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Functional MR

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https://www.readbyqxmd.com/read/28097524/pubovisceralis-muscle-fiber-architecture-determination-comparison-between-biomechanical-modeling-and-diffusion-tensor-imaging
#1
Sofia Brandão, Marco Parente, Elisabete Silva, Thuane Da Roza, Teresa Mascarenhas, João Leitão, João Cunha, Renato Natal Jorge, Rita Gouveia Nunes
Biomechanical analysis of pelvic floor dysfunction requires knowledge of certain biomechanical parameters, such as muscle fiber direction, in order to adequately model function. Magnetic resonance (MR) diffusion tensor imaging (DTI) provides an estimate of overall muscle fiber directionality based on the mathematical description of water diffusivity. This work aimed at evaluating the concurrence between pubovisceralis muscle fiber representations obtained from DTI, and the maximum principal stress lines obtained through the finite element method...
January 17, 2017: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/28097185/immediate-improvement-in-severe-mitral-regurgitation-after-aortic-valve-replacement-for-severe-aortic-insufficiency
#2
Ahmad Zeeshan, Mojun Zhu, John A Elefteriades
A 57-year-old male with ascending aortic aneurysm, severe aortic regurgitation, and severe mitral regurgitation (MR) underwent ascending aortic replacement and aortic valve replacement. MR in this patient with normal mitral valve morphology was considered secondary to aortic valve incompetency. Consequently, a surgical approach to restore aortic valve function was adopted with successful MR resolution. This case report demonstrates the possibility of reversing early functional mitral regurgitation without surgically approaching the mitral valve...
June 2016: Aorta (Stamford, Conn.)
https://www.readbyqxmd.com/read/28093636/non-surgical-treatment-of-pubic-overload-and-groin-pain-in-amateur-football-players-a-prospective-double-blinded-randomised-controlled-study
#3
M Schöberl, L Prantl, O Loose, J Zellner, P Angele, F Zeman, M Spreitzer, M Nerlich, W Krutsch
PURPOSE: The incidence of groin pain in athletes is steadily increasing. Symptomatic pubic overload with groin pain and aseptic osteitis pubis represent well-known and frequently misdiagnosed overuse injuries in athletes. This study investigated the benefits of standardised non-surgical treatment for swift return-to-football. METHODS: In a prospective double-blinded controlled study, 143 amateur football players with groin pain as well as radiological signs and clinical symptoms of pubic overload were analysed for 1 year...
January 16, 2017: Knee Surgery, Sports Traumatology, Arthroscopy: Official Journal of the ESSKA
https://www.readbyqxmd.com/read/28093494/exercise-dynamics-in-secondary-mitral-regurgitation-pathophysiology-and-therapeutic-implications
#4
Philippe B Bertrand, Ehud Schwammenthal, Robert A Levine, Pieter M Vandervoort
Secondary mitral valve regurgitation (MR) remains a challenging problem in the diagnostic workup and treatment of patients with heart failure. Although secondary MR is characteristically dynamic in nature and sensitive to changes in ventricular geometry and loading, current therapy is mainly focused on resting conditions. An exercise-induced increase in secondary MR, however, is associated with impaired exercise capacity and increased mortality. In an era where a multitude of percutaneous solutions are emerging for the treatment of patients with heart failure, it becomes important to address the dynamic component of secondary MR during exercise as well...
January 17, 2017: Circulation
https://www.readbyqxmd.com/read/28092203/machine-learning-of-three-dimensional-right-ventricular-motion-enables-outcome-prediction-in-pulmonary-hypertension-a-cardiac-mr-imaging-study
#5
Timothy J W Dawes, Antonio de Marvao, Wenzhe Shi, Tristan Fletcher, Geoffrey M J Watson, John Wharton, Christopher J Rhodes, Luke S G E Howard, J Simon R Gibbs, Daniel Rueckert, Stuart A Cook, Martin R Wilkins, Declan P O'Regan
Purpose To determine if patient survival and mechanisms of right ventricular failure in pulmonary hypertension could be predicted by using supervised machine learning of three-dimensional patterns of systolic cardiac motion. Materials and Methods The study was approved by a research ethics committee, and participants gave written informed consent. Two hundred fifty-six patients (143 women; mean age ± standard deviation, 63 years ± 17) with newly diagnosed pulmonary hypertension underwent cardiac magnetic resonance (MR) imaging, right-sided heart catheterization, and 6-minute walk testing with a median follow-up of 4...
