著者

斎藤 勇哉 Peter A. Wijeratne 鎌形 康司 Christina Andica 内田 航 明石 俊昭 和田 昭彦 堀 正明 青木 茂樹

出版者

日本磁気共鳴医学会

雑誌

日本磁気共鳴医学会雑誌 (ISSN:09149457)

巻号頁・発行日

pp.2023-1790, (Released:2023-05-25)

参考文献数

28

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Corticobasal syndrome (CBS) and progressive supranuclear palsy (PSP) are sporadic atypical parkinsonian disorders associated with 4-repeat tauopathies. These neurodegenerative conditions closely overlap in their clinical information, pathology, and genetic risk factors ; therefore, it is difficult to accurately diagnose CBS and PSP. Recently, an unsupervised machine-learning technique, called Subtype and Stage Inference (SuStaIn), has been proposed to reveal the data-driven disease phenotypes with distinct temporal progression patterns from widely available cross-sectional data. To clarify the differences in the temporal white matter (WM) degeneration patterns between CBS and PSP, this study applied SuStaIn for fractional anisotropy (FA) in regional WM, which was sensitive to WM degeneration, based on cross-sectional brain diffusion MRI (dMRI) data. We obtained dMRI data from 15 healthy controls, 26 patients with CBS, and 25 patients with PSP. FA was calculated after fitting the diffusion tensor model to the corrected dMRI data for susceptibility and eddy-current induced geometric distortions and inter-volume subject motion. SuStaIn was applied to the cross-sectional regional WM tract FAs to identify both the disease subtypes and their trajectories with distinct WM degeneration patterns. To assess the performance of SuStaIn, the classification accuracy and sensitivity for CBS and PSP were calculated. SuStaIn revealed that the CBS degeneration started from the fornix and stria terminalis (FSTs) and corpus callosum (CC), followed by the posterior corona radiata (PCR), posterior thalamic radiation (PTR), and cerebral peduncle (CP), and subsequently extended to the cingulum. Finally, it reached the superior cerebral peduncle (SCP) and corticospinal tract (CST). In contrast, the PSP degeneration started from the SCP and cingulum, followed by the CST, and subsequently extended to the FST and CC. Eventually, it reached the PCR, PTR, and CP. Accordingly, SuStaIn classified CBS and PSP with 0.863 accuracy (sensitivity : CBS, 0.885 ; PSP, 0.840). The results suggested the utility of SuStaIn for classifying patients with CBS and PSP and identifying temporal WM degeneration patterns in patients with CBS and PSP.

著者

巨瀬 勝美

出版者

日本磁気共鳴医学会

雑誌

日本磁気共鳴医学会雑誌 (ISSN:09149457)

巻号頁・発行日

vol.41, no.3, pp.61-66, 2021-08-15 (Released:2021-09-06)

参考文献数

9

---

Recent MRI technology and pulse sequences have become increasingly complex and difficult to understand. However, the Bloch equations, which are the basic principle of MRI, have remained unchanged since it was proposed in 1973. Here we have presented a method to numerically solve the Bloch equations to understand the principle of MRI. This method enables us to reproduce complex pulse sequences on a computer and to understand various phenomena related to pulse sequences.

著者

押尾 晃一

出版者

日本磁気共鳴医学会

雑誌

日本磁気共鳴医学会雑誌 (ISSN:09149457)

巻号頁・発行日

vol.41, no.2, pp.37, 2021-05-15 (Released:2021-06-04)

参考文献数

1

---

According to the view that cerebrospinal fluid (CSF) and ISF exchange dynamically and form a pathway to remove waste products from the brain, CSF is likely to contain a high concentration of waste products. Based on recent results of T2 analyses, CSF seems to contain low protein, suggesting that this might not be the case.

