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Magnetic Resonance in Medical Sciences: MRMS

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https://www.readbyqxmd.com/read/28367906/spiral-mri-on-a-9-4t-vertical-bore-superconducting-magnet-using-unshielded-and-self-shielded-gradient-coils
#1
Nao Kodama, Ayana Setoi, Katsumi Kose
Spiral magnetic resonance imaging (MRI) sequences were developed for a 9.4T vertical standard bore (54 mm) superconducting magnet using unshielded and self-shielded gradient coils. Clear spiral images with 64-shot scan were obtained with the self-shielded gradient coil, but severe shading artifacts were observed for the spiral-scan images acquired with the unshielded gradient coil. This shading artifact was successfully corrected with a phase-correction technique using reference scans that we developed based on eddy current field measurements...
March 27, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28367905/4d-flow-mr-imaging-of-ophthalmic-artery-flow-in-patients-with-internal-carotid-artery-stenosis
#2
Tetsuro Sekine, Ryo Takagi, Yasuo Amano, Yasuo Murai, Erika Orita, Yoshimitsu Fukushima, Yoshio Matsumura, Shin-Ichiro Kumita
BACKGROUND AND PURPOSE: To assess the clinical feasibility of time-resolved three-dimensional phase contrast (4D Flow) magnetic resonance imaging (MRI) assessment of the ophthalmic artery (OphA) flow in patients with internal carotid artery stenosis (ICS). MATERIALS AND METHODS: Twenty-one consecutive patients with unilateral ICS were recruited. 4D Flow MRI and acetazolamide-stress brain perfusion single photon emission computed tomography (SPECT) were performed...
March 27, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28367904/quantitative-susceptibility-mapping-using-the-multiple-dipole-inversion-combination-with-k-space-segmentation-method
#3
Ryota Sato, Toru Shirai, Yo Taniguchi, Takenori Murase, Yoshitaka Bito, Hisaaki Ochi
Quantitative susceptibility mapping (QSM) is a new magnetic resonance imaging (MRI) technique for noninvasively estimating the magnetic susceptibility of biological tissue. Several methods for QSM have been proposed. One of these methods can estimate susceptibility with high accuracy in tissues whose contrast is consistent between magnitude images and susceptibility maps, such as deep gray-matter nuclei. However, the susceptibility of small veins is underestimated and not well depicted by using the above approach, because the contrast of small veins is inconsistent between a magnitude image and a susceptibility map...
March 27, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28367903/longitudinal-assessment-of-dentate-nuclei-relaxometry-during-massive-gadobutrol-exposure
#4
Enrico Tedeschi, Sirio Cocozza, Pasquale Borrelli, Lorenzo Ugga, Vincenzo Brescia Morra, Giuseppe Palma
We report the assessment of Dentate Nuclei (DN) R1 (1/T1) and R2* (1/R2*) values in a patient with relapsing-remitting Multiple Sclerosis, exposed to 22 standard (0.1 mmol/kg) doses of gadobutrol, who underwent eight relaxometric magnetic resonance (MR) measurements within two years. DN R1 did not significantly increase nor correlated with cumulative gadobutrol administration, even after a total dose of 130 ml. Likewise, DN R2* relaxometry remained unchanged. In conclusion, massive gadobutrol exposure did not induce significant DN relaxometry changes...
March 27, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28302937/update-your-knowledge-of-abdominal-mri-recent-results-which-may-change-your-practice
#5
Utaroh Motosugi
No abstract text is available yet for this article.
March 9, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28250355/passive-shimming-of-mri-static-magnetic-field-using-regularization-of-truncated-singular-value-decomposition
#6
Mitsushi Abe
PURPOSE: To develop a new shimming calculation method, which can calculate iron piece placements rapidly to make the magnetic field homogeneous at intended homogeneity and then to make the shimming working time short. MATERIALS AND METHODS: The shimming calculation yields magnetic moment (MM) distribution, which is calculated by the truncated singular value decomposition (SVD) from the measured magnetic field. The MM distribution is described by a superposition of eigenmodes obtained by SVD of a response matrix from the moment distributions to magnetic fields at the field of view (FOV)...
