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T1 mapping

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https://www.readbyqxmd.com/read/28338005/the-association-between-diffuse-myocardial-fibrosis-on-cardiac-magnetic-resonance-t1-mapping-and-myocardial-dysfunction-in-diabetic-rabbits
#1
Mu Zeng, Yingyan Qiao, Zhaoying Wen, Jun Liu, Enhua Xiao, Changlian Tan, Yibin Xie, Jing An, Zishu Zhang, Zhanming Fan, Debiao Li
The objective of this study was to assess the relationship between imaging surrogates for diffuse fibrosis and myocardial dysfunction. Thirty-six New Zealand white rabbits were classified into two groups: a control group (n = 18) and an alloxan-induced diabetes mellitus (DM) group (n = 18). For all rabbits, conventional ultrasonography, two-dimensional speckle tracking, and cardiac magnetic resonance (CMR) T1 mapping were performed; all of the rabbits were then sacrificed for Masson's staining. The extracellular volume (ECV) was calculated from pre- and post-contrast T1 values and compared with myocardial function measured by echocardiography using Pearson's correlation...
March 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28337941/lesion-symptom-map-of-cognitive-postural-interference-in-multiple-sclerosis
#2
Serena Ruggieri, Fulvia Fanelli, Letizia Castelli, Nikolaos Petsas, Laura De Giglio, Luca Prosperini
OBJECTIVE: To investigate the disease-altered structure-function relationship underlying the cognitive-postural interference (CPI) phenomenon in multiple sclerosis (MS). METHODS: We measured postural sway of 96 patients and 48 sex-/age-matched healthy controls by force platform in quiet standing (single-task (ST)) while performing the Stroop test (dual-task (DT)) to estimate the dual-task cost (DTC) of balance. In patient group, binary T2 and T1 lesion masks and their corresponding lesion volumes were obtained from magnetic resonance imaging (MRI) of brain...
March 1, 2017: Multiple Sclerosis: Clinical and Laboratory Research
https://www.readbyqxmd.com/read/28337872/safety-and-pharmacodynamic-mechanism-of-ropivacaine-lumbar-anesthesia-in-cesarean-section
#3
Q Liu, J J Wang, H Y Yan, Y Q Wang, C W Qin, M L Li
Lumbar anesthesia is the preferred anesthetic approach for puerperae undergoing cesarean section in China. To observe the safety of administering different doses of ropivacaine for cesarean section and its pharmacodynamic mechanism, we randomly divided 180 pregnant women undergoing cesarean section into three groups: group A, 10 mg ropivacaine (0.50%); group B, 12 mg ropivacaine (0.50%); and group C, 14 mg ropivacaine (0.50%). Pharmacodynamic index, anesthesia quality and incidence of untoward reactions of each group were observed...
January 2017: Journal of Biological Regulators and Homeostatic Agents
https://www.readbyqxmd.com/read/28337119/analysis-of-the-precision-of-variable-flip-angle-t1-mapping-with-emphasis-on-the-noise-propagated-from-rf-transmit-field-maps
#4
Yoojin Lee, Martina F Callaghan, Zoltan Nagy
In magnetic resonance imaging, precise measurements of longitudinal relaxation time (T1) is crucial to acquire useful information that is applicable to numerous clinical and neuroscience applications. In this work, we investigated the precision of T1 relaxation time as measured using the variable flip angle method with emphasis on the noise propagated from radiofrequency transmit field ([Formula: see text]) measurements. The analytical solution for T1 precision was derived by standard error propagation methods incorporating the noise from the three input sources: two spoiled gradient echo (SPGR) images and a [Formula: see text] map...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28330561/functional-characterization-of-a-novel-brassica-leafy-homolog-from-indian-mustard-expression-pattern-and-gain-of-function-studies
#5
Priyanka Dhakate, Shikha Tyagi, Anupama Singh, Anandita Singh
LEAFY plays a central role in regulation of flowering time and floral meristem identity in plants. Unfortunately, LFY function remains uncharacterized in agronomicaly important Brassicas. Herein, we illustrate fine-mapping of expression domains of LFY in 15 cultivars of 6 Brassica species and describe gain-of-function phenotypes in Arabidopsis and Brassica. We depict early flowering and altered fatty-acid composition in transgenic seed. The cDNA encoding BjuLFY (417aa) shared only 85% identity with reported homolog of B...