著者

山口 さち子 井澤 修平 前谷津 文雄 圡井 司 引地 健生 藤田 秀樹 今井 信也 赤羽 学 王 瑞生

出版者

日本磁気共鳴医学会

雑誌

日本磁気共鳴医学会雑誌 (ISSN:09149457)

巻号頁・発行日

vol.38, no.4, pp.103-119, 2018 (Released:2018-12-10)

参考文献数

27

---

In this study, we surveyed policies on allocating MRI scan duties to pregnant employees, and investigated the respondents' level of awareness of non-ionizing radiation. We sent 5763 questionnaires to facilities equipped with MRI devices in Japan (the corresponding respondent was a member of the personnel responsible for MRI scan duties). The questionnaire comprised: 1) Basic information; 2) General questions about the employees' pregnancies (e.g., whether the hospital has a particular policy); 3) The policy on MRI scan duties while pregnant and alternative duties ; and 4) Level of awareness of non-ionizing radiation in general. The results revealed inconsistent handling within Japan. Answers stating that ``increase the opportunity of allocation to MRI scan duties compared with the current situation'' accounted for 7.6%, ``maintaining the current frequency of allocation to MRI scan duties'' for 32.3%, and ``reduce the opportunity of allocation to MRI scan duties compared with current situation'' for 52.6%. Around half of facilities prepared work options (e.g. access restriction into MRI scan room or assign extra staff to MRI scan duties) in MRI scan duties during pregnancy. In an attitude survey for non-ionizing radiation emitted by medical devices, respondents showed higher attention compared with that for the radiation emitted by home electronic devices. This report describes a summary of the survey. Further analysis is in progress and will be reported soon.

著者

五十嵐 博中 湯浅 龍彦

出版者

日本磁気共鳴医学会

雑誌

日本磁気共鳴医学会雑誌 (ISSN:09149457)

巻号頁・発行日

vol.38, no.4, pp.93-95, 2018 (Released:2018-12-10)

参考文献数

3

著者

曽我 茂義 大西 文夫 奥田 茂男 見越 綾子 三鍋 俊春 陣崎 雅弘 新本 弘

出版者

日本磁気共鳴医学会

雑誌

日本磁気共鳴医学会雑誌 (ISSN:09149457)

巻号頁・発行日

vol.42, no.2, pp.53-57, 2022-05-15 (Released:2022-06-10)

参考文献数

11

---

This retrospective study analyzed the magnetic resonance lymphography (MRL) findings of 112 lower limbs of 56 lymphedema patients, and identified characteristic patterns of lymphatic impairment that change with the location in lower limbs and clinical stage. The authors proposed an MRL staging system that enables a new patient stratification based on the severity of the lymphatic injury, thus potentially improving clinical management.

著者

松田 豪

出版者

日本磁気共鳴医学会

雑誌

日本磁気共鳴医学会雑誌 (ISSN:09149457)

巻号頁・発行日

vol.38, no.4, pp.96-102, 2018 (Released:2018-12-10)

参考文献数

23

---

Proton magnetic resonance spectroscopy (MRS) is widely used to detect alterations in cerebral metabolite levels in various neurological disorders. Data acquisitions with a short echo-time (TE) are recommended. Subsequently, provided that time permits, it is also recommended to apply long TE with shimming/adjustment of radiofrequency pulses and careful setting of voxels of interest. In those cases where contrast agents are administered, it is preferable to perform short-TE acquisitions using non-ionic media. Advanced systems with higher static magnetic field enable the detection of low-concentration metabolites, particularly when using short TE. MRS data acquisition and processing can be performed semi-automatically; however, sufficient knowledge and skills are needed to obtain high quality spectra.

著者

秋山 新平 新津 守 松尾 周也 野崎 太希 山田 惠

出版者

日本磁気共鳴医学会

雑誌

日本磁気共鳴医学会雑誌 (ISSN:09149457)

巻号頁・発行日

vol.40, no.1, pp.30-32, 2020-02-15 (Released:2020-03-13)

参考文献数

8

---

Six hundred and ninety consecutive MRI images obtained on 1.5 T or 3.0 T devices were reviewed to investigate the prevalence and diagnostic pitfalls of the vacuum phenomenon (VP) of the knee joint. The VP was identified on 13 knees and 7 knees (53.8%) were diagnosed with osteoarthritis. Gradient-echo imaging facilitated the delineation of minute VP within the joint space with susceptibility artifacts.

