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1 History, Present, and Future of Diagnostic Imaging: Magnetic Resonance Imaging (MRI) Yutaka Imai, M.D. and Tomohiro Yamashita, M.D. Department of Radiology, Tokai University School of Medicine NICHIDOKU-IHO Vol. 50 No (2005) Summary MR imaging has become an indispensable imaging modality in clinical medicine. The history of MRI is not a short one, with the development of NMR beginning as a new method to analyze the spatial structure of solids. During the early 1930s, Isidor Isaac Rabi s laboratory at Columbia University studied how to measure the nuclear magnetic moment, and Cornelis Jacobus Gorter first used the term nuclear magnetic resonance in a publication in In 1946, after the Second World War, two scientists in the United States, Felix Bloch and Edward Mills Purcell, independently described a physicochemical phenomenon that was based on the magnetic properties of certain nuclei. Bloch had reported the successful detection of nuclear induction, and Purcell succeeded in determining the absorption of radiofrequency by protons in paraffin wax by magnetic resonance. During the next few decades, NMR developed in a wide range of applications. Raymond Damadien measured T1 and T2 relaxation times of excised normal and cancerous rat tissue, and found that tumorous tissue had longer relaxation times than normal tissue. Paul C. Lauterbur of the State University of New York had the idea of applying magnetic field gradients in all three dimensions and applied the back-projection technique of computed tomography to creating NMR images in Lauterbur called his imaging technique Zeugmatography. Richard Ernst proposed the method of switched magnetic field gradients in the time domain, which is the basic reconstruction of current MRI phase and frequency encoding. This led to the 1975 publication by Ernst s group, NMR Fourier zeugmatography. Peter Mansfield at the University of Nottingham demonstrated a new method for the determination of spatial structures in solids that relies on the NMR diffraction effect. Alan Garroway and Mansfield published a paper about imaging formation by a selective irradiation process in Mansfield proposed a line technique that led to the first image of in vivo human finger in 1977, and the first abdominal imaging in In the early 1980s, the sequence developments for the fast imaging of MRI began. Mansfield developed echoplanar imaging (EPI) in However, the first movie images could only be obtained by EPI in 1981, after the invention of shielded gradients. Jürgen Hennig of the University of Freiburg introduced the RARE sequence in This technique was extended to multi-shot RARE (the commercial names of fast or turbo spin-echo) by Nobuya Higuchi of Keio University in Another rapid imaging technique using the gradient-echo sequence, FLASH, was developed by the group from the Max-Planck Institute, as was GRASS by Felix W. Wehrli in the 1980s. The development of MRI has been achieved through combined knowledge from the fields of mathematics, chemistry, physics, radiology, and computer science. The historical flow of MR imaging development continues, and is unlikely to slow in the future.

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10 日獨医報第50巻第 1 号 RF Amp. 1 2 デジタルレシーバーデジタルレシーバー Body デジタルレシーバー 4 3 データの合成合成画像 A B デジタルレシーバー図7 Phased array coil A B 1990年にGE社が開発したphased array coil 骨盤用のphased array coil Phased array coilの構造図8 Functional MRI Bonn大学の3T MRIで撮影 49 49

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日本職業・災害医学会会誌第51巻第5号

日本職業・災害医学会会誌第51巻第5号太田ら同時多発性高血圧性脳葉出血の 1 手術例図 1 搬入時 CT 上段単純 CT 下段造影 CT 図 2 術後の脳血管撮影検査では明らかな出血源は認めない 379 Reprint request: MULTIPLE SIMULTANEOUS HYPERTENSIVE LOBAR HEMORRHAGE Hirotsugu OHTA M.D. 1) and Akira YOKOTA M.D.