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MR image segmentation

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https://www.readbyqxmd.com/read/28932900/-68ga-pentixafor-pet-mri-for-the-detection-of-chemokine-receptor-4-expression-in-atherosclerotic-plaques
#1
Xiang Li, Daniel Heber, Tatjana Leike, Dietrich Beitzke, Xia Lu, Xiaoli Zhang, Yongxiang Wei, Markus Mitterhauser, Wolfgang Wadsak, Saskia Kropf, Hans J Wester, Christian Loewe, Marcus Hacker, Alexander R Haug
PURPOSE: The expression of chemokine receptor type 4 (CXCR4) was found co-localized with macrophages on the atherosclerotic vessel wall and participated in the initial emigration of leukocytes. Gallium-68 [(68)Ga]Pentixafor has recently been introduced for the imaging of atherosclerosis by targeting CXCR4. We sought to evaluate human atherosclerotic lesions using [(68)Ga]Pentixafor PET/MRI. METHODS: Thirty-eight oncology patients underwent [(68)Ga]Pentixafor PET/MR imaging at baseline...
September 21, 2017: European Journal of Nuclear Medicine and Molecular Imaging
https://www.readbyqxmd.com/read/28927390/computer-aided-evaluation-of-inflammatory-changes-over-time-on-mri-of-the-spine-in-patients-with-suspected-axial-spondyloarthritis-a-feasibility-study
#2
Evgeni Aizenberg, Rosaline van den Berg, Zineb Ez-Zaitouni, Désirée van der Heijde, Monique Reijnierse, Oleh Dzyubachyk, Boudewijn P F Lelieveldt
BACKGROUND: Evaluating inflammatory changes over time on MR images of the spine in patients with suspected axial Spondyloarthritis (axSpA) can be a labor-intensive task, requiring readers to manually search for and perceptually align a set of vertebrae between two scans. The purpose of this study was to assess the feasibility of computer-aided (CA) evaluation of such inflammatory changes in a framework where scans from two time points are fused into a single color-encoded image integrated into an interactive scoring tool...
September 19, 2017: BMC Medical Imaging
https://www.readbyqxmd.com/read/28926610/image-similarity-evaluation-of-the-bulk-density-assigned-synthetic-ct-derived-from-mri-of-intracranial-regions-for-radiation-treatment
#3
Shin-Wook Kim, Hun-Joo Shin, Jin-Ho Hwang, Jin-Sol Shin, Sung-Kwang Park, Jin-Young Kim, Ki-Jun Kim, Chul-Seung Kay, Young-Nam Kang
OBJECTIVE: Various methods for radiation-dose calculation have been investigated over previous decades, focusing on the use of magnetic resonance imaging (MRI) only. The bulk-density-assignment method based on manual segmentation has exhibited promising results compared to dose-calculation with computed tomography (CT). However, this method cannot be easily implemented in clinical practice due to its time-consuming nature. Therefore, we investigated an automatic anatomy segmentation method with the intention of providing the proper methodology to evaluate synthetic CT images for a radiation-dose calculation based on MR images...
2017: PloS One
https://www.readbyqxmd.com/read/28926131/region-specific-impairment-of-the-cervical-spinal-cord-sc-in-amyotrophic-lateral-sclerosis-a-preliminary-study-using-sc-templates-and-quantitative-mri-diffusion-tensor-imaging-inhomogeneous-magnetization-transfer
#4
Henitsoa Rasoanandrianina, Aude-Marie Grapperon, Manuel Taso, Olivier M Girard, Guillaume Duhamel, Maxime Guye, Jean-Philippe Ranjeva, Shahram Attarian, Annie Verschueren, Virginie Callot
In this preliminary study, our objective was to investigate the potential of high-resolution anatomical imaging, diffusion tensor imaging (DTI) and conventional/inhomogeneous magnetization transfer imaging [magnetization transfer (MT)/inhomogeneous magnetization transfer (ihMT)] at 3 T, analyzed with template-extracted regions of interest, to measure the atrophy and structural changes of white (WM) and gray (GM) matter spinal cord (SC) occurring in patients with amyotrophic lateral sclerosis (ALS). Ten patients with ALS and 20 age-matched healthy controls were recruited...
September 19, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28925823/deep-learning-mr-imaging-based-attenuation-correction-for-pet-mr-imaging
#5
Fang Liu, Hyungseok Jang, Richard Kijowski, Tyler Bradshaw, Alan B McMillan
Purpose To develop and evaluate the feasibility of deep learning approaches for magnetic resonance (MR) imaging-based attenuation correction (AC) (termed deep MRAC) in brain positron emission tomography (PET)/MR imaging. Materials and Methods A PET/MR imaging AC pipeline was built by using a deep learning approach to generate pseudo computed tomographic (CT) scans from MR images. A deep convolutional auto-encoder network was trained to identify air, bone, and soft tissue in volumetric head MR images coregistered to CT data for training...
