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Proceedings of SPIE

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https://www.readbyqxmd.com/read/28781415/development-and-characterization-of-an-8%C3%A3-8-spad-array-module-for-gigacount-per-second-applications
#1
Francesco Ceccarelli, Angelo Gulinatti, Ivan Labanca, Ivan Rech, Massimo Ghioni
In recent years the development of Single-Photon Avalanche Diodes (SPADs) had a big impact on single-photon counting applications requiring high-performance detectors in terms of Dark Count Rate (DCR), Photon Detection Efficiency (PDE), afterpulsing probability, etc. Among these, it is possible to find applications in single-molecule fluorescence spectroscopy that suffer from long-time measurements. In these cases SPAD arrays can be a solution in order to shorten the measurement time, thanks to the high grade of parallelism they can provide...
April 24, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28966430/subject-specific-longitudinal-shape-analysis-by-coupling-spatiotemporal-shape-modeling-with-medial-analysis
#2
Sungmin Hong, James Fishbaugh, Morteza Rezanejad, Kaleem Siddiqi, Hans Johnson, Jane Paulsen, Eun Young Kim, Guido Gerig
Modeling subject-specific shape change is one of the most important challenges in longitudinal shape analysis of disease progression. Whereas anatomical change over time can be a function of normal aging; anatomy can also be impacted by disease related degeneration. Shape changes to anatomy may also be affected by external structural changes from neighboring structures, which may cause non-linear pose variations. In this paper, we propose a framework to analyze disease related shape changes by coupling extrinsic modeling of the ambient anatomical space via spatiotemporal deformations with intrinsic shape properties from medial surface analysis...
April 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28458443/renal-stone-characterization-using-high-resolution-imaging-mode-on-a-photon-counting-detector-ct-system
#3
A Ferrero, R Gutjahr, A Henning, S Kappler, A Halaweish, D Abdurakhimova, Z Peterson, J Montoya, S Leng, C McCollough
In addition to the standard-resolution (SR) acquisition mode, a high-resolution (HR) mode is available on a research photon-counting-detector (PCD) whole-body CT system. In the HR mode each detector consists of a 2x2 array of 0.225 mm × 0.225 mm subpixel elements. This is in contrast to the SR mode that consists of a 4x4 array of the same sub-elements, and results in 0.25 mm isotropic resolution at iso-center for the HR mode. In this study, we quantified ex vivo the capabilities of the HR mode to characterize renal stones in terms of morphology and mineral composition...
March 9, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/29046597/ultrasound-tomography-imaging-with-waveform-sound-speed-parenchymal-changes-in-women-undergoing-tamoxifen-therapy
#4
Mark Sak, Neb Duric, Peter Littrup, Mark Sherman, Gretchen Gierach
Ultrasound tomography (UST) is an emerging modality that can offer quantitative measurements of breast density. Recent breakthroughs in UST image reconstruction involve the use of a waveform reconstruction as opposed to a ray-based reconstruction. The sound speed (SS) images that are created using the waveform reconstruction have a much higher image quality. These waveform images offer improved resolution and contrasts between regions of dense and fatty tissues. As part of a study that was designed to assess breast density changes using UST sound speed imaging among women undergoing tamoxifen therapy, UST waveform sound speed images were then reconstructed for a subset of participants...
March 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/29033488/automated-liver-elasticity-calculation-for-3d-mre
#5
Bogdan Dzyubak, Kevin J Glaser, Armando Manduca, Richard L Ehman
Magnetic Resonance Elastography (MRE) is a phase-contrast MRI technique which calculates quantitative stiffness images, called elastograms, by imaging the propagation of acoustic waves in tissues. It is used clinically to diagnose liver fibrosis. Automated analysis of MRE is difficult as the corresponding MRI magnitude images (which contain anatomical information) are affected by intensity inhomogeneity, motion artifact, and poor tissue- and edge-contrast. Additionally, areas with low wave amplitude must be excluded...
March 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28989221/deformable-3d-2d-registration-for-guiding-k-wire-placement-in-pelvic-trauma-surgery
#6
J Goerres, M Jacobson, A Uneri, T De Silva, M Ketcha, S Reaungamornrat, S Vogt, G Kleinszig, J-P Wolinsky, G Osgood, J H Siewerdsen
Pelvic Kirschner wire (K-wire) insertion is a challenging surgical task requiring interpretation of complex 3D anatomical shape from 2D projections (fluoroscopy) and delivery of device trajectories within fairly narrow bone corridors in proximity to adjacent nerves and vessels. Over long trajectories (~10-25 cm), K-wires tend to curve (deform), making conventional rigid navigation inaccurate at the tip location. A system is presented that provides accurate 3D localization and guidance of rigid or deformable surgical devices ("components" - e...
