Journals Magnetic Resonance in Medical ...

Magnetic Resonance in Medical Sciences : MRMS
Kengo Kiso, Takahiro Tsuboyama, Hiromitsu Onishi, Kazuya Ogawa, Atsushi Nakamoto, Mitsuaki Tatsumi, Takashi Ota, Hideyuki Fukui, Keigo Yano, Toru Honda, Shinji Kakemoto, Yoshihiro Koyama, Hiroyuki Tarewaki, Noriyuki Tomiyama
PURPOSE: To compare the effects of deep learning reconstruction (DLR) on respiratory-triggered T2-weighted MRI of the liver between single-shot fast spin-echo (SSFSE) and fast spin-echo (FSE) sequences. METHODS: Respiratory-triggered fat-suppressed liver T2-weighted MRI was obtained with the FSE and SSFSE sequences at the same spatial resolution in 55 patients. Conventional reconstruction (CR) and DLR were applied to each sequence, and the SNR and liver-to-lesion contrast were measured on FSE-CR, FSE-DLR, SSFSE-CR, and SSFSE-DLR images...
March 29, 2023: Magnetic Resonance in Medical Sciences: MRMS
Vadim Malis, Won C Bae, Asako Yamamoto, Yoshimori Kassai, Marin A McDonald, Mitsue Miyazaki
PURPOSE: Fatty acid composition of the orbit makes it challenging to achieve complete fat suppression during orbit MR imaging. Implementation of a fat suppression technique capable of suppressing signals from saturated (aliphatic) and unsaturated (olefinic or protons at double-bonded carbon sites) fat would improve the visualization of an optical nerve. Furthermore, the ability to semi-quantify the fractions of aliphatic and olefinic fat may potentially provide valuable information in assessing orbit pathology...
March 23, 2023: Magnetic Resonance in Medical Sciences: MRMS
Masatoshi Iwamura, Satoru Ide, Kenya Sato, Akihisa Kakuta, Soichiro Tatsuo, Atsushi Nozaki, Tetsuya Wakayama, Tatsuya Ueno, Rie Haga, Misako Kakizaki, Yoko Yokoyama, Ryoichi Yamauchi, Fumiyasu Tsushima, Koichi Shibutani, Masahiko Tomiyama, Shingo Kakeda
PURPOSE: Brain MRI with high spatial resolution allows for a more detailed delineation of multiple sclerosis (MS) lesions. The recently developed deep learning-based reconstruction (DLR) technique enables image denoising with sharp edges and reduced artifacts, which improves the image quality of thin-slice 2D MRI. We, therefore, assessed the diagnostic value of 1 mm-slice-thickness 2D T2-weighted imaging (T2WI) with DLR (1 mm T2WI with DLR) compared with conventional MRI for identifying MS lesions...
March 16, 2023: Magnetic Resonance in Medical Sciences: MRMS
Makoto Obara, Jihun Kwon, Masami Yoneyama, Yu Ueda, Marc Van Cauteren
Since its first observation in the 18th century, the diffusion phenomenon has been actively studied by many researchers. Diffusion-weighted imaging (DWI) is a technique to probe the diffusion of water molecules and create a MR image with contrast based on the local diffusion properties. The DWI pixel intensity is modulated by the hindrance the diffusing water molecules experience. This hindrance is caused by structures in the tissue and reflects the state of the tissue. This characteristic makes DWI a unique and effective tool to gain more insight into the tissue's pathophysiological condition...
March 15, 2023: Magnetic Resonance in Medical Sciences: MRMS
Mitsue Miyazaki, Vadim Malis, Asako Yamamoto, Jirach Kungsamutr, Linda K McEvoy, Marin A McDonald, Won C Bae
PURPOSE: Cerebrospinal fluid (CSF) clearance is essential for maintaining a healthy brain and cognition by removal of metabolic waste from the central nervous system. Physical exercise has been shown to improve human health; however, the effect of physical exercise on intrinsic CSF outflow in humans remains unexplored. The purpose of this study was to investigate intrinsic CSF outflow pathways and quantitative metrics of healthy individuals with active and sedentary lifestyles. In addition, the effect of exercise was investigated among the sedentary subjects before and after 3 weeks of physical activity...
March 11, 2023: Magnetic Resonance in Medical Sciences: MRMS
Hiroaki Shimizu, Naoko Mori, Shunji Mugikura, Yui Maekawa, Minoru Miyashita, Tatsuo Nagasaka, Satoko Sato, Kei Takase
PURPOSE: To evaluate the effectiveness of the texture analysis of axillary high-resolution 3D T2-weighted imaging (T2WI) in distinguishing positive and negative lymph node (LN) metastasis in patients with clinically node-negative breast cancer. METHODS: Between December 2017 and May 2021, 242 consecutive patients underwent high-resolution 3D T2WI and were classified into the training (n = 160) and validation cohorts (n = 82). We performed manual 3D segmentation of all visible LNs in axillary level I to extract the texture features...