March 2, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28202854/three-dimensional-cardiac-mr-imaging-related-techniques-and-clinical-applications
#7
Yasuo Amano, Fumi Yanagisawa, Masaki Tachi, Kuniya Asai, Yasuyuki Suzuki, Hidenobu Hashimoto, Kiyohisa Ishihara, Shinichiro Kumita
Three-dimensional (3D) cardiac magnetic resonance (MR) imaging has several advantages, including the easy coverage of the entire heart without misregistration, reduction of breath-holding times, and availability for postprocessing reconstruction. These advantages are associated with some techniques such as breath-hold or navigator gating and parallel imaging. However, the image quality of 3D cardiac MR images is compromised by the use of a shorter repetition time and parallel imaging. Thus, a steady-state free precession sequence, contrast agent administration, and presaturation pulses are used to maintain the image quality...
February 16, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28202853/structures-showing-negative-correlations-of-signal-intensity-with-postnatal-age-on-t1-weighted-imaging-of-the-brain-of-newborns-and-infants
#8
Saeka Hori, Toshiaki Taoka, Tomoko Ochi, Toshiteru Miyasaka, Masahiko Sakamoto, Katsutoshi Takayama, Takeshi Wada, Kaoru Myochin, Yukihiro Takahashi, Kimihiko Kichikawa
PURPOSE: Although the neonatal and infantile brain typically shows sequential T1 shortening according to gestational age as a result of myelination, several structures do not follow this rule. We evaluated the relationship between the signal intensity of various structures in the neonatal and infantile brain on T1-weighted imaging (T1WI) and either postnatal or gestational age. MATERIALS AND METHODS: We examined magnetic resonance images from 120 newborns and infants without any abnormalities in the central nervous system...
February 16, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28190854/evaluation-of-diffusion-weighted-mr-imaging-as-a-technique-for-detecting-bone-marrow-edema-in-patients-with-osteitis-pubis
#9
Iclal Erdem Toslak, Bulent Cekic, Aysen Turk, Ali Eraslan, A Eda Parlak
PURPOSE: Our aims were to determine the feasibility of diffusion-weighted magnetic resonance imaging (DWI) in the detection of bone marrow edema (BME) and explore the apparent diffusion coefficient (ADC) alterations in patients with osteitis pubis (OP). MATERIALS AND METHODS: Fourty two consecutive patients clinically suspected to have athletic pubalgia and 31 control subjects were enrolled in the study. All subjects underwent diagnostic focused magnetic resonance imaging (MRI) and DWI at b values of 0 and 600 s/mm(2)...
February 13, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28190853/high-snr-acquisitions-improve-the-repeatability-of-liver-fat-quantification-using-confounder-corrected-chemical-shift-encoded-mr-imaging
#10
Utaroh Motosugi, Diego Hernando, Curtis Wiens, Peter Bannas, Scott B Reeder
PURPOSE: To determine whether high signal-to-noise ratio (SNR) acquisitions improve the repeatability of liver proton density fat fraction (PDFF) measurements using confounder-corrected chemical shift-encoded magnetic resonance (MR) imaging (CSE-MRI). MATERIALS AND METHODS: Eleven fat-water phantoms were scanned with 8 different protocols with varying SNR. After repositioning the phantoms, the same scans were repeated to evaluate the test-retest repeatability. Next, an in vivo study was performed with 20 volunteers and 28 patients scheduled for liver magnetic resonance imaging (MRI)...
