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Segmented MRI

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https://www.readbyqxmd.com/read/28550649/improved-formula-see-text-determination-in-23-na-35-cl-and-17-o-mri-using-iterative-partial-volume-correction-based-on-1-h-mri-segmentation
#1
Sebastian C Niesporek, Reiner Umathum, Thomas M Fiedler, Peter Bachert, Mark E Ladd, Armin M Nagel
OBJECTIVE: Functional parameters can be measured with the help of quantitative non-proton MRI where exact relaxometry parameters are needed. Investigation of [Formula: see text] is often biased by strong partial volume (PV) effects. Hence, in this work a PV correction algorithm approach was evaluated that uses iteratively adapted [Formula: see text]-values and high-resolution structural (1)H data to determine transverse relaxation in non-proton MRI more accurately. MATERIALS AND METHODS: Simulations, a phantom study and in vivo (23)Na, (17)O and (35)Cl MRI measurements of five healthy volunteers were performed to evaluate the algorithm...
May 26, 2017: Magma
https://www.readbyqxmd.com/read/28549883/a-non-iterative-multi-scale-approach-for-intensity-inhomogeneity-correction-in-mri
#2
Maryjo M George, S Kalaivani, M S Sudhakar
Intensity inhomogeneity is the prime obstacle for MR image processing like automatic segmentation, registration etc. This complication has strong dependence on the associated acquisition hardware and patient anatomy which recommends retrospective correction. In this paper, a new method is developed for correcting the intensity inhomogeneity using a non-iterative multi-scale approach that doesn't necessitate segmentation and any prior knowledge on the scanner or subject. The proposed algorithm extracts bias field at different scales using a Log-Gabor filter bank followed by smoothing operation...
May 23, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28549310/segmentation-of-lumen-and-outer-wall-of-abdominal-aortic-aneurysms-from-3d-black-blood-mri-with-a-registration-based-geodesic-active-contour-model
#3
Yan Wang, Florent Seguro, Evan Kao, Yue Zhang, Farshid Faraji, Chengcheng Zhu, Henrik Haraldsson, Michael Hope, David Saloner, Jing Liu
Segmentation of the geometric morphology of abdominal aortic aneurysm is important for interventional planning. However, the segmentation of both the lumen and the outer wall of aneurysm in magnetic resonance (MR) image remains challenging. This study proposes a registration based segmentation methodology for efficiently segmenting MR images of abdominal aortic aneurysms. The proposed methodology first registers the contrast enhanced MR angiography (CE-MRA) and black-blood MR images, and then uses the Hough transform and geometric active contours to extract the vessel lumen by delineating the inner vessel wall directly from the CE-MRA...
May 19, 2017: Medical Image Analysis
https://www.readbyqxmd.com/read/28548605/changes-to-the-septo-fornical-area-might-play-a-role-in-the-pathogenesis-of-anxiety-in-multiple-sclerosis
#4
Miklos Palotai, Andrea Mike, Michele Cavallari, Erzsebet Strammer, Gergely Orsi, Brian C Healy, Katharina Schregel, Zsolt Illes, Charles Rg Guttmann
BACKGROUND: Reports on the relationships between white matter lesion load (WMLL) and fatigue and anxiety in multiple sclerosis (MS) are inconsistent. OBJECTIVE: To investigate the association of total and tract-specific WMLL with fatigue and anxiety. METHODS: Total and regional T2 WMLL was assessed for 19 tracts in 48 MS patients (30 females). ICBM-DTI-81 Atlas-based parcellation was combined with WMLL segmentation of T2-weighted magnetic resonance imaging (MRI)...
May 1, 2017: Multiple Sclerosis: Clinical and Laboratory Research
https://www.readbyqxmd.com/read/28544575/analysis-of-physical-characteristics-of-tumor-treating-fields-for-human-glioblastoma
#5
Edwin Lok, Pyay San, Van Hua, Melissa Phung, Eric T Wong
Tumor Treating Fields (TTFields) therapy is an approved treatment that has known clinical efficacy against recurrent and newly diagnosed glioblastoma. However, the distribution of the electric fields and the corresponding pattern of energy deposition in the brain are poorly understood. To evaluate the physical parameters that may influence TTFields, postacquisition MP-RAGE, T1 and T2 MRI sequences from a responder with a right parietal glioblastoma were anatomically segmented and then solved using finite-element method to determine the distribution of the electric fields and rate of energy deposition at the gross tumor volume (GTV) and other intracranial structures...
