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https://www.readbyqxmd.com/read/28458443/renal-stone-characterization-using-high-resolution-imaging-mode-on-a-photon-counting-detector-ct-system
#1
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/28642629/improved-brain-tumor-segmentation-by-utilizing-tumor-growth-model-in-longitudinal-brain-mri
#2
Linmin Pei, Syed M S Reza, Wei Li, Christos Davatzikos, Khan M Iftekharuddin
In this work, we propose a novel method to improve texture based tumor segmentation by fusing cell density patterns that are generated from tumor growth modeling. In order to model tumor growth, we solve the reaction-diffusion equation by using Lattice-Boltzmann method (LBM). Computational tumor growth modeling obtains the cell density distribution that potentially indicates the predicted tissue locations in the brain over time. The density patterns is then considered as novel features along with other texture (such as fractal, and multifractal Brownian motion (mBm)), and intensity features in MRI for improved brain tumor segmentation...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28638171/3d-printed-abdominal-aortic-aneurysm-phantom-for-image-guided-surgical-planning-with-a-patient-specific-fenestrated-endovascular-graft-system
#3
Karen M Meess, Richard L Izzo, Maciej L Dryjski, Richard E Curl, Linda M Harris, Michael Springer, Adnan H Siddiqui, Stephen Rudin, Ciprian N Ionita
Following new trends in precision medicine, Juxatarenal Abdominal Aortic Aneurysm (JAAA) treatment has been enabled by using patient-specific fenestrated endovascular grafts. The X-ray guided procedure requires precise orientation of multiple modular endografts within the arteries confirmed via radiopaque markers. Patient-specific 3D printed phantoms could familiarize physicians with complex procedures and new devices in a risk-free simulation environment to avoid periprocedural complications and improve training...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28638170/atlas-based-automatic-measurements-of-the-morphology-of-the-tibiofemoral-joint
#4
M Brehler, G Thawait, W Shyr, J Ramsay, J H Siewerdsen, W Zbijewski
PURPOSE: Anatomical metrics of the tibiofemoral joint support assessment of joint stability and surgical planning. We propose an automated, atlas-based algorithm to streamline the measurements in 3D images of the joint and reduce user-dependence of the metrics arising from manual identification of the anatomical landmarks. METHODS: The method is initialized with coarse registrations of a set of atlas images to the fixed input image. The initial registrations are then refined separately for the tibia and femur and the best matching atlas is selected...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28638169/organ-and-effective-dose-reduction-for-region-of-interest-roi-cbct-and-fluoroscopy
#5
Zhenyu Xiong, Sarath Vijayan, Stephen Rudin, Daniel R Bednarek
In some medical-imaging procedures using CBCT and fluoroscopy, it may be needed to visualize only the center of the field-of-view with optimal quality. To reduce the dose to the patient as well as enable increased contrast in the region of interest (ROI) during CBCT and fluoroscopy procedures, a 0.7 mm thick Cu ROI attenuator with a circular aperture 12% of the FOV was used. The aim of this study was to quantify the dose-reduction benefit of ROI imaging during a typical CBCT and interventional fluoroscopy procedures in the head and torso...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28626291/machine-learning-in-a-graph-framework-for-subcortical-segmentation
#6
Zhihui Guo, Satyananda Kashyap, Milan Sonka, Ipek Oguz
Automated and reliable segmentation of subcortical structures from human brain magnetic resonance images is of great importance for volumetric and shape analyses in quantitative neuroimaging studies. However, poor boundary contrast and variable shape of these structures make the automated segmentation a tough task. We propose a 3D graph-based machine learning method, called LOGISMOS-RF, to segment the caudate and the putamen from brain MRI scans in a robust and accurate way. An atlas-based tissue classification and bias-field correction method is applied to the images to generate an initial segmentation for each structure...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28626290/joint-optimization-of-fluence-field-modulation-and-regularization-in-task-driven-computed-tomography
#7
G J Gang, J H Siewerdsen, J W Stayman
PURPOSE: This work presents a task-driven joint optimization of fluence field modulation (FFM) and regularization in quadratic penalized-likelihood (PL) reconstruction. Conventional FFM strategies proposed for filtered-backprojection (FBP) are evaluated in the context of PL reconstruction for comparison. METHODS: We present a task-driven framework that leverages prior knowledge of the patient anatomy and imaging task to identify FFM and regularization. We adopted a maxi-min objective that ensures a minimum level of detectability index (d') across sample locations in the image volume...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28626289/comparison-of-high-resolution-x-ray-detectors-with-conventional-fpds-using-experimental-mtfs-and-apodized-aperture-pixel-design-for-reduced-aliasing
#8
A Shankar, M Russ, S Vijayan, D R Bednarek, S Rudin