May 2017: Plant Science: An International Journal of Experimental Plant Biology
https://www.readbyqxmd.com/read/28329275/tissue-characterization-by-t1-and-t2-mapping-cardiovascular-magnetic-resonance-imaging-to-monitor-myocardial-inflammation-in-healing-myocarditis
#6
S Bohnen, U K Radunski, G K Lund, F Ojeda, Y Looft, M Senel, L Radziwolek, M Avanesov, E Tahir, C Stehning, B Schnackenburg, G Adam, S Blankenberg, K Muellerleile
Aims: Monitoring disease activity in myocarditis is important for tailored therapeutic strategies. This study evaluated the ability of T1 and T2 mapping cardiovascular magnetic resonance (CMR) to monitor the course of myocardial inflammation in healing myocarditis. Methods and results: Forty-eight patients with strictly defined acute myocarditis underwent CMR at 1.5 T in the acute stage, at 3-months (n = 39), and at 12-months follow-up (FU) (n = 21). Normal values were obtained in a control group of 27 healthy subjects...
March 8, 2017: European Heart Journal Cardiovascular Imaging
https://www.readbyqxmd.com/read/28328993/agreement-between-functional-connectivity-and-cortical-thickness-driven-correlation-maps-of-the-medial-frontal-cortex
#7
Hyunjin Park, Yeong-Hun Park, Jungho Cha, Sang Won Seo, Duk L Na, Jong-Min Lee
Parcellation of the human cortex has important implications in neuroscience. Parcellation is often a crucial requirement before meaningful regional analysis can occur. The human cortex can be parcellated into distinct regions based on structural features, such as gyri and sulci. Brain network patterns in a given region with respect to its neighbors, known as connectional fingerprints, can be used to parcellate the cortex. Distinct imaging modalities might provide complementary information for brain parcellation...
2017: PloS One
https://www.readbyqxmd.com/read/28323379/effects-of-short-term-levothyroxine-therapy-on-myocardial-injuries-in-patients-with-severe-overt-hypothyroidism-evidence-from-a-cardiac-mri-study
#8
Xia Gao, Zhe Chen, Min Liu, Yu-Mei Jia, Ning Yang, Zhi Yao, Xiao-Meng Feng, Yuan Xu, Guang Wang
PURPOSE: To investigate using magnetic resonance imaging (MRI) myocardial injuries and cardiac function in patients with newly diagnosed severe primary overt hypothyroidism (HT) before and after achieving euthyroidism by short-term levothyroxine treatment. Levothyroxine treatment improves cardiovascular performance and ventricular remodeling in patients with HT, but diffuse myocardial injuries induced by HT are difficult to detect clinically. MATERIALS AND METHODS: Myocardial longitudinal relaxation time (T1 ) mapping using the modified Look-Locker inversion-recovery (MOLLI) sequences at 3...
March 21, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28323377/accuracy-of-pdff-estimation-by-magnitude-based-and-complex-based-mri-in-children-with-mr-spectroscopy-as-a-reference
#9
William M Haufe, Tanya Wolfson, Catherine A Hooker, Jonathan C Hooker, Yesenia Covarrubias, Alex N Schlein, Gavin Hamilton, Michael S Middleton, Jorge E Angeles, Diego Hernando, Scott B Reeder, Jeffrey B Schwimmer, Claude B Sirlin
PURPOSE: To assess and compare the accuracy of magnitude-based magnetic resonance imaging (MRI-M) and complex-based MRI (MRI-C) for estimating hepatic proton density fat fraction (PDFF) in children, using MR spectroscopy (MRS) as the reference standard. A secondary aim was to assess the agreement between MRI-M and MRI-C. MATERIALS AND METHODS: This was a HIPAA-compliant, retrospective analysis of data collected in children enrolled in prospective, Institutional Review Board (IRB)-approved studies between 2012 and 2014...
March 21, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28321246/medical-image-fusion-based-on-feature-extraction-and-sparse-representation
#10
Yin Fei, Gao Wei, Song Zongxi
As a novel multiscale geometric analysis tool, sparse representation has shown many advantages over the conventional image representation methods. However, the standard sparse representation does not take intrinsic structure and its time complexity into consideration. In this paper, a new fusion mechanism for multimodal medical images based on sparse representation and decision map is proposed to deal with these problems simultaneously. Three decision maps are designed including structure information map (SM) and energy information map (EM) as well as structure and energy map (SEM) to make the results reserve more energy and edge information...
2017: International Journal of Biomedical Imaging
https://www.readbyqxmd.com/read/28319118/functional-mri-for-characterization-of-renal-perfusion-impairment-and-edema-formation-due-to-acute-kidney-injury-in-different-mouse-strains
#11
Susanne Tewes, Faikah Gueler, Rongjun Chen, Marcel Gutberlet, Mi-Sun Jang, Martin Meier, Michael Mengel, Dagmar Hartung, Frank Wacker, Song Rong, Katja Hueper
PURPOSE: The purpose was to characterize acute kidney injury (AKI) in C57BL/6 (B6)- and 129/Sv (Sv)-mice by noninvasive measurement of renal perfusion and tissue edema using functional MRI. METHODS: Different severities of AKI were induced in B6- and Sv-mice by renal ischemia reperfusion injury (IRI). Unilateral clamping of the renal pedicle for 35 min (moderate AKI) or 45 min (severe AKI) was done. MRI (7-Tesla) was performed 1, 7 and 28 days after surgery using a flow alternating inversion recovery (FAIR) arterial spin labeling (ASL) sequence...