著者

寺田 康彦 中尾 愛 中込 真優

出版者

日本磁気共鳴医学会

雑誌

日本磁気共鳴医学会雑誌 (ISSN:09149457)

巻号頁・発行日

vol.38, no.3, pp.61-75, 2018-08-15 (Released:2018-10-03)

参考文献数

62

被引用文献数

1 1

---

Compressed sensing (CS) is a rapidly developing technique for reducing scanning times while maintaining image contrast and quality. CS theory affirms that certain images can be recovered from highly compressed k-space data with an appropriate reconstruction algorithm. This article reviews the fundamentals of CS, its methods, pulse sequence designs, the reconstruction algorithm, and potential artifacts and their causes, which are important for implementing the CS technique in clinical practice.

著者

黒木 嘉典 大橋 望 渡辺 圭司 新村 友季子 新村 眞司 池原 在 伊波 恵

出版者

日本磁気共鳴医学会

雑誌

日本磁気共鳴医学会雑誌 (ISSN:09149457)

巻号頁・発行日

vol.39, no.1, pp.25-28, 2019-02-15 (Released:2019-03-18)

参考文献数

16

---

We analyzed the efficacy of time-intensity curve and texture analysis of dynamic contrast enhanced study (DCE), and also mean apparent diffusion coefficient (ADC) and histogram analysis of diffusion-weighted imaging in a neoadjuvant chemotherapy (NAC) non-effective group and an NAC effective group of patients with breast cancer. Based on texture and histogram analysis, it was speculated that early response was predictable.

著者

巨瀬亮一 巨瀬勝美

出版者

日本磁気共鳴医学会

雑誌

第43回日本磁気共鳴医学会大会

巻号頁・発行日

2015-08-31

著者

Shinji Naganawa Toshiaki Taoka Hisashi Kawai Masahiro Yamazaki Kojiro Suzuki

出版者

日本磁気共鳴医学会

雑誌

Magnetic Resonance in Medical Sciences (ISSN:13473182)

巻号頁・発行日

pp.mp.2017-0088, (Released:2017-09-29)

参考文献数

31

被引用文献数

9

---

Purpose: Circumventricular organs (CVOs) lack a blood brain barrier and are also called “brain windows”. Among CVOs, the organum vasculosum of the lamina terminalis (OVLT) is an osmotic regulator involved in the release of vasopressin. In a previous study of healthy subjects, it was reported that contrast enhancement in the OVLT can be recognized in only 34% of 3 Tesla thin slice contrast-enhanced T1-weighted images. The purpose of this study was to evaluate the leakage of gadolinium contrast from the OVLT in healthy subjects using heavily T2-weighted three dimensional-fluid attenuated inversion recovery (3D-FLAIR) (HF) imaging.Methods: Eight healthy male subjects were included in this study. A standard dose (0.1 mmol/kg) of gadoteridol was intravenously administered. magnetic resonance cisternography (MRC) and HF were obtained before and 0.5, 1.5, 3, 4.5 and 6 h after the injection. Enhancement of the OVLT including the surrounding cerebral spinal fluid (CSF) was measured by manually drawing a rectangular region of interest (ROI) centered on the OVLT. The ROI was copied to the HF image and the signal intensity was measured. The signal intensity ratio (SIR) was obtained by dividing the signal intensity value of the OVLT ROI by that of the midbrain.Results: The differences between the mean SIR at pre-contrast and those at 0.5, 1.5, 3, 4.5, and 6 h were significant (P < 0.05). The mean SIR at 0.5 h was higher than those at all other time points (P < 0.05).Conclusion: Using HF imaging, enhancement around the OVLT was observed in all subjects at 0.5 h after intravenous administration of single dose gadoteridol.

