Bioimaging and Biomedical Optics Commons^™

A Software Application For Cardiac-Gated Computerized Tomography Scanning, Stephen Caldwell, Trevor Engelsman

Williams Honors College, Honors Research Projects

Computerized tomography (CT) scans are a common clinical imaging procedure used worldwide. Operating in the X-Ray spectrum, these machines rotate scanners around a stationary body in order to compile two-dimensional images into a unified three-dimensional image. With adjustment to scan frequency and intensity, internal features such as muscles, organs, and tendons can easily be viewed. However, the heart has long evaded CT use due to its near-constant motion. Recently, cardiac-gated scans have entered the market as a technique to image the heart at a specific moment in time when it is nearly still - the quiescent period. Occurring during rapid …

Design And Development Of Optical Elastography Setup, Abhinav Madhavachandran

Dissertations, Master's Theses and Master's Reports

The mechanical properties of the skin are an indication of its physiological condition. The properties can serve as potential information for dermatologists for diagnosis and qualitative assessment. Elastography is a medical imaging modality developed to extract the elastic properties of a tissue by application of an external force. Optical elastography is a technique of elastography which uses laser speckle tracking to study the elastic properties of several soft tissue including skin.

This work is aimed at developing an optical elastography setup that can study the elastic properties of skin. The setup includes an imaging system and a force-application system controlled …

Effects Of Scattering And Absorption On Laser Speckle Contrast Imaging, Kosar Khaksari

Dissertations, Master's Theses and Master's Reports

Laser Speckle Contrast Imaging (LSCI) is a real-time, non-invasive method in used to investigate blood flow and perfusion in biological tissues with high temporal and spatial resolution. A reduction in speckle contrast due to particle motion is the primary contrast mechanism in LSCI. Motion results in speckle fluctuations in time and reduces the contrast over a given camera integration period. There are a variety of parameters that effect contrast besides motion. The optical properties of the scattering medium are one of the parameters effecting LSCI values. Changes in blood hematocrit levels manifest as changes in optical properties. In this work, …

Feasibility Of Using Raman-Based Techniques For Breast Cancer Detection, Sara Mollamohammada

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Breast cancer is one of the common types of cancer among women all over the world. Early diagnosis is an effective way that improve the treatment process and gives the patients a better chance of survival. Many of the patients infected by breast cancer choose breast conservation surgery (BCS). However, some of those will be subjected to mastectomy, and many will have tumor recurrence as there is no precise technique to show the tumor margins. Raman-based methods are powerful techniques with potential to rapidly differentiate normal from tumor tissues and provides a solution to detect tumor margin. This is because …

Improved Sensitivity To Fluorescence For Cancer Detection In Wide-Field Image-Guided Neurosurgery, Michael Jermyn, Yoann Gosselin, Pablo A. Valdes, Mira Sibai, Kolbein Kolste

Dartmouth Scholarship

In glioma surgery, Protoporphyrin IX (PpIX) fluorescence may identify residual tumor that could be resected while minimizing damage to normal brain. We demonstrate that improved sensitivity for wide-field spectroscopic fluorescence imaging is achieved with minimal disruption to the neurosurgical workflow using an electron-multiplying charge-coupled device (EMCCD) relative to a state-of-the-art CMOS system. In phantom experiments the EMCCD system can detect at least two orders-of-magnitude lower PpIX. Ex vivo tissue imaging on a rat glioma model demonstrates improved fluorescence contrast compared with neurosurgical fluorescence microscope technology, and the fluorescence detection is confirmed with measurements from a clinically-validated spectroscopic probe. Greater PpIX …

Calibration And Optimization Of 3d Digital Breast Tomosynthesis Guided Near Infrared Spectral Tomography, Kelly E. Michaelsen, Venkataramanan Krishnaswamy, Linxi Shi, Srinivasan Vedantham, Steven Poplack, Andrew Karellas, Brian Pogue, Keith Paulsen

Dartmouth Scholarship

Calibration of a three-dimensional multimodal digital breast tomosynthesis (DBT) x-ray and non-fiber based near infrared spectral tomography (NIRST) system is challenging but essential for clinical studies. Phantom imaging results yielded linear contrast recovery of total hemoglobin (HbT) concentration for cylindrical inclusions of 15 mm, 10 mm and 7 mm with a 3.5% decrease in the HbT estimate for each 1 cm increase in inclusion depth. A clinical exam of a patient's breast containing both benign and malignant lesions was successfully imaged, with greater HbT was found in the malignancy relative to the benign abnormality and fibroglandular regions (11 μM vs. …

Noninvasive Assessment Of Photoreceptor Structure And Function In The Human Retina, Robert Francis Cooper

Dissertations (1934 -)

The human photoreceptor mosaic underlies the first steps of vision; thus, even subtle defects in the mosaic can result in severe vision loss. The retina can be examined directly using clinical tools; however these devices lack the resolution necessary to visualize the photoreceptor mosaic. The primary limiting factor of these devices is the optical aberrations of the human eye. These aberrations are surmountable with the incorporation of adaptive optics (AO) to ophthalmoscopes, enabling imaging of the photoreceptor mosaic with cellular resolution. Despite the potential of AO imaging, much work remains before this technology can be translated to the clinic. Metrics …

