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image quality metric

Sara Moccia, Elena De Momi, Sara El Hadji, Leonardo S Mattos
BACKGROUND: Blood vessel segmentation is a topic of high interest in medical image analysis since the analysis of vessels is crucial for diagnosis, treatment planning and execution, and evaluation of clinical outcomes in different fields, including laryngology, neurosurgery and ophthalmology. Automatic or semi-automatic vessel segmentation can support clinicians in performing these tasks. Different medical imaging techniques are currently used in clinical practice and an appropriate choice of the segmentation algorithm is mandatory to deal with the adopted imaging technique characteristics (e...
May 2018: Computer Methods and Programs in Biomedicine
Thomas K F Foo, Evangelos Laskaris, Mark Vermilyea, Minfeng Xu, Paul Thompson, Gene Conte, Christopher Van Epps, Christopher Immer, Seung-Kyun Lee, Ek T Tan, Dominic Graziani, Jean-Baptise Mathieu, Christopher J Hardy, John F Schenck, Eric Fiveland, Wolfgang Stautner, Justin Ricci, Joseph Piel, Keith Park, Yihe Hua, Ye Bai, Alex Kagan, David Stanley, Paul T Weavers, Erin Gray, Yunhong Shu, Matthew A Frick, Norbert G Campeau, Joshua Trzasko, John Huston, Matt A Bernstein
PURPOSE: To build and evaluate a small-footprint, lightweight, high-performance 3T MRI scanner for advanced brain imaging with image quality that is equal to or better than conventional whole-body clinical 3T MRI scanners, while achieving substantial reductions in installation costs. METHODS: A conduction-cooled magnet was developed that uses less than 12 liters of liquid helium in a gas-charged sealed system, and standard NbTi wire, and weighs approximately 2000 kg...
March 13, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Satomi Shiraishi, Michael P Grams, Luis E Fong de Los Santos
PURPOSE: To demonstrate an objective quality control framework for the image review process. METHODS AND MATERIALS: 927 cone-beam computed tomography (CBCT) registrations were retrospectively analyzed for 33 bilateral head and neck cancer patients who received definitive radiotherapy. Two registration tracking volumes (RTVs) - cervical spine (C-spine) and mandible - were defined, within which a similarity metric was calculated and used as a registration quality tracking metric over the course of treatment...
March 12, 2018: Medical Physics
John W Hayes, Daniel Gomez-Cardona, Ran Zhang, Ke Li, Juan Pablo Cruz-Bastida, Guang-Hong Chen
PURPOSE: Low signal correction (LSC) in the raw counts domain has been shown to effectively reduce noise streaks in CT because the data inconsistency associated with photon-starved regions may be mitigated prior to the log transformation step. However, a systematic study of the performance of these raw data correction methods is still missing in literature. The purpose of this work was to provide such a systematic study for two well-known low signal correction schemes using either the adaptive trimmed mean (ATM) filter or the anisotropic diffusion (AD) filter in the raw counts domain...
March 12, 2018: Medical Physics
F E Sahin, A R Tanguay
An imaging system design procedure for miniature wide-angle computational cameras with subsequent software correction of distortion is described. Such miniature wide-angle computational cameras have a broad range of applications, including eye-tracked extraocular cameras for retinal prostheses, and also wearable visual aids for the blind and those with low vision. As significant (typically barrel) distortion is commonplace in wide-field-of-view imaging systems, digital post-processing is often employed to generate rectilinear output images...
March 5, 2018: Optics Express
Darragh Mullins, Derek Coburn, Louise Hannon, Edward Jones, Eoghan Clifford, Martin Glavin
Wastewater treatment facilities are continually challenged to meet both environmental regulations and reduce running costs (particularly energy and staffing costs). Improving the efficiency of operational monitoring at wastewater treatment plants (WWTPs) requires the development and implementation of appropriate performance metrics; particularly those that are easily measured, strongly correlate to WWTP performance, and can be easily automated, with a minimal amount of maintenance or intervention by human operators...
March 2018: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Xiaokang Yu, Na Lei, Yalin Wang, Xianfeng Gu
3D dynamic surface tracking is an important research problem and plays a vital role in many computer vision and medical imaging applications. However, it is still challenging to efficiently register surface sequences which has large deformations and strong noise. In this paper, we propose a novel automatic method for non-rigid 3D dynamic surface tracking with surface Ricci flow and Teichmüller map methods. According to quasi-conformal Teichmüller theory, the Techmüller map minimizes the maximal dilation so that our method is able to automatically register surfaces with large deformations...
October 2017: Proceedings
Dennis N Stanley, Karl Rasmussen, Neil Kirby, Nikos Papanikolaou, Alonso N Gutiérrez
INTRODUCTION: A robust image quality assurance and analysis methodology for image-guided localization systems is crucial to ensure the accurate localization and visualization of target tumors. In this study, the long-term stability of selected image parameters was assessed and evaluated for the cone-beam computed tomography (CBCT) mode, planar radiographic kV mode, and the radiographic MV mode of an Elekta VersaHD. MATERIALS AND METHODS: The CATPHAN, QckV-1, and QC-3 phantoms were used to evaluate the image quality parameters...
