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https://www.readbyqxmd.com/read/28092785/integrated-ssfp-for-functional-brain-mapping-at-7t-with-reduced-susceptibility-artifact
#1
Kaibao Sun, Rong Xue, Peng Zhang, Zhentao Zuo, Zhongwei Chen, Bo Wang, Thomas Martin, Yi Wang, Lin Chen, Sheng He, Danny J J Wang
Balanced steady-state free precession (bSSFP) offers an alternative and potentially important tool to the standard gradient-echo echo-planar imaging (GE-EPI) for functional MRI (fMRI). Both passband and transition band based bSSFP have been proposed for fMRI. The applications of these methods, however, are limited by banding artifacts due to the sensitivity of bSSFP signal to off-resonance effects. In this article, a unique case of the SSFP-FID sequence, termed integrated-SSFP or iSSFP, was proposed to overcome the obstacle by compressing the SSFP profile into the width of a single voxel...
December 30, 2016: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28092580/determination-of-the-edge-of-criticality-in-echo-state-networks-through-fisher-information-maximization
#2
Lorenzo Livi, Filippo Maria Bianchi, Cesare Alippi
It is a widely accepted fact that the computational capability of recurrent neural networks (RNNs) is maximized on the so-called "edge of criticality." Once the network operates in this configuration, it performs efficiently on a specific application both in terms of: 1) low prediction error and 2) high short-term memory capacity. Since the behavior of recurrent networks is strongly influenced by the particular input signal driving the dynamics, a universal, application-independent method for determining the edge of criticality is still missing...
January 16, 2017: IEEE Transactions on Neural Networks and Learning Systems
https://www.readbyqxmd.com/read/28092533/linear-system-models-for-ultrasonic-imaging-intensity-signal-statistics
#3
Craig Abbey, Yang Zhu, Sara Bahramian, Michael Insana
Despite a great deal of work characterizing the statistical properties of radio-frequency backscattered ultrasound signals, less is known about the statistical properties of demodulated intensity signals. Analysis of intensity is made more difficult by a strong nonlinearity that arises in the process of demodulation. This limits our ability to characterize the spatial resolution and noise properties of B-mode ultrasound images. In this work, we generalize earlier results on two-point intensity covariance using a multivariate systems approach...
January 16, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28092527/block-matching-distortion-correction-of-echo-planar-images-with-opposite-phase-encoding-directions
#4
Renaud Hedouin, Olivier Commowick, Elise Bannier, Benoit Scherrer, Maxime Taquet, Simon Warfield, Christian Barillot
By shortening the acquisition time of MRI, Echo Planar Imaging (EPI) enables the acqui- sition of a large number of images in a short time, com- patible with clinical constraints as required for diffusion or functional MRI. However such images are subject to large, local distortions disrupting their correspondence with the underlying anatomy. The correction of those distortions is an open problem, especially in regions where large deformations occur. We propose a new block-matching registration method to perform EPI distortion correction based on the acquisition of two EPI with opposite phase encoding directions (PED)...
January 9, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28092272/material-dependent-implant-artifact-reduction-using-semac-vat-and-mavric-a-prospective-mri-phantom-study
#5
Lukas Filli, Lukas Jud, Roger Luechinger, Daniel Nanz, Gustav Andreisek, Val M Runge, Sebastian Kozerke, Nadja A Farshad-Amacker
OBJECTIVE: The aim of this study was to compare the degree of artifact reduction in magnetic resonance imaging achieved with slice encoding for metal artifact correction (SEMAC) in combination with view angle tilting (VAT) and multiacquisition variable resonance image combination (MAVRIC) for standard contrast weightings and different metallic materials. METHODS: Four identically shaped rods made of the most commonly used prosthetic materials (stainless steel, SS; titanium, Ti; cobalt-chromium-molybdenum, CoCr; and oxidized zirconium, oxZi) were scanned at 3 T...