January 16, 2017: Radiology
https://www.readbyqxmd.com/read/28090451/potential-of-pet-mri-for-imaging-of-non-oncologic-musculoskeletal-disease
#6
REVIEW
Feliks Kogan, Audrey P Fan, Garry E Gold
Early detection of musculoskeletal disease leads to improved therapies and patient outcomes, and would benefit greatly from imaging at the cellular and molecular level. As it becomes clear that assessment of multiple tissues and functional processes are often necessary to study the complex pathogenesis of musculoskeletal disorders, the role of multi-modality molecular imaging becomes increasingly important. New positron emission tomography-magnetic resonance imaging (PET-MRI) systems offer to combine high-resolution MRI with simultaneous molecular information from PET to study the multifaceted processes involved in numerous musculoskeletal disorders...
December 2016: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28089903/advances-in-mr-angiography-with-7t-mri-from-microvascular-imaging-to-functional-angiography
#7
Chan-A Park, Chang-Ki Kang, Young-Bo Kim, Zang-Hee Cho
Over the past few decades, vascular flow-dependent imaging techniques have proven to be effective for the visualization of large vessel diseases. However, these approaches are unlikely to be efficacious for small vessels because the affected small vessels cannot always be visualized directly, owing to a lack of detection sensitivity. Recently, many researchers have introduced state-of-the-art imaging techniques to visualize cerebral microvessels using ultra-high-field (UHF) magnetic resonance angiography (MRA)...
January 12, 2017: NeuroImage
https://www.readbyqxmd.com/read/28089704/brain-mineralocorticoid-receptor-function-in-control-of-salt-balance-and-stress-adaptation
#8
REVIEW
E Ronald de Kloet, Marian Joëls
We will highlight in honor of Randall Sakai the peculiar characteristics of the brain mineralocorticoid receptor (MR) in its response pattern to the classical mineralocorticoid aldosterone and the naturally occurring glucocorticoids corticosterone and cortisol. Neurons in the nucleus tractus solitarii (NTS) express MR, which mediate selectively the action of aldosterone on salt appetite, sympathetic outflow and volume regulation. The MR-containing NTS neurons innervate limbic-forebrain circuits enabling aldosterone to also modulate reciprocally arousal, motivation, fear and reward...
January 13, 2017: Physiology & Behavior
https://www.readbyqxmd.com/read/28088078/genetically-tailored-magnetosomes-used-as-mri-probe-for-molecular-imaging-of-brain-tumor
#9
M Boucher, F Geffroy, S Prévéral, L Bellanger, E Selingue, G Adryanczyk-Perrier, M Péan, C T Lefèvre, D Pignol, N Ginet, S Mériaux
We investigate here the potential of single step production of genetically engineered magnetosomes, bacterial biogenic iron-oxide nanoparticles embedded in a lipid vesicle, as a new tailorable magnetic resonance molecular imaging probe. We demonstrate in vitro the specific binding and the significant internalization into U87 cells of magnetosomes decorated with RGD peptide. After injection at the tail vein of glioblastoma-bearing mice, we evidence in the first 2 h the rapid accumulation of both unlabeled and functionalized magnetosomes inside the tumor by Enhanced Permeability and Retention effects...
December 19, 2016: Biomaterials
https://www.readbyqxmd.com/read/28086888/non-rigid-mr-trus-image-registration-for-image-guided-prostate-biopsy-using-correlation-ratio-based-mutual-information
#10
Lun Gong, Haifeng Wang, Chengtao Peng, Yakang Dai, Min Ding, Yinghao Sun, Xiaodong Yang, Jian Zheng
BACKGROUND: To improve the accuracy of ultrasound-guided biopsy of the prostate, the non-rigid registration of magnetic resonance (MR) images onto transrectal ultrasound (TRUS) images has gained increasing attention. Mutual information (MI) is a widely used similarity criterion in MR-TRUS image registration. However, the use of MI has been challenged because of intensity distortion, noise and down-sampling. Hence, we need to improve the MI measure to get better registration effect. METHODS: We present a novel two-dimensional non-rigid MR-TRUS registration algorithm that uses correlation ratio-based mutual information (CRMI) as the similarity criterion...
January 10, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28077817/prognostic-significance-of-non-dilated-left-ventricular-size-and-mitral-regurgitation-in-patients-with-dilated-phase-of-hypertrophic-cardiomyopathy
#11
Toru Kubo, Yuichi Baba, Takayoshi Hirota, Katsutoshi Tanioka, Naohito Yamasaki, Yoshinori L Doi, Hiroaki Kitaoka
Although a subtype of hypertrophic cardiomyopathy (HCM), dilated phase of HCM (D-HCM) characterized by left ventricular (LV) systolic dysfunction, has been reported to have a poor prognosis, some patients with D-HCM survive for a relatively long period. The degree of LV dilatation and functional mitral regurgitation (MR) are generally thought to be important predictors of poor prognosis in patients with LV systolic dysfunction. However, there is little information available on the relations among LV size, presence of significant MR, and prognosis in D-HCM patients...
