• 제목/요약/키워드: Magnetic resonance imaging

검색결과 3,281건 처리시간 0.02초

Magnetic Resonance Imaging with Intermolecular Double Quantum Coherences

  • Ahn, Sang-Doo
    • 한국자기공명학회논문지
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    • 제8권2호
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    • pp.108-114
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    • 2004
  • Recently a new method for magnetic resonance imaging based on the detection of relatively strong signal from intermolecular multiple quantum coherences (iMQCs) is reported. Such a signal would not be observable in the conventional framework of magnetic resonance; it originates in long-range dipolar couplings that are traditionally ignored. In this paper, we present the results of experimental studies to assess the feasibility of intermolecular double quantum coherences (iDQCs) imaging in humans. We show that the iDQC images are readily observable at 4T and that they do indeed provide different contrast than appears in conventional images.

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동물에서 자기 공명 영상 진단의 물리적 원리 (Physical Principles of Magnetic Resonance Imaging in Animal)

  • 김종규
    • 한국임상수의학회지
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    • 제16권1호
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    • pp.75-79
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    • 1999
  • Magnetic resonance imaging (MRI) is an imaging technique used to produce high quality images of the inside of the animal body. MRI is based on the principles of nuclear magnetic resonance (NMR) and started out as a tomographic imaging technique, that is it produced an image of the NMR signal in a thin slice through the animal body. The animal body is primarily fat and water, Fat and water have many hydrogen atoms. Hydrogen nuclei have an NMR signal. For these reasons magnetic resonance imaging primarily images the NMR signal from the hydrogen nuclei. Hydrogen protons, within the body align with the magnetic field. By applying short radio frequency (RF) pulses to a specific anatomical slice, the protons in the slice absorb energy at this resonant frequency causing them to spin perpendicular to the magnetic field. As the protons relax back into alignment with the magnetic field, a signal is received by an RF coil that acts as an antennae. This signal is processed by a computer to produce diagnostic images of the anatomical area of interest.

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The Fornix: Functional Anatomy, Normal Neuroimaging, and Various Pathological Conditions

  • Choi, Young Jae;Lee, Eun Ja;Lee, Jung Eun
    • Investigative Magnetic Resonance Imaging
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    • 제25권2호
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    • pp.59-75
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    • 2021
  • The fornix is the major white-matter outflow tract from the hippocampus; it has a significant role in cognitive function. It is readily imaged via magnetic resonance imaging; its main parts are the crura, commissure, body, and columns. In this pictorial essay, we describe and illustrate the functional and imaging anatomy of the fornix and limbic system, as well as various disease entities involving the fornix.

Magnetic Resonance Imaging of Idiopathic Herniation of the Lingual Gyrus: a Case Report

  • Seok, Hee Young;Lee, Dong Hoon
    • Investigative Magnetic Resonance Imaging
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    • 제21권3호
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    • pp.195-198
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    • 2017
  • Idiopathic brain herniation is a rare condition. We believe that this is the first reported case of idiopathic herniation of the lingual gyrus. The case involves a 57-year-old woman presenting with frontal headache without overt visual symptoms. Magnetic resonance imaging (MRI) revealed an idiopathic herniation of the lingual gyrus of the occipital lobe extending into the quadrigeminal cistern. No other adjacent intracranial abnormalities were observed. Although some conditions may be considered in the differential diagnosis, accurate diagnosis of idiopathic brain herniation in medical practice can prevent unnecessary additional imaging procedures and invasive open biopsy in patients with typical imaging findings.

The Magnetic Resonance (MR) Imaging Features of Myxoid Liposarcoma Arising from the Mesentery: a Case Report

  • Ahn, Taehoon;Lee, Young Hwan;Lee, Guy Mok;Kim, Youe Ree;Yoon, Kwon-Ha
    • Investigative Magnetic Resonance Imaging
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    • 제21권4호
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    • pp.252-258
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    • 2017
  • Primary mesenteric liposarcoma is rare. It is difficult to make an accurate preoperative diagnosis of the myxoid type of liposarcoma by using imaging such as ultrasound or computed tomography (CT) due to the very small amount of fat that is located in the tumor. We report a case of primary myxoid liposarcoma of the mesentery which was difficult to differentiate from other solid mesenteric tumors with a myxoid component such as low grade fibromyxoid sarcoma, myxoid leiomyosarcoma or myxoma. Use of chemical shift magnetic resonance (MR) imaging to detect small fat components and its cystic appearance with solid components on the MR images can be useful to differentiate myxoid liposarcoma from the other mesenteric tumors with a myxoid component.

