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T1 mapping

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https://www.readbyqxmd.com/read/29162523/specific-visualization-of-neuromelanin-iron-complex-and-ferric-iron-in-the-human-post-mortem-substantia-nigra-using-mr-relaxometry-at-7t
#1
Hansol Lee, Sun-Yong Baek, Se Young Chun, Jae-Hyeok Lee, HyungJoon Cho
Neuromelanin (NM) is an endogenous iron chelating molecule of pigmented neurons in the human substantia nigra (SN). Along with the increase in iron deposition, the reduction in NM-containing dopaminergic neurons and the variation of iron load on NM are generally considered to be important factors participating to pathogenesis of Parkinson's disease (PD). The aim of this study was to non-invasively delineate the spatial distributions of paramagnetic magnetic susceptibility perturbers, such as NM-iron complex and ferric iron in SN...
November 18, 2017: NeuroImage
https://www.readbyqxmd.com/read/29159946/extracellular-volume-with-bolus-only-technique-in-amyloidosis-patients-diagnostic-accuracy-correlation-with-other-clinical-cardiac-measures-and-ability-to-track-changes-in-amyloid-load-over-time
#2
Giulia Zumbo, Sharon V Barton, Douglas Thompson, Min Sun, Amna Abdel-Gadir, Thomas A Treibel, Daniel Knight, Ana Martinez-Naharro, Lane Thirusha, Julian D Gillmore, James C Moon, Philip N Hawkins, Marianna Fontana
BACKGROUND: Extracellular volume (ECV) by T1 mapping requires the contrast agent distribution to be at equilibrium. This can be achieved either definitively with a primed contrast infusion (infusion ECV), or sufficiently with a delay postbolus (bolus-only ECV). For large ECV, the bolus-only approach measures higher than the infusion ECV, causing some uncertainty in diseases such as amyloidosis. PURPOSE: To characterize the relationship between the bolus-only and current gold-standard infusion ECV in patients with amyloidosis...
November 21, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/29159883/phase-sensitive-b1-mapping-effects-of-relaxation-and-rf-spoiling
#3
Jie Wen, Alexander L Sukstanskii, Dmitriy A Yablonskiy
PURPOSE: To develop a phase-based B1 mapping technique accounting for the effects of imperfect RF spoiling and magnetization relaxation. THEORY AND METHODS: The technique is based on a multi-gradient-echo sequence with 2 successive orthogonal radiofrequency (RF) excitation pulses followed by the train of gradient echoes measurements. We have derived a theoretical expression relating the MR signal phase produced by the 2 successive RF pulses to the B1 field and B0 -related frequency shift...
November 20, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29159855/b1-artifact-reduction-in-abdominal-dce-mri-using-kt-points-first-clinical-assessment-of-dynamic-rf-shimming-at-3t
#4
Raphaël Tomi-Tricot, Vincent Gras, Franck Mauconduit, François Legou, Nicolas Boulant, Matthias Gebhardt, Dieter Ritter, Berthold Kiefer, Pierre Zerbib, Alain Rahmouni, Alexandre Vignaud, Alain Luciani, Alexis Amadon
BACKGROUND: The excitation inhomogeneity artifact occurring at 3T in the abdomen can lead to dramatic loss of signal and contrast, thereby hampering diagnosis. PURPOSE: To assess excitation homogeneity and image quality achieved by nonselective prototypical kT -points pulses, compared to tailored static RF shimming, in clinical routine on a commercial dual-transmit scanner. STUDY TYPE: Retrospective study with Institutional Review Board approval; informed consent was waived...
November 21, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/29157260/high-resolution-and-accelerated-multi-parametric-mapping-with-automated-characterization-of-vessel-disease-using-intravascular-mri
#5
Guan Wang, Yi Zhang, Shashank Sathyanarayana Hegde, Paul A Bottomley
BACKGROUND: Atherosclerosis is prevalent in cardiovascular disease, but present imaging modalities have limited capabilities for characterizing lesion stage, progression and response to intervention. This study tests whether intravascular magnetic resonance imaging (IVMRI) measures of relaxation times (T1, T2) and proton density (PD) in a clinical 3 Tesla scanner could characterize vessel disease, and evaluates a practical strategy for accelerated quantification. METHODS: IVMRI was performed in fresh human artery segments and swine vessels in vivo, using fast multi-parametric sequences, 1-2 mm diameter loopless antennae and 200-300 μm resolution...