著者

Yoshimasa MATSUDA Shinya ONO Yosuke OTAKE Shinya HANDA Katsumi KOSE Tomoyuki HAISHI Shigeto YAMADA Chikako UWABE Kohei SHIOTA

出版者

日本磁気共鳴医学会

雑誌

Magnetic Resonance in Medical Sciences (ISSN:13473182)

巻号頁・発行日

vol.6, no.3, pp.139-146, 2007 (Released:2007-11-20)

参考文献数

15

被引用文献数

18 38

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Using 4 and 8-channel super-parallel magnetic resonance (MR) microscopes with a horizontal bore 2.34T superconducting magnet developed for 3-dimensional MR microscopy of the large Kyoto Collection of Human Embryos, we acquired T1-weighted 3D images of 1204 embryos at a spatial resolution of (40 μm)3 to (150 μm)3 in about 2 years. Similarity of image contrast between the T1-weighted images and stained anatomical sections indicated that T1-weighted 3D images could be used for an anatomical 3D image database for human embryology.

著者

町田好男

出版者

日本磁気共鳴医学会

雑誌

第42回日本磁気共鳴医学会大会

巻号頁・発行日

2014-09-11

---

圧縮センシング(Compressed Sensing: 以下CS)とは、「観測対象データがある表現空間では「スパース(疎)」であると仮定して、少数の観測データから対象を復元する手法」である。近年、ランダムな成分を持つ観測マトリクスの場合に復元可能であることが情報理論分野において示され、さらに、観測データをランダムサンプリングできるMRIはCSのよい適用となっていることが示された(Lustig, 2007)。図は、CS-MRIにおける再構成の概要を示したものである。再構成したい画像(対象データ)をmとしよう。CS-MRIでは、「(1)表現空間データΨmが疎であること」と「(2)アンダーサンプルしたフーリエ変換像Fumが観測(収集)データyに近いこと」を条件としてmを求める。(適当なモデルのもとで解を求められることがCS理論の教えるところである。) 通常のMR断面像ではΨとしてWavelet変換などが用いられる。CS-MRIにおいては、観測データ、対象データ、疎表現データの3つを切り分けて考えること、あるいはそれらをうまく割り当てることが重要であるが、この時の自由度が高く従って応用範囲が広いのがMRIの特長となっている。本講演では、原理説明に続きいくつかのアプリケーションを紹介する。また現在我々が検討しているCS画質の評価検討について一部紹介したい。

著者

池上匡 萩原浩明 田山芳史 金野義紀

出版者

日本磁気共鳴医学会

雑誌

第42回日本磁気共鳴医学会大会

巻号頁・発行日

2014-09-11

---

【目的】Kanda らの衝撃的な報告により、頻回にわたってガドリニウム(Gd)造影剤を使用された患者の淡蒼球と小脳歯状核にGdが沈着している可能性が示唆された。しかしリニア型とマクロ環型の造影剤では、キレートからのGd遊離量に大きな差があると考えられる。そこでリニア型またはマクロ環型の造影剤を複数回使用された患者で、小脳歯状核のT1高信号化に差があるかどうかを検討した。【対象と方法】2011年7月より2014年3月に頭部造影MR検査を受けた患者258人をスクリーニングして、それより以前を含めて初回の造影検査からリニア型造影剤のみ(Gd-DTPAまたはGd-DTPA-BMA)(リニア群)あるいはマクロ環型造影剤のみ(Gd-DOTA)(DOTA群)を5回以上投与された患者群、それぞれ21人と11人を後ろ向き解析の対象とした。Kanda らの方法に従い、各回のMR検査時の単純T1強調画像の歯状核/橋の信号強度比を測定した。統計解析には初回、5回目、最終回(各群平均8.1回と7.9回)の検査時の信号強度比を用いた。【結果】両群間の年齢、性別、検査期間の平均eGFR、総造影回数には有意差を認めなかった。リニア群ではKandaらの報告の通りに、造影回数が増えるにつれて歯状核信号の上昇を認めたが、DOTA群では信号上昇を認めず、両群間に有意な差を生じた。最終回検査の信号強度比を目的変数として重回帰分析を行うと、年齢、性別、eGFR、総造影回数、原疾患の良悪性、頭部放射線治療の有無、初回から5回目検査までの日数に関わらず、造影剤の種類のみが有意な予知因子であった。【結論】Kandaらの発見した頻回造影患者における小脳歯状核の信号上昇は、リニア型造影剤の使用により起こる現象であり、遊離Gdのはるかに少ないGd-DOTAでは起こりにくいと考えられる。【 開示すべき利益相反はありません】