Bone Involvement of Diffuse Large B Cell Lymphoma (DLBCL) Showing Unusual Manifestations Mimicking Chronic Osteomyelitis in a 58-Year-Old Man: Case Report and Clinical Application of Diffusion Weighted Magnetic Resonance Imaging

  • Lee, Kyung Ryeol;Maeng, Young Hee
    • Investigative Magnetic Resonance Imaging
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    • 제23권3호
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    • pp.270-275
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    • 2019
  • This study presents a case of diffuse large B cell lymphoma (DLBCL) in a 58-year-old man showing unusual manifestations mimicking chronic osteomyelitis. In this case review, we describe the imaging findings of DLBCL which mimics chronic osteomyelitis and review existing reports regarding the differential diagnosis of bone involvement of lymphoma and osteomyelitis through imaging and laboratory findings and diffusion-weighted magnetic resonance imaging (DWI) such as the advanced MRI sequence.

Cranial Nerve Disorders: Clinical Application of High-Resolution Magnetic Resonance Imaging Techniques

  • Lee, Ji Ye;Park, Hye Min;Lee, Boeun;Kim, Ji-hoon
    • Investigative Magnetic Resonance Imaging
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    • 제25권4호
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    • pp.281-292
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    • 2021
  • Cranial-nerve disorders can be caused by a wide spectrum of diseases, including congenital, inflammatory, and tumorous diseases, and are often encountered in practice. However, the imaging of cranial-nerve disorders is challenging, and understanding the anatomical differences of each region is essential for conducting the best protocols and for detecting subtle changes in cranial nerves during magnetic resonance imaging (MRI) examinations. In this review we discuss which MRI techniques are best for observing normal and pathologic appearance, according to the different regions of the cranial nerves.

자가공명영상(Magnetic Resonance Imaging)의 기본원리 (Basic Principles of Magnetic Resonance Imaging)

  • 조봉혜
    • 치과방사선
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    • 제29권1호
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    • pp.7-20
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    • 1999
  • Magnetic resonance imaging with its superior soft tissue contrast resolution and absence of beam hardening artifacts, combined with its ability to perform multiplanar imaging, is now effective tool in diagnostic imagings. Magnetic resonance is primarily a phenomenon that involves atomic nuclei. It provides totally new clinical informations with no known hazards through the use of very weak interactions with endogenous stable magnetic atomic nuclei. This article briefly summarizes the basic mechanism of generation and detection of the signals and general sorts of tissue properties which can influence the signals and thereby give rise to tissue contrast. It also describes how the machine-operating parameters can be used to manipulate the tissue contrast observed in the image.

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Advances in Fast Vessel-Wall Magnetic Resonance Imaging Using High-Density Coil Arrays

  • Yin, Xuetong;Li, Nan;Jia, Sen;Zhang, Xiaoliang;Li, Ye
    • Investigative Magnetic Resonance Imaging
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    • 제25권4호
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    • pp.229-251
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    • 2021
  • Arteriosclerosis is the leading cause of stroke, with a fatality rate surpassing that of ischemic heart disease. High-resolution vessel wall magnetic resonance imaging is generally recognized as a non-invasive and panoramic method for the evaluation of arterial plaque; however, this method requires improved signal-to-noise ratio and scanning speed. Recent advances in high-density head and neck coil arrays are characterized by broad coverage, multiple channels, and closefitting designs. This review analyzes fast magnetic resonance imaging from the perspective of accelerated algorithms for vessel wall imaging and demonstrates the need for effective algorithms for signal acquisition using advanced radiofrequency system. We summarize different phased-array structures under various experimental objectives and equipment conditions, introduce current research results, and propose prospective research studies in the future.