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https://www.readbyqxmd.com/read/28444772/multi-atlas-approach-with-local-registration-goodness-weighting-for-mri-based-electron-density-mapping-of-head-and-neck-anatomy
#1
Reza Farjam, Neelam Tyagi, Harini Veeraraghavan, Aditya Apte, Kristen Zakian, Margie A Hunt, Joseph O Deasy
PURPOSE: The growing use of magnetic resonance imaging (MRI) as a substitute for computed tomography-based treatment planning requires the development of effective algorithms to generate electron density maps for treatment planning and patient setup verification. The purpose of this work was to develop a method to synthesize computerized tomography (CT) for MR-only radiotherapy of head and neck cancer patients. METHODS: The algorithm is based on registration of multiple patient datasets containing both MRI and CT images (a "multi-atlas" algorithm)...
April 26, 2017: Medical Physics
https://www.readbyqxmd.com/read/28444524/in-vitro-optical-quality-of-monofocal-aspheric-toric-intraocular-lenses-effect-of-cylindrical-power
#2
Teresa Ferrer-Blasco, Alberto Domínguez-Vicent, Santiago García-Lázaro, María Amparo Diez, José F Alfonso, José J Esteve-Taboada
PURPOSE: To assess the in vitro optical quality of monofocal aspheric toric intraocular lenses (IOLs) as a function of the cylindrical power. METHODS: The in vitro optical quality of the AcrySof IQ Toric IOLs SN6AT2, SN6AT3, SN6AT4, SN6AT5 and SN6AT6 (Alcon Laboratories Inc., Forth Worth, TX, USA) was assessed with an instrument conceived for measuring Zernike's coefficients at 3.0- and 5.0-mm apertures. As a reference, the aspheric monofocal lens AcrySof IQ Aspheric SN60WF (Alcon Laboratories Inc...
April 25, 2017: International Ophthalmology
https://www.readbyqxmd.com/read/28437922/from-toes-to-top-of-atmosphere-fowler-s-sneaker-depth-index-of-water-clarity-for-the-chesapeake-bay
#3
Benjamin Crooke, Lachlan I W McKinna, Ivona Cetinić
Fowler's Sneaker Depth (FSD), analogous to the well known Secchi disk depth (Zsd), is a visually discerned citizen scientist metric used to assess water clarity in the Patuxent River estuary. In this study, a simple remote sensing algorithm was developed to derive FSD from space-borne spectroradiometric imagery. An empirical model was formed that estimates FSD from red-end remote sensing reflectances at 645 nm, Rrs(645). The model is based on a hyperbolic function relating water clarity to Rrs(645) that was established using radiative transfer modeling and fine tuned using in-water FSD measurements and coincident Rrs(645) data observed by NASA's Moderate Resolution Imaging Spectroradiometer aboard the Aqua spacecraft (MODISA)...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437565/relaxed-ordered-subset-preconditioned-alternating-projection-algorithm-for-pet-reconstruction-with-automated-penalty-weight-selection
#4
C Ross Schmidtlein, Yizun Lin, Si Li, Andrzej Krol, Bradley J Beattie, John L Humm, Yuesheng Xu
PURPOSE: Performance of the preconditioned alternating projection algorithm (PAPA) using relaxed ordered subsets (ROS) with a non-smooth penalty function was investigated in positron emission tomography (PET). A higher order total variation (HOTV) regularizer was applied and a method for unsupervised selection of penalty weights based on the measured data is introduced. METHODS: A ROS version of PAPA with HOTV penalty (ROS-HOTV-PAPA) for PET image reconstruction was developed and implemented...
April 24, 2017: Medical Physics
https://www.readbyqxmd.com/read/28436849/reverse-classification-accuracy-predicting-segmentation-performance-in-the-absence-of-ground-truth
#5
Vanya V Valindria, Ioannis Lavdas, Wenjia Bai, Konstantinos Kamnitsas, Eric O Aboagye, Andrea G Rockall, Daniel Rueckert, Ben Glocker
When integrating computational tools such as automatic segmentation into clinical practice, it is of utmost importance to be able to assess the level of accuracy on new data, and in particular, to detect when an automatic method fails. However, this is difficult to achieve due to absence of ground truth. Segmentation accuracy on clinical data might be different from what is found through cross-validation because validation data is often used during incremental method development, which can lead to overfitting and unrealistic performance expectations...
