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https://www.readbyqxmd.com/read/28297454/evaluation-of-cassette-based-digital-radiography-detectors-using-standardized-image-quality-metrics-aapm-tg-150-draft-image-detector-tests
#1
Guang Li, Travis C Greene, Thomas K Nishino, Charles E Willis
The purpose of this study was to evaluate several of the standardized image quality metrics proposed by the American Association of Physics in Medicine (AAPM) Task Group 150. The task group suggested region-of-interest (ROI)-based techniques to measure nonuniformity, minimum signal-to-noise ratio (SNR), number of anomalous pixels, and modulation transfer function (MTF). This study evaluated the effects of ROI size and layout on the image metrics by using four different ROI sets, assessed result uncertainty by repeating measurements, and compared results with two commercially available quality control tools, namely the Carestream DIRECTVIEW Total Quality Tool (TQT) and the GE Healthcare Quality Assurance Process (QAP)...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28296320/a-comparative-study-based-on-image-quality-and-clinical-task-performance-for-ct-reconstruction-algorithms-in-radiotherapy
#2
Hua Li, Steven Dolly, Hsin-Chen Chen, Mark A Anastasio, Daniel A Low, Harold H Li, Jeff M Michalski, Wade L Thorstad, Hiram Gay, Sasa Mutic
CT image reconstruction is typically evaluated based on the ability to reduce the radiation dose to as-low-as-reasonably-achievable (ALARA) while maintaining acceptable image quality. However, the determination of common image quality metrics, such as noise, contrast, and contrast-to-noise ratio, is often insufficient for describing clinical radiotherapy task performance. In this study we designed and implemented a new comparative analysis method associating image quality, radiation dose, and patient size with radiotherapy task performance, with the purpose of guiding the clinical radiotherapy usage of CT reconstruction algorithms...
July 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28296301/imaging-acquisition-display-performance-an-evaluation-and-discussion-of-performance-metrics-and-procedures
#3
Michael S Silosky, Rebecca M Marsh, Ann L Scherzinger
When The Joint Commission updated its Requirements for Diagnostic Imaging Services for hospitals and ambulatory care facilities on July 1, 2015, among the new requirements was an annual performance evaluation for acquisition workstation displays. The purpose of this work was to evaluate a large cohort of acquisition displays used in a clinical environment and compare the results with existing performance standards provided by the American College of Radiology (ACR) and the American Association of Physicists in Medicine (AAPM)...
July 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28295903/feasibility-of-intraoperative-breast-mri-and-the-role-of-prone-versus-supine-positioning-in-surgical-planning-for-breast-conserving-surgery
#4
Melissa A Mallory, Yasuaki Sagara, Fatih Aydogan, Stephen DeSantis, Jagadeesan Jayender, Diana Caragacianu, Eva Gombos, Kirby G Vosburgh, Ferenc A Jolesz, Mehra Golshan
We assessed the feasibility of supine intraoperative MRI (iMRI) during breast-conserving surgery (BCS), enrolling 15 patients in our phase I trial between 2012 and 2014. Patients received diagnostic prone MRI, BCS, pre-excisional supine iMRI, and postexcisional supine iMRI. Feasibility was assessed based on safety, sterility, duration, and image-quality. Twelve patients completed the study; mean duration = 114 minutes; all images were adequate; no complications, safety, or sterility issues were encountered...
March 10, 2017: Breast Journal
https://www.readbyqxmd.com/read/28287984/learning-a-no-reference-quality-assessment-model-of-enhanced-images-with-big-data
#5
Ke Gu, Dacheng Tao, Jun-Fei Qiao, Weisi Lin
In this paper, we investigate into the problem of image quality assessment (IQA) and enhancement via machine learning. This issue has long attracted a wide range of attention in computational intelligence and image processing communities, since, for many practical applications, e.g., object detection and recognition, raw images are usually needed to be appropriately enhanced to raise the visual quality (e.g., visibility and contrast). In fact, proper enhancement can noticeably improve the quality of input images, even better than originally captured images, which are generally thought to be of the best quality...
March 6, 2017: IEEE Transactions on Neural Networks and Learning Systems
https://www.readbyqxmd.com/read/28287963/a-dataset-and-a-technique-for-generalized-nuclear-segmentation-for-computational-pathology
#6
Neeraj Kumar, Ruchika Verma, Sanuj Sharma, Surabhi Bhargava, Abhishek Vahadane, Amit Sethi
Nuclear segmentation in digital microscopic tissue images can enable extraction of high-quality features for nuclear morphometrics and other analysis in computational pathology. Conventional image processing techniques such as Otsu thresholding and watershed segmentation do not work effectively on challenging cases, such as chromatin-sparse and crowded nuclei. In contrast, machine learning-based segmentation can generalize across various nuclear appearances. However, training machine learning algorithms require datasets of images in which a vast number of nuclei have been annotated...
