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Echo Planar Imaging

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https://www.readbyqxmd.com/read/28653477/radiomic-analysis-of-soft-tissues-sarcomas-can-distinguish-intermediate-from-high-grade-lesions
#1
Valentina D A Corino, Eros Montin, Antonella Messina, Paolo G Casali, Alessandro Gronchi, Alfonso Marchianò, Luca T Mainardi
PURPOSE: To assess the feasibility of grading soft tissue sarcomas (STSs) using MRI features (radiomics). MATERIALS AND METHODS: MRI (echo planar SE, 1.5T) from 19 patients with STSs and a known histological grading, were retrospectively analyzed. The apparent diffusion coefficient (ADC) maps, obtained by diffusion-weighted imaging acquisitions, were analyzed through 65 radiomic features, intensity-based (first order statistics, FOS) and texture (gray level co-occurrence matrix, GLCM; and gray level run length matrix, GLRLM) features...
June 27, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28653470/characterization-of-pseudo-continuous-arterial-spin-labeling-simulations-and-experimental-validation
#2
Kathrin Lorenz, Toralf Mildner, Torsten Schlumm, Harald E Möller
PURPOSE: To characterize pseudo-continuous arterial spin labeling (pCASL) through simulations of spin inversion and to discuss suitable parameter settings for measuring cerebral perfusion. METHODS: Simulations of arterial spin inversion in pCASL were performed based on the Bloch equation. Both the labeling and the control condition of pCASL were analyzed separately, and the labeling efficiency, α, was calculated depending on the averages of both, the radiofrequency (RF) field amplitude and labeling gradient strength...
June 26, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28653363/quiet-echo-planar-imaging-for-functional-and-diffusion-mri
#3
Jana Hutter, Anthony N Price, Lucilio Cordero-Grande, Shaihan Malik, Giulio Ferrazzi, Andreia Gaspar, Emer J Hughes, Daan Christiaens, Laura McCabe, Torben Schneider, Mary A Rutherford, Joseph V Hajnal
PURPOSE: To develop a purpose-built quiet echo planar imaging capability for fetal functional and diffusion scans, for which acoustic considerations often compromise efficiency and resolution as well as angular/temporal coverage. METHODS: The gradient waveforms in multiband-accelerated single-shot echo planar imaging sequences have been redesigned to minimize spectral content. This includes a sinusoidal read-out with a single fundamental frequency, a constant phase encoding gradient, overlapping smoothed CAIPIRINHA blips, and a novel strategy to merge the crushers in diffusion MRI...
June 26, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28652524/single-breath-hold-whole-heart-unenhanced-coronary-mra-using-multi-shot-gradient-echo-epi-at-3t-comparison-with-free-breathing-turbo-field-echo-coronary-mra-on-healthy-volunteers
#4
Yuji Iyama, Takeshi Nakaura, Yasunori Nagayama, Seitaro Oda, Daisuke Utsunomiya, Masafumi Kidoh, Hideaki Yuki, Kenichiro Hirata, Tomohiro Namimoto, Mika Kitajima, Kosuke Morita, Yoshinori Funama, Atsushi Takemura, Tomoyuki Okuaki, Yasuyuki Yamashita
PURPOSE: We investigated the feasibility of single breath hold unenhanced coronary magnetic resonance angiography (MRA) using multi-shot gradient echo planar imaging (MSG-EPI) on a 3T-scanner. METHODS: Fourteen volunteers underwent single breath hold coronary MRA with a MSG-EPI and free-breathing turbo field echo (TFE) coronary MRA at 3T. The acquisition time, signal to noise ratio (SNR), and the contrast of the sequences were compared with the paired t-test. Readers evaluated the image contrast, noise, sharpness, artifacts, and the overall image quality...
June 26, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28639370/b0-concomitant-field-compensation-for-mri-systems-employing-asymmetric-transverse-gradient-coils
#5
Paul T Weavers, Shengzhen Tao, Joshua D Trzasko, Louis M Frigo, Yunhong Shu, Matthew A Frick, Seung-Kyun Lee, Thomas K-F Foo, Matt A Bernstein
PURPOSE: Imaging gradients result in the generation of concomitant fields, or Maxwell fields, which are of increasing importance at higher gradient amplitudes. These time-varying fields cause additional phase accumulation, which must be compensated for to avoid image artifacts. In the case of gradient systems employing symmetric design, the concomitant fields are well described with second-order spatial variation. Gradient systems employing asymmetric design additionally generate concomitant fields with global (zeroth-order or B0 ) and linear (first-order) spatial dependence...