April 17, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28435432/foundation-and-methodologies-in-computer-aided-diagnosis-systems-for-breast-cancer-detection
#6
REVIEW
Afsaneh Jalalian, Syamsiah Mashohor, Rozi Mahmud, Babak Karasfi, M Iqbal B Saripan, Abdul Rahman B Ramli
Breast cancer is the most prevalent cancer that affects women all over the world. Early detection and treatment of breast cancer could decline the mortality rate. Some issues such as technical reasons, which related to imaging quality and human error, increase misdiagnosis of breast cancer by radiologists. Computer-aided detection systems (CADs) are developed to overcome these restrictions and have been studied in many imaging modalities for breast cancer detection in recent years. The CAD systems improve radiologists' performance in finding and discriminating between the normal and abnormal tissues...
2017: EXCLI journal
https://www.readbyqxmd.com/read/28429195/computer-assisted-diagnosis-system-for-breast-cancer-in-computed-tomography-laser-mammography-ctlm
#7
Afsaneh Jalalian, Syamsiah Mashohor, Rozi Mahmud, Babak Karasfi, M Iqbal Saripan, Abdul Rahman Ramli
Computed tomography laser mammography (Eid et al. Egyp J Radiol Nucl Med, 37(1): p. 633-643, 1) is a non-invasive imaging modality for breast cancer diagnosis, which is time-consuming and challenging for the radiologist to interpret the images. Some issues have increased the missed diagnosis of radiologists in visual manner assessment in CTLM images, such as technical reasons which are related to imaging quality and human error due to the structural complexity in appearance. The purpose of this study is to develop a computer-aided diagnosis framework to enhance the performance of radiologist in the interpretation of CTLM images...
April 20, 2017: Journal of Digital Imaging: the Official Journal of the Society for Computer Applications in Radiology
https://www.readbyqxmd.com/read/28412952/rayleigh-maximum-likelihood-bilateral-filter-for-ultrasound-image-enhancement
#8
Haiyan Li, Jun Wu, Aimin Miao, Pengfei Yu, Jianhua Chen, Yufeng Zhang
BACKGROUND: Ultrasound imaging plays an important role in computer diagnosis since it is non-invasive and cost-effective. However, ultrasound images are inevitably contaminated by noise and speckle during acquisition. Noise and speckle directly impact the physician to interpret the images and decrease the accuracy in clinical diagnosis. Denoising method is an important component to enhance the quality of ultrasound images; however, several limitations discourage the results because current denoising methods can remove noise while ignoring the statistical characteristics of speckle and thus undermining the effectiveness of despeckling, or vice versa...
April 17, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28410683/evaluation-of-automatic-image-quality-assessment-in-chest-ct-a-human-cadaver-study
#9
Caro Franck, An De Crop, Bieke De Roo, Peter Smeets, Merel Vergauwen, Tom Dewaele, Mathias Van Borsel, Eric Achten, Tom Van Hoof, Klaus Bacher
PURPOSE: The evaluation of clinical image quality (IQ) is important to optimize CT protocols and to keep patient doses as low as reasonably achievable. Considering the significant amount of effort needed for human observer studies, automatic IQ tools are a promising alternative. The purpose of this study was to evaluate automatic IQ assessment in chest CT using Thiel embalmed cadavers. METHODS: Chest CT's of Thiel embalmed cadavers were acquired at different exposures...
April 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28405539/quantifying-biomass-consumption-and-carbon-release-from-the-california-rim-fire-by-integrating-airborne-lidar-and-landsat-oli-data
#10
Mariano Garcia, Sassan Saatchi, Angeles Casas, Alexander Koltunov, Susan Ustin, Carlos Ramirez, Jorge Garcia-Gutierrez, Heiko Balzter
Quantifying biomass consumption and carbon release is critical to understanding the role of fires in the carbon cycle and air quality. We present a methodology to estimate the biomass consumed and the carbon released by the California Rim fire by integrating postfire airborne LiDAR and multitemporal Landsat Operational Land Imager (OLI) imagery. First, a support vector regression (SVR) model was trained to estimate the aboveground biomass (AGB) from LiDAR-derived metrics over the unburned area. The selected model estimated AGB with an R(2) of 0...