February 13, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28190852/characteristics-of-hepatic-schwannoma-presenting-as-an-unusual-multi-cystic-mass-on-gadoxetic-acid-disodium-enhanced-mr-imaging
#11
Hiroki Haradome, Jun Woo, Hisashi Nakayama, Haruna N Watanabe, Masahiro Ogawa, Mitsuhiko Moriyama, Masahiko Sugitani, Tadatoshi Takayama, Osamu Abe
Hepatic schwannoma is a very rare hepatic tumor, usually appearing as a hypervascular solid mass with or without various degrees of cystic changes; however, to the best of our knowledge, only the two cases of hepatic schwannoma showing a multi-cystic appearance have previously been reported. We report herein a benign hepatic schwannoma presenting as an unusually large multi-cystic mass. The gadoxetic acid disodium-enhanced magnetic resonance imaging features are described with the histopathologic correlation and briefly review the literature...
February 13, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28163295/shrunken-hepatic-hemangioma-following-delineated-peritumoral-hyperintensity-on-gadoxetic-acid-disodium-enhanced-mr-imaging
#12
Hiroki Haradome, Takao Okubo, Yusuke Toda, Jun Woo, Tadatoshi Takayama, Osamu Abe
No abstract text is available yet for this article.
February 6, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/27476458/real-based-polarity-preserving-asymmetric-fourier-imaging-repafi
#13
Tokunori Kimura, Hiroshi Kusahara
We proposed and assessed a modified asymmetric Fourier imaging (AFI) technique named real-based polarity-preserving AFI (RepAFI), in which the low-pass filter kernel for background phase estimation in AFI is optimized to preserve the magnetization polarity information for blood vessels and cerebrospinal fluid (CSF) even for data obtained using phase-sensitive inversion-recovery spin-echo-based (PSIR-SE) sequences with asymmetrical sampling in the k-space. Our proposed RepAFI technique achieves a practical balance of image quality and simplicity to provide better performance than conventional AFI methods...
April 10, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/27385553/image-non-uniformity-correction-for-3-t-gd-eob-dtpa-enhanced-mr-imaging-of-the-liver
#14
Gou Ogasawara, Yusuke Inoue, Keiji Matsunaga, Kaoru Fujii, Hirofumi Hata, Yuki Takato
PURPOSE: Image non-uniformity may cause substantial problems in magnetic resonance (MR) imaging especially when a 3-T scanner is used. We evaluated the effect of image non-uniformity correction in gadolinium ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MR imaging using a 3-T scanner. METHODS: Two commercially available methods for image non-uniformity correction, surface coil intensity correction (SCIC), and phased-array uniformity enhancement (PURE), were applied to Gd-EOB-DTPA-enhanced images acquired at 3-T in 20 patients...
April 10, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/27151747/influence-of-the-magnetic-field-strength-on-image-contrast-in-gd-eob-dtpa-enhanced-mr-imaging-comparison-between-1-5t-and-3-0t
#15
Hirofumi Hata, Yusuke Inoue, Ai Nakajima, Shotaro Komi, Hiroki Miyatake
PURPOSE: We quantitatively investigated hepatic enhancement in gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) imaging at 1.5T and 3.0T. METHODS: A total of 40 patients who underwent Gd-EOB-DTPA-enhanced MR imaging were included in the study. Precontrast and hepatobiliary-phase images acquired at a low flip angle (FA, 12°) and hepatobiliary-phase images acquired at a high FA (30°) were analyzed. From these images, the liver-to-muscle signal intensity ratio (LMR) and liver-to-spleen signal intensity ratio (LSR) were estimated, and the contrast enhancement ratio (CER) was calculated from the liver signal, LMR, and LSR as the ratio of the low-FA hepatobiliary-phase value to the precontrast value...
April 10, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/27001395/visualization-of-middle-ear-ossicles-in-elder-subjects-with-ultra-short-echo-time-mr-imaging
#16
Shinji Naganawa, Toshiki Nakane, Hisashi Kawai, Toshiaki Taoka, Kojiro Suzuki, Shingo Iwano, Hiroko Satake, David Grodzki
PURPOSE: To evaluate the visualization of middle ear ossicles by ultra-short echo time magnetic resonance (MR) imaging at 3T in subjects over 50 years old. MATERIALS AND METHODS: Sixty ears from 30 elder patients that underwent surgical or interventional treatment for neurovascular diseases were included (ages: 50-82, median age: 65; 10 men, 20 women). Patients received follow-up MR imaging including routine T1- and T2-weighted images, time-of-flight MR angiography, and ultra-short echo time imaging (PETRA, pointwise encoding time reduction with radial acquisition)...
