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Functional MR

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https://www.readbyqxmd.com/read/27913820/cerebral-blood-flow-transit-time-and-apparent-diffusion-coefficient-in-moyamoya-disease-before-and-after-acetazolamide
#1
Christian Federau, Soren Christensen, Zungho Zun, Sun-Won Park, Wendy Ni, Michael Moseley, Greg Zaharchuk
INTRODUCTION: The goal of this study was to assess the changes in arterial spin labeling (ASL) cerebral blood flow (CBF) and arterial transit time (ATT), and in apparent diffusion coefficient (ADC), before and after an acetazolamide challenge in moyamoya patients, as function of arterial stenosis severity. METHODS: Pre-operative patients diagnosed with moyamoya disease who could undergo MRI at 3.0T were recruited for this study. A multi-delay pseudo-continuous ASL and a diffusion-weighted sequence were acquired before and 15 min after acetazolamide injection...
December 2, 2016: Neuroradiology
https://www.readbyqxmd.com/read/27913428/migration-pathways-of-thalamic-neurons-and-development-of-thalamocortical-connections-in-humans-revealed-by-diffusion-mr-tractography
#2
Molly Wilkinson, Tara Kane, Rongpin Wang, Emi Takahashi
The thalamus plays an important role in signal relays in the brain, with thalamocortical (TC) neuronal pathways linked to various sensory/cognitive functions. In this study, we aimed to see fetal and postnatal development of the thalamus including neuronal migration to the thalamus and the emergence/maturation of the TC pathways. Pathways from/to the thalami of human postmortem fetuses and in vivo subjects ranging from newborns to adults with no neurological histories were studied using high angular resolution diffusion MR imaging (HARDI) tractography...
December 2, 2016: Cerebral Cortex
https://www.readbyqxmd.com/read/27910866/biomechanical-analysis-of-normal-brain-development-during-the-first-year-of-life-using-finite-strain-theory
#3
Jeong Chul Kim, Li Wang, Dinggang Shen, Weili Lin
The first year of life is the most critical time period for structural and functional development of the human brain. Combining longitudinal MR imaging and finite strain theory, this study aimed to provide new insights into normal brain development through a biomechanical framework. Thirty-three normal infants were longitudinally imaged using MRI from 2 weeks to 1 year of age. Voxel-wise Jacobian determinant was estimated to elucidate volumetric changes while Lagrange strains (both normal and shear strains) were measured to reveal directional growth information every 3 months during the first year of life...
December 2, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27908187/dosimetric-characterization-of-mri-only-treatment-planning-for-brain-tumors-in-atlas-based-pseudo-ct-images-generated-from-standard-t1-weighted-mr-images
#4
Benjamin Demol, Christine Boydev, Juha Korhonen, Nick Reynaert
PURPOSE: Magnetic resonance imaging (MRI)-only radiotherapy treatment planning requires accurate pseudo-CT (pCT) images for precise dose calculation. The current work introduced an atlas-based method combined with MR intensity information. pCT analyses and Monte Carlo dose calculations for intracranial stereotactic treatments were performed. METHODS: Twenty-two patients, representing 35 tumor targets, were scanned using a 3D T1-weighted MRI sequence according to the clinical protocol...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27908177/automatic-segmentation-of-right-ventricle-in-cardiac-cine-mr-images-using-a-saliency-analysis
#5
Angélica Atehortúa, Maria A Zuluaga, Juan D García, Eduardo Romero
PURPOSE: Accurate measurement of the right ventricle (RV) volume is important for the assessment of the ventricular function and a biomarker of the progression of any cardiovascular disease. However, the high RV variability makes difficult a proper delineation of the myocardium wall. This paper introduces a new automatic method for segmenting the RV volume from short axis cardiac magnetic resonance (MR) images by a salient analysis of temporal and spatial observations. METHODS: The RV volume estimation starts by localizing the heart as the region with the most coherent motion during the cardiac cycle...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27908173/pacemaker-and-icd-oversensing-induced-by-movements-near-the-mri-scanner-bore
#6
E Mattei, F Censi, G Calcagnini, R Falsaperla, E Genovese, A Napolitano, V Cannatà
