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Quantitative imaging

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https://www.readbyqxmd.com/read/29906714/an-adaptive-beamforming-method-for-ultrasound-imaging-based-on-the-mean-to-standard-deviation-factor
#1
Yuanguo Wang, Chichao Zheng, Hu Peng, Qiang Chen
The beamforming performance has a large impact on image quality in ultrasound imaging. Previously, several adaptive weighting factors including coherence factor (CF) and generalized coherence factor (GCF) have been proposed to improved image resolution and contrast. In this paper, we propose a new adaptive weighting factor for ultrasound imaging, which is called signal mean-to-standard-deviation factor (SMSF). SMSF is defined as the mean-to-standard-deviation of the aperture data and is used to weight the output of delay-and-sum (DAS) beamformer before image formation...
June 12, 2018: Ultrasonics
https://www.readbyqxmd.com/read/29906634/whole-head-quantitative-susceptibility-mapping-using-a-least-norm-direct-dipole-inversion-method
#2
Hongfu Sun, Yuhan Ma, M Ethan MacDonald, G Bruce Pike
A new dipole field inversion method for whole head quantitative susceptibility mapping (QSM) is proposed. Instead of performing background field removal and local field inversion sequentially, the proposed method performs dipole field inversion directly on the total field map in a single step. To aid this under-determined and ill-posed inversion process and obtain robust QSM images, Tikhonov regularization is implemented to seek the local susceptibility solution with the least-norm (LN) using the L-curve criterion...
June 12, 2018: NeuroImage
https://www.readbyqxmd.com/read/29906449/transient-osmotic-perturbation-causes-long-term-alteration-to-the-gut-microbiota
#3
Carolina Tropini, Eli Lin Moss, Bryan Douglas Merrill, Katharine Michelle Ng, Steven Kyle Higginbottom, Ellen Pun Casavant, Carlos Gutierrez Gonzalez, Brayon Fremin, Donna Michelle Bouley, Joshua Eric Elias, Ami Siddharth Bhatt, Kerwyn Casey Huang, Justin Laine Sonnenburg
Osmotic diarrhea is a prevalent condition in humans caused by food intolerance, malabsorption, and widespread laxative use. Here, we assess the resilience of the gut ecosystem to osmotic perturbation at multiple length and timescales using mice as model hosts. Osmotic stress caused reproducible extinction of highly abundant taxa and expansion of less prevalent members in human and mouse microbiotas. Quantitative imaging revealed decimation of the mucus barrier during osmotic perturbation, followed by recovery...
June 14, 2018: Cell
https://www.readbyqxmd.com/read/29906284/multi-parametric-quantitative-mri-reveals-three-different-white-matter-subtypes
#4
Jack R Foucher, Olivier Mainberger, Julien Lamy, Mathieu D Santin, Alexandre Vignaud, Mathilde M Roser, Paulo L de Sousa
INTRODUCTION: Magnetic resonance imaging (MRI) shows slight spatial variations in brain white matter (WM). We used quantitative multi-parametric MRI to evaluate in what respect these inhomogeneities could correspond to WM subtypes with specific characteristics and spatial distribution. MATERIALS AND METHODS: Twenty-six controls (12 women, 38 ±9 Y) took part in a 60-min session on a 3T scanner measuring 7 parameters: R1 and R2, diffusion tensor imaging which allowed to measure Axial and Radial Diffusivity (AD, RD), magnetization transfer imaging which enabled to compute the Macromolecular Proton Fraction (MPF), and a susceptibility-weighted sequence which permitted to quantify R2* and magnetic susceptibility (χm)...
2018: PloS One
https://www.readbyqxmd.com/read/29905737/quantitative-differential-phase-contrast-imaging-at-high-resolution-with-radially-asymmetric-illumination
#5
Yu-Zi Lin, Kuang-Yuh Huang, Yuan Luo
Half-circle illumination-based differential phase contrast (DPC) microscopy has been utilized to recover phase images through a pair of images along multiple axes. Recently, the half-circle based DPC using 12-axis measurements significantly provides a circularly symmetric phase transfer function to improve accuracy for more stable phase recovery. Instead of using half-circle-based DPC, we propose a new scheme of DPC under radially asymmetric illumination to achieve circularly symmetric phase transfer function and enhance the accuracy of phase recovery in a more stable and efficient fashion...