February 2017: Journal of Geophysical Research. Biogeosciences
https://www.readbyqxmd.com/read/28393623/clinical-comparison-of-conventional-and-mobile-endockscope-videocystoscopy-using-an-air-or-fluid-medium
#11
Rahul Dutta, Renai Yoon, Roshan M Patel, Kyle Spradling, Zhamshid Okhunov, William Sohn, Hak J Lee, Jaime Landman, Ralph Clayman
OBJECTIVE: To compare conventional videocystoscopy to a novel and affordable (approximately $45) mobile cystoscopy system, the Endockscope. We evaluated the Endockscope system using both fluid (Endockscope-Fluid) and air (Endockscope-Air) to fill the bladder in an effort to expand the global range of flexible cystoscopy. METHODS: The Endockscope system is comprised of a portable 1,000 lumen LED self-contained cordless light source and a 3D printed adaptor which connects a mobile phone to a flexible fiberoptic cystoscope...
April 8, 2017: Journal of Endourology
https://www.readbyqxmd.com/read/28393301/structured-reporting-of-ct%C3%A2-enterography%C3%A2-for%C3%A2-inflammatory-bowel-disease-effect-on-key-feature%C3%A2-reporting-accuracy-across-training-levels-and-subjective-assessment-of-disease-by-referring-physicians
#12
Benjamin Wildman-Tobriner, Brian C Allen, Mustafa R Bashir, Morgan Camp, Chad Miller, Lauren E Fiorillo, Alan Cubre, Sanaz Javadi, Alex D Bibbey, Wendy L Ehieli, Nancy McGreal, Reinaldo Quevedo, Julie K Thacker, Maciej Mazurowski, Tracy A Jaffe
PURPOSE: To compare the content and accuracy of structured reporting (SR) versus non-structured reporting (NSR) for computed tomographic enterography (CTE) of inflammatory bowel disease (IBD). MATERIALS AND METHODS: This IRB-approved, HIPAA-compliant, retrospective study included 30 adult subjects (15 male, 15 female; mean age 41.9 years) with IBD imaged with CTE. Nine radiologists (3 faculty, 3 abdominal imaging fellows, and 3 senior radiology residents) independently interpreted all examinations using both NSR and SR, separated by four weeks...
April 9, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28391187/double-stage-delay-multiply-and-sum-beamforming-algorithm-application-to-linear-array-photoacoustic-imaging
#13
Moein Mozaffarzadeh, Ali Mahloojifar, Mahdi Orooji, Saba Adabi, Mohammadreza Nasiriavanaki
Photoacoustic imaging (PAI) is an emerging medical imaging modality capable of providing high spatial resolution of Ultrasound (US) imaging and high contrast of optical imaging. Delay-and-Sum (DAS) is the most common beamforming algorithm in PAI. However, using DAS beamformer leads to low resolution images and considerable contribution of offaxis signals. A new paradigm namely Delay-Multiply-and-Sum (DMAS), which was originally used as a reconstruction algorithm in confocal microwave imaging, was introduced to overcome the challenges in DAS...
April 5, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28380937/digital-adaptive-optics-confocal-microscopy-based-on-iterative-retrieval-of-optical-aberration-from-a-guidestar-hologram
#14
Changgeng Liu, Damber Thapa, Xincheng Yao
Guidestar hologram based digital adaptive optics (DAO) is one recently emerging active imaging modality. It records each complex distorted line field reflected or scattered from the sample by an off-axis digital hologram, measures the optical aberration from a separate off-axis digital guidestar hologram, and removes the optical aberration from the distorted line fields by numerical processing. In previously demonstrated DAO systems, the optical aberration was directly retrieved from the guidestar hologram by taking its Fourier transform and extracting the phase term...
