We present a laser speckle contrast imaging (LSCI) device equipped with an image conduit to image microvascular blood flow in remote tissues like ear, nose, throat (ENT) and cervical region. The system is validated using a tissue mimicking microfluidic flow phantom with different widths and flow speeds. The proposed system is being developed as a point of care testing (POCT) device best suited for at-home self-monitoring in resource-limited areas as it is non-invasive, portable, affordable and real time.
We present a novel approach that combines Monte Carlo simulations to propagate photons in a turbid media having the dynamics modelled using stochastic differential equations, resulting in simulating diffuse laser speckles for in-vivo blood flow imaging applications. The proposed method allows to model the tissue dynamics with a pre-defined probability density function and spatially varying autocorrelation.
Phantoms that accurately simulate in-vivo tissue properties are essential for the advancement of medical imaging methods. In this paper, we propose a novel approach to develop a fast and tunable dynamical phantom that mimics in-vivo blood flow, based on stochastic differential equations (SDE) and piezoelectric actuators. We validate the phantom using in-vivo human blood flow studies.
We introduce a novel cerebral perfusion phantom to calibrate laser speckle imaging systems for small animal brain imaging. A method based on Hele-Shaw cell technique is used to create fractal like structures which serves as the mould for the phantom making. The structure is casted to create micro channels in PDMS phantoms which is found to closely mimic the structure of superficial cerebral blood vessels in small animals. The proposed method has the potential to fabricate optically and anatomically accurate cerebral perfusion phantom using a quick and inexpensive fabrication technique suitable for blood flow imaging studies.
Laser speckle based superficial and deep tissue blood flow imaging is gaining interest with the advent of high speed cameras. Multi-exposure speckle intensity images are often utilized for this purpose, owing to the better quantification of flow. However, any uncertainty in selecting the required exposure range apriori and the data acquisition time associated with multi-exposure intensity measurements limit the temporal resolution of these systems. To address these concerns, we propose a deep learning-based imputation using Generative Adversarial Imputation Network (GAIN) to generate additional temporal samples from coarsely acquired multi-exposure speckle data. The feasibility of the proposed method has been verified by using simulations where the trade-off between temporal resolution and the accuracy of flow measurement is minimized.
Laser speckle contrast imaging (LSCI) methods are extensively used in assessment of blood flow to detect various pathological conditions in different parts of human body. In contrast to LSCI being deployed for larger region of interest (few centimeters), we present a laser speckle imaging at microscopic level. Rather than utilizing the conventional speckle contrast, we use intensity auto-correlation using recently developed Multi-step Volterra Integral method(MVIM) to quantify the micro-perfusion. The proposed laser speckle correlation microscopy (LSCM) system is validated using microfluidic flow phantom experiments.
A portable, compact and modular small-animal imaging platform is designed for measurement of deep tissue and superficial cerebral blood flow. The platform is integrated with optics, data acquisition unit, display unit and on-board single-board computer (SBC) that supports a Graphical User Interface (GUI). It also contains a customizable stereotaxic frame for both mice and rats for housing the animals along with provision for anesthesia, pulse oximeters and temperature probes. Functional studies have been conducted in the olfactory bulb and somatosensory cortex in mice brain using the imaging platform to measure relative cerebral blood flow (rCBF). We show longitudinal blood flow changes in the pre-cortical brain region associated with multiple odours, categorized broadly into ester, phenyl propanoid and terpenoids chemical group. A forepaw stimulation study has also been conducted to show blood flow changes in the cortical region of the brain. The surface as well as depth-wise blood flow changes due to the stimulations have been shown using Laser Speckle Contrast Imaging (LSCI) and Multi-speckle Diffuse Correlation Tomography (M-DCT) respectively.
We present a computationally fast algorithm for estimating the optical property distribution of turbid media using diffuse optics principles without the inversion of Jacobian matrix. The algorithm is validated by simulations and experimental studies.
KEYWORDS: Blood circulation, Speckle, Laser speckle contrast imaging, Sensors, Photons, Skull, Signal to noise ratio, Diffusion, In vivo imaging, Cameras
We explore various source configurations (such as point source, line sources and its variants, uniform illumination) for laser speckle-based imaging of blood flow and validate by simulation studies and in-vivo imaging of mice brain.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.