Apodized Aperture Pixel (AAP) design, proposed by Ismailova et. al, is an alternative to the conventional pixel design(1). The advantages of AAP processing with a sinc filter in comparison with using other filters include non-degradation of MTF values and elimination of signal and noise aliasing, resulting in an increased performance at higher frequencies, approaching the Nyquist frequency(3). If high resolution small field-of-view (FOV) detectors with small pixels used during critical stages of Endovascular Image Guided Interventions (EIGIs) could also be extended to cover a full field-of-view typical of flat panel detectors (FPDs) and made to have larger effective pixels, then methods must be used to preserve the MTF over the frequency range up to the Nyquist frequency of the FPD while minimizing aliasing...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28615794/deepinfer-open-source-deep-learning-deployment-toolkit-for-image-guided-therapy
#9
Alireza Mehrtash, Mehran Pesteie, Jorden Hetherington, Peter A Behringer, Tina Kapur, William M Wells, Robert Rohling, Andriy Fedorov, Purang Abolmaesumi
Deep learning models have outperformed some of the previous state-of-the-art approaches in medical image analysis. Instead of using hand-engineered features, deep models attempt to automatically extract hierarchical representations at multiple levels of abstraction from the data. Therefore, deep models are usually considered to be more flexible and robust solutions for image analysis problems compared to conventional computer vision models. They have demonstrated significant improvements in computer-aided diagnosis and automatic medical image analysis applied to such tasks as image segmentation, classification and registration...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28615793/classification-of-clinical-significance-of-mri-prostate-findings-using-3d-convolutional-neural-networks
#10
Alireza Mehrtash, Alireza Sedghi, Mohsen Ghafoorian, Mehdi Taghipour, Clare M Tempany, William M Wells, Tina Kapur, Parvin Mousavi, Purang Abolmaesumi, Andriy Fedorov
Prostate cancer (PCa) remains a leading cause of cancer mortality among American men. Multi-parametric magnetic resonance imaging (mpMRI) is widely used to assist with detection of PCa and characterization of its aggressiveness. Computer-aided diagnosis (CADx) of PCa in MRI can be used as clinical decision support system to aid radiologists in interpretation and reporting of mpMRI. We report on the development of a convolution neural network (CNN) model to support CADx in PCa based on the appearance of prostate tissue in mpMRI, conducted as part of the SPIE-AAPM-NCI PROSTATEx challenge...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28615792/a-cmos-based-high-resolution-fluoroscope-hrf-detector-prototype-with-49-5-%C3%AE-m-pixels-for-use-in-endovascular-image-guided-interventions-eigi
#11
M Russ, A Shankar, S V Setlur Nagesh, C N Ionita, D R Bednarek, S Rudin
X-ray detectors to meet the high-resolution requirements for endovascular image-guided interventions (EIGIs) are being developed and evaluated. A new 49.5-micron pixel prototype detector is being investigated and compared to the current suite of high-resolution fluoroscopic (HRF) detectors. This detector featuring a 300-micron thick CsI(Tl) scintillator, and low electronic noise CMOS readout is designated the HRF-CMOS50. To compare the abilities of this detector with other existing high resolution detectors, a standard performance metric analysis was applied, including the determination of the modulation transfer function (MTF), noise power spectra (NPS), noise equivalent quanta (NEQ), and detective quantum efficiency (DQE) for a range of energies and exposure levels...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28615791/monte-carlo-investigation-of-backscatter-point-spread-function-for-x-ray-imaging-examinations
#12
Zhenyu Xiong, Sarath Vijayan, Stephen Rudin, Daniel R Bednarek
X-ray imaging examinations, especially complex interventions, may result in relatively high doses to the patient's skin inducing skin injuries. A method was developed to determine the skin-dose distribution for non-uniform x-ray beams by convolving the backscatter point-spread-function (PSF) with the primary-dose distribution to generate the backscatter distribution that, when added to the primary dose, gives the total-dose distribution. This technique was incorporated in the dose-tracking system (DTS), which provides a real-time color-coded 3D-mapping of skin dose during fluoroscopic procedures...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28596636/no-gold-standard-evaluation-of-image-acquisition-methods-using-patient-data
#13
Abhinav K Jha, Eric Frey
Several new and improved modalities, scanners, and protocols, together referred to as image-acquisition methods (IAMs), are being developed to provide reliable quantitative imaging. Objective evaluation of these IAMs on the clinically relevant quantitative tasks is highly desirable. Such evaluation is most reliable and clinically decisive when performed with patient data, but that requires the availability of a gold standard, which is often rare. While no-gold-standard (NGS) techniques have been developed to clinically evaluate quantitative imaging methods, these techniques require that each of the patients be scanned using all the IAMs, which is expensive, time consuming, and could lead to increased radiation dose...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28596635/an-investigation-of-low-dose-3d-scout-scans-for-computed-tomography
#14
Juliana Gomes, Grace J Gang, Aswin Mathews, J Webster Stayman