2017: PloS One
https://www.readbyqxmd.com/read/28317398/cardiac-transplantation-towards-a-new-noninvasive-approach-of-cardiac-allograft-rejection
#12
Sophie I Mavrogeni, George Athanasopoulos, Aggeliki Gouziouta, Evangelos Leontiadis, Stamatis Adamopoulos, Genovefa Kolovou
Cardiac allograft rejection (CAR) may occur after transplantation and remains silent, until hemodynamic deterioration takes place. Endomyocardial biopsy (EMB) is applied to early detect CAR. Although, flexible bioptoms have decreased the incidence of lethal complications, EMB remains an invasive procedure carrying risk of tamponade and permanent heart block. Therefore, a new non-invasive approach is needed. Areas covered: AlloMap molecular expression testing and graft-derived cell-free DNA (GcfDNA) test can be used as blood indices of acute and chronic CAR, respectively...
March 21, 2017: Expert Review of Cardiovascular Therapy
https://www.readbyqxmd.com/read/28314659/diagnostic-and-prognostic-value-of-cmr-t1-mapping-in-patients-with-heart-failure-and-preserved-ejection-fraction
#13
Karl-Philipp Rommel, Christian Lücke, Philipp Lurz
Heart failure with preserved ejection fraction (HFpEF) presents a major challenge in modern cardiology. Although this syndrome is of increasing prevalence and is associated with unfavorable outcomes, treatment trials have failed to establish effective therapies. Currently, solutions to this dilemma are being investigated, including categorizing and characterizing patients more diversely to individualize treatment. In this regard, new imaging techniques might provide important information. Diastolic dysfunction is a diagnostic and pathophysiological cornerstone in HFpEF and is believed to be caused by systemic inflammation with the development of interstitial myocardial fibrosis and myocardial stiffening...
March 14, 2017: Revista Española de Cardiología
https://www.readbyqxmd.com/read/28303617/joint-system-relaxometry-jsr-and-cr%C3%A3-mer-rao-lower-bound-optimization-of-sequence-parameters-a-framework-for-enhanced-precision-of-despot-t1-and-t2-estimation
#14
Rui Pedro A G Teixeira, Shaihan J Malik, Joseph V Hajnal
PURPOSE: This study aims to increase the precision of single-compartment DESPOT relaxometry by two means: (i) a joint system relaxometry (JSR) approach that estimates parameters in a single step using all available data; and (ii) optimizing acquisition parameters by deploying a robust design tool based on the Crámer-Rao lower bound (CRLB). METHODS: Following the development of the analysis and design capabilities, phantom and four in vivo subject experiments were performed to compare directly the precision achieved with DESPOT and JSR estimation using published protocols and protocols designed using a proposed CRLB framework...
March 16, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28301086/b1-mapping-for-bias-correction-in-quantitative-t1-imaging-of-the-brain-at-3t-using-standard-pulse-sequences
#15
Mathieu Boudreau, Christine L Tardif, Nikola Stikov, John G Sled, Wayne Lee, G Bruce Pike
PURPOSE: B1 mapping is important for many quantitative imaging protocols, particularly those that include whole-brain T1 mapping using the variable flip angle (VFA) technique. However, B1 mapping sequences are not typically available on many magnetic resonance imaging (MRI) scanners. The aim of this work was to demonstrate that B1 mapping implemented using standard scanner product pulse sequences can produce B1 (and VFA T1 ) maps comparable in quality and acquisition time to advanced techniques...
March 16, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28284189/changes-in-intraocular-pressure-and-optic-nerve-sheath-diameter-in-patients-undergoing-robotic-assisted-laparoscopic-prostatectomy-in-steep-45%C3%A2-trendelenburg-position
#16
Sebastian Blecha, Marion Harth, Felix Schlachetzki, Florian Zeman, Christiane Blecha, Pierre Flora, Maximilian Burger, Stefan Denzinger, Bernhard M Graf, Horst Helbig, Michael T Pawlik
BACKGROUND: To evaluate changes in intraocular pressure (IOP) and intracerebral pressure (ICP) reflected by the optic nerve sheath diameter (ONSD) in patients undergoing robotic-assisted laparoscopic prostatectomy (RALP) in permanent 45° steep Trendelenburg position (STP). METHODS: Fifty-one patients undergoing RALP under a standardised anaesthesia. IOP was perioperatively measured in awake patients (T0) and IOP and ONSD 20 min after induction of anaesthesia (T1), after insufflation of the abdomen in supine position (T2), after 30 min in STP (T3), when controlling Santorini's plexus in STP (T4) and before awakening while supine (T5)...