March 1, 2023: Magnetic Resonance in Medical Sciences: MRMS
Yushi Tsujita, Keitaro Sofue, Eisuke Ueshima, Yoshiko Ueno, Masatoshi Hori, Masakatsu Tsurusaki, Takamichi Murakami
The incidence of hepatocellular carcinoma (HCC) is still on the rise in North America and Europe and is the second leading cause of cancer-related mortality. The treatment of HCC varies, with surgery and locoregional therapy (LRT) such as radiofrequency ablation and transcatheter arterial chemoembolization, and radiation therapy being the primary treatment. Currently, systemic therapy with molecular-targeted agents and immune checkpoint inhibitors (ICIs) is becoming a major treatment option for the unresectable HCC...
February 16, 2023: Magnetic Resonance in Medical Sciences: MRMS
Shoto Ikegami, Dai Ishiyama, Yoshiki Oda, Kinuko Niihara, Masafumi Yoshida, Keiichi Honda, Takashi A Inoue, Kagayaki Kuroda
Metamorphosis in the pupae of the Trypoxylus dichotomus was continuously observed at 9.4T until their emergence. A large liquid-like mass occupied most of the volume in the trunk, while the surrounding tissue already existed at the beginning of the observation period. As the mass shrunk, tissues such as flight muscle formed, whereas the reservoir became prolonged to form the intestinal tract. This implies that the liquid-like mass worked as the raw material for creating adult tissues.
February 8, 2023: Magnetic Resonance in Medical Sciences: MRMS
Hinako Oshiro, Junichi Hata, Daisuke Nakashima, Naoya Hayashi, Yawara Haga, Kei Hagiya, Daisuke Yoshimaru, Hideyuki Okano
PURPOSE: Diffusion MRI is a physical measurement method that quantitatively indicates the displacement of water molecules diffusing in voxels. However, there are insufficient data to characterize the diffusion process physically in a uniform structure such as a phantom. This study investigated the transitional relationship between structure scale, temperature, and diffusion time for simple restricted diffusion using a capillary phantom. METHODS: We performed diffusion-weighted pulsed-gradient stimulated-echo acquisition mode (STEAM) MRI with a 9...
February 8, 2023: Magnetic Resonance in Medical Sciences: MRMS
Tomohiko Nishino, Kazuhiro Takahashi, Sayaka Ono, Masakazu Mimaki
PURPOSE: Despite the usefulness of blood oxygenation level-dependent (BOLD) MRI in assessing glomerulonephritis activity, its relationship with histological findings remains unclear. Because glomerulonephritis presents multiple complex injury patterns, analysis of each pattern is essential. We aimed to elucidate the relationship between the histological findings of the kidney and BOLD MRI findings in mesangial proliferative glomerulonephritis. METHODS: Children under 16 years of age diagnosed with mesangial proliferative glomerulonephritis by kidney biopsy at our university hospital between January 2013 and September 2022 were included in this study...
February 7, 2023: Magnetic Resonance in Medical Sciences: MRMS
Hiroyuki Kabasawa, Shigeru Kiryu
The liver moves with respiratory motion. Respiratory motion causes image artifacts as MRI is a motion-sensitive imaging modality; thus, MRI scan speed improvement has been an important technical development target for liver MRI for years. Recent pulse sequence and image reconstruction technology advancement has realized a fast liver MRI acquisition method. Such new technologies allow us to obtain liver MRI in a shorter time, particularly, within breath-holding time. Other benefits of new the technology and the higher spatial resolution liver MRI within a given scan time are improved slice coverage and smaller pixel size...
February 7, 2023: Magnetic Resonance in Medical Sciences: MRMS
Kenichiro Ihara, Hideko Onoda, Masahiro Tanabe, Etsushi Iida, Takaaki Ueda, Taiga Kobayashi, Mayumi Higashi, Marcel Dominik Nickel, Hiroshi Imai, Katsuyoshi Ito
PURPOSE: To evaluate the feasibility of breath-hold (BH) high-resolution (HR) T1-weighted gradient echo hepatobiliary phase (HBP) imaging using compressed sensing (CS) in gadoxetic acid-enhanced liver MRI in comparison with standard HBP imaging using parallel imaging (PI). METHODS: The study included 122 patients with liver tumors with hypointensity in the HBP who underwent both HR HBP imaging with CS and standard HBP imaging with PI. Two radiologists evaluated the liver edge sharpness, hepatic vessel conspicuity, bile duct conspicuity, image noise, and overall image quality, as well as the lesion conspicuity on HR and standard HBP imaging and the contrast-enhanced (CE) MR cholangiography (MRC) image quality reconstructed from HBP images...
February 4, 2023: Magnetic Resonance in Medical Sciences: MRMS
Shintaro Ichikawa, Satoshi Goshima
MRI is widely used in clinical practice for detecting liver diseases. Since the introduction of gadoxetic acid, MRI has become the most effective modality for the detection and characterization of focal liver lesions. According to previous meta-analyses, the area under the receiver operating characteristic curve (AUROC) was 0.97-0.99 for the diagnosis of small hepatocellular carcinoma (≥ 2 cm) by gadoxetic-acid-enhanced MRI. Moreover, the AUROC for the diagnosis of colorectal liver metastases was significantly high (0...
