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Magnetic Resonance in Medical Sciences: MRMS

Yoshihito Kadota, Toshinori Hirai, Hideo Nakamura, Keishi Makino, Shigetoshi Yano, Shinichiro Nishimura, Machiko Tateishi, Minako Azuma, Mika Kitajima, Yasuyuki Yamashita
PURPOSE: We aimed to determine whether 3T diffusion-weighted imaging (DWI) has an additive value relative to contrast-enhanced MR imaging for the detection of disseminated lesions in patients with primary malignant brain tumors. METHODS: We included consecutive 12 patients with nodular disseminated lesions of primary malignant brain tumors that were confirmed by surgery or follow-up MR imaging. All underwent conventional MR imaging, DWI at b = 1000 and 3000 s/mm(2), post-contrast T1-weighted and 3D gradient-echo imaging at 3T...
October 11, 2016: Magnetic Resonance in Medical Sciences: MRMS
Zaw Aung Khant, Toshinori Hirai, Yoshihito Kadota, Rie Masuda, Takanori Yano, Minako Azuma, Yukiko Suzuki, Kuniyuki Tashiro
We report a 34-year-old male who manifested T1 shortening of the cerebral cortices after more than 86 contrast-enhanced MRI studies. We observed high-signal intensity (SI) on T1-weighted images (T1WIs) not only in the globus pallidus, dentate nucleus, and pulvinar of thalamus, but also in the cortices of the pre- and post-central gyri and around the calcarine sulcus. High SI in the cerebral cortices was not clearly demonstrated on T1WI scans performed 11 years earlier. The high SI we observed in these areas of the brain corresponded to areas with a normal iron-deposition predilection...
October 11, 2016: Magnetic Resonance in Medical Sciences: MRMS
Kengo Yoshimitsu, Yoshinobu Shinagawa, Toshimichi Mitsufuji, Emi Mutoh, Hiroshi Urakawa, Keiko Sakamoto, Ritsuko Fujimitsu, Koichi Takano
PURPOSE: To elucidate whether any differences are present in the stiffness map obtained with a multiscale direct inversion algorithm (MSDI) vs that with a multimodel direct inversion algorithm (MMDI), both qualitatively and quantitatively. MATERIALS AND METHODS: The MR elastography (MRE) data of 37 consecutive patients who underwent liver MR elastography between September and October 2014 were retrospectively analyzed by using both MSDI and MMDI. Two radiologists qualitatively assessed the stiffness maps for the image quality in consensus, and the measured liver stiffness and measurable areas were quantitatively compared between MSDI and MMDI...
October 11, 2016: Magnetic Resonance in Medical Sciences: MRMS
Kyoung-Nam Kim, Sang-Doc Han, Jeung-Hoon Seo, Phil Heo, Dongkyeom Yoo, Geun Ho Im, Jung Hee Lee
The birdcage (BC) coil is currently being utilized for uniform radiofrequency (RF) transmit/receive (Tx/Rx) or Tx-only configuration in many magnetic resonance (MR) imaging applications, but insufficient magnetic flux (|B1|) density and their non-uniform distribution still exists in high-field (HF) environments. We demonstrate that the asymmetric birdcage (ABC) transmit/receive (Tx/Rx) volume coil, which is a modified standard birdcage (SBC) coil with the end ring split into two halves, is suitable for improving the |B1| sensitivity in 7T small-animal MR imaging...
September 30, 2016: Magnetic Resonance in Medical Sciences: MRMS
Kohsuke Kudo, Ikuko Uwano, Toshinori Hirai, Ryuji Murakami, Hideo Nakamura, Noriyuki Fujima, Fumio Yamashita, Jonathan Goodwin, Satomi Higuchi, Makoto Sasaki
PURPOSE: The purpose of the present study was to compare different software algorithms for processing DSC perfusion images of cerebral tumors with respect to i) the relative CBV (rCBV) calculated, ii) the cutoff value for discriminating low- and high-grade gliomas, and iii) the diagnostic performance for differentiating these tumors. METHODS: Following approval of institutional review board, informed consent was obtained from all patients. Thirty-five patients with primary glioma (grade II, 9; grade III, 8; and grade IV, 18 patients) were included...
September 20, 2016: Magnetic Resonance in Medical Sciences: MRMS
Chiharu Yoshimoto, Junko Takahama, Takuya Iwabuchi, Masato Uchikoshi, Hiroshi Shigetomi, Hiroshi Kobayashi
PURPOSE: Heme and iron accumulation due to repeated hemorrhage in endometriosis may contribute to a pivotal role in carcinogenesis. We evaluate the clinical application of MR relaxometry in a series of ovarian endometriosis (OE) and endometriosis-associated ovarian cancer (EAOC). MATERIALS AND METHODS: A prospective study of diagnostic accuracy was conducted among 82 patients (67 OE and 15 EAOC) to compare MR relaxometry and biochemical measurement of cyst fluid total iron concentration...
