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https://www.readbyqxmd.com/read/28438709/characterization-of-high-resolution-gradient-echo-and-spin-echo-epi-for-fmri-in-the-human-visual-cortex-at-7t
#1
Catarina Rua, Mauro Costagli, Mark R Symms, Laura Biagi, Graziella Donatelli, Mirco Cosottini, Alberto Del Guerra, Michela Tosetti
The increased signal-to-noise ratio (SNR) offered by functional Magnetic Resonance Imaging (fMRI) at 7T allows the acquisition of functional data at sub-millimetric spatial resolutions. However, simply reducing partial volume effects is not sufficient to precisely localize task-induced activation due to the indirect mechanisms that relate brain function and the changes in the measured signal. In this work T2* and T2 weighted Echo Planar Imaging (EPI) schemes based on Gradient Recalled Echo (GRE) and Spin Echo (SE) were evaluated in terms of temporal SNR, percent signal change, contrast to noise ratio (CNR), activation volume, and sensitivity and specificity to gray matter...
April 21, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28438298/intravoxel-incoherent-motion-magnetic-resonance-imaging-in-head-and-neck-cancer-a-systematic-review-of-the-diagnostic-and-prognostic-value
#2
REVIEW
Daniel P Noij, Roland M Martens, J Tim Marcus, Remco de Bree, C René Leemans, Jonas A Castelijns, Marcus C de Jong, Pim de Graaf
Intravoxel incoherent motion (IVIM) imaging is increasingly applied in the assessment of head and neck cancer (HNC). Our purpose was to determine the diagnostic and prognostic performance of IVIM in HNC by performing a critical review of the literature. Pubmed and EMBASE were searched until May 2016. Study and patients characteristics, imaging protocol and diagnostic or prognostic outcomes were extracted by 2 independent reviewers. The studied IVIM parameters were diffusion coefficient (D), pseudodiffusion coefficient (D∗), and perfusion fraction (f)...
May 2017: Oral Oncology
https://www.readbyqxmd.com/read/28432796/an-acetone-based-phantom-for-quantitative-diffusion-mri
#3
Xiaoke Wang, Scott B Reeder, Diego Hernando
PURPOSE: To propose and evaluate an acetone-D2 O phantom that has an extended range of apparent diffusion coefficient (ADC) for quantitative diffusion magnetic resonance imaging (MRI), as well as to compare its properties to previously described water-based phantoms. MATERIALS AND METHODS: The proposed acetone-D2 O, and previously described sucrose water solution and polyvinylpyrrolidone (PVP) water solution phantoms, were constructed in a number of concentrations between 0% and 50%...
April 22, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28430583/non-invasive-prediction-of-the-tumor-growth-rate-using-advanced-diffusion-models-in-head-and-neck-squamous-cell-carcinoma-patients
#4
Noriyuki Fujima, Tomohiro Sakashita, Akihiro Homma, Taisuke Harada, Yukie Shimizu, Khin Khin Tha, Kohsuke Kudo, Hiroki Shirato
We assessed parameters of advanced diffusion weighted imaging (DWI) models for the prediction of the tumor growth rate in 55 head and neck squamous cell carcinoma (HNSCC) patients. The DWI acquisition used single-shot spin-echo echo-planar imaging with 12 b-values (0-2000). We calculated 14 DWI parameters using mono-exponential, bi-exponential, tri-exponential, stretched exponential and diffusion kurtosis imaging models. We directly measured the tumor growth rate from two sets of different-date imaging data...
April 5, 2017: Oncotarget
https://www.readbyqxmd.com/read/28424572/functional-sensitivity-of-2d-simultaneous-multi-slice-echo-planar-imaging-effects-of-acceleration-on-g-factor-and-physiological-noise
#5
Nick Todd, Oliver Josephs, Peter Zeidman, Guillaume Flandin, Steen Moeller, Nikolaus Weiskopf
Accelerated data acquisition with simultaneous multi-slice (SMS) imaging for functional MRI studies leads to interacting and opposing effects that influence the sensitivity to blood oxygen level-dependent (BOLD) signal changes. Image signal to noise ratio (SNR) is decreased with higher SMS acceleration factors and shorter repetition times (TR) due to g-factor noise penalties and saturation of longitudinal magnetization. However, the lower image SNR is counteracted by greater statistical power from more samples per unit time and a higher temporal Nyquist frequency that allows for better removal of spurious non-BOLD high frequency signal content...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28423540/correlations-between-intravoxel-incoherent-motion-ivim-parameters-and-histological-findings-in-rectal-cancer-preliminary-results
#6
Alexey Surov, Hans Jonas Meyer, Anne-Kathrin Höhn, Curd Behrmann, Andreas Wienke, Rolf Peter Spielmann, Nikita Garnov
Our purpose was to correlate different intravoxel incoherent motion (IVIM), histopathological and clinical parameters in rectal cancer. 17 patients with histologically proven rectal cancer investigated on a 3.T device were included into the study. DWI was performed using a multi-slice single-shot echo-planar imaging sequence with b values of 0, 50, 200, 500 and 1000 s/mm.2 A polygonal region of interest was drawn within the tumors on every b image. The following parameters were retrieved from IVIM: apparent diffusion coefficient (ADC), true diffusion (D), pseudo diffusion coefficient (D*), perfusion factor (f), and relative perfusion f·D*...