May 23, 2017: Cancer Medicine
https://www.readbyqxmd.com/read/28543915/cross-sectional-correlation-between-hepatic-r2-and-proton-density-fat-fraction-pdff-in-children-with-hepatic-steatosis
#6
Adrija Mamidipalli, Gavin Hamilton, Paul Manning, Cheng William Hong, Charlie C Park, Tanya Wolfson, Jonathan Hooker, Elhamy Heba, Alexandra Schlein, Anthony Gamst, Janis Durelle, Melissa Paiz, Michael S Middleton, Jeffrey B Schwimmer, Claude B Sirlin
PURPOSE: To determine the relationship between hepatic proton density fat fraction (PDFF) and R2* in vivo. MATERIALS AND METHODS: In this Health Insurance Portability and Accountability Act (HIPAA)-compliant, Institutional Review Board (IRB)-approved, cross-sectional study, we conducted a secondary analysis of 3T magnetic resonance imaging (MRI) exams performed as part of prospective research studies in children in whom conditions associated with iron overload were excluded clinically...
May 25, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28543069/real-time-dynamic-mr-image-reconstruction-using-compressed-sensing-and-principal-component-analysis-cs-pca-demonstration-in-lung-tumor-tracking
#7
Bryson Dietz, Eugene Yip, Jihyun Yun, B Gino Fallone, Keith Wachowicz
PURPOSE: This work presents a real-time dynamic image reconstruction technique, that combines compressed sensing and principal component analysis (CS-PCA), to achieve real-time adaptive radiotherapy with the use of a linac-magnetic resonance imaging system. METHODS: Six retrospective fully sampled dynamic data sets of patients diagnosed with non-small cell lung cancer were used to investigate the CS-PCA algorithm. Using a database of fully sampled k-space, principal components (PC's) were calculated to aid in the reconstruction of undersampled images...
May 19, 2017: Medical Physics
https://www.readbyqxmd.com/read/28536087/workflow-sensitivity-of-post-processing-methods-in-renal-dce-mri
#8
Erik Hanson, Eli Eikefjord, Jarle Rørvik, Erling Andersen, Arvid Lundervold, Erlend Hodneland
OBJECTIVE: Estimation of renal filtration using dynamic contrast-enhanced imaging (DCE-MRI) requires a series of analysis steps. The possible number of distinct post-processing chains is large and grows rapidly with increasing number of processing steps or options. In this study we introduce a framework for systematic evaluation of the post-processing chains. The framework is later used to highlight the workflow processing chain sensitivity towards accuracy in estimation of glomerular filtration rate (GFR)...
May 20, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28536045/toward-defining-deep-brain-stimulation-targets-in-mni-space-a-subcortical-atlas-based-on-multimodal-mri-histology-and-structural-connectivity
#9
REVIEW
Siobhan Ewert, Philip Plettig, Ningfei Li, Mallar Chakravarty, Louis Collins, Todd Herrington, Andrea Kühn, Andreas Horn
Three-dimensional atlases of subcortical brain structures are valuable tools to reference anatomy in neuroscience and neurology. For instance, they can be used to study the position and shape of the three most common deep brain stimulation (DBS) targets, the subthalamic nucleus (STN), internal part of the pallidum (GPi) and ventral intermediate nucleus of the thalamus (VIM) in stereotactic space and in spatial relationship to DBS electrodes. Here, we present a composite atlas that is based on manual segmentations of a multimodal high resolution brain template, histology and structural connectivity...
May 20, 2017: NeuroImage
https://www.readbyqxmd.com/read/28535911/validation-of-a-free-software-for-unsupervised-assessment-of-abdominal-fat-in-mri
#10
Michele Maddalo, Ivan Zorza, Stefano Zubani, Giorgio Nocivelli, Giulio Calandra, Pierantonio Soldini, Lorella Mascaro, Roberto Maroldi
PURPOSE: To demonstrate the accuracy of an unsupervised (fully automated) software for fat segmentation in magnetic resonance imaging. The proposed software is a freeware solution developed in ImageJ that enables the quantification of metabolically different adipose tissues in large cohort studies. METHODS: The lumbar part of the abdomen (19cm in craniocaudal direction, centered in L3) of eleven healthy volunteers (age range: 21-46years, BMI range: 21.7-31.6kg/m(2)) was examined in a breath hold on expiration with a GE T1 Dixon sequence...