PURPOSE: The effect of the movement near the MRI scanner bore for people with a pacemaker (PM) or an implantable cardioverter defibrillator (ICD) is experimentally evaluated and discussed. METHODS: The authors performed in vitro measurements on a saline-filled human-shaped phantom (male, 170 cm height), equipped first with an MR-conditional PM (bicameral configuration, DDD programming), then with an MR-conditional ICD (biventricular configuration, detection algorithms enable but shock delivery disable)...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27907007/exploring-regulatory-mechanisms-of-atrial-myocyte-hypertrophy-of-mitral-regurgitation-through-gene-expression-profiling-analysis-role-of-nfat-in-cardiac-hypertrophy
#7
Tzu-Hao Chang, Mien-Cheng Chen, Jen-Ping Chang, Hsien-Da Huang, Wan-Chun Ho, Yu-Sheng Lin, Kuo-Li Pan, Yao-Kuang Huang, Wen-Hao Liu, Chia-Chen Wu
BACKGROUND: Left atrial enlargement in mitral regurgitation (MR) predicts a poor prognosis. The regulatory mechanisms of atrial myocyte hypertrophy of MR patients remain unknown. METHODS AND RESULTS: This study comprised 14 patients with MR, 7 patients with aortic valve disease (AVD), and 6 purchased samples from normal subjects (NC). We used microarrays, enrichment analysis and quantitative RT-PCR to study the gene expression profiles in the left atria. Microarray results showed that 112 genes were differentially up-regulated and 132 genes were differentially down-regulated in the left atria between MR patients and NC...
2016: PloS One
https://www.readbyqxmd.com/read/27905543/rapid-functional-cardiac-imaging-after-gadolinium-injection-evaluation-of-a-highly-accelerated-sequence-with-sparse-data-sampling-and-iterative-reconstruction
#8
Johannes Budjan, Holger Haubenreisser, Thomas Henzler, Sonja Sudarski, Michaela Schmidt, Christina Doesch, Ibrahim Akin, Martin Borggrefe, Nadja M Meßner, Stefan O Schoenberg, Ulrike I Attenberger, Theano Papavassiliu
To generate a patient-friendly, time-efficient cardiac MRI examination protocol, a highly accelerated real-time CINE MR sequence (SSIR) was acquired in the idle time in between contrast injection and late gadolinium enhancement phase. 20 consecutive patients underwent a cardiac MRI examination including a multi-breath-hold sequence as gold standard (Ref) as well as SSIR sequences with (SSIR-BH) and without breath-hold (SSIR-nonBH). SSIR sequences were acquired 4 minutes after gadolinium injection. Right- (RV) and left-ventricular (LV) volumetric functional parameters were evaluated and compared between Ref and SSIR sequences...
December 1, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27902751/exploration-of-a-polygenic-risk-score-for-alcohol-consumption-a-longitudinal-analysis-from-the-alspac-cohort
#9
Michelle Taylor, Andrew J Simpkin, Philip C Haycock, Frank Dudbridge, Luisa Zuccolo
BACKGROUND: Uncertainty remains about the true extent by which alcohol consumption causes a number of health outcomes. Genetic variants, or combinations of variants built into a polygenic risk score (PGRS), can be used in an instrumental variable framework to assess causality between a phenotype and disease outcome of interest, a method known as Mendelian randomisation (MR). We aimed to identify genetic variants involved in the aetiology of alcohol consumption, and develop a PGRS for alcohol...
2016: PloS One
https://www.readbyqxmd.com/read/27899435/imaging-oxygen-metabolism-with-hyperpolarized-magnetic-resonance-a-novel-approach-for-cardiac-and-renal-function%C3%A2-assessement
#10
Marie Schroeder, Christoffer Lausten
Every tissue in the body critically depends on meeting its energetic demands with sufficient oxygen supply. Oxygen supply/demand imbalances underlie the diseases that inflict the greatest socioeconomic burden globally. The purpose of this review is to examine how hyperpolarized contrast media, used in combination with MR data acquisition methods, may advance our ability to assess oxygen metabolism non-invasively and thus improve management of clinical disease. We first introduce the concept of hyperpolarization and how hyperpolarized contrast media have been practically implemented to achieve translational and clinical research...
November 29, 2016: Bioscience Reports
https://www.readbyqxmd.com/read/27899332/artificial-neural-network-for-suppression-of-banding-artifacts-in-balanced-steady-state-free-precession-mri
#11
Ki Hwan Kim, Sung-Hong Park
The balanced steady-state free precession (bSSFP) MR sequence is frequently used in clinics, but is sensitive to off-resonance effects, which can cause banding artifacts. Often multiple bSSFP datasets are acquired at different phase cycling (PC) angles and then combined in a special way for banding artifact suppression. Many strategies of combining the datasets have been suggested for banding artifact suppression, but there are still limitations in their performance, especially when the number of phase-cycled bSSFP datasets is small...