March 6, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28286318/spinal-cord-grey-matter-segmentation-challenge
#7
Ferran Prados, John Ashburner, Claudia Blaiotta, Tom Brosch, Julio Carballido-Gamio, Manuel Jorge Cardoso, Benjamin N Conrad, Esha Datta, Gergely Dávid, Benjamin De Leener, Sara M Dupont, Patrick Freund, Claudia A M Gandini Wheeler-Kingshott, Francesco Grussu, Roland Henry, Bennett A Landman, Emil Ljungberg, Bailey Lyttle, Sebastien Ourselin, Nico Papinutto, Salvatore Saporito, Regina Schlaeger, Seth A Smith, Paul Summers, Roger Tam, Marios C Yiannakas, Alyssa Zhu, Julien Cohen-Adad
An important image processing step in spinal cord magnetic resonance imaging is the ability to reliably and accurately segment grey and white matter for tissue specific analysis. There are several semi- or fully-automated segmentation methods for cervical cord cross-sectional area measurement with an excellent performance close or equal to the manual segmentation. However, grey matter segmentation is still challenging due to small cross-sectional size and shape, and active research is being conducted by several groups around the world in this field...
March 7, 2017: NeuroImage
https://www.readbyqxmd.com/read/28283654/a-model-based-personalized-cancer-screening-strategy-for-detecting-early-stage-tumors-using-blood-borne-biomarkers
#8
Sharon Seiko Hori, Amelie M Lutz, Ramasamy Paulmurugan, Sanjiv S Gambhir
An effective cancer blood biomarker screening strategy must distinguish aggressive from non-aggressive tumors at an early, intervenable time. However, for blood-based strategies to be useful, the quality and quantiy of the biomarker shed into the blood and its relationship to tumor growth or progression must be validated. To study how blood biomarker levels correlate with early-stage viable tumor growth in an mouse model of human cancer, we monitored early tumor growth of engineered human ovarian cancer cells (A2780) implanted orthotopically into nude mice...
March 10, 2017: Cancer Research
https://www.readbyqxmd.com/read/28279386/trials-of-quality-improvement-in-imaging
#9
REVIEW
Kavitha M Chinnaiyan, Rory B Weiner
Cardiovascular imaging plays a central role in the diagnosis and treatment of cardiovascular disease. Recently, increased emphasis has been placed on quality in cardiovascular imaging, and it is becoming a central priority for various stakeholders, including patients, physicians, and payers. The changing health care landscape and associated challenges imposed on cardiac imagers, including reductions in reimbursement and growing need for pre-authorization, have also helped bring quality metrics to the forefront...
March 2017: JACC. Cardiovascular Imaging
https://www.readbyqxmd.com/read/28279371/carotid-plaque-lipid-content-and-fibrous-cap-status-predict-systemic-cv-outcomes-the-mri-substudy-in-aim-high
#10
Jie Sun, Xue-Qiao Zhao, Niranjan Balu, Moni B Neradilek, Daniel A Isquith, Kiyofumi Yamada, Gádor Cantón, John R Crouse, Todd J Anderson, John Huston, Kevin O'Brien, Daniel S Hippe, Nayak L Polissar, Chun Yuan, Thomas S Hatsukami
OBJECTIVES: The aim of this study was to investigate whether and what carotid plaque characteristics predict systemic cardiovascular outcomes in patients with clinically established atherosclerotic disease. BACKGROUND: Advancements in atherosclerosis imaging have allowed assessment of various plaque characteristics, some of which are more directly linked to the pathogenesis of acute cardiovascular events compared to plaque burden. METHODS: As part of the event-driven clinical trial AIM-HIGH (Atherothrombosis Intervention in Metabolic Syndrome with Low HDL/High Triglycerides: Impact on Global Health Outcomes), subjects with clinically established atherosclerotic disease underwent multicontrast carotid magnetic resonance imaging (MRI) to detect plaque tissue composition and high-risk features...