March 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28989220/high-resolution-extremity-cone-beam-ct-with-a-cmos-detector-task-based-optimization-of-scintillator-thickness
#7
Q Cao, M Brehler, A Sisniega, J W Stayman, J Yorkston, J H Siewerdsen, W Zbijewski
PURPOSE: CMOS x-ray detectors offer small pixel sizes and low electronic noise that may support the development of novel high-resolution imaging applications of cone-beam CT (CBCT). We investigate the effects of CsI scintillator thickness on the performance of CMOS detectors in high resolution imaging tasks, in particular in quantitative imaging of bone microstructure in extremity CBCT. METHODS: A scintillator thickness-dependent cascaded systems model of CMOS x-ray detectors was developed...
March 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28989219/task-driven-orbit-design-and-implementation-on-a-robotic-c-arm-system-for-cone-beam-ct
#8
S Ouadah, M Jacobson, J W Stayman, T Ehtiati, C Weiss, J H Siewerdsen
PURPOSE: This work applies task-driven optimization to the design of non-circular orbits that maximize imaging performance for a particular imaging task. First implementation of task-driven imaging on a clinical robotic C-arm system is demonstrated, and a framework for orbit calculation is described and evaluated. METHODS: We implemented a task-driven imaging framework to optimize orbit parameters that maximize detectability index d'. This framework utilizes a specified Fourier domain task function and an analytical model for system spatial resolution and noise...
March 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28989218/geometric-calibration-using-line-fiducials-for-cone-beam-ct-with-general-non-circular-source-detector-trajectories
#9
M W Jacobson, M Ketcha, A Uneri, J Goerres, T De Silva, S Reaungamornrat, S Vogt, G Kleinszig, J H Siewerdsen
PURPOSE: Traditional BB-based geometric calibration methods for cone-beam CT (CBCT) rely strongly on foreknowledge of the scan trajectory shape. This is a hindrance to the implementation of variable trajectory CBCT systems, normally requiring a dedicated calibration phantom or software algorithm for every scan orbit of interest. A more flexible method of calibration is proposed here that accommodates multiple orbit types - including strongly noncircular trajectories - with a single phantom and software routine...
March 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28989217/epi-direction-detected-multimodal-imaging-of-an-unstained-mouse-retina-with-a-yb-fiber-laser
#10
Gabrielle A Murashova, Christopher A Mancuso, Sanae Sakami, Krzysztof Palczewski, Grazyna Palczewska, Marcos Dantus
In this work, we present all epi-direction detected images of an unstained mouse retina using multiphoton microscopy with a sub-50 fs Yb-fiber laser centered at 1.07 μm. This wavelength is particularly interesting as the fundamental wavelength is transparent to the anterior segment of the eye and the higher harmonics are above DNA-damaging UV wavelengths. We present a characterization of the multimodal signals emitted from the different retinal layers, as well as from the choroid and the sclera. By characterizing native multiphoton signals from the retina, we move closer to having Yb-fiber considered for in vivo diagnosis of retinal disease through multiphoton microscopy as well as for corrective therapies...
March 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28947842/semi-automatic-segmentation-of-the-placenta-into-fetal-and-maternal-compartments-using-intravoxel-incoherent-motion-mri
#11
Wonsang You, Nickie Andescavage, Zungho Zun, Catherine Limperopoulos
Intravoxel incoherent motion (IVIM) magnetic resonance imaging is an emerging non-invasive technique that has been recently applied to quantify in vivo global placental perfusion. We propose a robust semi-automated method for segmenting the placenta into fetal and maternal compartments from IVIM data, using a multi-label image segmentation algorithm called 'GrowCut'. Placental IVIM data were acquired on a 1.5T scanner from 16 healthy pregnant women between 21-37 gestational weeks. The voxel-wise perfusion fraction was then estimated after non-rigid image registration...
March 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28943700/dual-energy-ct-kidney-stone-differentiation-in-photon-counting-computed-tomography
#12
R Gutjahr, C Polster, A Henning, S Kappler, S Leng, C H McCollough, M U Sedlmair, B Schmidt, B Krauss, T G Flohr
This study evaluates the capabilities of a whole-body photon counting CT system to differentiate between four common kidney stone materials, namely uric acid (UA), calcium oxalate monohydrate (COM), cystine (CYS),and apatite (APA) ex vivo. Two different x-ray spectra (120 kV and 140 kV) were applied and two acquisition modes were investigated; The macro-mode generates two energy threshold based image-volumes and two energy bin based image-volumes. In the chesspattern-mode, however, four energy thresholds are applied...
March 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28943699/practical-implementation-of-channelized-hotelling-observers-effect-of-roi-size
#13
Andrea Ferrero, Christopher P Favazza, Lifeng Yu, Shuai Leng, Cynthia H McCollough
Fundamental to the development and application of channelized Hotelling observer (CHO) models is the selection of the region of interest (ROI) to evaluate. For assessment of medical imaging systems, reducing the ROI size can be advantageous. Smaller ROIs enable a greater concentration of interrogable objects in a single phantom image, thereby providing more information from a set of images and reducing the overall image acquisition burden. Additionally, smaller ROIs may promote better assessment of clinical patient images as different patient anatomies present different ROI constraints...