November 26, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27897263/principal-function-of-mineralocorticoid-signaling-suggested-by-constitutive-knockout-of-the-mineralocorticoid-receptor-in-medaka-fish
#12
Tatsuya Sakamoto, Madoka Yoshiki, Hideya Takahashi, Masayuki Yoshida, Yukiko Ogino, Toshitaka Ikeuchi, Tomoya Nakamachi, Norifumi Konno, Kouhei Matsuda, Hirotaka Sakamoto
As in osmoregulation, mineralocorticoid signaling is implicated in the control of brain-behavior actions. Nevertheless, the understanding of this role is limited, partly due to the mortality of mineralocorticoid receptor (MR)-knockout (KO) mice due to impaired Na(+) reabsorption. In teleost fish, a distinct mineralocorticoid system has only been identified recently. Here, we generated a constitutive MR-KO medaka as the first adult-viable MR-KO animal, since MR expression is modest in osmoregulatory organs but high in the brain of adult medaka as for most teleosts...
November 29, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27896625/mri-characterization-in-the-acute-phase-of-experimental-subarachnoid-hemorrhage
#13
Dewei Guo, D Andrew Wilkinson, B Gregory Thompson, Aditya S Pandey, Richard F Keep, Guohua Xi, Ya Hua
A number of mechanisms have been proposed for the early brain injury after subarachnoid hemorrhage (SAH). In this study, we investigated the radiographic characteristics and influence of gender on early brain injury after experimental SAH. SAH was induced by endovascular perforation in male and female rats. Magnetic resonance imaging was performed in a 7.0-T Varian MR scanner at 24 h after SAH. The occurrence and size of T2 lesions, ventricular dilation, and white matter injury (WMI) were determined on T2-weighted images (T2WI)...
November 28, 2016: Translational Stroke Research
https://www.readbyqxmd.com/read/27892889/the-impact-of-functional-vs-degenerative-mitral-regurgitation-on-clinical-outcomes-among-patients-undergoing-transcatheter-aortic-valve-implantation
#14
René Vollenbroich, Stefan Stortecky, Fabien Praz, Jonas Lanz, Anna Franzone, Katarzyna Zuk, Dik Heg, Marco Valgimigli, Crochan John O'Sullivan, Corinna Heinisch, Eva Roost, Peter Wenaweser, Stephan Windecker, Thomas Pilgrim
BACKGROUND: Among patients undergoing transcatheter aortic valve implantation (TAVI), concomitant mitral regurgitation (MR) has been associated with adverse prognosis. We aimed to assess long-term clinical outcomes according to MR etiology. METHODS: In a single-center registry of consecutive patients undergoing TAVI, we investigated the impact of functional (FMR) vs degenerative (DMR) MR on cardiovascular (CV) mortality throughout 2years of follow-up. RESULTS: Among 603 patients (mean age 82...
October 28, 2016: American Heart Journal
https://www.readbyqxmd.com/read/27890732/programmed-near-infrared-light-responsive-drug-delivery-system-for-combined-magnetic-tumor-targeting-magnetic-resonance-imaging-and-chemo-phototherapy
#15
Qianhua Feng, Yuanyuan Zhang, Wanxia Zhang, Yongwei Hao, Yongchao Wang, Hongling Zhang, Lin Hou, Zhenzhong Zhang
: In this study, an intelligent drug delivery system was developed by capping doxorubicin (DOX)-loaded hollow mesoporous CuS nanoparticles (HMCuS NPs) with superparamagnetic iron oxide nanoparticles (IONPs). Under near infrared (NIR) light irradiation, the versatile HMCuS NPs could exploit the merits of both photothermal therapy (PTT) and photodynamic therapy (PDT) simultaneously. Herein, the multifunctional IONPs as gatekeeper with the enhanced capping efficiency were supposed to realize "zero premature release" and minimize the adverse side effects during the drug delivery in vivo...