March 11, 2017: BMC Anesthesiology
https://www.readbyqxmd.com/read/28283723/intravoxel-incoherent-motion-magnetic-resonance-imaging-of-the-knee-joint-in-children-with-juvenile-idiopathic-arthritis
#17
Fabian Hilbert, Annette Holl-Wieden, Alexander Sauer, Herbert Köstler, Henning Neubauer
BACKGROUND: MRI of synovitis relies on use of a gadolinium-based contrast agent. Diffusion-weighted MRI (DWI) visualises thickened synovium but is of limited use in the presence of joint effusion. OBJECTIVE: To investigate the feasibility and diagnostic accuracy of diffusion-weighted MRI with intravoxel incoherent motion (IVIM) for diagnosing synovitis in the knee joint of children with juvenile idiopathic arthritis. MATERIALS AND METHODS: Twelve consecutive children with confirmed or suspected juvenile idiopathic arthritis (10 girls, median age 11 years) underwent MRI with contrast-enhanced T1-weighted imaging and DWI at 1...
March 10, 2017: Pediatric Radiology
https://www.readbyqxmd.com/read/28280088/radiomics-features-of-multiparametric-mri-as-novel-prognostic-factors-in-advanced-nasopharyngeal-carcinoma
#18
Shuixing Zhang, Bin Zhang, Jie Tian, Di Dong, Dong Sheng Gu, Yu Hao Dong, Lu Zhang, Zhou Yang Lian, Jing Liu, Xiao Ning Luo, Shu Fang Pei, Xiao Kai Mo, Wen Hui Huang, Fu Sheng Ouyang, Bao Liang Guo, Long Liang, Wenbo Chen, Chang H Liang
PURPOSE: To identify MRI-based radiomics as prognostic factors in patients with advanced nasopharyngeal carcinoma (NPC). EXPERIMENTAL DESIGN: One-hundred and eighteen patients (training cohort: n = 88; validation cohort: n = 30) with advanced NPC were enrolled. A total of 970 radiomics features were extracted from T2-weighted (T2-w) and contrast-enhanced T1-weighted (CET1-w) MRI. Least absolute shrinkage and selection operator (LASSO) regression was applied to select features for progression-free survival (PFS) nomograms...
March 9, 2017: Clinical Cancer Research: An Official Journal of the American Association for Cancer Research
https://www.readbyqxmd.com/read/28275700/peripheral-inflammatory-markers-indicate-microstructural-damage-within-periventricular-white-matter-hyperintensities-in%C3%A2-alzheimer-s-disease-a-preliminary-report
#19
Walter Swardfager, Di Yu, Joel Ramirez, Hugo Cogo-Moreira, Gregory Szilagyi, Melissa F Holmes, Christopher J M Scott, Gustavo Scola, Pak C Chan, Jialun Chen, Parco Chan, Demetrios J Sahlas, Nathan Herrmann, Krista L Lanctôt, Ana C Andreazza, Jacqueline A Pettersen, Sandra E Black
INTRODUCTION: White matter hyperintensities (WMH) presumed to reflect cerebral small vessel disease and increased peripheral inflammatory markers are found commonly in Alzheimer's disease (AD), but their interrelationships remain unclear. METHODS: Inflammatory markers were assayed in 54 elderly participants (n = 16 with AD). Periventricular WMH were delineated from T1, T2/proton density, and fluid-attenuated magnetic resonance imaging using semiautomated fuzzy lesion extraction and coregistered with maps of fractional anisotropy (FA), a measure of microstructural integrity assessed using diffusion tensor imaging...
2017: Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring
https://www.readbyqxmd.com/read/28274834/resolution-considerations-in-imaging-of-the-cortical-layers
#20
Shlomi Lifshits, Omri Tomer, Ittai Shamir, Daniel Barazany, Galia Tsarfaty, Saharon Rosset, Yaniv Assaf
The cortical layers are a finger print of brain development, function, connectivity and pathology. Obviously, the formation of the layers and their composition is essential to cognition and behavior. The layers were traditionally measured by histological means but recent studies utilizing MRI suggested that T1 relaxation imaging consist of enough contrast to separate the layers. Indeed extreme resolution, post mortem, studies demonstrated this phenomenon. Yet, one of the limiting factors of using T1 MRI to visualize the layers in neuroimaging research is partial volume effect...
March 6, 2017: NeuroImage
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