March 2017: JACC. Cardiovascular Imaging
https://www.readbyqxmd.com/read/28273347/a-phantom-study-should-124-i-mibg-pet-ct-replace-123-i-mibg-spect-ct
#11
Casper Beijst, Bart de Keizer, Marnix G E H Lam, Geert O Janssens, Godelieve A M Tytgat, Hugo W A M de Jong
PURPOSE: The isotope (123) I is commonly labeled with meta-iodobenzylguanidine (mIBG) for imaging of neuroendocrine tumors, such as pheochromocytomas and neuroblastomas. (123) I-mIBG SPECT/CT imaging is performed for staging, follow-up and selection of patients for treatment with (131) I mIBG. As an alternative to (123) I, (124) I-mIBG PET/CT may be used, potentially taking advantage of the superior PET image quality. The purpose of this study was to investigate whether (124) I PET/CT improves image quality as compared with (123) I SPECT/CT for equal patient effective radiation dose (in mSv)...
March 8, 2017: Medical Physics
https://www.readbyqxmd.com/read/28270976/low-dose-ct-via-convolutional-neural-network
#12
Hu Chen, Yi Zhang, Weihua Zhang, Peixi Liao, Ke Li, Jiliu Zhou, Ge Wang
In order to reduce the potential radiation risk, low-dose CT has attracted an increasing attention. However, simply lowering the radiation dose will significantly degrade the image quality. In this paper, we propose a new noise reduction method for low-dose CT via deep learning without accessing original projection data. A deep convolutional neural network is here used to map low-dose CT images towards its corresponding normal-dose counterparts in a patch-by-patch fashion. Qualitative results demonstrate a great potential of the proposed method on artifact reduction and structure preservation...
February 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28266059/fractional-anisotropy-derived-from-the-diffusion-tensor-distribution-function-boosts-power-to-detect-alzheimer-s-disease-deficits
#13
Talia M Nir, Neda Jahanshad, Julio E Villalon-Reina, Dmitry Isaev, Artemis Zavaliangos-Petropulu, Liang Zhan, Alex D Leow, Clifford R Jack, Michael W Weiner, Paul M Thompson
PURPOSE: In diffusion MRI (dMRI), fractional anisotropy derived from the single-tensor model (FA(DTI) ) is the most widely used metric to characterize white matter (WM) microarchitecture, despite known limitations in regions with crossing fibers. Due to time constraints when scanning patients in clinical settings, high angular resolution diffusion imaging acquisition protocols, often used to overcome these limitations, are still rare in clinical population studies. However, the tensor distribution function (TDF) may be used to model multiple underlying fibers by representing the diffusion profile as a probabilistic mixture of tensors...
March 7, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28259462/standardization-proposal-of-soft-tissue-artefact-description-for-data-sharing-in-human-motion-measurements
#14
Andrea Cereatti, Tecla Bonci, Massoud Akbarshahi, Kamiar Aminian, Arnaud Barré, Mickael Begon, Daniel L Benoit, Caecilia Charbonnier, Fabien Dal Maso, Silvia Fantozzi, Cheng-Chung Lin, Tung-Wu Lu, Marcus G Pandy, Rita Stagni, Antonie J van den Bogert, Valentina Camomilla
Soft tissue artefact (STA) represents one of the main obstacles for obtaining accurate and reliable skeletal kinematics from motion capture. Many studies have addressed this issue, yet there is no consensus on the best available bone pose estimator and the expected errors associated with relevant results. Furthermore, results obtained by different authors are difficult to compare due to the high variability and specificity of the phenomenon and the different metrics used to represent these data. Therefore, the aim of this study was twofold: firstly, to propose standards for description of STA; and secondly, to provide illustrative STA data samples for body segments in the upper and lower extremities and for a range of motor tasks specifically, level walking, stair ascent, sit-to-stand, hip- and knee-joint functional movements, cutting motion, running, hopping, arm elevation and functional upper-limb movements...
February 21, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28253268/multiband-multi-echo-imaging-of-simultaneous-oxygenation-and-flow-timeseries-for-resting-state-connectivity
#15
Alexander D Cohen, Andrew S Nencka, R Marc Lebel, Yang Wang
A novel sequence has been introduced that combines multiband imaging with a multi-echo acquisition for simultaneous high spatial resolution pseudo-continuous arterial spin labeling (ASL) and blood-oxygenation-level dependent (BOLD) echo-planar imaging (MBME ASL/BOLD). Resting-state connectivity in healthy adult subjects was assessed using this sequence. Four echoes were acquired with a multiband acceleration of four, in order to increase spatial resolution, shorten repetition time, and reduce slice-timing effects on the ASL signal...