September 19, 2017: Radiology
https://www.readbyqxmd.com/read/28921669/respiratory-variation-in-left-ventricular-cardiac-function-with-3d-double-golden-angle-whole-heart-cine-imaging
#6
Karen Holst, Martin Ugander, Andreas Sigfridsson
PURPOSE: To develop a 3-dimensional free-breathing cardiovascular MR technique for quantifying the variation in left ventricular end-diastolic volume (LVEDV) during the respiratory cycle. METHODS: A 3-dimensional radial trajectory with double golden-angle ordering was used for free-running data acquisition during free breathing in healthy volunteers (N = 8). A respiratory self-gating signal was extracted from the center of k-space, and data were retrospectively binned into eight respiratory phases in end-diastole...
September 17, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28921541/automatic-labeling-of-mr-brain-images-through-extensible-learning-and-atlas-forests
#7
Lijun Xu, Hong Liu, Enmin Song, Meng Yan, Renchao Jin, Chih-Cheng Hung
PURPOSE: Multi-atlas-based method is extensively used in MR brain images segmentation because of its simplicity and robustness. This method provides excellent accuracy while time-consuming and limited in terms of obtaining information about new atlases. In this study, an automatic labeling of MR brain images through extensible learning and atlas forest is presented to address these limitations. METHODS: We propose an extensible learning model which allows the multi-atlas-based framework capable of managing the datasets with numerous atlases or dynamic atlas datasets and simultaneously ensure the accuracy of automatic labeling...
September 18, 2017: Medical Physics
https://www.readbyqxmd.com/read/28921170/comparison-of-novel-multi-level-otsu-mo-pet-and-conventional-pet-segmentation-methods-for-measuring-fdg-metabolic-tumor-volume-in-patients-with-soft-tissue-sarcoma
#8
Inki Lee, Hyung-Jun Im, Meiyappan Solaiyappan, Steve Y Cho
BACKGROUND: We have previously developed a novel and highly consistent PET segmentation algorithm using a multi-level Otsu method (MO-PET). The aim of this study was to evaluate the reliability of MO-PET compared to conventional PET segmentation methods for measuring (18)F-FDG (FDG) PET metabolic tumor volume (MTV) in patients with soft tissue sarcoma (STS). Clinical and imaging data were obtained from the Cancer Imaging Archive. Forty-eight STS patients with FDG PET/CT and MR prior to therapy were analyzed...
September 18, 2017: EJNMMI Physics
https://www.readbyqxmd.com/read/28918316/mr-guided-joint-reconstruction-of-activity-and-attenuation-in-brain-pet-mr
#9
Abolfazl Mehranian, Habib Zaidi, Andrew J Reader
With the advent of time-of-flight (TOF) PET scanners, joint maximum-likelihood reconstruction of activity and attenuation (MLAA) maps has recently regained attention for the estimation of PET attenuation maps from emission data. However, the estimated attenuation and activity maps are scaled by unknown scaling factors. We recently demonstrated that in hybrid PET-MR, the scaling issue of this algorithm can be effectively addressed by imposing MR spatial constraints on the estimation of attenuation maps using a penalized MLAA (P-MLAA(+)) algorithm...
September 13, 2017: NeuroImage
https://www.readbyqxmd.com/read/28915102/acceleration-selective-arterial-spin-labeling-mr-angiography-used-to-visualize-distal-cerebral-arteries-and-collateral-vessels-in-moyamoya-disease
#10
Osamu Togao, Akio Hiwatashi, Makoto Obara, Koji Yamashita, Kazufumi Kikuchi, Ryotaro Kamei, Ataru Nishimura, Koichi Arimura, Koji Yoshimoto, Koji Iihara, Marc Van Cauteren, Hiroshi Honda
Purpose To evaluate and compare the performance of acceleration-selective arterial spin labeling (AccASL) magnetic resonance (MR) angiography in the visualization of cerebral arteries and collateral vessels in patients with Moyamoya disease with that of time-of-flight (TOF) MR angiography, with digital subtraction angiography (DSA) as the reference standard. Materials and Methods Thirty-six cerebral hemispheres from 22 patients with Moyamoya disease underwent TOF and AccASL MR angiography and DSA. Qualitative evaluations included imaging of the terminal internal carotid artery (ICA), distal middle cerebral arteries (MCAs), Moyamoya vessels, and leptomeningeal anastomosis (LMA) collaterals with reference to DSA...