June 21, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28639310/high-resolution-31-p-echo-planar-spectroscopic-imaging-in-vivo-at-7t
#6
Andreas Korzowski, Peter Bachert
PURPOSE: Conventional (31) P chemical shift imaging is time-consuming and yields only limited spatial resolution. The purpose of this study was to demonstrate feasibility of (31) P echo-planar spectroscopic imaging (EPSI) in vivo at 7T. METHODS: A 3D (31) P EPSI sequence with trapezoidal-shaped gradient pulses was implemented on a 7T MR scanner. To increase spectral width with reduced demand on gradient performance, a multishot approach was chosen. Acquisition weighting and (31) P-{(1) H} double resonance for nuclear Overhauser signal enhancement were applied to increase sensitivity...
June 21, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28637508/hyperpolarized-13-c-urea-myocardial-first-pass-perfusion-imaging-using-velocity-selective-excitation
#7
Maximilian Fuetterer, Julia Busch, Sophie M Peereboom, Constantin von Deuster, Lukas Wissmann, Miriam Lipiski, Thea Fleischmann, Nikola Cesarovic, Christian T Stoeck, Sebastian Kozerke
BACKGROUND: A velocity-selective binomial excitation scheme for myocardial first-pass perfusion measurements with hyperpolarized (13)C substrates, which preserves bolus magnetization inside the blood pool, is presented. The proposed method is evaluated against gadolinium-enhanced (1)H measurements in-vivo. METHODS: The proposed excitation with an echo-planar imaging readout was implemented on a clinical CMR system. Dynamic myocardial stress perfusion images were acquired in six healthy pigs after bolus injection of hyperpolarized (13)C urea with the velocity-selective vs...
June 21, 2017: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/28634512/diffusion-weighted-imaging-for-the-detection-and-evaluation-of-cholesteatoma
#8
REVIEW
Benjamin Henninger, Christian Kremser
Cholesteatoma is a collection of keratinous debris and stratified squamous epithelium. It is trapped in the middle ear and can lead to bony erosion. The disease is treated surgically often followed by a second-look procedure to check for residual tissue or recurrence. Cholesteatoma has specific signal-intensity characteristics on magnetic resonance imaging with very high signal intensity on diffusion weighted imaging (DWI). Various DWI techniques exist: Echo-planar imaging (EPI)-based and non-EPI-based techniques as well as new approaches like multi-shot EPI DWI...
May 28, 2017: World Journal of Radiology
https://www.readbyqxmd.com/read/28629572/3t-diffusion-weighted-mri-in-the-response-assessment-of-colorectal-liver-metastases-after-chemotherapy-correlation-between-adc-value-and-histological-tumour-regression-grading
#9
Francescamaria Donati, Piero Boraschi, Federica Pacciardi, Rosa Cervelli, Maura Castagna, Lucio Urbani, Fabio Falaschi, Davide Caramella
PURPOSE: The purpose of the study was to correlate the apparent diffusion coefficient (ADC) values of diffusion-weighted MR imaging (DW-MRI) by 3T device with the histological tumour regression grading (TRG) analysis of colorectal liver metastases after preoperative chemotherapy. MATERIALS AND METHODS: Our study included thirty-five patients with colorectal liver metastases who had undergone MRI by 3T device (GE DISCOVERY MR750; GE Healthcare) after preoperative chemotherapy...
June 2017: European Journal of Radiology
https://www.readbyqxmd.com/read/28627984/diagnostic-accuracy-of-proton-magnetic-resonance-spectroscopy-and-perfusion-weighted-imaging-in-brain-gliomas-follow-up-a-single-institutional-experience
#10
Monica Anselmi, Alessia Catalucci, Valentina Felli, Valentina Vellucci, Alessandra Di Sibio, Giovanni Luca Gravina, Mario Di Staso, Ernesto Di Cesare, Carlo Masciocchi
Objectives The objective of this study was to evaluate whether proton magnetic resonance spectroscopy and perfusion magnetic resonance imaging (MRI) are able to increase diagnostic accuracy in the follow-up of brain gliomas, identifying the progression of disease before it becomes evident in the standard MRI; also to evaluate which of the two techniques has the best diagnostic accuracy. Methods Eighty-three patients with cerebral glioma (50 high-grade gliomas (HGGs), 33 low-grade gliomas (LGGs)) were retrospectively enrolled...