January 11, 2017: International Heart Journal
https://www.readbyqxmd.com/read/28077268/development-of-high-resolution-3d-hyperpolarized-carbon-13-mr-molecular-imaging-techniques
#12
Eugene Milshteyn, Cornelius von Morze, Galen D Reed, Hong Shang, Peter J Shin, Zihan Zhu, Hsin-Yu Chen, Robert Bok, Andrei Goga, John Kurhanewicz, Peder E Z Larson, Daniel B Vigneron
The goal of this project was to develop and apply techniques for T2 mapping and 3D high resolution (1.5 mm isotropic; 0.003 cm(3)) (13)C imaging of hyperpolarized (HP) probes [1-(13)C]lactate, [1-(13)C]pyruvate, [2-(13)C]pyruvate, and [(13)C,(15)N2]urea in vivo. A specialized 2D bSSFP sequence was implemented on a clinical 3T scanner and used to obtain the first high resolution T2 maps of these different hyperpolarized compounds in both rats and tumor-bearing mice. These maps were first used to optimize timings for highest SNR for single time-point 3D bSSFP acquisitions with a 1...
January 7, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28076368/functional-laterality-of-task-evoked-activation-in-sensorimotor-cortex-of-preterm-infants-an-optimized-3-t-fmri-study-employing-a-customized-neonatal-head-coil
#13
Lukas Scheef, Jurek A Nordmeyer-Massner, Adam Pr Smith-Collins, Nicole Müller, Gaby Stegmann-Woessner, Jacob Jankowski, Jürgen Gieseke, Mark Born, Hermann Seitz, Peter Bartmann, Hans H Schild, Klaas P Pruessmann, Axel Heep, Henning Boecker
BACKGROUND: Functional magnetic resonance imaging (fMRI) in neonates has been introduced as a non-invasive method for studying sensorimotor processing in the developing brain. However, previous neonatal studies have delivered conflicting results regarding localization, lateralization, and directionality of blood oxygenation level dependent (BOLD) responses in sensorimotor cortex (SMC). Amongst the confounding factors in interpreting neonatal fMRI studies include the use of standard adult MR-coils providing insufficient signal to noise, and liberal statistical thresholds, compromising clinical interpretation at the single subject level...
2017: PloS One
https://www.readbyqxmd.com/read/28076003/reducing-functional-mr-imaging-acquisition-times-by-optimizing-workflow
#14
Wilson B Chwang, Michael Iv, Jason Smith, Aleksandrs Kalnins, Jake Mickelsen, Roland Bammer, Dominik Fleischmann, David B Larson, Max Wintermark, Michael Zeineh
Functional magnetic resonance (MR) imaging is a complex, specialized examination that is able to noninvasively measure information critical to patient care such as hemispheric language lateralization ( 1 ). Diagnostic functional MR imaging requires extensive patient interaction as well as the coordinated efforts of the entire health care team. We observed in our practice at an academic center that the times to perform functional MR imaging examinations were excessively lengthy, making scheduling of the examination difficult...
January 2017: Radiographics: a Review Publication of the Radiological Society of North America, Inc
https://www.readbyqxmd.com/read/28070866/finite-element-analysis-of-patient-specific-mitral-valve-with-mitral-regurgitation
#15
Thuy Pham, Fanwei Kong, Caitlin Martin, Qian Wang, Charles Primiano, Raymond McKay, John Elefteriades, Wei Sun
Functional mitral regurgitation (FMR) is a significant complication of left ventricular dysfunction and strongly associated with a poor prognosis. In this study, we developed a patient-specific finite element (FE) model of the mitral apparatus in a FMR patient which included: both leaflets with thickness, annulus, chordae tendineae, and chordae insertions on the leaflets and origins on the papillary muscles. The FE model incorporated human age- and gender-matched anisotropic hyperelastic material properties, and MV closure at systole was simulated...
January 9, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/28070844/gd-eob-dtpa-enhanced-mri-t1-mapping-for-assessment-of-liver-function-in-rabbit-fibrosis-model-comparison-of-hepatobiliary-phase-images-obtained-at-10-and-20%C3%A2-min
#16
Zhi-Peng Zhou, Li-Ling Long, Li-Juan Huang, Teng-Fei Yang, Zhong-Kui Huang
OBJECTIVES: To compare hepatobiliary phase (HBP) images obtained at 10 and 20 min after Gd-EOB-DTPA-enhanced MRI for assessment of liver function in rabbit fibrosis model on 3.0 T MR imaging. METHODS: 34 animals were separated into three groups: 5 for a control group, 14 for a mild fibrosis group, and 15 for a severe fibrosis group based on pathological proof. T1 relaxation times (T1rt) were measured on T1 mapping and reduction rates of T1rt (rrT1rt) were calculated...