November 24, 2016: Acta Biomaterialia
https://www.readbyqxmd.com/read/27889894/glucocorticoid-induced-leucine-zipper-in-central-nervous-system-health-and-disease
#16
REVIEW
Mythily Srinivasan, Debomoy K Lahiri
The central nervous system (CNS) is a large network of intercommunicating cells that function to maintain tissue health and homeostasis. Considerable evidence suggests that glucocorticoids exert both neuroprotective and neurodegenerative effects on the CNS. Glucocorticoids act by binding two related receptors in the cytoplasm, the mineralocorticoid receptor (MR) and the glucocorticoid receptor (GR). The glucocorticoid receptor complex mediates cellular responses by transactivating target genes and by protein: protein interactions...
November 26, 2016: Molecular Neurobiology
https://www.readbyqxmd.com/read/27889022/advanced-mr-imaging-in-pediatric-brain-tumors-clinical-applications
#17
REVIEW
Maarten Lequin, Jeroen Hendrikse
Advanced MR imaging techniques, such as spectroscopy, perfusion, diffusion, and functional imaging, have improved the diagnosis of brain tumors in children and also play an important role in defining surgical as well as therapeutic responses in these patients. In addition to the anatomic or structural information gained with conventional MR imaging sequences, advanced MR imaging techniques also provide physiologic information about tumor morphology, metabolism, and hemodynamics. This article reviews the physiology, techniques, and clinical applications of diffusion-weighted and diffusion tensor imaging, MR spectroscopy, perfusion MR imaging, susceptibility-weighted imaging, and functional MR imaging in the setting of neuro-oncology...
February 2017: Neuroimaging Clinics of North America
https://www.readbyqxmd.com/read/27888699/tumor-detection-using-magnetosome-nanoparticles-functionalized-with-a-newly-screened-egfr-her2-targeting-peptide
#18
Zhichu Xiang, Xiaoliang Yang, Junjie Xu, Wenjia Lai, Zihua Wang, Zhiyuan Hu, Jiesheng Tian, Lingling Geng, Qiaojun Fang
A novel peptide (P75) targeting EGFR and HER2 is successfully screened from a one-bead-one-compound (OBOC) library containing approximately 2 × 10(5) peptides built with the aid of computational simulation. In vitro and in vivo analyses show that P75 binds to human epithelial growth factor receptor (EGFR) with nanomolar affinity and to epithelial growth factor receptor-2 (HER2) with a lower affinity but comparable to other reported peptides. The peptide is used to modify the surface of magnetosome nanoparticles (NPs) for targeted magnetic resonance imaging (MRI)...
November 16, 2016: Biomaterials
https://www.readbyqxmd.com/read/27887852/morphological-and-functional-imaging-of-neck-paragangliomas
#19
J-P Guichard, N Fakhry, J Franc, P Herman, C-A Righini, D Taieb
OBJECTIVE: To review the optimal techniques for localization and characterization of neck paragangliomas (PGL). MATERIAL AND METHODS: Systematic review of the literature from the PubMed/Medline database. RESULTS: Neck PGL are hypervascular tumours essentially arising from paraganglionic tissue situated at the carotid bifurcation (carotid body) and along the vagus nerve. Morphological and functional imaging are indicated to confirm the diagnosis, identify multifocal disease and for local and regional staging...
November 22, 2016: European Annals of Otorhinolaryngology, Head and Neck Diseases
https://www.readbyqxmd.com/read/27887692/mechanisms-of-effort-intolerance-in-patients-with-heart-failure-and-borderline-ejection-fraction
#20
Yan Topilsky, Zach Rozenbaum, Shafik Khoury, Gregg S Pressman, Yaniv Gura, Jack Sherez, Avi Man, Jason Shimiaie, Sanford Edwards, Joshua Berookhim, Thierry Le Tourneau, Amir Halkin, Simon Biner, Gad Keren, Galit Aviram
Combining echocardiography and cardiopulmonary stress testing allows noninvasive assessment of hemodynamics, and oxygen extraction (A-VO2 difference). We evaluated mechanisms of effort intolerance in patients with heart failure with borderline (40% to 49%) left ventricular ejection fraction (EF) (HF and Borderline Ejection fraction). We included 89 consecutive patients with HF and Borderline Ejection fraction (n = 25; 63.6 ± 14 years, 64% men), control subjects (n = 22), patients with HF with preserved EF (n = 26; EF ≥50%), and patients with HF with reduced EF (n = 16; <40%)...
November 1, 2016: American Journal of Cardiology
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