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Echo Planar Imaging

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https://www.readbyqxmd.com/read/28333776/transcanal-endoscopic-ear-surgery-for-middle-ear-cholesteatoma
#1
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
#2
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
https://www.readbyqxmd.com/read/28331748/diagnostic-value-of-diffusion-weighted-imaging-and-apparent-diffusion-coefficient-values-in-the-differentiation-of-breast-lesions-histpathologic-subgroups-and-correlat%C3%A4-on-with-prognost%C3%A4-c-factors-using-3-0-tesla-mr
#3
Yasin Akın, M Ümit Uğurlu, Handan Kaya, Erkin Arıbal
OBJECTIVE: The aim of this study was to evaluate the effect of the apparent diffusion coefficient (ADC) and diffusion-weighted imaging in differentiating benign from malignant breast lesions, histopathologic subtypes of breast tumors, and to find a correlation with prognostic factors using 3T MR. MATERIALS AND METHODS: A total of 165 patients aged between 16 and 78 years with 181 histopathologically-verifed breast lesions were enrolled in this study. A 3T MR system and bilateral phased array breast coil was used...
July 2016: J Breast Health (2013)
https://www.readbyqxmd.com/read/28330685/renal-clear-cell-carcinoma-diffusion-tensor-imaging-diagnostic-accuracy-and-correlations-with-clinical-and-histopathological-factors
#4
Q Feng, W Fang, X P Sun, S H Sun, R M Zhang, Z J Ma
AIM: To investigate whether diffusion tensor imaging (DTI) can be used to assess renal clinical histopathology, including the nuclear grade (NG), cell density (CD), and the presence of ki-67. MATERIALS AND METHODS: Thirty patients were enrolled in the study and were confirmed at surgical histopathology to have clear cell renal cell carcinoma (CCRCC). For DTI, a coronal echo-planar imaging sequence was performed (1400 ms repetition time, 76 ms echo time, diffusion direction=6, number of excitations=4; b=0 and 800 s/mm(2), 6 mm section thickness with no intersection gap)...
March 19, 2017: Clinical Radiology
https://www.readbyqxmd.com/read/28330373/readout-segmented-echo-planar-diffusion-weighted-imaging-in-the-assessment-of-orbital-tumors-comparison-with-conventional-single-shot-echo-planar-imaging-in-image-quality-and-diagnostic-performance
#5
Xiaoquan Xu, Yanjun Wang, Hao Hu, Guoyi Su, Hu Liu, Haibin Shi, Feiyun Wu
Background Readout-segmented echo-planar imaging (RS-EPI) could improve the imaging quality of diffusion-weighted imaging (DWI) in various organs. However, whether it could improve the imaging quality and diagnostic performance for the patients with orbital tumors is still unknown. Purpose To compare the image quality and diagnostic performance of RS-EPI DWI with that of conventional single-shot EPI (SS-EPI) DWI in patients with orbital tumors. Material and Methods SS-EPI and RS-EPI DW images of 32 patients with pathologically diagnosed orbital tumors were retrospectively analyzed...
January 1, 2017: Acta Radiologica
https://www.readbyqxmd.com/read/28321904/rotating-single-shot-acquisition-rosa-with-composite-reconstruction-for-fast-high-resolution-diffusion-imaging
#6
Qiuting Wen, Chandana Kodiweera, Brian M Dale, Giri Shivraman, Yu-Chien Wu
PURPOSE: To accelerate high-resolution diffusion imaging, rotating single-shot acquisition (RoSA) with composite reconstruction is proposed. Acceleration was achieved by acquiring only one rotating single-shot blade per diffusion direction, and high-resolution diffusion-weighted (DW) images were reconstructed by using similarities of neighboring DW images. A parallel imaging technique was implemented in RoSA to further improve the image quality and acquisition speed. RoSA performance was evaluated by simulation and human experiments...