September 16, 2016: Magnetic Resonance in Medical Sciences: MRMS
Yusaku Moribata, Aki Kido, Koji Fujimoto, Yuki Himoto, Yasuhisa Kurata, Fuki Shitano, Kayo Kiguchi, Ikuo Konishi, Kaori Togashi
PURPOSE: To evaluate the feasibility of computed diffusion weighted imaging (DWI) in cervical cancer and investigate the optimal b-value using computed DWI. METHODS: The present retrospective study involved 85 patients with cervical cancer in the International Federation of Gynecology and Obstetrics (FIGO) stage IB, IIA or IIB. DWI was obtained with b-values of 0, 100, 500 and 1000 s/mm(2). Computed DWI with b-values of 800, 1000, 1300, 1600 and 2000 s/mm(2) (cDWI800, cDWI1000, cDWI1300, cDWI1600, cDWI2000) were generated from all measured DWI (mDWI) data...
September 16, 2016: Magnetic Resonance in Medical Sciences: MRMS
Minoru Mitsuda, Yuichi Suzuki, Akira Kunimatsu, Akihiro Kasahara, Yasushi Watanabe, Kenji Ino, Keiichi Yano, Kuni Ohtomo
We report that diffusion tensor imaging (DTI) and tractography (DTT) of the pyramidal tracts using multi-band (MB) EPI could be a useful tool with a 1.5T MRI. We compared images using single-band EPI (SB-EPI) and MB-EPI. MB-EPI could reduce the scanning time by about 40%. We demonstrated that it is comparable between image qualities of SB-EPI and MB-EPI using tract-specific analysis and dice coefficients. Therefore, MB-EPI can promote high-speed DTI and DTT in clinical applications.
September 6, 2016: Magnetic Resonance in Medical Sciences: MRMS
Yoichiro Ikushima, Takashi Hashido, Yoshiyuki Watanabe, Tsukasa Doi
PURPOSE: To quantitatively investigate in vitro the effects of flip angle (FA), receiver bandwidth (BW), echo time (TE), and magnetic field strength (FS) on image noise and artifacts induced by stent-assisted coiling on contrast-enhanced MR angiography (CE-MRA) images, as a first step towards optimization of imaging parameters. METHODS: A phantom simulating a cerebral aneurysm treated using stent-assisted coiling was filled with diluted gadolinium contrast medium, and MR angiography were obtained using varied parameters: FA (10°-60°), BW (164-780 Hz/pixel), and FS (1...
September 6, 2016: Magnetic Resonance in Medical Sciences: MRMS
Munemura Suzuki, Norihiko Kotooka, Masashi Sakuma, Takahiko Nakazono, Koichi Node, Hiroyuki Irie
PURPOSE: Three-chamber view (3ch.) three-directional encoded phase-contrast magnetic resonance velocity vector mapping (PCMRVM) has been used for visualization and assessment of intra-cardiac flow. Although transmitral inflow velocity can be determined using this method by tracing mitral tips during the cardiac phase, its feasibility for clinical applications has not been established. Our aim was to investigate the validity and reproducibility of 3ch. PCMRVM for determining transmitral inflow velocity...
September 6, 2016: Magnetic Resonance in Medical Sciences: MRMS
Donald von Borstel, Michael Wang, Kirstin Small, Taiki Nozaki, Hiroshi Yoshioka
This study is intended as a review of 3Tesla (T) magnetic resonance (MR) imaging of the triangular fibrocartilage complex (TFCC). The recent advances in MR imaging, which includes high field strength magnets, multi-channel coils, and isotropic 3-dimensional (3D) sequences have enabled the visualization of precise TFCC anatomy with high spatial and contrast resolution. In addition to the routine wrist protocol, there are specific techniques used to optimize 3T imaging of the wrist; including driven equilibrium sequence (DRIVE), parallel imaging, and 3D imaging...
August 16, 2016: Magnetic Resonance in Medical Sciences: MRMS
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...
July 29, 2016: Magnetic Resonance in Medical Sciences: MRMS
Toshio Ohashi, Shinji Naganawa, Mai Kanou, Mitsuru Ikeda
PURPOSE: Diffusion-weighted imaging (DWI) using readout-segmented EPI (rs-EPI) can minimize distortion and blurring artifacts; however, we sometimes encounter cerebrospinal fluid (CSF) pulsation artifacts on apparent diffusion coefficient (ADC) maps, especially when the number of readout segments (NRS) is increased. The purpose of this study was to evaluate the effect of the NRS on the CSF pulsation artifacts in the ADC maps of healthy volunteers. METHODS: In 10 healthy volunteers, we obtained DWI from rs-EPI with a b-value of 0 and 1000 s/mm(2)...
July 13, 2016: Magnetic Resonance in Medical Sciences: MRMS
Shinji Naganawa, Toshiki Nakane, Hisashi Kawai, Toshiaki Taoka
PURPOSE: In textbooks, the perivascular space (PVS) is described as non-enhancing after the intravenous administration of gadolinium-based contrast agent (IV-GBCA). We noticed that the PVS sometimes has high signal intensity (SI) on heavily T2-weighted 3D-FLAIR (hT2-FL) images obtained 4 h after IV-GBCA. The purpose of this study was to retrospectively evaluate the contrast enhancement of the PVS. MATERIALS AND METHODS: In 8 healthy subjects and 19 patients with suspected endolymphatic hydrops, magnetic resonance cisternography (MRC) and hT2-FL images were obtained before and 4 h after a single dose of IV-GBCA...