March 28, 2017: Oncotarget
https://www.readbyqxmd.com/read/28419851/an-emergent-functional-parcellation-of-the-temporal-cortex
#7
REVIEW
Rebecca L Jackson, Claude J Bajada, Grace E Rice, Lauren L Cloutman, Matthew A Lambon Ralph
The temporal lobe has been associated with various cognitive functions which include memory, auditory cognition and semantics. However, at a higher level of conceptualisation, all of the functions associated with the temporal lobe can be considered as lying along one major axis; from modality-specific to modality-general processing. This paper used a spectral reordering technique on resting-state and task-based functional data to extract the major organisational axis of the temporal lobe in a bottom-up, data-driven fashion...
April 15, 2017: NeuroImage
https://www.readbyqxmd.com/read/28410964/comparison-of-turbo-spin-echo-and-echo-planar-imaging-for-intravoxel-incoherent-motion-and-diffusion-tensor-imaging-of-the-kidney-at-3tesla
#8
Fabian Hilbert, Tobias Wech, Henning Neubauer, Simon Veldhoen, Thorsten Alexander Bley, Herbert Köstler
Echo Planar Imaging (EPI) is most commonly applied to acquire diffusion-weighted MR-images. EPI is able to capture an entire image in very short time, but is prone to distortions and artifacts. In diffusion-weighted EPI of the kidney severe distortions may occur due to intestinal gas. Turbo Spin Echo (TSE) is robust against distortions and artifacts, but needs more time to acquire an entire image compared to EPI. Therefore, TSE is more sensitive to motion during the readout. In this study we compare diffusion-weighted TSE and EPI of the human kidney with regard to intravoxel incoherent motion (IVIM) and diffusion tensor imaging (DTI)...
April 12, 2017: Zeitschrift Für Medizinische Physik
https://www.readbyqxmd.com/read/28409563/glutamate-in-pediatric-obsessive-compulsive-disorder-and-response-to-cognitive-behavioral-therapy-randomized-clinical-trial
#9
Joseph O'Neill, John Piacentini, Susanna Chang, Ronald Ly, Tsz M Lai, Casey C Armstrong, Lindsey Bergman, Michelle Rozenman, Tara Peris, Allison Vreeland, Ross Mudgway, Jennifer G Levitt, Noriko Salamon, Stefan Posse, Gerhard S Hellemann, Jeffry R Alger, James T McCracken, Erika L Nurmi
Cognitive-behavioral therapy (CBT) is effective for pediatric obsessive-compulsive disorder (OCD), but non-response is common. Brain glutamate (Glu) signaling may contribute to OCD pathophysiology and moderate CBT outcomes. We assessed whether Glu measured with magnetic resonance spectroscopy (MRS) was associated with OCD and/or CBT response. Youths aged 8-17 with DSM-IV OCD and typically-developing controls underwent 3T proton echo-planar spectroscopic imaging (PEPSI) MRS scans of pregenual anterior cingulate cortex (pACC) and ventral posterior cingulate cortex (vPCC)-regions possibly affected by OCD-at baseline...
April 14, 2017: Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology
https://www.readbyqxmd.com/read/28408633/heterogeneity-of-cortical-lesion-susceptibility-mapping-in-multiple-sclerosis
#10
M Castellaro, R Magliozzi, A Palombit, M Pitteri, E Silvestri, V Camera, S Montemezzi, F B Pizzini, A Bertoldo, R Reynolds, S Monaco, M Calabrese
BACKGROUND AND PURPOSE: Quantitative susceptibility mapping has been used to characterize iron and myelin content in the deep gray matter of patients with multiple sclerosis. Our aim was to characterize the susceptibility mapping of cortical lesions in patients with MS and compare it with neuropathologic observations. MATERIALS AND METHODS: The pattern of microglial activation was studied in postmortem brain tissues from 16 patients with secondary-progressive MS and 5 age-matched controls...
