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.
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.
An autocorrelation study has been conducted on Mueller matrix images of stromal region of cervical tissue sections for early cancer detection. Changes in multiple scattering and deterioration of stromal architecture through their spatial autocorrelation maps are observed among healthy and various grades of cervical precancerous tissues. Autocorrelation maps of diagonal elements reflects increasing depolarization property while the disease progresses. These maps of Mueller elements governing polariance, di-attenuation and birefringence properties qualitatively establish a demarcation of different grades of cancer from normal tissue. Moreover, spatial autocorrelation on optical parameters like circular di-attenuation, liner and linear-45 di-attenuation along with circular birefringence is decreasing with the evolution of cervical cancer. These preliminary results about the stromal biology are very promising in the early detection of cervical cancer.
Throat precancer detection using fluorescence from human saliva is reported here. It may be noted that accessing the throat for investigation is cumbersome and use of saliva as a diagnostic medium may ease the process. The study has been conducted on three groups of patients: oral squamous cell carcinoma (OSCC), dysplasia, and normal (control). An in-house developed compact set-up has been used for fluorescence measurements. The compact system consist of a 375 nm laser diode, collimating lens, long pass filter, fibers, and cuvette holder. Major and minor bands of flavin adenine dinucleotide (FAD) and porphyrin are observed in the spectra. A receiver operating characteristic (ROC) analysis has been used to evaluate the diagnostic performance. Area under the spectra has been chosen for discrimination among the groups and is able to differentiate OSCC to normal, dysplasia to normal, and OSCC to dysplasia with sensitivities 100% (48/48), 92% (32/35), 77% (37/48), and specificities 96% (50/52), 96% (50/52), 89% (31/35) with the accuracy of 98%, 94% and 82% respectively. Sensitivity and specificity, when differentiating OSCC to normal and dysplasia to normal, are significantly large, which indicates that human saliva may be an excellent diagnostic medium for early detection of throat cancer.
A systematic study has been conducted on application of wavelet based multifractal de-trended fluctuation analysis (MFDFA) on Mueller matrix (MM) images of cervical tissue sections for early cancer detection. Changes in multiple scattering and orientation of fibers are observed by utilizing a discrete wavelet transform (Daubechies) which identifies fluctuations over polynomial trends. Fluctuation profiles, after 9th level decomposition, for all elements of MM qualitatively establish a demarcation of different grades of cancer from normal tissue. Moreover, applying MFDFA on MM images, Hurst exponent profiles for images of MM qualitatively are seen to display differences. In addition, the values of Hurst exponent increase for the diagonal elements of MM with increasing grades of the cervical cancer, while the value for the elements which correspond to linear polarizance decrease. However, for circular polarizance the value increases with increasing grades. These fluctuation profiles reveal the trend of local variation of refractive -indices and along with Hurst exponent profile, may serve as a useful biological metric in the early detection of cervical cancer. The quantitative measurements of Hurst exponent for diagonal and first column (polarizance governing elements) elements which reflect changes in multiple scattering and structural anisotropy in stroma, may be sensitive indicators of pre-cancer.
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.