March 20, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28321902/modeling-real-shim-fields-for-very-high-degree-and-order-b0-shimming-of-the-human-brain-at-9-4%C3%A2-t
#7
Paul Chang, Sahar Nassirpour, Anke Henning
PURPOSE: To describe the process of calibrating a B0 shim system using high-degree (or high order) spherical harmonic models of the measured shim fields, to provide a method that considers amplitude dependency of these models, and to show the advantage of very high-degree B0 shimming for whole-brain and single-slice applications at 9.4 Tesla (T). METHODS: An insert shim with up to fourth and partial fifth/sixth degree (order) spherical harmonics was used with a Siemens 9...
March 20, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28321901/a-pneumatic-phantom-for-mimicking-respiration-induced-artifacts-in-spinal-mri
#8
Philippe De Tillieux, Ryan Topfer, Alexandru Foias, Iris Leroux, Imanne El Maâchi, Hugues Leblond, Nikola Stikov, Julien Cohen-Adad
PURPOSE: To design a phantom capable of mimicking human respiration to serve as a testing platform for correction of the static and time-evolving magnetic field distortions typically encountered in MRI of the spinal cord. METHODS: An inflation system to mimic the air variation of the human lungs was constructed. The inflation system was linked to a phantom containing synthetic lungs and an ex vivo human spine. The relationship between air pressure and phantom lung volume was evaluated via imaging experiment...
March 20, 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
#9
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/28295824/wavelet-entropy-of-bold-time-series-an-application-to-rolandic-epilepsy
#10
Lalit Gupta, Jacobus F A Jansen, Paul A M Hofman, René M H Besseling, Anton J A de Louw, Albert P Aldenkamp, Walter H Backes
PURPOSE: To assess the wavelet entropy for the characterization of intrinsic aberrant temporal irregularities in the time series of resting-state blood-oxygen-level-dependent (BOLD) signal fluctuations. Further, to evaluate the temporal irregularities (disorder/order) on a voxel-by-voxel basis in the brains of children with Rolandic epilepsy. MATERIALS AND METHODS: The BOLD time series was decomposed using the discrete wavelet transform and the wavelet entropy was calculated...
March 11, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28295820/comparison-of-readout-segmented-and-conventional-single-shot-for-echo-planar-diffusion-weighted-imaging-in-the-assessment-of-kidney-interstitial-fibrosis
#11
Iris Friedli, Lindsey Alexandra Crowe, Thomas de Perrot, Lena Berchtold, Pierre-Yves Martin, Sophie de Seigneux, Jean-Paul Vallée
PURPOSE: To compare readout-segmented echo-planar imaging (EPI) (RESOLVE) to single-shot EPI (ss-EPI) diffusion-weighted imaging (DWI) for the assessment of renal interstitial fibrosis. MATERIALS AND METHODS: A phantom, eight healthy volunteers (under 30 years to avoid age-fibrosis related) and 27 chronic kidney disease (CKD) patients (scheduled for kidney biopsy) were scanned (at 3T) with ss-EPI and 5-shot RESOLVE DWI (resolution: 2 × 2 × 5 mm(3) , 10 b-values)...
March 10, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28295736/diffusion-prepared-stimulated-echo-turbo-spin-echo-dpsti-tse-an-eddy-current-insensitive-sequence-for-three-dimensional-high-resolution-and-undistorted-diffusion-weighted-imaging
#12
Qinwei Zhang, Bram F Coolen, Maarten J Versluis, Gustav J Strijkers, Aart J Nederveen
In this study, we present a new three-dimensional (3D), diffusion-prepared turbo spin echo sequence based on a stimulated-echo read-out (DPsti-TSE) enabling high-resolution and undistorted diffusion-weighted imaging (DWI). A dephasing gradient in the diffusion preparation module and rephasing gradients in the turbo spin echo module create stimulated echoes, which prevent signal loss caused by eddy currents. Near to perfect agreement of apparent diffusion coefficient (ADC) values between DPsti-TSE and diffusion-weighted echo planar imaging (DW-EPI) was demonstrated in both phantom transient signal experiments and phantom imaging experiments...