March 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/29138527/longitudinal-analysis-of-mouse-sdoct-volumes
#14
Bhavna J Antony, Aaron Carass, Andrew Lang, Byung-Jin Kim, Donald J Zack, Jerry L Prince
Spectral-domain optical coherence tomography (SDOCT), in addition to its routine clinical use in the diagnosis of ocular diseases, has begun to find increasing use in animal studies. Animal models are frequently used to study disease mechanisms as well as to test drug efficacy. In particular, SDOCT provides the ability to study animals longitudinally and non-invasively over long periods of time. However, the lack of anatomical landmarks makes the longitudinal scan acquisition prone to inconsistencies in orientation...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28867867/computer-assisted-adjuncts-for-aneurysmal-morphologic-assessment-toward-more-precise-and-accurate-approaches
#15
Hamidreza Rajabzadeh-Oghaz, Nicole Varble, Jason M Davies, Ashkan Mowla, Hakeem J Shakir, Ashish Sonig, Hussain Shallwani, Kenneth V Snyder, Elad I Levy, Adnan H Siddiqui, Hui Meng
Neurosurgeons currently base most of their treatment decisions for intracranial aneurysms (IAs) on morphological measurements made manually from 2D angiographic images. These measurements tend to be inaccurate because 2D measurements cannot capture the complex geometry of IAs and because manual measurements are variable depending on the clinician's experience and opinion. Incorrect morphological measurements may lead to inappropriate treatment strategies. In order to improve the accuracy and consistency of morphological analysis of IAs, we have developed an image-based computational tool, AView...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28781414/test-suite-for-image-based-motion-estimation-of-the-brain-and-tongue
#16
Jordan Ramsey, Jerry L Prince, Arnold D Gomez
Noninvasive analysis of motion has important uses as qualitative markers for organ function and to validate biomechanical computer simulations relative to experimental observations. Tagged MRI is considered the gold standard for noninvasive tissue motion estimation in the heart, and this has inspired multiple studies focusing on other organs, including the brain under mild acceleration and the tongue during speech. As with other motion estimation approaches, using tagged MRI to measure 3D motion includes several preprocessing steps that affect the quality and accuracy of estimation...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28781413/improving-graph-based-oct-segmentation-for-severe-pathology-in-retinitis-pigmentosa-patients
#17
Andrew Lang, Aaron Carass, Ava K Bittner, Howard S Ying, Jerry L Prince
Three dimensional segmentation of macular optical coherence tomography (OCT) data of subjects with retinitis pigmentosa (RP) is a challenging problem due to the disappearance of the photoreceptor layers, which causes algorithms developed for segmentation of healthy data to perform poorly on RP patients. In this work, we present enhancements to a previously developed graph-based OCT segmentation pipeline to enable processing of RP data. The algorithm segments eight retinal layers in RP data by relaxing constraints on the thickness and smoothness of each layer learned from healthy data...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28781412/multi-modal-and-targeted-imaging-improves-automated-mid-brain-segmentation
#18
Andrew J Plassard, Pierre F D'Haese, Srivatsan Pallavaram, Allen T Newton, Daniel O Claassen, Benoit M Dawant, Bennett A Landman
The basal ganglia and limbic system, particularly the thalamus, putamen, internal and external globus pallidus, substantia nigra, and sub-thalamic nucleus, comprise a clinically relevant signal network for Parkinson's disease. In order to manually trace these structures, a combination of high-resolution and specialized sequences at 7T are used, but it is not feasible to scan clinical patients in those scanners. Targeted imaging sequences at 3T such as F-GATIR, and other optimized inversion recovery sequences, have been presented which enhance contrast in a select group of these structures...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28781411/multi-scale-hippocampal-parcellation-improves-atlas-based-segmentation-accuracy
#19
Andrew J Plassard, Maureen McHugo, Stephan Heckers, Bennett A Landman
Known for its distinct role in memory, the hippocampus is one of the most studied regions of the brain. Recent advances in magnetic resonance imaging have allowed for high-contrast, reproducible imaging of the hippocampus. Typically, a trained rater takes 45 minutes to manually trace the hippocampus and delineate the anterior from the posterior segment at millimeter resolution. As a result, there has been a significant desire for automated and robust segmentation of the hippocampus. In this work we use a population of 195 atlases based on T1-weighted MR images with the left and right hippocampus delineated into the head and body...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28781410/automatic-selection-of-landmarks-in-t1-weighted-head-mri-with-regression-forests-for-image-registration-initialization
#20
Jianing Wang, Yuan Liu, Jack H Noble, Benoit M Dawant
Medical image registration establishes a correspondence between images of biological structures and it is at the core of many applications. Commonly used deformable image registration methods are dependent on a good preregistration initialization. The initialization can be performed by localizing homologous landmarks and calculating a point-based transformation between the images. The selection of landmarks is however important. In this work, we present a learning-based method to automatically find a set of robust landmarks in 3D MR image volumes of the head to initialize non-rigid transformations...
February 11, 2017: Proceedings of SPIE
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