April 13, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28396997/diffusion-weighted-dw-mri-in-lung-cancers-adc-test-retest-repeatability
#11
Alex Weller, Marianthi Vasiliki Papoutsaki, John C Waterton, Arturo Chiti, Sigrid Stroobants, Joost Kuijer, Matthew Blackledge, Veronica Morgan, Nandita M deSouza
PURPOSE: To determine the test-retest repeatability of Apparent Diffusion Coefficient (ADC) measurements across institutions and MRI vendors, plus investigate the effect of post-processing methodology on measurement precision. METHODS: Thirty malignant lung lesions >2 cm in size (23 patients) were scanned on two occasions, using echo-planar-Diffusion-Weighted (DW)-MRI to derive whole-tumour ADC (b = 100, 500 and 800smm(-2)). Scanning was performed at 4 institutions (3 MRI vendors)...
April 10, 2017: European Radiology
https://www.readbyqxmd.com/read/28394085/dual-echo-epi-sequence-for-integrated-distortion-correction-in-3d-time-resolved-hyperpolarized-13-c-mri
#12
Benjamin J Geraghty, Justin Y C Lau, Albert P Chen, Charles H Cunningham
PURPOSE: To provide built-in off-resonance correction in time-resolved, volumetric hyperpolarized (13) C metabolic imaging by implementing a novel dual-echo 3D echo-planar imaging (EPI) sequence and reconstruction. METHODS: A spectral-spatial pulse for single-resonance excitation followed by a dual-echo 3D EPI readout was implemented to provide 64 × 8 × 6 cm(3) coverage at 5 × 5 × 5 mm(3) nominal resolution. Multiple sources of EPI distortions were encoded using a multi-echo (1) H EPI reference scan...
April 10, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28382658/regional-assessment-of-in-vivo-myocardial-stiffness-using-3d-magnetic-resonance-elastography-in-a-porcine-model-of-myocardial-infarction
#13
Shivaram P Arunachalam, Arvin Arani, Francis Baffour, Joseph A Rysavy, Phillip J Rossman, Kevin J Glaser, David S Lake, Joshua D Trzasko, Armando Manduca, Kiaran P McGee, Richard L Ehman, Philip A Araoz
PURPOSE: The stiffness of a myocardial infarct affects the left ventricular pump function and remodeling. Magnetic resonance elastography (MRE) is a noninvasive imaging technique for measuring soft-tissue stiffness in vivo. The purpose of this study was to investigate the feasibility of assessing in vivo regional myocardial stiffness with high-frequency 3D cardiac MRE in a porcine model of myocardial infarction, and compare the results with ex vivo uniaxial tensile testing. METHODS: Myocardial infarct was induced in a porcine model by embolizing the left circumflex artery...
April 5, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28379055/performance-of-apparent-diffusion-coefficient-of-medial-and-lateral-rectus-muscles-in-graves-orbitopathy
#14
Ahmed Ak Abdel Razek, Mohamed El-Hadidy, Mohamed E Moawad, Nader El-Metwaly, Amr A El-Said
Objective The purpose of this study was to determine the performance of the apparent diffusion coefficient in the detection of involvement of the medial and lateral rectus muscles in patients with Graves' orbitopathy. Methods and materials This prospective study was conducted on 33 consecutive patients (16 males, 17 females with a mean age of 36 years) with Graves' orbitopathy and 18 age- and sex-matched volunteers. The patients and volunteers underwent diffusion-weighted magnetic resonance imaging of the orbit in the axial plane using echo-planar imaging...
January 1, 2017: Neuroradiology Journal
https://www.readbyqxmd.com/read/28358833/differentiation-of-malignant-and-benign-breast-lesions-added-value-of-the-qualitative-analysis-of-breast-lesions-on-diffusion-weighted-imaging-dwi-using-readout-segmented-echo-planar-imaging-at-3-0-t
#15
Yeong Yi An, Sung Hun Kim, Bong Joo Kang
OBJECTIVE: To determine the added value of qualitative analysis as an adjunct to quantitative analysis for the discrimination of benign and malignant lesions in patients with breast cancer using diffusion-weighted imaging (DWI) with readout-segmented echo-planar imaging (rs-EPI). METHODS: A total of 99 patients with 144 lesions were reviewed from our prospectively collected database. DWI data were obtained using rs-EPI acquired at 3.0 T. The diagnostic performances of DWI in the qualitative, quantitative, and combination analyses were compared with that of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI)...