March 13, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28291025/evaluation-of-reproducibility-of-diffusion-tensor-imaging-in-the-brachial-plexus-at-3-0-t
#13
Michael J Ho, Andrei Manoliu, Felix Pierre Kuhn, Bram Stieltjes, Markus Klarhöfer, Thorsten Feiweier, Magda Marcon, Gustav Andreisek
OBJECTIVE: The aim of this study was to evaluate the reproducibility of 3 T magnetic resonance imaging diffusion tensor imaging (DTI) of the brachial plexus in healthy subjects. METHODS: Ten healthy volunteers were included, and morphological and DTI sequences of the nerve roots of the brachial plexus from C5 to T1 of both sides were repeatedly acquired on a 3 T magnetic resonance system (MAGNETOM Skyra; Siemens Healthcare, Erlangen, Germany). A prototype diffusion-weighted single-shot echo-planar imaging sequence-enabling slice-specific shim adjustments was performed with b-values of 0 and 800 s/mm in 30 gradient directions, resulting in an acquisition time of about 6 minutes each in axial orientation...
March 13, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28274833/investigating-the-spatiotemporal-characteristics-of-the-deoxyhemoglobin-related-and-deoxyhemoglobin-unrelated-functional-hemodynamic-response-across-cortical-layers-in-awake-marmosets
#14
Cecil Chern-Chyi Yen, Daniel Papoti, Afonso C Silva
Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) has become a major tool to map neural activity. However, the spatiotemporal characteristics of the BOLD functional hemodynamic response across the cortical layers remain poorly understood. While human fMRI studies suffer from low spatiotemporal resolution, the use of anesthesia in animal models introduces confounding factors. Additionally, inflow contributions to the fMRI signal become non-negligible when short repetition times (TRs) are used...
March 6, 2017: NeuroImage
https://www.readbyqxmd.com/read/28270762/evaluation-of-field-map-and-nonlinear-registration-methods-for-correction-of-susceptibility-artifacts-in-diffusion-mri
#15
Sijia Wang, Daniel J Peterson, J C Gatenby, Wenbin Li, Thomas J Grabowski, Tara M Madhyastha
Correction of echo planar imaging (EPI)-induced distortions (called "unwarping") improves anatomical fidelity for diffusion magnetic resonance imaging (MRI) and functional imaging investigations. Commonly used unwarping methods require the acquisition of supplementary images during the scanning session. Alternatively, distortions can be corrected by nonlinear registration to a non-EPI acquired structural image. In this study, we compared reliability using two methods of unwarping: (1) nonlinear registration to a structural image using symmetric normalization (SyN) implemented in Advanced Normalization Tools (ANTs); and (2) unwarping using an acquired field map...