May 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28534798/alzheimer-s-disease-diagnosis-using-landmark-based-features-from-longitudinal-structural-mr-images
#11
Jun Zhang, Mingxia Liu, Le An, Yaozong Gao, Dinggang Shen
Structural magnetic resonance imaging (MRI) has been proven to be an effective tool for Alzheimer's disease (AD) diagnosis. While conventional MRI-based AD diagnosis typically uses images acquired at a single time point, a longitudinal study is more sensitive in detecting early pathological changes of AD, making it more favorable for accurate diagnosis. In general, there are two challenges faced in MRI-based diagnosis. First, extracting features from structural MR images requires timeconsuming nonlinear registration and tissue segmentation, whereas the longitudinal study with involvement of more scans further exacerbates the computational costs...
May 16, 2017: IEEE Journal of Biomedical and Health Informatics
https://www.readbyqxmd.com/read/28533943/etiology-and-treatment-of-amyotrophic-lateral-sclerosis
#12
Hernando Rafael, Juan Oscar David, Antonio Santiago Vilca
BACKGROUND: To date all researchers conclude that the etiology of Amyotrophic lateral sclerosis (ALS) is not known. On the contrary, since August 2009, we believe that disease is of ischemic origin in the anterior surface of the medulla oblongata. MATERIAL AND METHOD: We present our surgical experience into 45 patients with ALS (bulbar form in 36 cases and spinal form in 9). Preoperative MRI scans revealed microinfarcts in the medulla oblongata and/or cervical cord...
2017: American Journal of Neurodegenerative Disease
https://www.readbyqxmd.com/read/28532907/nerve-atrophy-and-a-small-trigeminal-pontine-angle-in-primary-trigeminal-neuralgia-a-morphometric-mri-study
#13
Jian Cheng, Jinli Meng, Wenke Liu, Heng Zhang, Ding Lei, Xuhui Hui
OBJECTIVE: To prospectively evaluate the morphological and structural changes of trigeminal nerve in patients with trigeminal neuralgia (TN) and to perform a comparison with healthy controls. METHODS: We conducted a prospective case-control study of 60 consective patients diagnosed with TN and 30 sex-and age-matched healthy controls. All subjects underwent high-resolution three-dimensional MRI. The volume and length of the cisternal segment of trigeminal nerve and the angle between the trigeminal nerve and the anterior surface of the pons (trigeminal pontine angle) were measured and compared...
May 19, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28532491/evaluation-of-an-automated-thresholding-algorithm-for-the-quantification-of-paraspinal-muscle-composition-from-mri-images
#14
Maryse Fortin, Mona Omidyeganeh, Michele Crites Battié, Omair Ahmad, Hassan Rivaz
BACKGROUND: The imaging assessment of paraspinal muscle morphology and fatty infiltration has gained considerable attention in the past decades, with reports suggesting an association between muscle degenerative changes and low back pain (LBP). To date, qualitative and quantitative approaches have been used to assess paraspinal muscle composition. Though highly reliable, manual thresholding techniques are time consuming and not always feasible in a clinical setting. The tedious and rater-dependent nature of such manual thresholding techniques provides the impetus for the development of automated or semi-automated segmentation methods...
May 22, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28530218/visualization-of-penile-suspensory-ligamentous-system-based-on-visible-human-data-sets
#15
Xianzhuo Chen, Yi Wu, Ling Tao, Yan Yan, Jun Pang, Shaoxiang Zhang, Shirong Li
BACKGROUND The aim of this study was to use a three-dimensional (3D) visualization technology to illustrate and describe the anatomical features of the penile suspensory ligamentous system based on the Visible Human data sets and to explore the suspensory mechanism of the penis for the further improvement of the penis-lengthening surgery. MATERIAL AND METHODS Cross-sectional images retrieved from the first Chinese Visible Human (CVH-1), third Chinese Visible Human (CVH-3), and Visible Human Male (VHM) data sets were used to segment the suspensory ligamentous system and its adjacent structures...