November 20, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/29153657/cardiac-magnetic-resonance-imaging-in-myocardial-inflammation-in-autoimmune-rheumatic-diseases-an-appraisal-of-the-diagnostic-strengths-and-limitations-of-the-lake-louise-criteria
#6
Sophie Mavrogeni, Juerg Schwitter, Albert van Rossum, Robin Nijveldt, Antony Aletras, Genovefa Kolovou, Gerald Pohost, Joao Lima
Myocardial inflammation in autoimmune rheumatic diseases (ARDs) is the endpoint of various pathophysiologic processes. The Lake Louise-criteria is the most popular approach for the diagnosis of myocarditis. However, due to the diversity of myocardial inflammation in ARDs, some issues should be acknowledged. Of the three Lake Louise indices, early and late gadolinium enhancement (EGE and LGE respectively) measurements may be affected by co-existing disease processes or be present due to a fibrotic ARD like systemic sclerosis, leaving T2-ratio as the only uniformly robust measurement across ARDs...
November 14, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/29153562/noncontrast-myocardial-t1-mapping-by-cardiac-magnetic-resonance-predicts-outcome-in-patients-with-aortic-stenosis
#7
Heesun Lee, Jun-Bean Park, Yeonyee E Yoon, Eun-Ah Park, Hyung-Kwan Kim, Whal Lee, Yong-Jin Kim, Goo-Yeong Cho, Dae-Won Sohn, Andreas Greiser, Seung-Pyo Lee
OBJECTIVES: The aim of this study was to evaluate whether native T1 value of the myocardium on cardiac magnetic resonance (CMR) could predict clinical events in patients with significant aortic stenosis (AS). BACKGROUND: Although previous studies have demonstrated the prognostic value of focal fibrosis using late gadolinium enhancement (LGE) by CMR in AS patients, the prognostic implication of diffuse myocardial fibrosis by noninvasive imaging remains unknown. METHODS: A prospective observational longitudinal study was performed in 127 consecutive patients with moderate or severe AS (68...
November 10, 2017: JACC. Cardiovascular Imaging
https://www.readbyqxmd.com/read/29152942/effects-of-positive-end-expiratory-pressure-on-intracranial-pressure-during-pneumoperitoneum-and-trendelenburg-position-in-a-porcine-mode
#8
Nurdan Bedirli, Gökçen Emmez, Yusuf Ünal, Mehmet Tönge, Hakan Emmez
Background/aim: This study was undertaken to evaluate the effects of positive end-expiratory pressure (PEEP) levels on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) and to determine the appropriate PEEP level during steep Trendelenburg position combined with pneumoperitoneum.Materials and methods: Ten pigs were included in this study. Pneumoperitoneum and Trendelenburg position were maintained and PEEP titration was initiated. Arterial pressure, heart rate, arterial blood gas, ICP, and CPP were recorded at the following time points: baseline (T0), 30 min after positioning and pneumoperitoneum (T1), PEEP 5 (T2), PEEP 10 (T3), PEEP 15 (T4), and PEEP 20 (T5)...
November 13, 2017: Turkish Journal of Medical Sciences
https://www.readbyqxmd.com/read/29152563/integrated-radiomic-framework-for-breast-cancer-and-tumor-biology-using-advanced-machine-learning-and-multiparametric-mri
#9
Vishwa S Parekh, Michael A Jacobs
Radiomics deals with the high throughput extraction of quantitative textural information from radiological images that not visually perceivable by radiologists. However, the biological correlation between radiomic features and different tissues of interest has not been established. To that end, we present the radiomic feature mapping framework to generate radiomic MRI texture image representations called the radiomic feature maps (RFM) and correlate the RFMs with quantitative texture values, breast tissue biology using quantitative MRI and classify benign from malignant tumors...
2017: NPJ Breast Cancer
https://www.readbyqxmd.com/read/29151166/t2-weighted-images-are-superior-to-other-mr-image-types-for-the-determination-of-diffuse-intrinsic-pontine-glioma-intratumoral-heterogeneity
#10
Stephen Harward, S Harrison Farber, Michael Malinzak, Oren Becher, Eric M Thompson
PURPOSE: Diffuse intrinsic pontine glioma (DIPG) remains the main cause of death in children with brain tumors. Given the inefficacy of numerous peripherally delivered agents to treat DIPG, convection enhanced delivery (CED) of therapeutic agents is a promising treatment modality. The purpose of this study was to determine which MR imaging type provides the best discrimination of intratumoral heterogeneity to guide future stereotactic implantation of CED catheters into the most cellular tumor regions...