2017: Frontiers in Neuroinformatics
https://www.readbyqxmd.com/read/28269512/distribution-aware-estimation-of-the-minimum-achievable-uncertainty-in-diffusion-tensor-imaging-dti
#16
Andrea Duggento, Marco Giannelli, Carlo Tessa, Simona Lanzafame, Maria Guerrisi, Nicola Toschi
Diffusion tensor imaging (DTI) provides exquisite sensitivity to structural and microstructural characteristics of brain tissue, and is routinely employed in advanced neuroimaging applications. DTI is commonly performed using intrinsically noisy echo-planar imaging techniques and poses high demands both on scanner performance and on in-scanner subject time, which in turn is directly related to the number of diffusion-weighting direction one requires. While DTI-derived indices such as fractional anisotropy (FA), diffusion tensor trace and anisotropy mode have proven extremely useful in characterizing disease-related aberrations, their estimation is commonly performed using fitting routines that do not properly take into account MRI noise distribution...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268519/comprehensive-reconstruction-of-multi-shot-multi-channel-diffusion-data-using-mussels
#17
Merry Mani, Vincent Magnotta, Douglas Kelley, Mathews Jacob
Echo planar imaging (EPI)-based magnetic resonance imaging (MRI) data are often corrupted by Nyquist ghost artifacts resulting from odd-even shifts of the EPI read-outs. Algorithms that corrects for the Nyquist ghost artifacts rely on calibration scans that are collected prior to the data acquisition. However, a more complex pattern of ghosting artifacts arises when diffusion-weighted data are acquired using segmented k-space EPI read-outs. The additional under-sampling present in the segmented acquisitions and the inter-shot motion during diffusion weighted acquistion cause ghosting artifacts in addition to the EPI ghosting arising from odd-even shifts...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28263425/fast-bilateral-breast-coverage-with-high-spectral-and-spatial-resolution-hiss-mri-at-3t
#18
Milica Medved, Hui Li, Hiroyuki Abe, Deepa Sheth, Gillian M Newstead, Olufunmilayo I Olopade, Maryellen L Giger, Gregory S Karczmar
PURPOSE: To develop and assess a full-coverage, sensitivity encoding (SENSE)-accelerated breast high spatial and spectral resolution (HiSS) magnetic resonance imaging (MRI) within clinically reasonable times as a potential nonenhanced MRI protocol for breast density measurement or breast cancer screening. MATERIALS AND METHODS: Sixteen women with biopsy-proven cancer or suspicious lesions, and 13 women who were healthy volunteers or were screened for breast cancer, received 3T breast MRI exams, including SENSE-accelerated HiSS MRI, which was implemented as a submillimeter spatial resolution echo-planar spectroscopic imaging (EPSI) sequence...
March 6, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28261904/high-resolution-in-vivo-diffusion-imaging-of-the-human-brain-with-generalized-slice-dithered-enhanced-resolution-simultaneous-multislice-gslider-sms
#19
Kawin Setsompop, Qiuyun Fan, Jason Stockmann, Berkin Bilgic, Susie Huang, Stephen F Cauley, Aapo Nummenmaa, Fuyixue Wang, Yogesh Rathi, Thomas Witzel, Lawrence L Wald
PURPOSE: To develop an efficient acquisition for high-resolution diffusion imaging and allow in vivo whole-brain acquisitions at 600- to 700-μm isotropic resolution. METHODS: We combine blipped-controlled aliasing in parallel imaging simultaneous multislice (SMS) with a novel slab radiofrequency (RF) encoding gSlider (generalized slice-dithered enhanced resolution) to form a signal-to-noise ratio-efficient volumetric simultaneous multislab acquisition. Here, multiple thin slabs are acquired simultaneously with controlled aliasing, and unaliased with parallel imaging...
March 5, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28260287/-value-of-readout-segmented-echo-planar-diffusion-imaging-on-3-0-t-mri-for-predicting-the-early-efficacy-of-concurrent-radiochemotherapy-of-advanced-stage-nasopharyngeal-carcinoma-patients
#20
C M Xu, J H Yuan, X J Chen, J R Qu, L F Wang, Y Zhao, H K Zhang, H Ge, X M Sun, X X Zhang, H L Li
Objective: To discuss the value of RESOLVE for predicting early therapeutic effect of concourrent radiochemotherapy in advanced stage nasopharngeal carcinoma patients. Methods: Sixty-eight patients with nasopharyngeal carcinoma were confirmed by pathology in Henan Cancer Hospital from June 2014 to January 2016.All patients underwent RESLOVE(b value=800 s/mm(2)) with a 3.0 T MRI scanner.The ADC value and the area of the tumor was measured before treatment and 2 weeks after treatment independently performed by two radiologists with 5 years experiences and the agreement evaluation was performed using ANOVA analysis...
February 21, 2017: Zhonghua Yi Xue za Zhi [Chinese medical journal]
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