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image quality metric

Sebastien Benali, Patrick R Johnston, Ali Gholipour, Monet E Dugan, Keith Heberlein, Himanshu Bhat, Sarah D Bixby
PURPOSE: To compare knee MRI performed with the integrated parallel acquisition technique (PAT) and simultaneous multislice (SMS) turbo spin echo (TSE) T2-weighted (T2w) sequences with conventional TSE sequences in pediatric patients. MATERIALS AND METHODS: This was a retrospective IRB-approved study. Seventy-four subjects (26 male, 48 female, mean age 15.3 years, range 8-20) underwent 3-T MRI of the knee with a T2w TSE pulse sequence prototype with four-fold PAT and SMS acceleration as well as the standard PAT-only accelerated sequences...
January 13, 2018: Skeletal Radiology
Shishun Tian, Lu Zhang, Luce Morin, Olivier Deforges
Benefiting from multi-view video plus depth and depth-image-based-rendering technologies, only limited views of a real 3-D scene need to be captured, compressed, and transmitted. However, the quality assessment of synthesized views is very challenging, since some new types of distortions, which are inherently different from the texture coding errors, are inevitably produced by view synthesis and depth map compression, and the corresponding original views (reference views) are usually not available. Thus the full-reference quality metrics cannot be used for synthesized views...
April 2018: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
Jesus Ruiz-Santaquiteria, Jose Luis Espinosa-Aranda, Oscar Deniz, Carlos Sanchez, Maria Borrego-Ramos, Saul Blanco, Gabriel Cristobal, Gloria Bueno
We study the effectiveness of several low-cost oblique illumination filters to improve overall image quality, in comparison with standard bright field imaging. For this purpose, a dataset composed of 3360 diatom images belonging to 21 taxa was acquired. Subjective and objective image quality assessments were done. The subjective evaluation was performed by a group of diatom experts by psychophysical test where resolution, focus, and contrast were assessed. Moreover, some objective nonreference image quality metrics were applied to the same image dataset to complete the study, together with the calculation of several texture features to analyze the effect of these filters in terms of textural properties...
January 2018: Journal of Biomedical Optics
Enid M Eslick, John Kipritidis, Denis Gradinscak, Mark J Stevens, Dale L Bailey, Benjamin Harris, Jeremy T Booth, Paul J Keall
BACKGROUND AND PURPOSE: CT ventilation imaging (CTVI) derived from four dimensional CT (4DCT) has shown only moderate spatial accuracy in humans due to 4DCT image artefacts. Here we assess the accuracy of an improved CTVI using high quality exhale/inhale breath-hold CT (BHCT). MATERIALS AND METHODS: Eighteen lung cancer patients underwent exhale/inhale BHCT, 4DCT and Galligas PET ventilation scans in a single imaging session. For each BHCT and 4DCT scan, we performed deformable image registration (DIR) between the inhale and exhale phase images to quantify ventilation using three published metrics: (i) breathing induced lung density change, CTVIDIR-HU (ii) breathing induced volume change CTVIDIR-Jac and (iii) the regional air-tissue product, CTVIHU Spatial accuracy was reported as the voxel-wise Spearman correlation r between CTVI and Galligas PET...
December 28, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
Nasrin Ghanbari, Eric Clarkson, Matthew Kupinski, Xin Li
A method for optimization of an adaptive Single Photon Emission Computed Tomography (SPECT) system is presented. Adaptive imaging systems can quickly change their hardware configuration in response to data being generated in order to improve image quality for a specific task. In this work we simulate an adaptive SPECT system and propose a method for finding the adaptation that maximizes the performance on a signal estimation task. To start with, a simulated object model containing a spherical signal is imaged with a scout configuration...
September 2017: IEEE Transactions on Radiation and Plasma Medical Sciences
Tim J Wood, Craig S Moore, John R Saunderson, Andy W Beavis
Effective Detective Quantum Efficiency (eDQE) describes the resolution and noise properties of an imaging system along with scatter and primary transmission, all measured under clinically appropriate conditions. Effective dose efficiency (eDE) is the eDQE normalised to mean glandular dose and has been proposed as a useful metric for the optimisation of clinical imaging systems. The aim of this study was to develop a methodology for measuring eDQE and eDE on a Philips MicroDose Mammography (MDM) L30 photon counting scanning system, and to compare performance with two conventional flat panel systems...