March 9, 2018: Journal of Applied Clinical Medical Physics
Kyle Edmunds, Magnús Gíslason, Sigurður Sigurðsson, Vilmundur Guðnason, Tamara Harris, Ugo Carraro, Paolo Gargiulo
Sarcopenic muscular degeneration has been consistently identified as an independent risk factor for mortality in aging populations. Recent investigations have realized the quantitative potential of computed tomography (CT) image analysis to describe skeletal muscle volume and composition; however, the optimum approach to assessing these data remains debated. Current literature reports average Hounsfield unit (HU) values and/or segmented soft tissue cross-sectional areas to investigate muscle quality. However, standardized methods for CT analyses and their utility as a comorbidity index remain undefined, and no existing studies compare these methods to the assessment of entire radiodensitometric distributions...
2018: PloS One
Elvis Dohmatob, Gael Varoquaux, Bertrand Thirion
In Echo-Planar Imaging (EPI)-based Magnetic Resonance Imaging (MRI), inter-subject registration typically uses the subject's T1-weighted (T1w) anatomical image to learn deformations of the subject's brain onto a template. The estimated deformation fields are then applied to the subject's EPI scans (functional or diffusion-weighted images) to warp the latter to a template space. Historically, such indirect T1w-based registration was motivated by the lack of clear anatomical details in low-resolution EPI images: a direct registration of the EPI scans to template space would be futile...
2018: Frontiers in Neuroscience
N A Shkumat, M M Shroff, P Muthusami
BACKGROUND AND PURPOSE: The benefit-risk assessment concerning radiation use in pediatric neuroangiography requires an extensive understanding of the doses delivered. This work evaluated the effective dose of 3D rotational angiography in a cohort of pediatric patients with complex neurovascular lesions and directly compared it with conventional 2D-biplane DSA. MATERIALS AND METHODS: Thirty-three 3D rotational angiography acquisitions were acquired in 24 pediatric patients (mean age, 10...
March 1, 2018: AJNR. American Journal of Neuroradiology
Charles S Mayo, Jean M Moran, Walter Bosch, Ying Xiao, Todd McNutt, Richard Popple, Jeff Michalski, Mary Feng, Lawrence B Marks, Clifton D Fuller, Ellen Yorke, Jatinder Palta, Peter E Gabriel, Andrea Molineu, Martha M Matuszak, Elizabeth Covington, Kathryn Masi, Susan L Richardson, Timothy Ritter, Tomasz Morgas, Stella Flampouri, Lakshmi Santanam, Joseph A Moore, Thomas G Purdie, Robert C Miller, Coen Hurkmans, Judy Adams, Qing-Rong Jackie Wu, Colleen J Fox, Ramon Alfredo Siochi, Norman L Brown, Wilko Verbakel, Yves Archambault, Steven J Chmura, Andre L Dekker, Don G Eagle, Thomas J Fitzgerald, Theodore Hong, Rishabh Kapoor, Beth Lansing, Shruti Jolly, Mary E Napolitano, James Percy, Mark S Rose, Salim Siddiqui, Christof Schadt, William E Simon, William L Straube, Sara T St James, Kenneth Ulin, Sue S Yom, Torunn I Yock
A substantial barrier to the single- and multi-institutional aggregation of data to supporting clinical trials, practice quality improvement efforts, and development of big data analytics resource systems is the lack of standardized nomenclatures for expressing dosimetric data. To address this issue, the American Association of Physicists in Medicine (AAPM) Task Group 263 was charged with providing nomenclature guidelines and values in radiation oncology for use in clinical trials, data-pooling initiatives, population-based studies, and routine clinical care by standardizing: (1) structure names across image processing and treatment planning system platforms; (2) nomenclature for dosimetric data (eg, dose-volume histogram [DVH]-based metrics); (3) templates for clinical trial groups and users of an initial subset of software platforms to facilitate adoption of the standards; (4) formalism for nomenclature schema, which can accommodate the addition of other structures defined in the future...
March 15, 2018: International Journal of Radiation Oncology, Biology, Physics
Anne T Davis, Antony L Palmer, Silvia Pani, Andrew Nisbet
PURPOSE: To define a method and investigate how the adjustment of scan parameters affected the image quality and Hounsfield units (HUs) on a CT scanner used for radiotherapy treatment planning. A lack of similar investigations in the literature may be a contributing factor in the apparent reluctance to optimise radiotherapy CT protocols. METHOD: A Catphan phantom was used to assess how image quality on a Toshiba Aquilion LB scanner changed with scan parameters. Acquisition and reconstruction field-of-view (FOV), collimation, image slice thickness, effective mAs per rotation and reconstruction algorithm were varied...