April 10, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/27001390/doppler-ultrasound-triggering-for-cardiovascular-mri-at-3t-in-a-healthy-volunteer-study
#17
Fabian Kording, Jin Yamamura, Gunnar Lund, Friedrich Ueberle, Caroline Jung, Gerhard Adam, Bjoern Philip Schoennagel
PURPOSE: Electrocardiogram (ECG) triggering for cardiac magnetic resonance (CMR) may be influenced by electromagnetic interferences with increasing magnetic field strength. The aim of this study was to evaluate the performance of Doppler ultrasound (DUS) as an alternative trigger technique for CMR in comparison to ECG and pulse oximetry (POX) at 3T and using different sequence types. METHODS: Balanced turbo field echo two-dimensional (2D) short axis cine CMR and 2D phase-contrast angiography of the ascending aorta was performed in 11 healthy volunteers at 3T using ECG, DUS, and POX for cardiac triggering...
April 10, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/27001389/-sun-ray-appearance-in-a-case-of-cardiac-angiosarcoma-a-comparison-of-mri-and-pet-ct
#18
Zbyněk Tüdös, Martin Köcher, Marie Černá, František Odstrčil, Zuzana Prouzová, Radim Formánek, Jan Přeček
Our article reports a case of a 35-year-old man with cardiac mass, who underwent a wide range of imaging methods, including cardiac magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT). Contrast-enhanced MRI images revealed "sun ray" pattern in the mass. Final histopathological diagnosis of angiosarcoma was confirmed during autopsy. To our knowledge, our case is the second direct observation of this MRI diagnostic pattern and the first one that allows a comparison with PET/CT findings...
April 10, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28132997/polymer-brush-afforded-spio-nanoparticles-show-a-unique-biodistribution-and-mr-imaging-contrast-in-mouse-organs
#19
Ting Chen, Yuki Mori, Chizuko Inui-Yamamoto, Yutaka Komai, Yoshiyuki Tago, Shinichi Yoshida, Yoshitsugu Takabatake, Yoshitaka Isaka, Kohji Ohno, Yoshichika Yoshioka
INTRODUCTION: To investigate the biodistribution and retention properties of the new super paramagnetic iron oxide (new SPIO: mean hydrodynamic diameter, 100 nm) nanoparticles, which have concentrated polymer brushes in the outer shell and are difficult for phagocytes to absorb, and to compare the new SPIO with clinically approved SPIO (Resovist: mean hydrodynamic diameter, 57 nm). MATERIALS AND METHODS: 16 male C57BL/6N mice were divided in two groups according to the administered SPIO (n = 8 for each group; intravenous injection does, 0...
January 30, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28132996/influence-of-spatial-resolution-in-three-dimensional-cine-phase-contrast-magnetic-resonance-imaging-on-the-accuracy-of-hemodynamic-analysis
#20
Atsushi Fukuyama, Haruo Isoda, Kento Morita, Marika Mori, Tomoya Watanabe, Kenta Ishiguro, Yoshiaki Komori, Takafumi Kosugi
INTRODUCTION: We aim to elucidate the effect of spatial resolution of three-dimensional cine phase contrast magnetic resonance (3D cine PC MR) imaging on the accuracy of the blood flow analysis, and examine the optimal setting for spatial resolution using flow phantoms. MATERIALS AND METHODS: The flow phantom has five types of acrylic pipes that represent human blood vessels (inner diameters: 15, 12, 9, 6, and 3 mm). The pipes were fixed with 1% agarose containing 0...
January 30, 2017: Magnetic Resonance in Medical Sciences: MRMS
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