January 9, 2017: La Radiologia Medica
https://www.readbyqxmd.com/read/28069456/neurocardiac-protection-with-milrinone-for-restoring-acute-cerebral-hypoperfusion-and-delayed-ischemic-injury-after-experimental-subarachnoid-hemorrhage
#17
Tomoko Mutoh, Tatsushi Mutoh, Kazumasu Sasaki, Kazuhiro Nakamura, Yasuko Tatewaki, Tatsuya Ishikawa, Yasuyuki Taki
BACKGROUND AND PURPOSE: Acute cerebral hypoperfusion following subarachnoid hemorrhage (SAH) is highly related to the pathogenesis of delayed cerebral ischemia (DCI), but the therapeutic option is poorly available. This study aimed to clarify the effect of milrinone (MIL) on cerebral blood flow (CBF) and related outcomes after experimental SAH. METHODS: Twenty-seven male C57BL/6 mice were assigned to either sham surgery (SAH-sham; n=6), SAH induced by endovascular perforation (control; n=10), or SAH followed by cardiac support with intravenous MIL (n=11) performed 1...
January 6, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/28067754/moderate-renal-failure-accentuates-t1-signal-enhancement-in-the-deep-cerebellar-nuclei-of-gadodiamide-treated-rats
#18
Marlène Rasschaert, Jean-Marc Idée, Philippe Robert, Nathalie Fretellier, Véronique Vives, Xavier Violas, Sébastien Ballet, Claire Corot
OBJECTIVES: The purpose of this preclinical study was to investigate whether moderate chronic kidney disease is a factor in potentiating gadolinium (Gd) uptake in the brain. MATERIALS AND METHODS: A comparative study was performed on renally impaired (subtotal nephrectomy) rats versus rats with normal renal function. The animals received 4 daily injections of 0.6 mmol Gd/kg a week for 5 weeks (cumulative dose of 12 mmol Gd/kg) of gadodiamide or saline solution. The MR signal enhancement in the deep cerebellar nuclei was monitored by weekly magnetic resonance imaging examinations...
November 28, 2016: Investigative Radiology
https://www.readbyqxmd.com/read/28066808/effect-of-mr-imaging-contrast-thresholds-on-prediction-of-neoadjuvant-chemotherapy-response-in-breast-cancer-subtypes-a-subgroup-analysis-of-the-acrin-6657-i-spy-1-trial
#19
Wen Li, Vignesh Arasu, David C Newitt, Ella F Jones, Lisa Wilmes, Jessica Gibbs, John Kornak, Bonnie N Joe, Laura J Esserman, Nola M Hylton
Functional tumor volume (FTV) measurements by dynamic contrast-enhanced magnetic resonance imaging can predict treatment outcomes for women receiving neoadjuvant chemotherapy for breast cancer. Here, we explore whether the contrast thresholds used to define FTV could be adjusted by breast cancer subtype to improve predictive performance. Absolute FTV and percent change in FTV (ΔFTV) at sequential time-points during treatment were calculated and investigated as predictors of pathologic complete response at surgery...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28063694/post-wbrt-cognitive-impairment-and-hippocampal-neuronal-depletion-measured-by-in-vivo-metabolic-mr-spectroscopy-results-of-prospective-investigational-study
#20
Petr Pospisil, Tomas Kazda, Ludmila Hynkova, Martin Bulik, Marie Dobiaskova, Petr Burkon, Nadia N Laack, Pavel Slampa, Radim Jancalek
BACKGROUND AND PURPOSE: The aim of this prospective study is to evaluate post-whole brain radiotherapy (WBRT) changes in hippocampal concentration of N-acetylaspartate (h-tNAA) as a marker of neuronal loss and to correlate those changes to neurocognitive function. MATERIAL AND METHODS: Thirty-five patients with brain metastases underwent baseline single slice multi-voxel MR spectroscopy (MRS) examination for measurement of hippocampal h-tNAA together with baseline battery of neurocognitive tests focused on memory (Auditory Verbal Learning Test and Brief Visuospatial Memory Test - Revised) as well as quality of life questionnaires (EORTC QLQ-C30 a EORTC QLQ-BN20)...
January 4, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
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