June 15, 2018: Optics Letters
https://www.readbyqxmd.com/read/29905736/efficient-polarization-direction-measurement-by-utilizing-the-polarization-axis-finder-and-digital-image-processing
#6
Bing Lei, Shugang Liu
We report a new quantitative measurement method of polarization direction based on the polarization axis finder (PAF) and digital image processing. The PAF acts as an azimuthal analyzer to determine the polarization direction of linearly polarized light and form an "hourglass" intensity pattern, and a digital camera is employed to record the pattern, and then the lightwave's polarization direction is obtained accurately by analyzing the pattern with a specially designed digital image processing algorithm...
June 15, 2018: Optics Letters
https://www.readbyqxmd.com/read/29905680/end-to-end-deep-neural-network-for-optical-inversion-in-quantitative-photoacoustic-imaging
#7
Chuangjian Cai, Kexin Deng, Cheng Ma, Jianwen Luo
An end-to-end deep neural network, ResU-net, is developed for quantitative photoacoustic imaging. A residual learning framework is used to facilitate optimization and to gain better accuracy from considerably increased network depth. The contracting and expanding paths enable ResU-net to extract comprehensive context information from multispectral initial pressure images and, subsequently, to infer a quantitative image of chromophore concentration or oxygen saturation (sO2 ). According to our numerical experiments, the estimations of sO2 and indocyanine green concentration are accurate and robust against variations in both optical property and object geometry...
June 15, 2018: Optics Letters
https://www.readbyqxmd.com/read/29905582/evaluating-the-accuracy-of-using-at-rest-images-to-determine-the-height-of-velopharyngeal-closure
#8
Kazlin N Mason, Kelly Hauhuth, Jamie L Perry, John E Riski
Prior to performing secondary surgeries, lateral cephalograms have been used during phonation to evaluate the point of attempted velopharyngeal contact along the posterior pharyngeal wall relative to the palatal plane and the first cervical vertebra. The ability to quantify the height of velopharyngeal closure is an important aspect of planning corrective surgeries for velopharyngeal dysfunction. However, issues with patient compliance during the imaging process can present difficulties for obtaining adequate preoperative imaging data...
June 13, 2018: Journal of Craniofacial Surgery
https://www.readbyqxmd.com/read/29905513/isolated-subdural-hematomas-in-mild-traumatic-brain-injury-part-1-the-association-between-radiographic-characteristics-and-neurosurgical-intervention
#9
Alessandro Orlando, A Stewart Levy, Benjamin A Rubin, Allen Tanner, Matthew M Carrick, Mark Lieser, David Hamilton, Charles W Mains, David Bar-Or
OBJECTIVE Isolated subdural hematomas (iSDHs) are one of the most common intracranial hemorrhage (ICH) types in the population with mild traumatic brain injury (mTBI; Glasgow Coma Scale score 13-15), account for 66%-75% of all neurosurgical procedures, and have one of the highest neurosurgical intervention rates. The objective of this study was to examine how quantitative hemorrhage characteristics of iSDHs in patients with mTBI at admission are associated with subsequent neurosurgical intervention. METHODS This was a 3...
June 15, 2018: Journal of Neurosurgery
https://www.readbyqxmd.com/read/29905462/the-human-biomolecular-corona-of-liposomal-doxorubicin-the-overlooked-factor-in-anticancer-drug-delivery
#10
Giulio Caracciolo, Sara Palchetti, Luca Digiacomo, Riccardo Zenezini Chiozzi, Anna Laura Capriotti, Heinz Amenitsch, Paolo Maria Tentori, Valentina Palmieri, Massimiliano Papi, Francesco Cardarelli, Daniela Pozzi, Aldo Laganà
More than twenty years after its approval by the Food and Drug Administration (FDA) liposomal doxorubicin (DOX) is still the drug of choice for the treatment of breast cancer and other conditions such as ovarian cancer and multiple myeloma. Yet, despite the efforts, liposomal DOX did not satisfy expectations at the clinical level. When liposomal drugs enter a physiological environment, their surface gets coated by a dynamic biomolecular corona (BC). The BC changes liposome's synthetic identity, providing it with a new one, referred to as 'biological identity' (size, aggregation state, and BC composition)...