May 22, 2017: Medical Science Monitor: International Medical Journal of Experimental and Clinical Research
https://www.readbyqxmd.com/read/28530209/reproducible-3d-printed-head-tanks-for-electrical-impedance-tomography-with-realistic-shape-and-conductivity-distribution
#16
James Avery, Kirill Aristovich, Barney Low, David Holder
OBJECTIVE: Electrical impedance tomography (EIT) has many promising applications in brain injury monitoring. To evaluate both instrumentation and reconstruction algorithms, experiments are first performed in head tanks. Existing methods, whilst accurate, produce a discontinuous conductivity, and are often made by hand, making it hard for other researchers to replicate. APPROACH: We have developed a method for constructing head tanks directly in a 3D printer. Conductivity was controlled through perforations in the skull surface, which allow for saline to pass through...
May 22, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28529876/pathology-of-callosal-damage-in-als-an-ex-vivo-7%C3%A2-t-diffusion-tensor-mri-study
#17
Agustin M Cardenas, Joelle E Sarlls, Justin Y Kwan, Devin Bageac, Zachary S Gala, Laura E Danielian, Abhik Ray-Chaudhury, Hao-Wei Wang, Karla L Miller, Sean Foxley, Saad Jbabdi, Robert C Welsh, Mary Kay Floeter
OBJECTIVES: The goal of this study was to better understand the changes in tissue microstructure that underlie white matter diffusion changes in ALS patients. METHODS: Diffusion tensor imaging was carried out in postmortem brains of 4 ALS patients and two subjects without neurological disease on a 7 T MRI scanner using steady-state free precession sequences. Fractional anisotropy (FA) was measured in the genu, body, and splenium of the corpus callosum in formalin-fixed hemispheres...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28528897/lateral-lumbar-interbody-fusion-at-the-lumbosacral-junction
#18
Timothy L T Siu, Kainu Lin
Due to the obstruction of the iliac crest and the retroperitoneal vessels, lateral lumbar interbody fusion (LLIF) is generally considered contraindicated at the lumbosacral junction (LSJ). In particular the 'rise' of the psoas from the vertebral column in the lower lumbar segments has been associated with significant overlap of the lumbar plexus with the vertebral body and exclusion of a safe transpsoas entry. However in selected individuals anatomical variations may help circumvent the difficulties and the anatomical corridor posterior to the lumbar plexus may provide an alternative to the conventional anterior approach...
May 18, 2017: Journal of Clinical Neuroscience: Official Journal of the Neurosurgical Society of Australasia
https://www.readbyqxmd.com/read/28528429/myocardial-edema-in-acute-myocarditis-relationship-of-t2-relaxometry-and-late-enhancement-burden-by-using-dual-contrast-turbo-spin-echo-mri
#19
A Mayr, G Klug, H J Feistritzer, S J Reinstadler, M Reindl, R Esterhammer, G Feuchtner, B Metzler, M F Schocke
To quantify myocardial edema by using a T2 relaxometry approach with a dual-contrast turbo spin-echo (dcTSE) sequence in patients with acute myocarditis regarding focal late gadolinium enhancement (LGE) burden. CMR T2 relaxometry was performed in 39 patients (age 41 ± 19 years; 36% women) with LGE in a typical myocarditis pattern and in ten healthy volunteers (age 46 ± 12; 60% woman). dcTSE sequence (echo time 29 and 75 ms, respectively) was used for T2 mapping, analysis were performed on the basis of region of interest (ROI)...
May 20, 2017: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/28527317/fully-automatic-segmentation-of-left-ventricular-anatomy-in-3-d-lge-mri
#20
Tanja Kurzendorfer, Christoph Forman, Michaela Schmidt, Christoph Tillmanns, Andreas Maier, Alexander Brost
The current challenge for electrophysiology procedures, targeting the left ventricle, is the localization and qualification of myocardial scar. Late gadolinium enhanced magnetic resonance imaging (LGE-MRI) is the current gold standard to visualize regions of myocardial infarction. Commonly, a stack of 2-D images is acquired of the left ventricle in short-axis orientation. Recently, 3-D LGE-MRI methods were proposed that continuously cover the whole heart with a high resolution within a single acquisition. The acquisition promises an accurate quantification of the myocardium to the extent of myocardial scarring...
May 8, 2017: Computerized Medical Imaging and Graphics: the Official Journal of the Computerized Medical Imaging Society
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