June 2017: Neuroradiology Journal
https://www.readbyqxmd.com/read/28616928/-clinical-study-of-rs-epi-dwi-to-improve-imaging-quality-and-assessment-on-intracranial-mass-lesions
#11
Kai Zhang, Chun-Chao Xia, Qiang Yue, Tao Guo, Wan-Lin Peng, Yu-Ming Li, Lei Li, Fei Zhao, Jin Pu, Qi Leng, Zhen-Lin Li
OBJECTIVES: To explore the clinical value of readout-segmented echo planar imaging (Rs-EPI) sequence in the assessment of intracranial mass lesions compared to the standard single-shot EPI (Ss-EPI) sequence. METHODS: We included 21 patients with intracranial mass lesions who underwent both Ss-EPI diffusion weighted imaging (DWI) and Rs-EPI DWI at 3.0T MR scanner with a twenty-channel head-neck coil. The quality of images was assessed by two experienced radiologists independently...
May 2017: Sichuan da Xue Xue Bao. Yi Xue Ban, Journal of Sichuan University. Medical Science Edition
https://www.readbyqxmd.com/read/28608411/interleaved-epi-diffusion-imaging-using-spirit-based-reconstruction-with-virtual-coil-compression
#12
Zijing Dong, Fuyixue Wang, Xiaodong Ma, Zhe Zhang, Erpeng Dai, Chun Yuan, Hua Guo
PURPOSE: To develop a novel diffusion imaging reconstruction framework based on iterative self-consistent parallel imaging reconstruction (SPIRiT) for multishot interleaved echo planar imaging (iEPI), with computation acceleration by virtual coil compression. METHODS: As a general approach for autocalibrating parallel imaging, SPIRiT improves the performance of traditional generalized autocalibrating partially parallel acquisitions (GRAPPA) methods in that the formulation with self-consistency is better conditioned, suggesting SPIRiT to be a better candidate in k-space-based reconstruction...
June 12, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28602499/susceptibility-weighted-angiography-and-diffusion-weighted-imaging-in-posterior-reversible-encephalopathy-syndrome-is-there-an-association-between-hemorrhage-cytotoxic-edema-blood-pressure-and-imaging-severity
#13
Shivaprakash Basavanthaiah Hiremath, Amol Anantrao Gautam, Shilpa Anil, Reji Thomas, Geena Benjamin
PURPOSE: To assess the significance of association and possible correlation between hemorrhage, cytotoxic edema, blood pressure and imaging severity in posterior reversible encephalopathy syndrome (PRES). MATERIALS AND METHODS: This retrospective study included the medical and imaging records of 35 consecutive patients with PRES. The clinical data analysis included the highest recorded blood pressure (BP) on the day of the ictus, MRI including spin-echo echo planar diffusion-weighted imaging (DWI), susceptibility weighted angiography (SWAN) and conventional sequences...
June 8, 2017: Journal of Neuroradiology. Journal de Neuroradiologie
https://www.readbyqxmd.com/read/28596547/echo-planar-j-resolved-spectroscopic-imaging-using-dual-read-outs-implementation-and-quantitation-of-human-brain-metabolites
#14
Manoj K Sarma, Rajakumar Nagarajan, Zohaib Iqbal, Paul M Macey, M Albert Thomas
Attempts have been made to reduce the total scan time in multi-dimensional J-resolved spectroscopic imaging (JRESI) using an echo-planar (EP) readout gradient, but acquisition duration remains a limitation for routine clinical use in the brain. We present here a significant acceleration achieved with a 4D EP-JRESI sequence that collects dual phase encoded lines within a single repetition time (TR) using two bipolar read-out trains. The performance and reliability of this novel 4D sequence, called Multi-Echo based Echo-Planar J-resolved Spectroscopic Imaging (ME-EP-JRESI), was evaluated in 10 healthy controls and a brain phantom using a 3 T MRI/MRS scanner...
June 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28590562/robust-epi-nyquist-ghost-removal-by-incorporating-phase-error-correction-with-sensitivity-encoding-pec-sense
#15
Victor B Xie, Mengye Lyu, Yilong Liu, Yanqiu Feng, Ed X Wu
PURPOSE: The existing approach of Nyquist ghost correction by parallel imaging in echo planar imaging (EPI) can suffer from image noise amplification. We propose a method that estimates a phase error map from multi-channel data itself and incorporates it into the sensitivity encoding (SENSE) reconstruction for Nyquist ghost correction without compromising the image SNR. METHODS: This method first reconstructs two ghost-free images from positive and negative echoes using SENSE, respectively, from which the phase error map is computed...