著者

横沢俊 越智久晃 尾藤良孝 伊藤賢司 佐々木真理

出版者

日本磁気共鳴医学会

雑誌

第42回日本磁気共鳴医学会大会

巻号頁・発行日

2014-09-11

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【背景】Diffusion kurtosis imaging (DKI)は,非正規分布の拡散モデルを用いた拡散イメージング手法の一つであり,従来のDTIと比し,軽微な白質・灰白質病変などの検出能向上が期待されている[1].しかし,DKIの解析は,DTIと比較してノイズに対する頑健性が低く,計算アーチファクトが発生しやすい.一般的に,前処理における平滑化フィルターの適用により頑健性は向上するが,画像のblurring発生が課題となる.本研究では,blurringを発生させずに計算アーチファクトを抑制するDKIの解析手法について検討した.【方法】本手法は,制約無しの非線形最小二乗法にて拡散係数と尖度係数を推定し,制約条件の範囲外に算出された係数について平滑化フィルターを適用したデータを用いて再計算する.5名の健常ボランティア(男性,26-45歳)を対象に,1.5 T MRI装置(ECHELON Vega, 日立メディコ)を用いて,MPG 21軸,b値1000, 2500 s/mm2,2NEXのDTIを2回撮像した.解析では,平滑化処理無しの手法,全データに平滑化処理を適用した手法,提案手法の三つの手法にてMK画像を算出した.計算アーチファクトおよびblurringを視覚的に評価し,2回計測の再現性をICC(intraclass correlation coefficient)にて評価した.【結果】提案手法のMK画像は,平滑化処理無しのMK画像と比較して,blurringが同等であるにもかかわらず,2回計測の再現性が有意に高く(ICC: 提案手法, 0.77±0.076; 平滑化処理無し, 0.73±0.079),計算アーチファクトが改善されていた.全データに平滑化処理を適用したMK画像は,平滑化の強度に応じて2回計測の再現性が向上するが,blurringが顕著となった.同等の再現性(ICC: 全データ平滑化, 0.76±0.080)で比較した場合,提案手法のMK画像は,全データを平滑化処理したMK画像と比較して,blurringが小さく計算アーチファクトが改善されていた.【結論】本研究により,DKI解析において頑健性の高い処理が可能であることが明らかとなり,臨床応用実現の可能性が示された.[1]Jensen JH. MRM. 2005;53:1432-40.

著者

Go URUMA Keiji HASHIMOTO Masahiro ABO

出版者

日本磁気共鳴医学会

雑誌

Magnetic Resonance in Medical Sciences (ISSN:13473182)

巻号頁・発行日

pp.2014-0104, (Released:2015-02-12)

被引用文献数

5

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Purpose: We developed a new and convenient method that employs voxel-based morphometry (VBM) to evaluate regional reduction in the volume of white matter after diffuse axonal injury (DAI).Methods: We studied 29 patients with moderate cognitive disability after DAI. Each subject underwent 3-dimensional volumetric magnetic resonance (MR) imaging. Images were preprocessed automatically using stand-alone software running on a Windows PC for VBM of volumetric MR imaging utilizing a statistical parametric mapping (SPM) version 8 software engine and an algorithm for diffeomorphic anatomic registration through exponentiated lie algebra (DARTEL). We then computed a Z-score for all coordinates on the white matter, which represented the relative reduction in white matter volume. Finally, we used voxel-based stereotactic extraction estimation (vbSEE) to compute the extent of regional reduction in the volume of white matter (rWMVR) for each region of interest (ROI), defined as the rate of coordinates with Z-scores exceeding 2.0 in the ROI. For each ROI, we used Pearson’s correlation analysis to examine the correlation between the extent of regional volume reduction and patient scores on the Wechsler Adult Intelligence Scale III (WAIS-III).Results: We detected marked rWMVR in several ROIs, including the corpus callosum, and rWMVR correlated significantly with performance IQ and processing speed index in the splenium of the corpus callosum.Conclusions: The results indicate the utility of our applications for the daily clinical evaluation of DAI. That they can be used on a PC and allow acquisition of volumetric data from standard MR images are their advantages.