December 20, 2017: Physics in Medicine and Biology
Nick Bottenus, Will Long, Matthew Morgan, Gregg Trahey
Current clinical abdominal imaging arrays are designed to maximize angular field of view rather than the extent of the coherent aperture. We illustrate, in ex vivo experiments, the use of a large effective aperture to perform high-resolution imaging, even in the presence of abdominal wall-induced acoustic clutter and aberration. Point and lesion phantom targets were imaged through a water path and through three excised cadaver abdominal walls to create different clinically relevant clutter effects with matched imaging targets...
December 14, 2017: Ultrasound in Medicine & Biology
Mark R Ferguson, Sandra L Poliachik, Christopher B Budech, Nancy E Gove, Gregory T Carter, Leo H Wang, Daniel G Miller, Dennis W W Shaw, Seth D Friedman
INTRODUCTION: MRI evaluation in facioscapulohumeral muscular dystrophy (FSHD) demonstrates fatty replacement and inflammation/edema in muscle. Our previous work demonstrated Short T1 Inversion Recovery (STIR)-hyperintense (STIR+) signal in muscle 2 years prior to fatty replacement. We evaluated leg muscle STIR changes and fatty replacement within 14 months. METHODS: FSHD subjects received 2 MRI scans of thigh and calf over a 6.9-13.8 month interval. Quality of life measures were collected...
December 13, 2017: Muscle & Nerve
Hendrik Mattern, Alessandro Sciarra, Frank Godenschweger, Daniel Stucht, Falk Lüsebrink, Georg Rose, Oliver Speck
PURPOSE: Higher magnetic field strengths enable time-of-flight (TOF) angiography with higher resolution to depict small-vessel pathologies. However, this potential is limited by the subject's ability to remain motionless. Even small-scale, involuntary motion can degrade vessel depiction, thus limiting the effective resolution. The aim of this study was to overcome this resolution limit by deploying prospectively motion-corrected (PMC) TOF. METHODS: An optical, marker-based, in-bore tracking system was used to update the imaging volume prospectively according to the subject's head motion...
December 11, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Ali Karaali, Claudio Rosito Jung
Objects that do not lie at the focal distance of a digital camera generate defocused regions in the captured image. This paper presents a new edge-based method for spatially varying defocus blur estimation using a single image based on reblurred gradient magnitudes. The proposed approach initially computes a scale-consistent edge map of the input image and selects a local reblurring scale aiming to cope with noise, edge mis-localization, and interfering edges. An initial blur estimate is computed at the detected scale-consistent edge points and a novel connected edge filter is proposed to smooth the sparse blur map based on pixel connectivity within detected edge contours...
March 2018: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
Mark Mikkelsen, Muhammad G Saleh, Jamie Near, Kimberly L Chan, Tao Gong, Ashley D Harris, Georg Oeltzschner, Nicolaas A J Puts, Kim M Cecil, Iain D Wilkinson, Richard A E Edden
PURPOSE: Detection of endogenous metabolites using multiplexed editing substantially improves the efficiency of edited magnetic resonance spectroscopy. Multiplexed editing (i.e., performing more than one edited experiment in a single acquisition) requires a tailored, robust approach for correction of frequency and phase offsets. Here, a novel method for frequency and phase correction (FPC) based on spectral registration is presented and compared against previously presented approaches...
December 7, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Declan O'Loughlin, Bárbara L Oliveira, Muhammad Adnan Elahi, Martin Glavin, Edward Jones, Milica Popović, Martin O'Halloran
Inaccurate estimation of average dielectric properties can have a tangible impact on microwave radar-based breast images. Despite this, recent patient imaging studies have used a fixed estimate although this is known to vary from patient to patient. Parameter search algorithms are a promising technique for estimating the average dielectric properties from the reconstructed microwave images themselves without additional hardware. In this work, qualities of accurately reconstructed images are identified from point spread functions...
December 6, 2017: Sensors
Roziana Ramli, Mohd Yamani Idna Idris, Khairunnisa Hasikin, Noor Khairiah A Karim, Ainuddin Wahid Abdul Wahab, Ismail Ahmedy, Fatimah Ahmedy, Nahrizul Adib Kadri, Hamzah Arof
Retinal image registration is important to assist diagnosis and monitor retinal diseases, such as diabetic retinopathy and glaucoma. However, registering retinal images for various registration applications requires the detection and distribution of feature points on the low-quality region that consists of vessels of varying contrast and sizes. A recent feature detector known as Saddle detects feature points on vessels that are poorly distributed and densely positioned on strong contrast vessels. Therefore, we propose a multiresolution difference of Gaussian pyramid with Saddle detector (D-Saddle) to detect feature points on the low-quality region that consists of vessels with varying contrast and sizes...