June 7, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28585229/tomoelastography-of-the-prostate-using-multifrequency-mr-elastography-and-externally-placed-pressurized-air-drivers
#16
Florian Dittmann, Rolf Reiter, Jing Guo, Matthias Haas, Patrick Asbach, Thomas Fischer, Jürgen Braun, Ingolf Sack
PURPOSE: To demonstrate the feasibility of in vivo multifrequency magnetic resonance elastography (MRE) of the prostate using externally placed drivers. METHODS: Three pressurized-air drivers were used to excite shear waves within the prostate at vibration frequencies of 60, 70, and 80 Hz. Full 3D wave fields were acquired by multislice spin-echo echo-planar imaging in conjunction with tomoelastography wave speed recovery for generating full field-of-view stiffness maps...
June 6, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28583626/does-apparent-diffusion-coefficient-predict-the-degree-of-liver-regeneration-of-donor-and-recipient-after-living-donor-liver-transplantation
#17
Koichiro Morita, Akihiro Nishie, Yoshiki Asayama, Kousei Ishigami, Yasuhiro Ushijima, Yukihisa Takayama, Daisuke Okamoto, Nobuhiro Fujita, Toru Ikegami, Tomoharu Yoshizumi, Ken Shirabe, Hiroshi Honda
OBJECTIVE: To elucidate the relationship between the ADCs of the liver graft and the remnant liver and the degree of liver regeneration in LDLT. MATERIALS AND METHODS: 15 recipients and 15 corresponding donors underwent magnetic resonance imaging and computed tomography 1-2 weeks after living donor liver transplantation (LDLT). For diffusion-weighted imaging (DWI), a single-shot echo-planar sequence with b-factors of 0, 500, and 1000s/mm(2) was scanned. ADCs of the liver parenchyma were calculated at b factors of 0 and 500 and 1000 (ADC 0-500-1000) or 0 and 500 (ADC 0-500) or 500 and 1000 (ADC 500-1000)...
May 2017: European Journal of Radiology
https://www.readbyqxmd.com/read/28583625/residual-tumour-detection-in-post-treatment-granulation-tissue-by-using-advanced-diffusion-models-in-head-and-neck-squamous-cell-carcinoma-patients
#18
Noriyuki Fujima, Daisuke Yoshida, Tomohiro Sakashita, Akihiro Homma, Kohsuke Kudo, Hiroki Shirato
PURPOSE: To evaluate the detectability of the residual tumour in post-treatment granulation tissue using parameters obtained with an advanced diffusion model in patients with head and neck squamous cell carcinoma (HNSCC) treated by chemoradiation therapy. MATERIALS AND METHODS: We retrospectively evaluated 23 patients with HNSCC after the full course of chemoradiation therapy. The diffusion-weighted image (DWI) acquisition used single-shot spin-echo echo-planar imaging with 11 b-values (0-1000)...
May 2017: European Journal of Radiology
https://www.readbyqxmd.com/read/28580597/false-fmri-activation-after-motion-correction
#19
Renat Yakupov, Juan Lei, Michael Hoffmann, Oliver Speck
Motion correction of echo-planar imaging (EPI) data used in functional MRI (fMRI) is an essential preprocessing step performed prior to statistical analysis. At ultra-high resolution fMRI, current requirements regarding translational and rotational motion may no longer be acceptable. This prompts the need for a systematic investigation of the effects of motion correction procedures with in vivo fMRI data. Here we systematically evaluated the effect of retrospective motion correction with freely available fMRI analysis software packages (FSL, AFNI, and SPM) on activation maps using fMRI data acquired with prospective motion detection, to identify and quantify confounding effects of retrospective motion correction, and to evaluate its dependence on spatial resolution and motion correction algorithms...
June 5, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28577332/hippocampal-fractional-amplitude-of-low-frequency-fluctuation-and-functional-connectivity-changes-in-premenstrual-syndrome
#20
Gaoxiong Duan, Huimei Liu, Yong Pang, Peng Liu, Yanfei Liu, Geliang Wang, Hai Liao, Lijun Tang, Wenfu Chen, Xiaping Mo, Danhong Wen, Hua Lin, Demao Deng
PURPOSE: To investigate differences in hippocampal activity between premenstrual syndrome (PMS) patients and healthy controls, to elucidate the neural mechanisms of PMS. MATERIALS AND METHODS: Twenty female patients with PMS (PMS group) and 21 healthy controls (HC group) underwent a single-shot gradient-recalled echo planar imaging (EPI) sequence scan during the luteal phase in 3.0 Tesla MRI. Spontaneous neural activity in hippocampus (HIPP) was measured by fractional amplitude of low-frequency fluctuation (fALFF)...
June 3, 2017: Journal of Magnetic Resonance Imaging: JMRI
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