension and sub-surface tumor margin is a challenge. In our study, we developed a laparoscopic optical coherence tomography (OCT) imaging platform based on a rigid Gradient Index (GRIN) lenses (diameter ~ 4.5 mm) for imaging subsurface bladder tissues. Bladder tissues from UPII-SV40T mice models were imaged by this system ex vivo and algorithm was developed to quantify sub-surface tumor extension.
Early assessment of sub-surface bladder tumor extension is challenging as there are no acceptable imaging modalities to determine sub-surface three-dimensional (3D) tumor extension. Current existing cystoscopy guided transurethral resection technique is limited on direct visualization of tumor surface. In this paper, a multi-modal optical imaging modality combing high-resolution optical coherence tomography (OCT) and depth-resolved high-sensitivity fluorescence laminar optical tomography (FLOT) for structural and molecular imaging was developed. Bladder tissues from UPII-SV40T mice model were imaged by the multi-modal system ex vivo and sub-surface tumor extension was reconstructed. Algorithm was developed to further quantified 3D bladder tumor morphology and molecular alterations.
Cellular layering is a hallmark of the mammalian neocortex. A key challenge in studying circuit function within the neocortex is to understand the spatial and temporal patterns of information flow between different columns and layers. In the paper, a mesoscopic functional imaging method for neural activities in mouse cortex in vivo was developed and demonstrated. We demonstrated the depth-resolved capability of 3D mesoscopic imaging by photostimulating the layer 5 neurons in Thy1-ChR2-YFP transgenic mice and further recorded the layer-specific functional projections between primary somatosensory cortex and primary motor cortex in vivo, following single whisker deflection.
Three-dimensional (3D) cell culture models are developed as a promising platform to screen anticancer therapeutics and treatments. However, current imaging techniques cannot provide 3D structures of tumor spheroids in situ. In this study, we employed label-free and noninvasive optical coherence tomography (OCT) for imaging and quantifying the 3D structures of tumor spheroids. We imaged ovarian cancer spheroids with OVCAR-8 cell line over a period of 10 days with 5,000 and 50,000 initial cell numbers. We successfully reconstructed the 3D necrotic regions via label-free intrinsic scattering attenuation contrast and evaluated the effect of Cisplatin treatment on tumor spheroids.
KEYWORDS: Neurons, Photostimulation, Luminescence, In vivo imaging, Brain, 3D image processing, Sensors, Neuroimaging, Voltage sensitive dyes, Imaging systems
Significance: Cellular layering is a hallmark of the mammalian neocortex with layer and cell type-specific connections within the cortical mantle and subcortical connections. A key challenge in studying circuit function within the neocortex is to understand the spatial and temporal patterns of information flow between different columns and layers.
Aim: We aimed to investigate the three-dimensional (3D) layer- and area-specific interactions in mouse cortex in vivo.
Approach: We applied a new promising neuroimaging method—fluorescence laminar optical tomography in combination with voltage-sensitive dye imaging (VSDi). VSDi is a powerful technique for interrogating membrane potential dynamics in assemblies of cortical neurons, but it is traditionally used for two-dimensional (2D) imaging. Our mesoscopic technique allows visualization of neuronal activity in a 3D manner with high temporal resolution.
Results: We first demonstrated the depth-resolved capability of 3D mesoscopic imaging technology in Thy1-ChR2-YFP transgenic mice. Next, we recorded the long-range functional projections between sensory cortex (S1) and motor cortex (M1) in mice, in vivo, following single whisker deflection.
Conclusions: The results show that mesoscopic imaging technique has the potential to investigate the layer-specific neural connectivity in the mouse cortex in vivo. Combination of mesoscopic imaging technique with optogenetic control strategy is a promising platform for determining depth-resolved interactions between cortical circuit elements.
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