2017: PloS One
https://www.readbyqxmd.com/read/28349894/application-value-of-diffusional-kurtosis-imaging-dki-in-evaluating-microstructural-changes-in-the-spinal-cord-of-patients-with-early-cervical-spondylotic-myelopathy
#16
Daowei Li, Xiaoming Wang
OBJECTIVE: To investigate the application value of diffusional kurtosis imaging (DKI) in evaluating microstructural changes in the spinal cord of patients with early cervical spondylotic myelopathy (CSM). PATIENTS AND METHODS: Twenty-five patients with early clinical stage CSM and twenty-five healthy controls underwent 3.0T MR scans with conventional MRI sequences and DKI with echo-planar imaging (EPI) sequence. DKI metrics such as fractional anisotropy (FA), mean diffusivity (MD), and mean diffusional kurtosis (MK) values were calculated separately for white matter (WM) and gray matter (GM)...
March 19, 2017: Clinical Neurology and Neurosurgery
https://www.readbyqxmd.com/read/28346330/differentiation-of-impaired-from-preserved-hemodynamics-in-patients-with-fontan-circulation-using-real-time-phase-velocity-cardiovascular-magnetic-resonance
#17
Hermann Körperich, Katja Müller, Peter Barth, Jürgen Gieseke, Nikolaus Haas, Ingram Schulze-Neick, Wolfgang Burchert, Deniz Kececioglu, Kai T Laser
PURPOSE: Progressive impairment of hemodynamics in patients with Fontan circulation is common, multifactorial, and associated with decreased quality of life and increased morbidity. We sought to assess hemodynamic differences between patients with preserved (preserved Fontans) and those with impaired circulation (impaired Fontans) after pulmonary vasodilation using oxygen and under forced breathing conditions. MATERIALS AND METHODS: Real-time phase-contrast cardiovascular magnetic resonance was performed using non-ECG triggered echo-planar imaging (temporal resolution=24 to 28 ms) in the ascending aorta (AAo) and superior vena cava (SVC)/inferior vena cava (IVC) on room air, after 100% oxygen inhalation (4 L/min; 10 min) and on forced breathing in 29 Fontan patients (17...
May 2017: Journal of Thoracic Imaging
https://www.readbyqxmd.com/read/28338417/a-3d-tissue-printing-approach-for-validation-of-diffusion-tensor-imaging-in-skeletal-muscle
#18
David B Berry, Shangting You, John Warner, Lawrence R Frank, Shaochen Chen, Samuel R Ward
The ability to noninvasively assess skeletal muscle microstructure, which predicts function and disease, would be of significant clinical value. One method that holds this promise is diffusion tensor magnetic resonance imaging (DT-MRI), which is sensitive to the microscopic diffusion of water within tissues and has become ubiquitous in neuroimaging as a way of assessing neuronal structure and damage. However, its application to the assessment of changes in muscle microstructure associated with injury, pathology, or age remains poorly defined, because it is difficult to precisely control muscle microstructural features in vivo...
March 24, 2017: Tissue Engineering. Part A
https://www.readbyqxmd.com/read/28333776/transcanal-endoscopic-ear-surgery-for-middle-ear-cholesteatoma
#19
Eran Glikson, Ruth Yousovich, Jobran Mansour, Michael Wolf, Lela Migirov, Yisgav Shapira
OBJECTIVE: To evaluate the clinical parameters, outcomes, and complications of transcanal endoscopic ear surgeries for middle ear cholesteatoma. STUDY DESIGN: Retrospective study. SETTING: Tertiary university-affiliated medical center. PATIENTS: Adult patients (age >18) who underwent transcanal endoscopic ear surgeries for cholesteatoma, between March 2009 and March 2015. INTERVENTION: Transcanal endoscopic surgery was indicated when the cholesteatoma did not extend posterior to the anterior limb of the lateral semicircular canal...
March 22, 2017: Otology & Neurotology
https://www.readbyqxmd.com/read/28332960/evaluation-of-transplanted-kidneys-and-comparison-with-healthy-volunteers-and-kidney-donors-with-diffusion-weighted-magnetic-resonance-imaging-initial-experience
#20
Ümit Özçelik, Halime Çevik, Hüseyin Yüce Bircan, Feza Yarbuğ Karakayalı, İclal Işıklar, Mehmet Haberal
OBJECTIVES: The aim of this study was to evaluate the feasibility of diffusion-weighted magnetic resonance, by comparing imaging in renal allograft recipients for functional assessment of kidney transplants versus imaging of these features in healthy volunteers and kidney donors with native kidneys. MATERIALS AND METHODS: Seventy renal transplant recipients (group A) with stable graft function at postoperative month 1, 40 healthy volunteers (group B), and 40 kidney donors (group C) underwent diffusion-weighted magnetic resonance imaging...
March 22, 2017: Experimental and Clinical Transplantation
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