June 15, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29904131/quantitative-study-of-abdominal-blood-flow-patterns-in-patients-with-aortic-dissection-by-4-dimensional-flow-mri
#11
Dongting Liu, Zhanming Fan, Yu Li, Nan Zhang, Zhonghua Sun, Jing An, Aurélien F Stalder, Andreas Greiser, Jiayi Liu
The purpose of this study is to evaluate the hemodynamic characteristics of the true lumen (TL) and the false lumen (FL) in 16 patients with aortic dissection (AD) using 4D flow magnetic resonance imaging (MRI) and thoracic and abdominal computed tomography (CT) angiography. The quantitative parameters that were measured in the TL and FL included velocity and flow. The mean area and regurgitant fraction of the TL were significantly lesser at all four levels (p < 0.05); the average through-plane velocity, peak velocity magnitude, average net flow, peak flow, and net forward volume in the TL were considerably higher (p < 0...
June 14, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29904055/quantitative-in-vivo-whole-genome-motility-screen-reveals-novel-therapeutic-targets-to-block-cancer-metastasis
#12
Konstantin Stoletov, Lian Willetts, Robert J Paproski, David J Bond, Srijan Raha, Juan Jovel, Benjamin Adam, Amy E Robertson, Francis Wong, Emma Woolner, Deborah L Sosnowski, Tarek A Bismar, Gane Ka-Shu Wong, Andries Zijlstra, John D Lewis
Metastasis is the most lethal aspect of cancer, yet current therapeutic strategies do not target its key rate-limiting steps. We have previously shown that the entry of cancer cells into the blood stream, or intravasation, is highly dependent upon in vivo cancer cell motility, making it an attractive therapeutic target. To systemically identify genes required for tumor cell motility in an in vivo tumor microenvironment, we established a novel quantitative in vivo screening platform based on intravital imaging of human cancer metastasis in ex ovo avian embryos...
June 14, 2018: Nature Communications
https://www.readbyqxmd.com/read/29903930/spatial-normalization-of-18-f-flutemetamol-pet-images-utilizing-an-adaptive-principal-components-template
#13
Johan Lilja, Antoine Leuzy, Konstantinos Chiotis, Irina Savitcheva, Jens Sörensen, Agneta Nordberg
Though currently approved for visual assessment only, there is evidence to suggest that quantification of amyloid-β (Aβ) PET images may reduce inter-reader variability and aid in the monitoring of treatment effects in clinical trials. Quantification typically involves a regional atlas in standard space, requiring PET images to be spatially normalized. Different uptake patterns in Aβ-positive and Aβ-negative subjects, however, makes spatial normalization challenging. In this study we propose a method to spatially normalize [18 F]flutemetamol images, using a synthetic template based on principal component images to overcome these challenges...
June 14, 2018: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/29903927/time-course-of-cerebral-perfusion-changes-in-children-with-migraine-with-aura-mimicking-stroke
#14
K M Cobb-Pitstick, N Munjal, R Safier, D D Cummings, G Zuccoli
Hemiplegic migraine is a common cause of acute brain attack in pediatrics. MR imaging sequences useful in differentiating hemiplegic migraine from other entities include arterial spin-labeling, SWI, MRA, and DWI. There has been limited exploration on the simultaneous use of these sequences in pediatrics. We present 12 pediatric patients with acute hemiplegic migraine or migraine with aura who underwent MR imaging within 12 hours of symptom onset. Quantitative and qualitative analyses were performed on arterial spin-labeling; and qualitative analysis, on SWI and MRA sequences...
June 14, 2018: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/29903498/betti-number-ratios-as-quantitative-indices-for-bone-morphometry-in-three-dimensions
#15
Takashi Teramoto, Takeshi Kamiya, Taira Sakurai, Fuminori Kanaya
BACKGROUND AND OBJECTIVE: Computational homology is an emerging mathematical tool for characterizing shapes of data. In this work, we present a methodology using computational homology for obtaining quantitative measurements of the connectivity in bone morphometry. We introduce the Betti number ratios as novel morphological descriptor for the classification of bone fine structures in three dimensions. METHODS: A total of 51 Japanese white rabbits were used to investigate the connectivity of bone trabeculae after the administration of alendronate in a tendon graft model in rabbits...
August 2018: Computer Methods and Programs in Biomedicine
https://www.readbyqxmd.com/read/29903484/image-quilting-and-wavelet-fusion-for-creation-of-synthetic-microscopy-nuclei-images
#16
Dimitris Glotsos, Spiros Kostopoulos, Panagiota Ravazoula, Dionisis Cavouras
BACKGROUND AND OBJECTIVE: In this study a texture simulation methodology is proposed for composing synthetic tissue microscopy images that could serve as a quantitative gold standard for the evaluation of the reliability, accuracy and performance of segmentation algorithms in computer-aided diagnosis. METHODS: A library of background and nuclei regions was generated using pre-segmented Haematoxylin and Eosin images of brain tumours. Background image samples were used as input to an image quilting algorithm that produced the synthetic background image...
