PurposeIntraoperative evaluation of bowel perfusion is currently dependent upon subjective assessment. Thus, quantitative and objective methods of bowel viability in intestinal anastomosis are scarce. To address this clinical need, a conditional adversarial network is used to analyze the data from laser speckle contrast imaging (LSCI) paired with a visible-light camera to identify abnormal tissue perfusion regions.ApproachOur vision platform was based on a dual-modality bench-top imaging system with red-green-blue (RGB) and dye-free LSCI channels. Swine model studies were conducted to collect data on bowel mesenteric vascular structures with normal/abnormal microvascular perfusion to construct the control or experimental group. Subsequently, a deep-learning model based on a conditional generative adversarial network (cGAN) was utilized to perform dual-modality image alignment and learn the distribution of normal datasets for training. Thereafter, abnormal datasets were fed into the predictive model for testing. Ischemic bowel regions could be detected by monitoring the erroneous reconstruction from the latent space. The main advantage is that it is unsupervised and does not require subjective manual annotations. Compared with the conventional qualitative LSCI technique, it provides well-defined segmentation results for different levels of ischemia.ResultsWe demonstrated that our model could accurately segment the ischemic intestine images, with a Dice coefficient and accuracy of 90.77% and 93.06%, respectively, in 2560 RGB/LSCI image pairs. The ground truth was labeled by multiple and independent estimations, combining the surgeons’ annotations with fastest gradient descent in suspicious areas of vascular images. The total processing time was 0.05 s for an image size of 256 × 256.ConclusionsThe proposed cGAN can provide pixel-wise and dye-free quantitative analysis of intestinal perfusion, which is an ideal supplement to the traditional LSCI technique. It has potential to help surgeons increase the accuracy of intraoperative diagnosis and improve clinical outcomes of mesenteric ischemia and other gastrointestinal surgeries.
KEYWORDS: RGB color model, Data modeling, Performance modeling, Surgery, Near infrared, Computer-aided diagnosis, Computer aided diagnosis and therapy, Imaging systems, Visual process modeling
Parathyroid glands (PGs), small endocrine glands in the neck, control calcium levels in the body and are crucial to maintaining homeostasis. Accidental removal of or direct damage to healthy parathyroid glands during thyroid surgery may occur due to its small size and similar appearance to surrounding anatomical structures, potentially leading to postoperative hypocalcemia. Thus precise and quick detection of normal parathyroid glands in real-time during surgery can improve the surgical outcome. In this study, we introduce a deep learning system (YOLOv5) based on dual RGB/NIR imaging for Computer-aided detection (CADe) of PG with high accuracy. This model can effectively detect parathyroid glands in real-time as it also includes the confidence level, which can help surgeons make decisions. We tested a computer-aided detection (CADe) using the co-registered RGB/NIR camera and ex-vivo thyroid tissue specimen. The average precisions of models were significantly higher when trained by the dual-RGB/NIR (0.99) data than NIR (0.94) and RGB (0.96) data alone at a high confidence threshold (0.7). The proposed CADe may increase the parathyroid detection rates clinically.
In thyroid surgeries, it is often difficult to visually distinguish parathyroid glands (PTGs) from their surrounding anatomical structures such as lymph nodes, fat, and thyroid tissues. There is a clear need to provide head and neck surgeons with intraoperative surgical guidance to safely distinguish PTGs and assess its viability to prevent the risk of hypocalcemia. This study aims to develop a portable hand-held imager that eliminates the need for complex set up for intraoperative imaging to increase the efficiency and performance for surgeons during thyroid surgeries. The performance of the device prototype was evaluated via in-vivo testing throughout preclinical studies.
General anesthetics are known to have profound effects on cerebral hemodynamics and neuronal activities. However, it remains a challenge to directly assess anesthetics-induced hemodynamic and oxygen-metabolic changes from the true baseline under wakefulness at the microscopic level, due to the lack of an enabling technology for high-resolution functional imaging of the awake mouse brain. To address this challenge, we have developed head-restrained photoacoustic microscopy (PAM), which enables simultaneous imaging of the cerebrovascular anatomy, total concentration and oxygen saturation of hemoglobin (CHb and sO2), and blood flow in awake mice. From these hemodynamic measurements, two important metabolic parameters, oxygen extraction fraction (OEF) and the cerebral metabolic rate of oxygen (CMRO2), can be derived. Side-by-side comparison of the mouse brain under wakefulness and anesthesia revealed multifaceted cerebral responses to isoflurane, a volatile anesthetic widely used in preclinical research and clinical practice. Key observations include elevated cerebral blood flow (CBF) and reduced oxygen extraction and metabolism.
Enabling simultaneous high-resolution imaging of the total concentration of hemoglobin (CHb), oxygen saturation of hemoglobin (sO2), and cerebral blood flow (CBF), multiparametric photoacoustic microscopy (PAM) holds the potential to quantify the cerebral metabolic rate of oxygen at the microscopic level. However, its imaging speed has been severely limited by the pulse repetition rate of the dual-wavelength photoacoustic excitation and the scanning mechanism. To address these limitations, we have developed a new generation of multiparametric PAM. Capitalizing on a self-developed high-repetition dual-wavelength pulsed laser and an optical–mechanical hybrid-scan configuration, this innovative technique has achieved an unprecedented A-line rate of 300 kHz, leading to a 20-fold increase in the imaging speed over our previously reported multiparametric PAM that is based on pure mechanical scanning. The performance of the high-speed multiparametric PAM has been examined both in vitro and in vivo. Simultaneous PAM of microvascular CHb, sO2, and CBF in absolute values over a ∼3-mm-diameter brain region of interest can be accomplished within 10 min.
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