January 2018: Physica Medica: PM
WuiAnn Woon, Paul B Ravindran, Piyasiri Ekayanake, Vikraman S, Yivonne Yf Lim, Jamsari Khalid
The main objectives of this study are to (1) analyze the sensitivity of various gamma index passing rates using different types of detectors having different resolutions and (2) investigate the sensitivity of various gamma criteria in intensity-modulated radiation therapy (IMRT) and volumetrically modulated arc therapy (VMAT) quality assurance (QA) for the detection of systematic multileaf collimator (MLC) errors using an electronic portal imaging device (EPID) and planar (MapCheck2) and cylindrical (ArcCheck) diode arrays...
February 20, 2018: Journal of Applied Clinical Medical Physics
David J Eaton, Jonathan Lee, Ian Paddick
PURPOSE: Stereotactic radiosurgery is indicated for treatment of multiple brain metastases. Various treatment platforms are available, but most comparisons are limited to single-center studies. As part of a national commissioning program, benchmark planning cases were completed by 21 clinical centers, providing a unique dataset of current practice across a large number of providers and equipment platforms. METHODS AND MATERIALS: Two brain metastases cases were provided, with images and structures predrawn, involving 3 and 7 lesions...
December 30, 2017: Practical Radiation Oncology
Kihong Son, Jieun Chang, Hoyeon Lee, Changhwan Kim, Taewon Lee, Seungryong Cho, Sohyun Park, Jin Sung Kim
To reduce the radiation dose given to patients, a tube current modulation (TCM) method has been widely used in diagnostic CT systems. However, the TCM method has not yet been applied to a kV-CBCT system on a LINAC machine. The purpose of this study is to investigate if a TCM method would be desirable in a kV-CBCT system for image-guided radiation therapy (IGRT) or not. We have developed an attenuation-based TCM method using prior knowledge from planning CT images of patients. The TCM method can provide optimized dose reductions without degrading image quality for kV-CBCT imaging...
2018: PloS One
Jessica L Nute, Megan C Jacobsen, Wolfgang Stefan, Wei Wei, Dianna D Cody
PURPOSE: A prototype QC phantom system and analysis process were developed to characterize the spectral capabilities of a fast kV-switching dual-energy computed tomography (DECT) scanner. This work addresses the current lack of quantitative oversight for this technology, with the goal of identifying relevant scan parameters and test metrics instrumental to the development of a dual-energy quality control (DEQC). METHODS: A prototype elliptical phantom (effective diameter: 35 cm) was designed with multiple material inserts for DECT imaging...
February 15, 2018: Medical Physics
Ester Bonmati, Yipeng Hu, Barbara Villarini, Rachael Rodell, Paul Martin, Lianghao Han, Ian Donaldson, Hashim U Ahmed, Caroline M Moore, Mark Emberton, Dean C Barratt
PURPOSE: Image-guided systems that fuse magnetic resonance imaging (MRI) with three-dimensional (3D) ultrasound (US) images for performing targeted prostate needle biopsy and minimally invasive treatments for prostate cancer are of increasing clinical interest. To date, a wide range of different accuracy estimation procedures and error metrics have been reported, which makes comparing the performance of different systems difficult. METHODS: A set of nine measures are presented to assess the accuracy of MRI-US image registration, needle positioning, needle guidance, and overall system error, with the aim of providing a methodology for estimating the accuracy of instrument placement using a MR/US-guided transperineal approach...
February 14, 2018: Medical Physics
Mailys C M Faraut, April A Carlson, Shannon Sullivan, Oana Tudusciuc, Ian Ross, Chrystal M Reed, Jeffrey M Chung, Adam N Mamelak, Ueli Rutishauser
We present a dataset of 1,576 single neurons recorded from the human amygdala and hippocampus in 65 sessions from 42 patients undergoing intracranial monitoring for localization of epileptic seizures. Subjects performed a recognition memory task with pictures as stimuli. Subjects were asked to identify whether they had seen a particular image the first time ('new') or second time ('old') on a 1-6 confidence scale. This comprehensive dataset includes the spike times of all neurons and their extracellular waveforms, behavior, electrode locations determined from post-operative MRI scans, demographics, and the stimuli shown...
February 13, 2018: Scientific Data
Wujie Zhou, Lu Yu, Yang Zhou, Weiwei Qiu, Ming-Wei Wu, Ting Luo
The blind quality evaluation of screen content images (SCIs) and natural scene images (NSIs) has become an important, yet very challenging issue. In this paper, we present an effective blind quality evaluation technique for SCIs and NSIs based on a dictionary of learned local and global quality features. First, a local dictionary is constructed using local normalized image patches and conventional -means clustering. With this local dictionary, the learned local quality features can be obtained using a locality-constrained linear coding with max pooling...
May 2018: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
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