Quantifying Cross-Scatter Contamination In Biplane Fluoroscopy Motion Analysis Systems, Janelle A. Cross, Ben Mchenry, Taly Gilat-Schmidt

Biomedical Engineering Faculty Research and Publications

Biplane fluoroscopy is used for dynamic in vivo three-dimensional motion analysis of various joints of the body. Cross-scatter between the two fluoroscopy systems may limit tracking accuracy. This study measured the magnitude and effects of cross-scatter in biplane fluoroscopic images. Four cylindrical phantoms of 4-, 6-, 8-, and 10-in. diameter were imaged at varying kVp levels to determine the cross-scatter fraction and contrast-to-noise ratio (CNR). Monte Carlo simulations quantified the effect of the gantry angle on the cross-scatter fraction. A cadaver foot with implanted beads was also imaged. The effect of cross-scatter on marker-based tracking accuracy was investigated. Results demonstrated …

Initial Validation Of A Novel Method Of Presurgical Language Localization Through Functional Connectivity (Fcmri), Stephanie M. Noble, Dustin Scheinost, Susan Y. Bookheimer, Patricia Walshaw, R Todd Constable, Christopher F. Benjamin

Yale Day of Data

OBJECTIVE: Neurosurgery is potentially curative in chronic epilepsy but can only be offered to patients if the surgical risk to language is known. Clinical functional magnetic resonance imaging (fMRI) is an ideal, noninvasive method for localizing language cortex yet remains to be validated for this purpose. We have recently presented a novel method for localizing language cortex. Here we present a preliminary evaluation of this method’s validity. We hypothesized language regions identified using this novel method would demonstrate stronger functional connectivity than randomly generated set of proximal networks. METHOD: fMRI data were collected from sixteen temporal lobe patients …

Review Of Fluorescence Guided Surgery Visualization And Overlay Techniques, Jonathan T. Elliott, Alisha V. Dsouza, Scott C. Davis, Jonathan D. Olson, Keith Paulsen, David Roberts, Brian Pogue

Dartmouth Scholarship

In fluorescence guided surgery, data visualization represents a critical step between signal capture and display needed for clinical decisions informed by that signal. The diversity of methods for displaying surgical images are reviewed, and a particular focus is placed on electronically detected and visualized signals, as required for near-infrared or low concentration tracers. Factors driving the choices such as human perception, the need for rapid decision making in a surgical environment, and biases induced by display choices are outlined. Five practical suggestions are outlined for optimal display orientation, color map, transparency/alpha function, dynamic range compression, and color perception check.

Direct Regularization From Co-Registered Anatomical Images For Mri-Guided Near-Infrared Spectral Tomographic Image Reconstruction, Limin Zhang, Yan Zhao, Shudong Jiang, Brian W. Pogue, Keith Paulsen

Dartmouth Scholarship

Combining anatomical information from high resolution imaging modalities to guide near-infrared spectral tomography (NIRST) is an efficient strategy for improving the quality of the reconstructed spectral images. A new approach for incorporating image information directly into the inversion matrix regularization was examined using Direct Regularization from Images (DRI), which encodes the gray-scale data into the NIRST image reconstruction problem. This process has the benefit of eliminating user intervention such as image segmentation of distinct regions. Specifically, the Dynamic Contrast Enhanced Magnetic Resonance (DCE-MR) image intensity value differences within the anatomical image were used to implement an exponentially-weighted regularization function between …

Angiotensin Ii-Induced Hypertension In Apolipoprotein E-Deficient Rats, Sydney N. Gorman, Craig J. Goergen, A Nicole Blaize

The Summer Undergraduate Research Fellowship (SURF) Symposium

Abdominal aortic aneurysms (AAAs) are characterized by a weakened vessel wall and a diameter 50% greater than normal. AAA are usually asymptomatic until they are near rupturing, which can be fatal if not treated immediately. Apolipoprotein E-deficient (ApoE) mice are commonly used as a model to study aneurysm growth. Our lab has created a similar model using rats, which are more similar to humans. This study focuses on the analysis of blood pressures collected from ApoE rats for comparison with a known mouse model. Five ApoE rats (1 female, 4 males) received subcutaneous implants of osmotic mini pumps that released …

Changes In Vessel Properties During Early Progression Of Murine Abdominal Aortic Aneurysms From In Vivo Ultrasound, Luis R. Avila Murati, Evan H. Phillips, Craig J. Goergen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Abdominal aortic aneurysms (AAA) are a common and frequently fatal disease characterized by the weakening and dilation of the aorta. The larger the aneurysm, the higher the chances are of rupturing and life-threatening hemorrhage. The aim of this study is to apply the angiotensin II (AngII) model of AAAs in male apolipoprotein-E-deficient mice (apoE^-/- C57Bl/6J), in order to analyze, quantify, and understand the pathologies and characteristics associated with early AAA development. To date, many studies focusing on the evaluation of AAA characteristics have been performed ex vivo. Therefore, we focused on in vivo assessment, through the use of …