February 1, 2023: Magnetic Resonance in Medical Sciences: MRMS
Takeshi Nakaura, Naoki Kobayashi, Naofumi Yoshida, Kaori Shiraishi, Hiroyuki Uetani, Yasunori Nagayama, Masafumi Kidoh, Toshinori Hirai
The application of machine learning (ML) and deep learning (DL) in radiology has expanded exponentially. In recent years, an extremely large number of studies have reported about the hepatobiliary domain. Its applications range from differential diagnosis to the diagnosis of tumor invasion and prediction of treatment response and prognosis. Moreover, it has been utilized to improve the image quality of DL reconstruction. However, most clinicians are not familiar with ML and DL, and previous studies about these concepts are relatively challenging to understand...
January 26, 2023: Magnetic Resonance in Medical Sciences: MRMS
Seiya Kishi, Masayuki Maeda, Fumine Tanaka, Ryota Kogue, Maki Umino, Hajime Sakuma
We observed a new SWI finding, "cortical brush sign," that represents prominent venous structures in the cortex of patients with acute cerebral infarct with or without moyamoya disease and cerebral venous thrombosis. The cortical brush sign disappeared on follow-up SWI in all cases. Cortical brush sign may help to understand the pathophysiology of venous structures in the cortex at acute phase.
January 24, 2023: Magnetic Resonance in Medical Sciences: MRMS
Mayumi Takeuchi, Kenji Matsuzaki, Yoshimi Bando, Masafumi Harada
PURPOSE: Adenomatoid tumor is a rare benign genital tract neoplasm of mesothelial origin. Uterine adenomatoid tumors occur in the outer myometrium and may mimic leiomyomas. Because hormonal treatment is not applicable to adenomatoid tumors and laparoscopic enucleation is not easy as myomectomy, it is important to differentiate adenomatoid tumors from leiomyomas for the adequate treatment. The purpose of this study is to evaluate the MRI findings of adenomatoid tumor for the differentiation from leiomyoma...
January 24, 2023: Magnetic Resonance in Medical Sciences: MRMS
Masaki Ishida, Jérôme Yerly, Haruno Ito, Masafumi Takafuji, Shiro Nakamori, Shinichi Takase, Yoshito Ichiba, Yoshiaki Komori, Kaoru Dohi, Davide Piccini, Jessica A M Bastiaansen, Matthias Stuber, Hajime Sakuma
Free-running 5D whole-heart coronary MR angiography (MRA) is gaining in popularity because it reduces scanning complexity by removing the need for specific slice orientations, respiratory gating, or cardiac triggering. At 3T, a gradient echo (GRE) sequence is preferred in combination with contrast injection. However, neither the injection scheme of the gadolinium (Gd) contrast medium, the choice of the RF excitation angle, nor the dedicated image reconstruction parameters have been established for 3T GRE free-running 5D whole-heart coronary MRA...
January 20, 2023: Magnetic Resonance in Medical Sciences: MRMS
Shinji Naganawa, Rintaro Ito, Mariko Kawamura, Toshiaki Taoka, Tadao Yoshida, Michihiko Sone
PURPOSE: To investigate the characteristics of the putative meningeal lymphatics located at the posterior wall of the sigmoid sinus (PML-PSS) in human subjects imaged before and after intravenous administration (IV) of a gadolinium-based contrast agent (GBCA). The appearance of the PML-PSS and the enhancement of the perivascular space of the basal ganglia (PVS-BG) were analyzed for an association with gender, age, and clearance of the GBCA from the cerebrospinal fluid (CSF). METHODS: Forty-two patients with suspected endolymphatic hydrops were included...
January 19, 2023: Magnetic Resonance in Medical Sciences: MRMS
Tomoki Amemiya, Suguru Yokosawa, Yo Taniguchi, Ryota Sato, Yoshihisa Soutome, Hisaaki Ochi, Toru Shirai
PURPOSE: To increase the number of images that can be acquired in MR examinations using quantitative parameters, we developed a method for obtaining arterial and venous images with mapping of proton density (PD), RF inhomogeneity (B1), longitudinal relaxation time (T1), apparent transverse relaxation time (T2*), and magnetic susceptibility through calculation, all with the same spatial resolution. METHODS: The proposed method uses partially RF-spoiled gradient echo sequences to obtain 3D images of a subject with multiple scan parameters...
December 21, 2022: Magnetic Resonance in Medical Sciences: MRMS
Vadim Malis, Won C Bae, Asako Yamamoto, Linda K McEvoy, Marin A McDonald, Mitsue Miyazaki
PURPOSE: Clearance of cerebrospinal fluid (CSF) is important for the removal of toxins from the brain, with implications for neurodegenerative diseases. Imaging evaluation of CSF outflow in humans has been limited, relying on venous or invasive intrathecal injections of contrast agents. The objective of this study was to introduce a novel spin-labeling MRI technique to detect and quantify the movement of endogenously tagged CSF, and then apply it to evaluate CSF outflow in normal humans of varying ages...
December 17, 2022: Magnetic Resonance in Medical Sciences: MRMS
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