November 18, 2017: Child's Nervous System: ChNS: Official Journal of the International Society for Pediatric Neurosurgery
https://www.readbyqxmd.com/read/29136015/the-influences-of-walking-running-and-stair-activity-on-knee-articular-cartilage-quantitative-mri-using-t1-rho-and-t2-mapping
#11
Meng Chen, Lin Qiu, Si Shen, Fei Wang, Jing Zhang, Cici Zhang, Sirun Liu
OBJECTIVE: To explore the different influences of walking, running and stair activity on knee articular cartilage with T1 rho and T2 mapping sequences. MATERIALS AND METHODS: MRI (3.0-T) scans of the right knee were performed in twenty-three young healthy adults immediately after 30 minutes of rest, walking, running and stair activity respectively. Articular cartilage was quantitatively assessed based on T1 rho and T2 relaxation times. Analysis of variance for random block design data, bonferroni test and paired samples t tests were performed to estimate the different influences of physiological activities on articular cartilage...
2017: PloS One
https://www.readbyqxmd.com/read/29131444/native-t1-reference-values-for-nonischemic-cardiomyopathies-and-populations-with-increased-cardiovascular-risk-a-systematic-review-and-meta-analysis
#12
REVIEW
Maaike van den Boomen, Riemer H J A Slart, Enzo V Hulleman, Rudi A J O Dierckx, Birgitta K Velthuis, Pim van der Harst, David E Sosnovik, Ronald J H Borra, Niek H J Prakken
BACKGROUND: Although cardiac MR and T1 mapping are increasingly used to diagnose diffuse fibrosis based cardiac diseases, studies reporting T1 values in healthy and diseased myocardium, particular in nonischemic cardiomyopathies (NICM) and populations with increased cardiovascular risk, seem contradictory. PURPOSE: To determine the range of native myocardial T1 value ranges in patients with NICM and populations with increased cardiovascular risk. STUDY TYPE: Systemic review and meta-analysis...
November 13, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/29128863/persistent-long-term-structural-functional-and-metabolic-changes-after-stress-induced-takotsubo-cardiomyopathy
#13
Caroline Scally, Amelia Rudd, Alice Mezincescu, Heather Wilson, Janaki Srinivasan, Graham Horgan, Paul Broadhurst, David E Newby, Anke Henning, Dana K Dawson
BACKGROUND : Takotsubo cardiomyopathy is an increasingly recognized acute heart failure syndrome precipitated by intense emotional stress. Although there is an apparent rapid and spontaneous recovery of left ventricular ejection fraction, the long-term clinical and functional consequences of takotsubo cardiomyopathy are ill-defined. METHODS : In an observational case-control study, we recruited 37 patients with prior (>12-month) takotsubo cardiomyopathy, and 37 age-, sex-, and comorbidity-matched control subjects...
November 11, 2017: Circulation
https://www.readbyqxmd.com/read/29123919/t2-mapping-and-post-contrast-t1-dgemric-of-the-patellar-cartilage-12-year-follow-up-after-patellar-stabilizing-surgery-in-childhood
#14
Eva Bengtsson Moström, Eveliina Lammentausta, Thröstur Finnbogason, Lars Weidenhielm, Per-Mats Janarv, Carl Johan Tiderius
Background: Cartilage degeneration has been reported after recurrent patellar dislocation. However, effects of surgical stabilization in childhood have not yet been described. Purpose: To examine the cartilage quality in very young adults operated with a patellar stabilizing procedure due to recurrent patellar dislocation in childhood, and evaluate if cartilage quality correlates with clinical parameters and patient-reported outcomes. Material and Methods: Seventeen patients were investigated ≥ 5 years (mean = 11...
October 2017: Acta Radiologica Open
https://www.readbyqxmd.com/read/29122631/mitral-valve-prolapse-multimodality-imaging-and-genetic-insights
#15
REVIEW
Purvi Parwani, Jean-Francois Avierinos, Robert A Levine, Francesca Nesta Delling
Mitral valve prolapse (MVP) is a common heritable valvulopathy affecting approximately 2.4% of the population. It is the most important cause of primary mitral regurgitation (MR) requiring surgery. MVP is characterized by fibromyxomatous changes and displacement of one or both mitral leaflets into the left atrium. Echocardiography represents the primary diagnostic modality for assessment of MVP. Accurate quantitation of ventricular volumes and function for surgical planning in asymptomatic severe MR can be provided with both echocardiography and cardiac magnetic resonance ...
November 6, 2017: Progress in Cardiovascular Diseases
https://www.readbyqxmd.com/read/29121086/improved-segmented-modified-look-locker-inversion-recovery-t1-mapping-sequence-in-mice
#16
Maryam Nezafat, Isabel T Ramos, Markus Henningsson, Andrea Protti, Tamer Basha, René M Botnar
OBJECT: To develop and evaluate a 2D modified Look-Locker (MOLLI) for high-resolution T1 mapping in mice using a 3T MRI scanner. MATERIALS AND METHODS: To allow high-resolution T1 mapping in mice at high heart rates a multi-shot ECG-triggered 2D MOLLI sequence was developed. In the proposed T1 mapping sequence the optimal number of sampling points and pause cardiac cycles following an initial adiabatic inversion pulse was investigated in a phantom. Seven native control and eight mice, 3 days post myocardial infarction (MI) after administration of gadolinium were scanned...