Review Of Biomedical Čerenkov Luminescence Imaging Applications, Kaveh Tanha, Ali Mahmoud Pashazadeh, Brian W. Pogue

Dartmouth Scholarship

Čerenkov radiation is a fascinating optical signal, which has been exploited for unique diagnostic biological sensing and imaging, with significantly expanded use just in the last half decade. Čerenkov Luminescence Imaging (CLI) has desirable capabilities for niche applications, using specially designed measurement systems that report on radiation distributions, radiotracer and nanoparticle concentrations, and are directly applied to procedures such as medicine assessment, endoscopy, surgery, quality assurance and dosimetry. When compared to the other imaging tools such as PET and SPECT, CLI can have the key advantage of lower cost, higher throughput and lower imaging time. CLI can also provide imaging …

Mobile Cloud Computing Based Non Rigid Registration For Image Guided Surgery, Arun Brahmavar Vishwanatha

Computer Science Theses & Dissertations

In this thesis we present the design and implementation of a Mobile Cloud computing platform for non-rigid registration required in Image Guided Surgery (MCIGS). MCIGS contributes in flexible, portable and accurate alignment of pre-operative brain data with intra-operative MRI, for image guided diagnosis and therapy and endoscopic skull base surgery. Improved precision of image guided therapy and specifically neurosurgery procedures is known to result in the improved prognosis for brain tumor patients. MCI GS system is tested with Physics Based Non-Rigid Registration method form ITK. Our preliminary results for brain images indicate that the proposed system over Wi-Fi can be …

A Non-Invasive Fluorescence-Based Oxygen Sensor And Platform For Studying Cell Responses To Metabolic Agents In Real-Time, Koutilya Reddy Buchapudi

Doctoral Dissertations

A fluorescence-based sensor in a transverse flow/stop measurement platform has been developed to determine real-time changes in oxygen consumption rates for cell metabolic studies. The oxygen sensitive fluorophore platinum octaethylporphyrin was embedded in a cellulose acetate matrix and affixed to a fiber optic bundle, which provided for transmission of the excitation and emission wavelengths of the film. The fiber optic bundle was sealed in a sensor head that can be used in standard 24-well plates common to research labs. The utility of the sensor and sensing platform were determined by measuring the changes in oxygen consumption rates of Candida albicans …

Measuring Blood Flow In The Skeletal Muscle Microcirculation Using Laser Speckle Flowmetry, Kenneth Howard Gouin Iii

Biomedical Engineering

The presence of a native collateral circulation, which serves as a natural bypass for blood flow around an occlusion, improves prognosis for patients with ischemic diseases, such as peripheral arterial occlusive disease (PAOD). However, not all patients have a native collateral circulation, and animal models suggest a genetic basis for this variability. In mice, such as the BALB/c, that lack native arteriolar collaterals, neocollateral formation from capillaries that connect two arterial trees can occur after arterial occlusion, resulting in reperfusion of the ischemic watershed. Immature arterialized collateral capillaries (ACCs) at 7 days post arterial occlusion do not vasodilate in response …

Characterization Of Two Vernier-Tuned Distributed Bragg Reflector (Vt-Dbr) Lasers Used In Swept Source Optical Coherence Tomography (Ss-Oct), Greg M. Bergdoll

Master's Theses

Insight Photonic Solutions Inc. has continued to develop their patented VT-DBR laser design; these wavelength tunable lasers promise marked image-quality and acquisition time improvements in SS-OCT applications.

To be well suited for SS-OCT, tunable lasers must be capable of producing a highly linear wavelength sweep across a tuning range well-matched to the medium being imaged; many different tunable lasers used in SS-OCT are compared to identify the optimal solution.

This work electrically and spectrally characterizes two completely new all-semiconductor VT-DBR designs to compare, as well. The Neptune VT-DBR, an O-band laser, operates around the 1310 nm range and is a …

Gold Nanostructures For Sensing And Functional Bioimaging, Maximilian Y. Fei

McKelvey School of Engineering Graduate Student Theses & Dissertations

Gold nanostructures offer an extremely promising path forward in the fields of imaging and sensing because of their unique optical and chemical properties. Here, we demonstrate that plasmonic nanostructures can be employed as nanoscale transducers to monitor the growth and phase transitions in ultrathin polymer films. In particular, gold nanorods with high refractive index sensitivity (~150 nm / refractive index unit (RIU)) were employed to probe the growth and swelling of polyelectrolyte multilayers (PEM). By comparing the wavelength shift and extinction intensity of the localized surface plasmon resonance (LSPR) of the gold nanorods coated with PEM in air and water, …

3d Printing In Healthcare, Caleb Branch

The Review: A Journal of Undergraduate Student Research

Technology is everywhere. Technology surrounds every aspect of 21^st century life. It is in the cell phones we use, the cars we drive, and even the food we eat. A large portion of modern technology used is taken for granted and overlooked. Despite this, some technology fields continue to grow. Biomedical engineering, specifically 3D printing’s applications to healthcare, has been often overlooked until. Regardless of its status in the mainstream, 3D printing is prosperous in healthcare and its future looks bright. This piece analyzes 3D printing in healthcare. It hones in on the finer details of each specific topic, …