January 13, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28092268/phenotypic-outcomes-in-mouse-and-human-foxc1-dependent-dandy-walker-cerebellar-malformation-suggest-shared-mechanisms
#6
Parthiv Haldipur, Derek Dang, Kimberly A Aldinger, Olivia K Janson, Fabien Guimiot, Homa Adle-Biasette, William B Dobyns, Joseph R Siebert, Rosa Russo, Kathleen J Millen
FOXC1 loss contributes to Dandy-Walker malformation (DWM), a common human cerebellar malformation.  Previously we found that complete Foxc1 loss leads to aberrations in proliferation, neuronal differentiation and migration in the embryonic mouse cerebellum (Haldipur et al., 2014). We now demonstrate that hypomorphic Foxc1 mutant mice have granule and Purkinje cell abnormalities causing subsequent disruptions in postnatal cerebellar foliation and lamination. Particularly striking is the presence of a partially formed posterior lobule echoing the posterior vermis DW "tail sign" observed in human imaging studies...
January 16, 2017: ELife
https://www.readbyqxmd.com/read/28092058/sub-regional-assessment-of-hpv-vaccination-among-female-adolescents-in-the-intermountain-west-and-implications-for-intervention-opportunities
#7
Julia Bodson, Qian Ding, Echo L Warner, Amy J Hawkins, Kevin A Henry, Deanna Kepka
Objectives We investigated the similarities and differences in the factors related to human papillomavirus (HPV) vaccination of female adolescents in three sub-regions of the Intermountain West (IW). Methods We analyzed 2011-2012 National Immunization Survey-Teen data. Respondents (parents) who were living in the IW and who had daughters aged 13-17 years old with provider-verified immunization records were included in our analyses. East, Central, and West sub-regions were defined based on geographic contiguity and similarity in HPV vaccination rates and sociodemographic characteristics...
January 13, 2017: Maternal and Child Health Journal
https://www.readbyqxmd.com/read/28091836/assessment-of-edema-using-stir-via-3d-cardiovascular-magnetic-resonance-imaging-in-patients-with-suspected-myocarditis
#8
Michael Jeserich, Bela Merkely, Pascal Schlosser, Simone Kimmel, Gabor Pavlik, Stephan Achenbach
OBJECTIVE: To evaluate three-dimensional T2-weighted fast spin echo triple inversion recovery sequences (STIR+) for the diagnosis of myocardial edema in patients with suspected early myocarditis after respiratory or gastrointestinal tract viral infection and at follow-up. MATERIALS AND METHODS: We prospectively examined 28 patients with suspected myocarditis and 37 controls matched for gender and age. An ECG-triggered STIR+ was used to cover the entire left ventricle in short-axis images with 10-mm slice thickness and no interslice gap...
January 16, 2017: Magma
https://www.readbyqxmd.com/read/28090666/quantitative-ultrashort-echo-time-imaging-for-assessment-of-massive-iron-overload-at-1-5-and-3-tesla
#9
Axel J Krafft, Ralf B Loeffler, Ruitian Song, Aaryani Tipirneni-Sajja, M Beth McCarville, Matthew D Robson, Jane S Hankins, Claudia M Hillenbrand
PURPOSE: Hepatic iron content (HIC) quantification via transverse relaxation rate (R2*)-MRI using multi-gradient echo (mGRE) imaging is compromised toward high HIC or at higher fields due to the rapid signal decay. Our study aims at presenting an optimized 2D ultrashort echo time (UTE) sequence for R2* quantification to overcome these limitations. METHODS: Two-dimensional UTE imaging was realized via half-pulse excitation and radial center-out sampling. The sequence includes chemically selective saturation pulses to reduce streaking artifacts from subcutaneous fat, and spatial saturation (sSAT) bands to suppress out-of-slice signals...
January 16, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28090656/real-time-monitoring-of-tissue-displacement-and-temperature-changes-during-mr-guided-high-intensity-focused-ultrasound
#10
Pierre Bour, Fabrice Marquet, Valéry Ozenne, Solenn Toupin, Erik Dumont, Jean-François Aubry, Matthieu Lepetit-Coiffe, Bruno Quesson
PURPOSE: The therapy endpoint most commonly used in MR-guided high intensity focused ultrasound is the thermal dose. Although namely correlated with nonviable tissue, it does not account for changes in mechanical properties of tissue during ablation. This study presents a new acquisition sequence for multislice, subsecond and simultaneous imaging of tissue temperature and displacement during ablation. METHODS: A single-shot echo planar imaging sequence was implemented using a pair of motion-encoding gradients, with alternated polarities...