September 15, 2017: Radiology
https://www.readbyqxmd.com/read/28893296/diagnostic-performance-of-image-navigated-coronary-cmr-angiography-in-patients-with-coronary-artery-disease
#11
Markus Henningsson, Joy Shome, Konstantinos Bratis, Miguel Silva Vieira, Eike Nagel, Rene M Botnar
BACKGROUND: The use of coronary MR angiography (CMRA) in patients with coronary artery disease (CAD) remains limited due to the long scan times, unpredictable and often non-diagnostic image quality secondary to respiratory motion artifacts. The purpose of this study was to evaluate CMRA with image-based respiratory navigation (iNAV CMRA) and compare it to gold standard invasive x-ray coronary angiography in patients with CAD. METHODS: Consecutive patients referred for CMR assessment were included to undergo iNAV CMRA on a 1...
September 11, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/28892997/quantification-of-liver-fat-with-mdixon-magnetic-resonance-imaging-comparison-with-the-computed-tomography-and-the-biopsy
#12
Venkatraman Bhat, Sundararaman Velandai, Vikram Belliappa, Jeyeram Illayraja, Karthik Gadabana Halli, Gayathri Gopalakrishnan
INTRODUCTION: Accurate, non-invasive method of fat estimation is a valuable test for evaluation of diseases with abnormal hepatic fat. AIM: To determine the accuracy of mDixon MR technique in assessment of liver fat over CT and to correlate the CT and MRI findings with biopsy. MATERIALS AND METHODS: A prospective observational study was conducted at Imaging Services of Narayana Multispeciality Hospital between March 2011- December 2012. Thirty patients who attended the clinic for non-hepatic complaints were included in the study...
July 2017: Journal of Clinical and Diagnostic Research: JCDR
https://www.readbyqxmd.com/read/28887825/performance-of-a-multi-leaf-collimator-system-for-mr-guided-radiation-therapy
#13
Bin Cai, Harold Li, Deshan Yang, Vivian Rodriguez, Austen Curcuru, Yuhe Wang, Jie Wen, Rojano Kashani, Sasa Mutic, Olga Green
PURPOSE: To investigate and characterize the performance of a Multi Leaf Collimator (MLC) designed for Cobalt-60 based MR-guided radiation therapy system in a 0.35T magnetic field. METHODS: The MLC design and unique assembly features in the ViewRay MRIdian system were first reviewed. The RF cage shielding of MLC motor and cables were evaluated using ACR phantoms with real time imaging and quantified by signal-to-noise ratio. The dosimetric characterizations, including the leaf transmission, leaf penumbra, tongue and groove effect, were investigated using radiosensitive films...
September 9, 2017: Medical Physics
https://www.readbyqxmd.com/read/28887274/the-qualitative-grading-of-muscle-fat-infiltration-in-whiplash-using-fat-water-magnetic-resonance-imaging
#14
Rebecca Abbott, Anneli Peolsson, Janne West, James M Elliott, Ulrika Åslund, Anette Karlsson, Olof Dahlqvist Leinhard
BACKGROUND CONTEXT: Development of muscle fat infiltration (MFI) in the neck muscles is associated with poor functional recovery following whiplash injury. Custom software and time-consuming manual segmentation of magnetic resonance (MR) images is required for quantitative analysis and presents as a barrier for clinical translation. PURPOSE: The purpose of this work was to establish a qualitative MR measure for MFI and evaluate its ability to differentiate between individuals with severe whiplash-associated disorder (WAD), mild/moderate WAD, and healthy controls...
September 5, 2017: Spine Journal: Official Journal of the North American Spine Society
https://www.readbyqxmd.com/read/28887206/reproducibility-and-relative-stability-in-magnetic-resonance-imaging-indices-of-tumor-vascular-physiology-over-a-period-of-24h-in-a-rat-9l-gliosarcoma-model
#15
Tavarekere N Nagaraja, Rasha Elmghirbi, Stephen L Brown, Lonni R Schultz, Ian Y Lee, Kelly A Keenan, Swayamprava Panda, Glauber Cabral, Tom Mikkelsen, James R Ewing
PURPOSE: The objective was to study temporal changes in tumor vascular physiological indices in a period of 24h in a 9L gliosarcoma rat model. METHODS: Fischer-344 rats (N=14) were orthotopically implanted with 9L cells. At 2weeks post-implantation, they were imaged twice in a 24h interval using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI). Data-driven model-selection-based analysis was used to segment tumor regions with varying vascular permeability characteristics...