2017: Journal of Healthcare Engineering
Lale Kostakoglu, Stéphane Chauvie
Although visual assessment using the Deauville criteria is strongly recommended by guidelines for treatment response monitoring in all FDG-avid lymphoma histologies, the high rate of false-positives and concerns about interobserver variability have motivated the development of quantitative tools to facilitate objective measurement of tumor response in both routine and clinical trial settings. Imaging studies using functional quantitative measures play a significant role in profiling oncologic processes. These quantitative metrics allow for objective end points in multicenter clinical trials...
January 2018: Seminars in Nuclear Medicine
Anna Kalathil Thomas, Richard Southard, John Curran, Robyn Augustyn
OBJECTIVE: Although advanced statistical iterative reconstruction (IR) techniques are valued in pediatric computed tomography (CT) imaging, there is little published data on how these techniques affect image quality and radiation dose in the pediatric population. This is particularly true in the context of pediatric head CT examinations. This study analyzed the differences in image quality and several standard metrics of radiation dose on multidetector pediatric head CT examinations performed using standard filtered back projection (FBP) with reconstructions using iDose, a fourth-generation statistical iterative reconstruction technique...
November 16, 2017: Journal of Computer Assisted Tomography
Roel G J Kierkels, Lydia A den Otter, Erik W Korevaar, Johannes A Langendijk, Arjen van der Schaaf, Antje-Christin Knopf, Nanna M Sijtsema
A prerequisite for adaptive dose-tracking in radiotherapy is the assessment of the deformable image registration (DIR) quality. In this work, various metrics that quantify DIR uncertainties are investigated using realistic deformation fields of 26 head and neck and 12 lung cancer patients. Metrics related to the physiologically feasibility (the Jacobian determinant, harmonic energy [HE], and shear strain) and numerically robustness of the deformation (the inverse consistency error, transitivity error, and distance discordance metric [DDM]) were investigated...
November 28, 2017: Physics in Medicine and Biology
Miguel P Eckstein, Miguel A Lago, Craig K Abbey
The field of medical image quality has relied on the assumption that metrics of image quality for simple visual detection tasks are a reliable proxy for the more clinically realistic visual search tasks. Rank order of signal detectability across conditions often generalizes from detection to search tasks. Here, we argue that search in 3D images represents a paradigm shift in medical imaging: radiologists typically cannot exhaustively scrutinize all regions of interest with the high acuity fovea requiring detection of signals with extra-foveal areas (visual periphery) of the human retina...
February 11, 2017: Proceedings of SPIE
Vimal Chandran, Mauricio Reyes, Philippe Zysset
Osteoporosis leads to hip fractures in aging populations and is diagnosed by modern medical imaging techniques such as quantitative computed tomography (QCT). Hip fracture sites involve trabecular bone, whose strength is determined by volume fraction and orientation, known as fabric. However, bone fabric cannot be reliably assessed in clinical QCT images of proximal femur. Accordingly, we propose a novel registration-based estimation of bone fabric designed to preserve tensor properties of bone fabric and to map bone fabric by a global and local decomposition of the gradient of a non-rigid image registration transformation...
2017: PloS One
Leidy J Rojas, Agnes M F Fausto, Anderson W Mol, Fermin G Velasco, P O S Abreu, G Henriques, T A C Furquim
PURPOSE: Optimization studies in digital mammography aid to assure the image quality and radiological protection of the patient. The aim of this work is to test effectiveness and applicability of a method based on a Figure of Merit (FOM=(IQFinv)2/AGD) to improve all the exposure parameters (Target/Filter combination, kVp and mAs) in order to improve the image acquisition technique that will provide the best compromise between image quality and the average glandular dose (AGD). METHODS: A contrast-detail analysis, employing the test object CDMAM, was carried out for the digital mammography unit manufactured by Lorad Hologic - model Selenia...
October 2017: Physica Medica: PM
Matthew J O'Hara, Nathaniel J Murray, Jennifer C Carter, Cynthia M Kellogg, Jeanne M Link
Zirconium-89 (89Zr) is a long-lived (t1/2 = 78.4h) positron-emitting isotope that is useful for positron emission tomography (PET) based diagnostic imaging using radiolabeled antibodies. Hydroxamate resin columns are predominantly used for the purification of 89Zr from cyclotron bombarded natY targets dissolved in strong HCl. 89Zr is conventionally eluted from the resin in 1M oxalic acid (H2C2O4), a complexant that is conducive to follow-on binding of 89Zr through a transchelation process to the deferoxamine siderophore...
November 21, 2017: Applied Radiation and Isotopes
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