著者

Takafumi HAYASHI Akihiko WADA Nobue UCHIDA Hajime KITAGAKI

出版者

日本磁気共鳴医学会

雑誌

Magnetic Resonance in Medical Sciences (ISSN:13473182)

巻号頁・発行日

vol.8, no.1, pp.33-38, 2009 (Released:2009-04-01)

参考文献数

22

被引用文献数

4 7

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Background: Imaging diagnosis of Alzheimer disease (AD), the leading cause of dementia, requires evaluation of the extent of hippocampal atrophy. Coronal magnetic resonance (MR) images of patients with AD often demonstrate outward rotation of the hippocampus that is altered from a long horizontal elliptical to a long vertical elliptical shape. Such rotation may be related to the disease process of AD. Purpose and Methods: To determine whether hippocampal rotation is associated with AD, we investigated MR images from 11 patients with AD and 11 normal controls, measuring the hippocampal angle (HA) and the volume of the left hippocampus on coronal T1-weighted MR images. The HA is the angle between a horizontal line orthogonal to the falx cerebri and the uncal sulcus line between the deepest point of the uncal sulcus and the point nearest to the side of the ambient cistern in the uncal gyrus facing the uncal sulcus. The HA is measured on the most rostral slice in which the uncal sulcus can be identified and increases with hippocampal rotation. Results: We found correlation between the HA and standardized hippocampal volume in the AD group, but not in controls. Conclusion: Hippocampal rotation is a new marker associated with the pathology of AD.

著者

Tomone AMATSUBO Daijiro YANAGISAWA Shigehiro MORIKAWA Hiroyasu TAGUCHI Ikuo TOOYAMA

出版者

日本磁気共鳴医学会

雑誌

Magnetic Resonance in Medical Sciences (ISSN:13473182)

巻号頁・発行日

vol.9, no.3, pp.95-99, 2010 (Released:2010-09-27)

参考文献数

23

被引用文献数

9 21

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The formation of senile plaques followed by deposition of amyloid β peptides (Aβ) are the earliest pathological changes of Alzheimer's disease (AD); thus, detection of the plaques remains the most important early diagnostic indicator of AD. Amyloid imaging is a noninvasive technique for visualizing senile plaques in the brains of patients with Alzheimer's using positron emission tomography (PET) or magnetic resonance (MR) imaging. Several types of probes have been developed for PET, but few ligands have been developed specifically for MR imaging detection of amyloid plaques. This review presents recent advances in amyloid imaging using MR imaging and includes our studies.

著者

Mayumi TAKEUCHI Kenji MATSUZAKI Yoshimi BANDO Mika SAKAKI Hiroyuki FURUMOTO Masafumi HARADA

出版者

日本磁気共鳴医学会

雑誌

Magnetic Resonance in Medical Sciences (ISSN:13473182)

巻号頁・発行日

pp.2013-0078, (Released:2014-07-02)

被引用文献数

3

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Villoglandular papillary adenocarcinoma (VGPA) is a rare subtype of cervical adenocarcinoma that generally affects young women and has a favorable prognosis. Its preoperative diagnosis is important to avoid excessive surgery. We report the magnetic resonance (MR) findings of a case in which the cervical tumor showed a fern-leaf-like appearance on high resolution T2-weighted images obtained at 3 tesla. MR imaging clearly showed this pathological feature that may suggest this disease.