2017: PloS One
https://www.readbyqxmd.com/read/28247427/assessing-the-effects-of-subject-motion-on-t2-relaxation-under-spin-tagging-trust-cerebral-oxygenation-measurements-using-volume-navigators
#16
Jeffrey N Stout, M Dylan Tisdall, Patrick McDaniel, Borjan Gagoski, Divya S Bolar, Patricia Ellen Grant, Elfar Adalsteinsson
PURPOSE: Subject motion may cause errors in estimates of blood T2 when using the T2 -relaxation under spin tagging (TRUST) technique on noncompliant subjects like neonates. By incorporating 3D volume navigators (vNavs) into the TRUST pulse sequence, independent measurements of motion during scanning permit evaluation of these errors. METHODS: The effects of integrated vNavs on TRUST-based T2 estimates were evaluated using simulations and in vivo subject data. Two subjects were scanned with the TRUST+vNav sequence during prescribed movements...
February 28, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28240621/weighted-mean-of-signal-intensity-for-unbiased-fiber-tracking-of-skeletal-muscles-development-of-a-new-method-and-comparison-with-other-correction-techniques
#17
Chiara Giraudo, Stanislav Motyka, Michael Weber, Christoph Resinger, Feiweier Thorsten, Hannes Traxler, Siegfried Trattnig, Wolfgang Bogner
OBJECTIVES: The aim of this study was to investigate the origin of random image artifacts in stimulated echo acquisition mode diffusion tensor imaging (STEAM-DTI), assess the role of averaging, develop an automated artifact postprocessing correction method using weighted mean of signal intensities (WMSIs), and compare it with other correction techniques. MATERIALS AND METHODS: Institutional review board approval and written informed consent were obtained. The right calf and thigh of 10 volunteers were scanned on a 3 T magnetic resonance imaging scanner using a STEAM-DTI sequence...
February 25, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28229910/optimized-energy-of-spectral-ct-for-infarct-imaging-experimental-validation-with-human-validation
#18
Veit Sandfort, Srikanth Palanisamy, Rolf Symons, Amir Pourmorteza, Mark A Ahlman, Kelly Rice, Tom Thomas, Cynthia Davies-Venn, Bernhard Krauss, Alan Kwan, Ankur Pandey, Stefan L Zimmerman, David A Bluemke
OBJECTIVES: Late contrast enhancement visualizes myocardial infarction, but the contrast to noise ratio (CNR) is low using conventional CT. The aim of this study was to determine if spectral CT can improve imaging of myocardial infarction. MATERIALS AND METHODS: A canine model of myocardial infarction was produced in 8 animals (90-min occlusion, reperfusion). Later, imaging was performed after contrast injection using CT at 90 kVp/150 kVpSn. The following reconstructions were evaluated: Single energy 90 kVp, mixed, iodine map, multiple monoenergetic conventional and monoenergetic noise optimized reconstructions...
February 11, 2017: Journal of Cardiovascular Computed Tomography
https://www.readbyqxmd.com/read/28220868/image-based-adaptive-optics-for-in-vivo-imaging-in-the-hippocampus
#19
D Champelovier, J Teixeira, J-M Conan, N Balla, L M Mugnier, T Tressard, S Reichinnek, S Meimon, R Cossart, H Rigneault, S Monneret, A Malvache
Adaptive optics is a promising technique for the improvement of microscopy in tissues. A large palette of indirect and direct wavefront sensing methods has been proposed for in vivo imaging in experimental animal models. Application of most of these methods to complex samples suffers from either intrinsic and/or practical difficulties. Here we show a theoretically optimized wavefront correction method for inhomogeneously labeled biological samples. We demonstrate its performance at a depth of 200 μm in brain tissue within a sparsely labeled region such as the pyramidal cell layer of the hippocampus, with cells expressing GCamP6...
February 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28212084/objective-quality-assessment-of-screen-content-images-by-uncertainty-weighting
#20
Yuming Fang, Jiebin Yan, Jiaying Liu, Shiqi Wang, Qiaohong Li, Zongming Guo
In this paper, we propose a novel full-reference objective quality assessment metric for screen content images (SCIs) by structure features and uncertainty weighting (SFUW). The input SCI is first divided into textual and pictorial regions. The visual quality of textual regions is estimated based on perceptual structural similarity, where the gradient information is adopted as the structural feature. To predict the visual quality of pictorial regions in SCIs, we extract the structural features and luminance features for similarity computation between the reference and distorted pictorial patches...
February 15, 2017: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
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