September 5, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28886885/segmentation-of-the-right-ventricle-in-four-chamber-cine-cardiac-mr-images-using-polar-dynamic-programming
#16
Jose A Rosado-Toro, Aiden Abidov, Maria I Altbach, Isabel B Oliva, Jeffrey J Rodriguez, Ryan J Avery
The four chamber plane is currently underutilized in the right ventricular segmentation community. Four chamber information can be useful to determine ventricular short axis stacks and provide a rough estimate of the right ventricle in short axis stacks. In this study, we develop and test a semi-automated technique for segmenting the right ventricle in four chamber cine cardiac magnetic resonance images. The three techniques that use minimum cost path algorithms were used. The algorithms are: Dijkstra's shortest path algorithm (Dijkstra), an A* algorithm that uses length, curvature and torsion into an active contour model (ALCT), and a variation of polar dynamic programming (PDP)...
August 18, 2017: Computerized Medical Imaging and Graphics: the Official Journal of the Computerized Medical Imaging Society
https://www.readbyqxmd.com/read/28882862/detection-of-volume-changing-metastatic-brain-tumors-on-longitudinal-mri-using-a-semiautomated-algorithm-based-on-the-jacobian-operator-field
#17
O Shearkhani, A Khademi, A Eilaghi, S-P Hojjat, S P Symons, C Heyn, M Machnowska, A Chan, A Sahgal, P J Maralani
BACKGROUND AND PURPOSE: Accurate follow-up of metastatic brain tumors has important implications for patient prognosis and management. The aim of this study was to develop and evaluate the accuracy of a semiautomated algorithm in detecting growing or shrinking metastatic brain tumors on longitudinal brain MRIs. MATERIALS AND METHODS: We used 50 pairs of successive MR imaging datasets, 30 on 1.5T and 20 on 3T, containing contrast-enhanced 3D T1-weighted sequences...
September 7, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28863308/clickable-and-imageable-multiblock-polymer-micelles-with-magnetically-guided-and-peg-switched-targeting-and-release-property-for-precise-tumor-theranosis
#18
Jing Wei, Xiaoyu Shuai, Rui Wang, Xueling He, Yiwen Li, Mingming Ding, Jiehua Li, Hong Tan, Qiang Fu
Targeted delivery of therapeutics and diagnostics using nanotechnology holds great promise to minimize the side effects of conventional chemotherapy and enable specific and real-time detection of diseases. To realize this goal, we report a clickable and imageable nanovehicle assembled from multiblock polyurethanes (MPUs). The soft segments of the polymers are based on detachable poly(ethylene glycol) (PEG) and degradable poly(ε-caprolactone) (PCL), and the hard segments are constructed from lysine- and cystine-derivatives bearing reduction-responsive disulfide linkages and click-active alkynyl moieties, allowing for post-conjugation of targeting ligands via a click chemistry...
August 18, 2017: Biomaterials
https://www.readbyqxmd.com/read/28859858/obesity-and-spinal-loads-a-combined-mr-imaging-and-subject-specific-modeling-investigation
#19
M H Akhavanfar, H Kazemi, A H Eskandari, N Arjmand
Epidemiological studies have identified obesity asa possible risk factor for low back disorders. Biomechanical models can help test such hypothesis and shed light on the mechanism involved. A novel subject-specific musculoskeletal-modelling approach is introduced to estimate spinal loads during static activities in five healthy obese (BMI>30kg/m(2)) and five normal-weight (20<BMI<25kg/m(2)) individuals. Subjects underwent T1 through S1 MR imaging thereby measuring cross-sectional-area (CSA) and moment arms of trunk muscles together with mass and center of mass (CoM) of T1-L5 segments...
August 20, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28855717/mri-and-additive-manufacturing-of-nasal-alar-constructs-for-patient-specific-reconstruction
#20
Dafydd O Visscher, Maureen van Eijnatten, Niels P T J Liberton, Jan Wolff, Mark B M Hofman, Marco N Helder, J Peter W Don Griot, Paul P M van Zuijlen
Surgical reconstruction of cartilaginous defects remains a major challenge. In the current study, we aimed to identify an imaging strategy for the development of patient-specific constructs that aid in the reconstruction of nasal deformities. Magnetic Resonance Imaging (MRI) was performed on a human cadaver head to find the optimal MRI sequence for nasal cartilage. This sequence was subsequently used on a volunteer. Images of both were assessed by three independent researchers to determine measurement error and total segmentation time...
August 30, 2017: Scientific Reports
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