August 2018: Computer Methods and Programs in Biomedicine
https://www.readbyqxmd.com/read/29903479/computer-aided-prediction-model-for-axillary-lymph-node-metastasis-in-breast-cancer-using-tumor-morphological-and-textural-features-on-ultrasound
#17
Woo Kyung Moon, I-Ling Chen, Ann Yi, Min Sun Bae, Sung Ui Shin, Ruey-Feng Chang
BACKGROUND AND OBJECTIVES: Axillary lymph node (ALN) status is a key indicator in assessing and determining the treatment strategy for patients with newly diagnosed breast cancer. Previous studies suggest that sonographic features of a primary tumor have the potential to predict ALN status in the preoperative staging of breast cancer. In this study, a computer-aided prediction (CAP) model as well as the tumor features for ALN metastasis in breast cancers were developed using breast ultrasound (US) images...
August 2018: Computer Methods and Programs in Biomedicine
https://www.readbyqxmd.com/read/29903059/size-controlled-biocompatible-silver-nanoplates-for-contrast-enhanced-intravital-photoacoustic-mapping-of-tumor-vasculature
#18
Xiaoyong Wang, Lan Zhang, Junqing Wang, Xuan Liu, Peng Lv, Jie Zeng, Gang Liu
Triangular Ag nanoplates with a thickness of 5 nm and tunable edge lengths were fabricated using a seed-mediated protocol, featuring enhanced near-infrared absorption as the edge length of nanoplates increased. The photoacoustic (PA) efficiency of these Ag nanoplates were assessed. Nanoplates with an edge length of 100 nm (r1) performed best among others in the in vitro assessment. In the following in vivo test, r1 nanoplates were also found to boost the PA signal of tumor vessels, while a detailed PA imaging of tumor vasculature was obtained...
August 1, 2018: Journal of Biomedical Nanotechnology
https://www.readbyqxmd.com/read/29902593/bone-matrix-development-in-steroid-induced-osteoporosis-is-associated-with-a-consistently-reduced-fibrillar-stiffness-linked-to-altered-bone-mineral-quality
#19
L Xi, P De Falco, E Barbieri, A Karunaratne, L Bentley, C T Esapa, N J Terrill, S D M Brown, R D Cox, G R Davis, N M Pugno, R V Thakker, H S Gupta
Glucocorticoid-induced osteoporosis (GIOP) is a major secondary form of osteoporosis, with the fracture risk significantly elevated - at similar levels of bone mineral density - in patients taking glucocorticoids compared with non-users. The adverse bone structural changes at multiple hierarchical levels in GIOP, and their mechanistic consequences leading to reduced load-bearing capacity, are not clearly understood. Here we combine experimental X-ray nanoscale mechanical imaging with analytical modelling of the bone matrix mechanics to determine mechanisms causing bone material quality deterioration during development of GIOP...
June 11, 2018: Acta Biomaterialia
https://www.readbyqxmd.com/read/29902566/background-field-removal-technique-based-on-non-regularized-variable-kernels-sophisticated-harmonic-artifact-reduction-for-phase-data-for-quantitative-susceptibility-mapping
#20
Hirohito Kan, Nobuyuki Arai, Masahiro Takizawa, Kazuyoshi Omori, Harumasa Kasai, Hiroshi Kunitomo, Yasujiro Hirose, Yuta Shibamoto
PURPOSE: We developed a non-regularized, variable kernel, sophisticated harmonic artifact reduction for phase data (NR-VSHARP) method to accurately estimate local tissue fields without regularization for quantitative susceptibility mapping (QSM). We then used a digital brain phantom to evaluate the accuracy of the NR-VSHARP method, and compared it with the VSHARP and iterative spherical mean value (iSMV) methods through in vivo human brain experiments. MATERIALS AND METHODS: Our proposed NR-VSHARP method, which uses variable spherical mean value (SMV) kernels, minimizes L2 norms only within the volume of interest to reduce phase errors and save cortical information without regularization...
June 11, 2018: Magnetic Resonance Imaging
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