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Article type: Cover
1991 Volume 47 Issue 10 Pages
Cover3-
Published: October 01, 1991
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Article type: Appendix
1991 Volume 47 Issue 10 Pages
App3-
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Article type: Appendix
1991 Volume 47 Issue 10 Pages
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Article type: Index
1991 Volume 47 Issue 10 Pages
Toc3-
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Article type: Index
1991 Volume 47 Issue 10 Pages
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Article type: Appendix
1991 Volume 47 Issue 10 Pages
i-vii
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Article type: Appendix
1991 Volume 47 Issue 10 Pages
viii-xii
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JUNJI MORISHITA, HIROSHI FUJITA, SYUICHI YAMAUCHI, KATSUHIKO UEDA, AKI ...
Article type: Article
1991 Volume 47 Issue 10 Pages
1787-1794
Published: October 01, 1991
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The "overall" Wiener spectra of a computed radiographic system (FCR-101) were measured, and compared with the Wiener spectrum of a conventional screen/film system (Hiscreen/RXH). In addition, the noise properties for different exposure conditions to imaging plate (IP), the effects of unsharp masking filter, and the effect of image reduction to output display (film) including the effect of varying the sampling distance were examined. Overall Wiener spectra obtained in the perpendicular direction relative to the laser beam scanning in the laser printer were greater at high spatial frequencies, but comparable at low frequencies, than those obtained in the parallel direction, and indicated the existence of a spectral peak around 10 cycles/mm mainly caused by banding artifact. The noise level of the CR system with HR, in the same exposure and gradient relative to the Hiscreen/RXH system, was comparable to that of the Hiscreen/RXH, however the noise level of CR with ST was superior to that of the Hiscreen/RXH. It was also found that the noise level of the CR was increased as the exposure decreased and that the frequency processing (unsharp masking) can increase the CR noise level. Moreover, the noise level was decreased by the effect of the image size reduction.
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MITSUJI HIGASHIDA, MASAKATSU HATAGAWA, RIE YOSHIDA, KENJI KISHIMOTO, M ...
Article type: Article
1991 Volume 47 Issue 10 Pages
1795-1799
Published: October 01, 1991
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A noise-equivalent number of quanta (u) (NEQ(u)) which included a gamma, a modulation transfer function (MTF) and a Wiener spectrum has provided useful means for evaluating the total image quality. However, the image quality evaluated by the NEQ(u) may be influenced by measuring errors of the gamma, the MTF and the Wiener spectrum, because the NEQ(u) is calculated from these three factors. Then, we measured fluctuations of measuring errors of these three factors employing two screen film systems of different speed and investigated effects for the NEQ(u). As the result, the NEQ(u) was influenced greatly by fluctuations of measured Wiener spectrum. But, fluctuations of NEQ(u) of these systems were quite little compared with NEQ(u) value of other systems. We concluded that the image quality of both systems can be distinguished clearly by using of NEQ(u) although the difference of the speed between two systems is quite little.
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YOSHIHARU SAKASHITA, SHIN MOTOSUGI, HIROKI OGURA, MASANOBU YAMADA, HID ...
Article type: Article
1991 Volume 47 Issue 10 Pages
1800-1807
Published: October 01, 1991
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Ultrafast CT scanner, C-100 (IMATRON Co., USA, hereinafter referred to as UFCT), is the equipment capable of scanning at up to 50 msec and about 30 units are now in clinical use throughout the world. Its ultrafast performance is contributing to the obtaining of distinct general images practically free from motion artifacts. UFCT enjoys selective scanning times according to its target organs and tissues, with no need for the patient to hold his breath and reduces the total injectable amount of the contrast medium, thereby reducing the burden experienced by the patient. A sharp decrease in motion artifacts due to respiration, heart beat, intestinal movement and the like has improved the accuracy of morphological diagnosis. Our clinical experiences indicated this equipment is excellent not only for chest and abdominal morphological and functional diagnoses but also for blood flow evaluations. Fast, repetitious scans make it possible to observe the hitherto-unseized heart beating condition, leading to higher accuracy regarding blood flow analysis.
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TSUYOSHI MATSUDA
Article type: Article
1991 Volume 47 Issue 10 Pages
1808-1813
Published: October 01, 1991
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Before the clinical application of in vivo MR spectroscopy we performed basic study to obtain better spectrum by using MR spectrometer exclusively designed for animal experiment. In in vivo animal experiment, we could obtained functional or metabolic in vitro information by high spatial resolution non-invasively and non-denstructively. In basic study, we evaluated various probes and radio frequency pulse sequence, and concluded the selection of the most suitable combination of probe and pulse sequence is important acording to reserchers object.