January 16, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28090589/spiral-perfusion-imaging-with-consecutive-echoes-spice%C3%A2-for-the-simultaneous-mapping-of-dsc-and-dce-mri-parameters-in-brain-tumor-patients-theory-and-initial-feasibility
#11
Eric S Paulson, Douglas E Prah, Kathleen M Schmainda
Dynamic contrast-enhanced (DCE) and dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) are the perfusion imaging techniques most frequently used to probe the angiogenic character of brain neoplasms. With these methods, T1- and T2/T2*-weighted imaging sequences are used to image the distribution of gadolinium (Gd)-based contrast agents. However, it is well known that Gd exhibits combined T1, T2, and T2* shortening effects in tissue, and therefore, the results of both DCE- and DSC-MRI can be confounded by these opposing effects...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28090450/quantitative-magnetic-resonance-imaging-of-the-lumbar-intervertebral-discs
#12
REVIEW
Dosik Hwang, Sewon Kim, Nirusha A Abeydeera, Sheronda Statum, Koichi Masuda, Christine B Chung, Palanan Siriwanarangsun, Won C Bae
Human lumbar spine is composed of multiple tissue components that serve to provide structural stability and proper nutrition. Conventional magnetic resonance (MR) imaging techniques have been useful for evaluation of IVD, but inadequate at imaging the discovertebral junction and ligamentous tissues due primarily to their short T2 nature. Ultrashort time to echo (UTE) MR techniques acquire sufficient MR signal from these short T2 tissues, thereby allowing direct and quantitative evaluation. This article discusses the anatomy of the lumbar spine, MR techniques available for morphologic and quantitative MR evaluation of long and short T2 tissues of the lumbar spine, considerations for T2 relaxation modeling and fitting, and existing and new techniques for spine image post-processing, focusing on segmentation...
December 2016: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28090449/ultrashort-time-to-echo-magnetic-resonance-techniques-for-the-musculoskeletal-system
#13
REVIEW
Palanan Siriwanarangsun, Sheronda Statum, Reni Biswas, Won C Bae, Christine B Chung
Magnetic resonance (MR) imaging has been widely implemented as a non-invasive modality to investigate musculoskeletal (MSK) tissue disease, injury, and pathology. Advancements in MR sequences provide not only enhanced morphologic contrast for soft tissues, but also quantitative biochemical evaluation. Ultrashort time to echo (UTE) sequence, in particular, enables novel morphologic and quantitative evaluation of previously unseen MSK tissues. By using short minimum echo times (TE) below 1 msec, the UTE sequence can unveil short T2 properties of tissues including the deepest layers of the articular cartilage, cartilaginous endplate at the discovertebral junction, the meniscus, and the cortical bone...
December 2016: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28090444/bone-marrow-edema-like-lesions-bmels-are-associated-with-higher-t1%C3%AF-and-t2-values-of-cartilage-in-anterior-cruciate-ligament-acl-reconstructed-knees-a-longitudinal-study
#14
Jingshan Gong, Valentina Pedoia, Luca Facchetti, Thomas M Link, C Benjamin Ma, Xiaojuan Li
BACKGROUND: To evaluate the longitudinal changes of bone marrow edema-like lesions (BMELs) in patients after anterior cruciate ligament (ACL) reconstruction and to investigate the effect of BMELs on cartilage matrix composition changes measured using MR T1ρ and T2 mapping. METHODS: Patients with acute ACL tear were enrolled in a prospective study. MR imaging was performed at baseline (before surgeries) and at 6-month, 1-year and 2-year after ACL reconstruction...