April 3, 2017: Optics Express
https://www.readbyqxmd.com/read/28380247/a-new-ct-reconstruction-technique-using-adaptive-deformation-recovery-and-intensity-correction-adric
#15
You Zhang, Jianhua Ma, Puneeth Iyenga, Yuncheng Zhong, Jing Wang
PURPOSE: Sequential same-patient CT images may involve deformation-induced and non-deformation-induced voxel intensity changes. An adaptive deformation recovery and intensity correction (ADRIC) technique was developed to improve the CT reconstruction accuracy, and to separate deformation from non-deformation-induced voxel intensity changes between sequential CT images. MATERIALS AND METHODS: ADRIC views the new CT volume as a deformation of a prior high-quality CT volume, but with additional non-deformation-induced voxel intensity changes...
April 5, 2017: Medical Physics
https://www.readbyqxmd.com/read/28380245/a-method-to-extract-image-noise-level-from-patient-images-in-ct
#16
Annelise Malkus, Timothy P Szczykutowicz
PURPOSE: Image quality in computed tomography (CT) is usually not quantified in real time from patient scans. Rather, phantom scans are employed to measure the contrast, noise, and spatial resolution properties of a given system. This approach, however, is not ideal because many factors are difficult to represent using phantoms like variations in patient size, composition, and position within the gantry. Several methods for measuring the noise found within patient scans have been proposed...
April 5, 2017: Medical Physics
https://www.readbyqxmd.com/read/28371772/spatial-evidential-clustering-with-adaptive-distance-metric-for-tumor-segmentation-in-fdg-pet-images
#17
Chunfeng Lian, Su Ruan, Thierry Denoeux, Hua Li, Pierre Vera
While the accurate delineation of tumor volumes in FDG-PET is a vital task for diverse objectives in clinical oncology, noise and blur due to the imaging system make it a challenging work. In this paper, we propose to address the imprecision and noise inherent in PET using Dempster-Shafer theory, a powerful tool for modeling and reasoning with uncertain and/or imprecise information. Based on Dempster-Shafer theory, a novel evidential clustering algorithm is proposed and tailored for the tumor segmentation task in 3D...
March 30, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28370389/is-an-objective-refraction-optimised-using-the-visual-strehl-ratio-better-than-a-subjective-refraction
#18
Gareth D Hastings, Jason D Marsack, Lan Chi Nguyen, Han Cheng, Raymond A Applegate
PURPOSE: To prospectively examine whether using the visual image quality metric, visual Strehl (VSX), to optimise objective refraction from wavefront error measurements can provide equivalent or better visual performance than subjective refraction and which refraction is preferred in free viewing. METHODS: Subjective refractions and wavefront aberrations were measured on 40 visually-normal eyes of 20 subjects, through natural and dilated pupils. For each eye a sphere, cylinder, and axis prescription was also objectively determined that optimised visual image quality (VSX) for the measured wavefront error...
March 30, 2017: Ophthalmic & Physiological Optics: the Journal of the British College of Ophthalmic Opticians (Optometrists)
https://www.readbyqxmd.com/read/28365785/selection-of-optimal-tube-potential-settings-for-dual-energy-ct-virtual-mono-energetic-imaging-of-iodine-in-the-abdomen
#19
Gregory Michalak, Joshua Grimes, Joel Fletcher, Ahmed Halaweish, Lifeng Yu, Shuai Leng, Cynthia McCollough
PURPOSE: To determine the appropriate tube potential settings for dual-source, dual-energy data acquisition across a range of phantom sizes, and to determine the optimal photon energies for virtual mono-energetic imaging. METHODS: Water phantoms (15-50-cm wide) containing an iodine test object were scanned on a third-generation dual-source CT scanner using all available tube potential pairs. Virtual mono-energetic images at 40, 50, 60, and 70 keV were produced using Mono-energetic Plus...
April 1, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28365419/mindcontrol-a-web-application-for-brain-segmentation-quality-control
#20
REVIEW
Anisha Keshavan, Esha Datta, Ian McDonough, Christopher R Madan, Kesshi Jordan, Roland G Henry
Tissue classification plays a crucial role in the investigation of normal neural development, brain-behavior relationships, and the disease mechanisms of many psychiatric and neurological illnesses. Ensuring the accuracy of tissue classification is important for quality research and, in particular, the translation of imaging biomarkers to clinical practice. Assessment with the human eye is vital to correct various errors inherent to all currently available segmentation algorithms. Manual quality assurance becomes methodologically difficult at a large scale - a problem of increasing importance as the number of data sets is on the rise...
March 29, 2017: NeuroImage
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