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YOSHIHIRO NISHIMURA
Article type: Article
1991 Volume 47 Issue 10 Pages
1814-1820
Published: October 01, 1991
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Technical aspects of image selected in vivo spectroscopy (ISIS) and fast rotating gradient spectroscopy (FROGS) are reported. Experiments were performed on a 1.5 T MRI system for human body by using a surface coil tuned to phosphorus-31. Phantoms filled with phosphoricacid solustions and normal ten volunteers were examined. We focused on the dependence of the signal intensity on RF transmitter power, volume selectivity, and the positional shift due to chemical shift. Results are as follows : Transmitter power to excite spins increased with conductivity and volume of phantoms. The peak hight of the spectrum of the heart of human volunteers changed depending on the transmitter power and repetition time. In ISIS, volume selectivity was good in large volume selection. While, in FROGS, it was good in thin slice selection. Positional shift due to chemical shift was not negligible in both techniques, but the distance changed depending on the strength of the gradient field used.
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HIROTSUGU HABA
Article type: Article
1991 Volume 47 Issue 10 Pages
1821-1826
Published: October 01, 1991
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Practical clinical application of MRS that enables us non-aggressively to estimate metabolic information in organisms, particularly energy metabolism of phosphorus can be surely anticipated in accordance with the propagation of high magnetic field MR apparatus for all body. Thus, we carried out MRS-measurement in liver, brain and muscles of lower extremities. In liver and brain energy metabolism in total tumor region, Pcr and each ATP decreased and PME increased. In brain tumors the measurement was carried out with respect to the type of tumors, whereby we found patterns of increasing and decreasing PME. These findings became the problem hereafter to be solved. We applied massage on muscles of lower extremities, whose efficacy was classified into three patterns : increasing, decreasing and constant Pcrs, according to the hardness of muscles. Routine application of MRS allowed us to investigate many clinical cases, we could hence grasp the metabolic change that was not detectable even from imaging and clinical symptoms.
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HIROBUMI MORITA
Article type: Article
1991 Volume 47 Issue 10 Pages
1827-1831
Published: October 01, 1991
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Recently, we have used the magnetic resonance spectroscopy (MRS), using a clinical MR imager/spectrometer as well as a high resolution spectrometer, as a tool for the clinical research. In vivo studies using a high resolution spectrometer have been limited to the clinical application due to a small bore size and a high field. The clinical MR imager/spectrometer, however, associates with different problems, such as clinical validity, scan time, quantification, and so on. In order to achieve the usefulness of MRS as a clinical validity, there are three significant points; clinical validity, easy-operation, and multi- and single-voxel localization. The clinical validity is the most important goal for MRS because MRS must be useful to clinical application. An easy-operation enables one to collect a spectrum within a reasonable time. The localization is the key point for MRS to clinical application in order to select a region of interest.
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[in Japanese]
Article type: Article
1991 Volume 47 Issue 10 Pages
1832-1833
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[in Japanese]
Article type: Article
1991 Volume 47 Issue 10 Pages
1834-1839
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Article type: Appendix
1991 Volume 47 Issue 10 Pages
1840-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese]
Article type: Article
1991 Volume 47 Issue 10 Pages
1841-1846
Published: October 01, 1991
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[in Japanese]
Article type: Article
1991 Volume 47 Issue 10 Pages
1847-1848
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記載無し
Article type: Article
1991 Volume 47 Issue 10 Pages
1848-
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1991 Volume 47 Issue 10 Pages
1848-
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1991 Volume 47 Issue 10 Pages
1848-1849
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1991 Volume 47 Issue 10 Pages
1849-
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1991 Volume 47 Issue 10 Pages
1849-
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Article type: Article
1991 Volume 47 Issue 10 Pages
1849-1850
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[in Japanese]
Article type: Article
1991 Volume 47 Issue 10 Pages
1850-
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Article type: Article
1991 Volume 47 Issue 10 Pages
1850-
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1991 Volume 47 Issue 10 Pages
1850-
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[in Japanese], [in Japanese]
Article type: Article
1991 Volume 47 Issue 10 Pages
1851-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1991 Volume 47 Issue 10 Pages
1851-
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Article type: Article
1991 Volume 47 Issue 10 Pages
1851-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1991 Volume 47 Issue 10 Pages
1851-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1991 Volume 47 Issue 10 Pages
1851-1852
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Article type: Article
1991 Volume 47 Issue 10 Pages
1852-
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Article type: Article
1991 Volume 47 Issue 10 Pages
1852-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1991 Volume 47 Issue 10 Pages
1852-
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1991 Volume 47 Issue 10 Pages
1852-
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Article type: Article
1991 Volume 47 Issue 10 Pages
1852-1853
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Article type: Article
1991 Volume 47 Issue 10 Pages
1853-
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Article type: Article
1991 Volume 47 Issue 10 Pages
1853-
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Article type: Article
1991 Volume 47 Issue 10 Pages
1853-
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Article type: Article
1991 Volume 47 Issue 10 Pages
1853-1854
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Article type: Article
1991 Volume 47 Issue 10 Pages
1854-
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Article type: Article
1991 Volume 47 Issue 10 Pages
1854-
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1991 Volume 47 Issue 10 Pages
1854-
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1991 Volume 47 Issue 10 Pages
1854-1855
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Article type: Article
1991 Volume 47 Issue 10 Pages
1855-
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Article type: Article
1991 Volume 47 Issue 10 Pages
1855-
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Article type: Article
1991 Volume 47 Issue 10 Pages
1855-
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1991 Volume 47 Issue 10 Pages
1855-
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