December 2016: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28090263/right-atrial-paraganglioma-an-extremely-rare-primary-cardiac-neoplasm-mimicking-myxoma
#15
Ashok Garg, Deepika Mishra, Manish Bansal, Hari Ram Maharia, Vikram Goyal
In this report, we present a case of 35-year-old lady who had presented with atypical chest pain and exertional breathlessness for past six months. Transthoracic and transesophageal echocardiograms showed a well-circumscribed, echo-dense mass in the right atrium, attached to the interatrial septum at the level of atrioventricular junction and in the vicinity of coronary sinus ostium. She underwent successful resection of the cardiac mass. Histopathology revealed paraganglioma, which was reconfirmed by immunohistochemistry study...
December 2016: Journal of Cardiovascular Ultrasound
https://www.readbyqxmd.com/read/28089491/satellite-and-central-transitions-selective-1-h-27-al-d-hmqc-experiments-at-very-fast-mas-for-quadrupolar-couplings-determination
#16
Nghia Tuan Duong, Yusuke Nishiyama
Recent study has demonstrated the application of the proton-detected heteronuclear multi-quantum coherence (HMQC) at ultrafast Magic Angle Spinning (MAS) to probe quadrupolar nuclei including (14)N and (35)Cl. In addition, for half-integer quadrupolar nucleus like (35)Cl, the quadrupolar product can be calculated based on the shift difference between the center band of satellite transition (ST) and the central transition (CT) peaks. The applicability of this technique is further investigated on spin I=5/2, namely (27)Al nucleus, and kaolin is chosen as the testing sample...
January 4, 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/28089254/volumetric-analysis-of-carotid-plaque-components-and-cerebral-microbleeds-a-correlative-study
#17
Luca Saba, Roberto Sanfilippo, Michele di Martino, Michele Porcu, Roberto Montisci, Pierleone Lucatelli, Michele Anzidei, Marco Francone, Jasjit S Suri
PURPOSE: The purpose of this work was to explore the association between carotid plaque volume (total and the subcomponents) and cerebral microbleeds (CMBs). MATERIALS AND METHODS: Seventy-two consecutive (male 53; median age 64) patients were retrospectively analyzed. Carotid arteries were studied by using a 16-detector-row computed tomography scanner whereas brain was explored with a 1.5 Tesla system. CMBs were studied using a T2*-weighted gradient-recalled echo sequence...
January 11, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28089034/echoing-concerns-related-to-endoscope-reprocessing
#18
EDITORIAL
Kavel Visrodia, Bret T Petersen
No abstract text is available yet for this article.
February 2017: Gastrointestinal Endoscopy
https://www.readbyqxmd.com/read/28088917/effects-of-heart-valve-prostheses-on-phase-contrast-flow-measurements-in-cardiovascular-magnetic-resonance-a-phantom-study
#19
Johanna Richau, Matthias A Dieringer, Julius Traber, Florian von Knobelsdorff-Brenkenhoff, Andreas Greiser, Carsten Schwenke, Jeanette Schulz-Menger
BACKGROUND: Cardiovascular Magnetic Resonance is often used to evaluate patients after heart valve replacement. This study systematically analyses the influence of heart valve prostheses on phase contrast measurements in a phantom trial. METHODS: Two biological and one mechanical aortic valve prostheses were integrated in a flow phantom. B0 maps and phase contrast measurements were acquired at a 1.5 T MR scanner using conventional gradient-echo sequences in predefined distances to the prostheses...
January 16, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/28088311/prevalence-of-preoperative-penile-abnormalities-among-voluntary-male-medical-circumcision-patients-in-swaziland
#20
Anthony R Oddo, Elizabeth Ruedrich, Christopher Zust, Lindsey Marugg, Echo VanderWal, Harry VanderWal, Rebekah Sartori, Ronald Markert, Mary C McCarthy
BACKGROUND: Circumcision has been found to be an effective strategy for lowering the transmission of HIV in Africa. The Luke Commission, a mobile hospital outreach program, has used this information to decrease the rate of HIV in Swaziland by performing voluntary male medical circumcisions throughout the country. During many of these circumcisions, genital medical conditions and penile abnormalities are simultaneously discovered and corrected. PURPOSE: The goal of our study was to evaluate the prevalence of penile abnormalities discovered and treated during voluntary male medical circumcisions performed by The Luke Commission (TLC) throughout rural Swaziland...
January 3, 2017: Journal of Pediatric Surgery
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