PURPOSE: Commonly 2D scouts or topograms are used prior to CT scan acquisition. However, low-dose 3D scouts could potentially provide additional information for more effective patient positioning and selection of acquisition protocols. We propose using model-based iterative reconstruction to reconstruct low exposure tomographic data to maintain image quality in both low-dose 3D scouts and reprojected topograms based on those 3D scouts. METHODS: We performed tomographic acquisitions on a CBCT test-bench using a range of exposure settings from 16...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28592911/marginal-shape-deep-learning-applications-to-pediatric-lung-field-segmentation
#15
Awais Mansoor, Juan J Cerrolaza, Geovanny Perez, Elijah Biggs, Gustavo Nino, Marius George Linguraru
Representation learning through deep learning (DL) architecture has shown tremendous potential for identification, localization, and texture classification in various medical imaging modalities. However, DL applications to segmentation of objects especially to deformable objects are rather limited and mostly restricted to pixel classification. In this work, we propose marginal shape deep learning (MaShDL), a framework that extends the application of DL to deformable shape segmentation by using deep classifiers to estimate the shape parameters...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28579665/foxp3-stained-image-analysis-for-follicular-lymphoma-optimal-adaptive-thresholding-with-maximal-nucleus-coverage
#16
C Senaras, M Pennell, W Chen, B Sahiner, A Shana'ah, A Louissaint, R P Hasserjian, G Lozanski, M N Gurcan
Immunohistochemical detection of FOXP3 antigen is a usable marker for detection of regulatory T lymphocytes (TR) in formalin fixed and paraffin embedded sections of different types of tumor tissue. TR plays a major role in homeostasis of normal immune systems where they prevent auto reactivity of the immune system towards the host. This beneficial effect of TR is frequently "hijacked" by malignant cells where tumor-infiltrating regulatory T cells are recruited by the malignant nuclei to inhibit the beneficial immune response of the host against the tumor cells...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28572694/c-arm-positioning-using-virtual-fluoroscopy-for-image-guided-surgery
#17
T De Silva, J Punnoose, A Uneri, J Goerres, M Jacobson, M D Ketcha, A Manbachi, S Vogt, G Kleinszig, A J Khanna, J-P Wolinksy, G Osgood, J H Siewerdsen
INTRODUCTION: Fluoroscopically guided procedures often involve repeated acquisitions for C-arm positioning at the cost of radiation exposure and time in the operating room. A virtual fluoroscopy system is reported with the potential of reducing dose and time spent in C-arm positioning, utilizing three key advances: robust 3D-2D registration to a preoperative CT; real-time forward projection on GPU; and a motorized mobile C-arm with encoder feedback on C-arm orientation. METHOD: Geometric calibration of the C-arm was performed offline in two rotational directions (orbit α, orbit β)...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28572693/fundamental-limits-of-image-registration-performance-effects-of-image-noise-and-resolution-in-ct-guided-interventions
#18
M D Ketcha, T de Silva, R Han, A Uneri, J Goerres, M Jacobson, S Vogt, G Kleinszig, J H Siewerdsen
PURPOSE: In image-guided procedures, image acquisition is often performed primarily for the task of geometrically registering information from another image dataset, rather than detection / visualization of a particular feature. While the ability to detect a particular feature in an image has been studied extensively with respect to image quality characteristics (noise, resolution) and is an ongoing, active area of research, comparatively little has been accomplished to relate such image quality characteristics to registration performance...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28515570/association-between-hemodynamic-modifications-and-clinical-outcome-of-intracranial-aneurysms-treated-using-flow-diverters
#19
Nikhil Paliwal, Robert J Damiano, Jason M Davies, Adnan H Siddiqui, Hui Meng
Treatment of intracranial aneurysms (IAs) has been revolutionized by the advent of endovascular Flow Diverters (FDs), which disrupt blood flow within the aneurysm to induce pro-thrombotic conditions, and serves as a scaffold for endothelial ingrowth and arterial remodeling. Despite good clinical success of FDs, complications like incomplete occlusion and post-treatment rupture leading to subarachnoid hemorrhage have been reported. In silico computational fluid dynamic analysis of the pre- and post-treated geometries of IA patients can shed light on the contrasting blood hemodynamics associated with different clinical outcomes...
February 11, 2017: Proceedings of SPIE
https://www.readbyqxmd.com/read/28413240/detection-of-increased-vasa-vasorum-in-artery-walls-improving-ct-number-accuracy-using-image-deconvolution
#20
Kishore Rajendran, Shuai Leng, Steven M Jorgensen, Dilbar Abdurakhimova, Erik L Ritman, Cynthia H McCollough
Changes in arterial wall perfusion are an indicator of early atherosclerosis. This is characterized by an increased spatial density of vasa vasorum (VV), the micro-vessels that supply oxygen and nutrients to the arterial wall. Detection of increased VV during contrast-enhanced computed tomography (CT) imaging is limited due to contamination from blooming effect from the contrast-enhanced lumen. We report the application of an image deconvolution technique using a measured system point-spread function, on CT data obtained from a photon-counting CT system to reduce blooming and to improve the CT number accuracy of arterial wall, which enhances detection of increased VV...
February 11, 2017: Proceedings of SPIE
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