July 12, 2016: Magnetic Resonance in Medical Sciences: MRMS
Shuya Matsuda, Utaroh Motosugi, Ryo Kato, Masaru Muraoka, Yuichiro Suzuki, Mitsuharu Sato, Kuniaki Shindo, Yasuhiro Nakayama, Taisuke Inoue, Shinya Maekawa, Minoru Sakamoto, Nobuyuki Enomoto
No abstract text is available yet for this article.
July 11, 2016: Magnetic Resonance in Medical Sciences: MRMS
Shinji Naganawa, Hisashi Kawai, Toshiaki Taoka, Kojiro Suzuki, Shingo Iwano, Hiroko Satake, Michihiko Sone, Mitsuru Ikeda
PURPOSE: Increased cochlear lymph fluid signals on three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) images obtained several minutes after intravenous administration of a single dose of gadolinium-based contrast agent (IV-SD-GBCA) in a patient with severe retrofenestral type otosclerosis had been reported. This increase was thought to represent breakdown of the blood-labyrinthine barrier. The purpose of this study was to evaluate cochlear lymph signal on heavily T2-weighted 3D-FLAIR (HF) images obtained 4 hours after IV-SD-GBCA in patients with otosclerosis, Ménière's disease, and healthy subjects...
July 11, 2016: Magnetic Resonance in Medical Sciences: MRMS
Kouhei Kamiya, Koji Kamagata, Masakazu Miyajima, Madoka Nakajima, Masaaki Hori, Kohei Tsuruta, Harushi Mori, Akira Kunimatsu, Hajime Arai, Shigeki Aoki, Kuni Ohtomo
PURPOSE: Diffusional kurtosis imaging (DKI) is an emerging technique that describes diffusion of water molecules in terms of deviation from Gaussian distribution. This study investigated correlations between DKI metrics and cognitive function in patients with idiopathic normal pressure hydrocephalus (iNPH). MATERIALS AND METHODS: DKI was performed in 29 iNPH patients and 14 age-matched controls. Mini-mental state examination (MMSE), frontal assessment battery (FAB), and trail making test A (TMT-A) were used as cognitive measures...
July 11, 2016: Magnetic Resonance in Medical Sciences: MRMS
Kohei Hamamoto, Katsuhiko Matsuura, Emiko Chiba, Tomohisa Okochi, Keisuke Tanno, Osamu Tanaka
PURPOSE: The purpose of this study was to evaluate the diagnostic performance of non-contrast-enhanced magnetic resonance angiography with time-spatial labeling inversion pulse (time-SLIP MRA) in the assessment of pulmonary arteriovenous malformation (PAVM). METHODS: Eleven consecutive patients with 38 documented PAVMs underwent time-SLIP MRA with a 3-tesla unit. Eight patients with 25 lesions were examined twice, once before and once after embolotherapy. The lesions were divided into two groups-initial diagnosis (n = 35) and follow-up (n = 28)-corresponding to untreated and treated lesions, respectively, and were evaluated separately...
July 11, 2016: Magnetic Resonance in Medical Sciences: MRMS
Shuki Maruyama, Junpei Ueda, Atsuomi Kimura, Kenya Murase
PURPOSE: To develop a novel probe for chemical exchange saturation transfer magnetic resonance imaging (CEST MRI) based on thermosensitive liposomes (lipoCEST) for theranostics, in which diagnostics and therapy are integrated into a single platform. METHODS: We developed two kinds of lipoCEST agents. The first kind encapsulated dysprosium (Dy)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-Na·3NaCl, terbium-DOTA-Na·3NaCl, or thulium-DOTA-Na·3NaCl into the inner cavity of thermosensitive liposomes, while the second kind encapsulated Dy-DOTA-Na and incorporated amphiphilic metal complex [thulium-diethylenetriamine pentaacetic acid-bis (stearylamide) (Tm-DTPA-BSA)] as a membrane constituent...
July 11, 2016: Magnetic Resonance in Medical Sciences: MRMS
Masanori Maehara, Masahiko Monma, Takeshi Nitanai, Tetsuya Matsumoto, Yukiko Fukuma
PURPOSE: We present a sequence for T1 relaxation-time mapping that enables a rapid and accurate measuring. The sequence is based on the Look-Locker method by employing turbo-field echo-planar imaging (TFEPI) acquisitions and time to free relaxation after constant application of the radiofrequency (RF) pulses. We optimized the sequence, and then evaluated the accuracy of the method in imaging of head and neck. MATERIALS AND METHODS: The method was implemented on a standard clinical scanner, and the accuracy of the T1 value was evaluated against that with the two-dimensional (2D) inversion recovery method...
July 11, 2016: Magnetic Resonance in Medical Sciences: MRMS
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