2017: PloS One
https://www.readbyqxmd.com/read/29117484/carotid-intraplaque-hemorrhage-imaging-with-quantitative-vessel-wall-t1-mapping-technical-development-and-initial-experience
#17
Haikun Qi, Jie Sun, Huiyu Qiao, Shuo Chen, Zechen Zhou, Xinlei Pan, Yishi Wang, Xihai Zhao, Rui Li, Chun Yuan, Huijun Chen
Purpose To develop a three-dimensional (3D) high-spatial-resolution time-efficient sequence for use in quantitative vessel wall T1 mapping. Materials and Methods A previously described sequence, simultaneous noncontrast angiography and intraplaque hemorrhage (SNAP) imaging, was extended by introducing 3D golden angle radial k-space sampling (GOAL-SNAP). Sliding window reconstruction was adopted to reconstruct images at different inversion delay times (different T1 contrasts) for voxelwise T1 fitting. Phantom studies were performed to test the accuracy of T1 mapping with GOAL-SNAP against a two-dimensional inversion recovery (IR) spin-echo (SE) sequence...
November 8, 2017: Radiology
https://www.readbyqxmd.com/read/29107626/mri-measurements-of-blood-brain-barrier-function-in-dementia-a-review-of-recent-studies
#18
REVIEW
Rajikha Raja, Gary A Rosenberg, Arvind Caprihan
Blood-brain barrier (BBB) separates the systemic circulation and the brain, regulating transport of most molecules to protect the brain microenvironment. Multiple structural and functional components preserve the integrity of the BBB. Several imaging modalities are available to study disruption of the BBB. However, the subtle changes in BBB leakage that occurs in vascular cognitive impairment and Alzheimer's disease have been less well studied. Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) is the most widely adopted non-invasive imaging technique for evaluating BBB breakdown...
October 28, 2017: Neuropharmacology
https://www.readbyqxmd.com/read/29104242/synthesis-and-anti-proliferative-effects-of-mono-and-bis-purinomimetics-targeting-kinases
#19
Andrea Bistrović, Anja Harej, Petra Grbčić, Mirela Sedić, Sandra Kraljević Pavelić, Mario Cetina, Silvana Raić-Malić
A series of mono-pyrrolo[2,3-d]pyrimidines 4a-4k, unsymmetrical bis-purine isosteres 5a-5e and symmetrical bis-pyrrolo[2,3-d]pyrimidines 6a and 6b connected via di(1,2,3-triazolyl)phenyl linker were synthesized by click chemistry. Whereas mono- 4g and bis-pseudopurine 5e showed selective inhibitory activities on cervical carcinoma (HeLa) cells, bis-pyrrolo[2,3-d]pyrimidine 6b exhibited potent and selective anti-proliferative effect in the nanomolar range on pancreatic carcinoma (CFPAC-1) cells. Among these, compound 6b induced a significant reduction in the expression level of CDK9 (cyclin-dependent kinase 9)/cyclin T1 in CFPAC-1 cells concomitant with attenuation of proliferative signaling mediated by c-Raf (rapidly accelerated fibrosarcoma) and p38 MAP (mitogen-activated protein) kinases...
November 1, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29103469/improved-clinical-workflow-for-simultaneous-whole-body-pet-mri-using-high-resolution-caipirinha-accelerated-mr-based-attenuation-correction
#20
Martin T Freitag, Matthias Fenchel, Philipp Bäumer, Thorsten Heußer, Christopher M Rank, Marc Kachelrieß, Daniel Paech, Klaus Kopka, Sebastian Bickelhaupt, Antonia Dimitrakopoulou-Strauss, Klaus Maier-Hein, Ralf Floca, Mark E Ladd, Heinz-Peter Schlemmer, Florian Maier
PURPOSE: To explore the value and reproducibility of a novel magnetic resonance based attenuation correction (MRAC) using a CAIPIRINHA-accelerated T1-weighted Dixon 3D-VIBE sequence for whole-body PET/MRI compared to the clinical standard. METHODS: The PET raw data of 19 patients from clinical routine were reconstructed with standard MRAC (MRACstd) and the novel MRAC (MRACcaipi), a prototype CAIPIRINHA accelerated Dixon 3D-VIBE sequence, both acquired in 19 s/bed position...
November 2017: European Journal of Radiology
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