| Japanese |
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| Title | 心電図同期心プールイメージのバックグラウンド除去に関する1新法 (逐次定数減算法) - 第1報 原理と方法 - |
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| Subtitle | 《原著》 |
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| Authors | 松平正道*, 中嶋憲一** |
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| Organization | *金沢大学医学部附属病院放射線部, **金沢大学医学部核医学教室 |
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| Journal | 核医学 |
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| Volume | 33 |
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| Number | 10 |
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| Page | 1053-1063 |
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| Year/Month | 1996/10 |
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| Article | 原著 |
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| Publisher | 日本核医学会 |
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| Abstract | 「要旨」心電図同期心プールイメージから容積曲線や心駆出率を求めるには正確なバックグラウンド(BG)除去が重要である. この心プールイメージからBGカウントを除去する新しい方法を考案した. 本法は心電図同期イメージからその画像の最高カウントの約5%に相当する定数(k)のn倍(nk: n=0, 1, 2, ...N-1)を逐次減算し(Iterative Constant Subtraction法: ICS法と仮称), この減算程度の異なる多数(N)の心電図同期イメージの容積曲線を解析することにより真のBGカウントを得るものである. BGカウントの除去されない容積曲線の第1フレームの値に各減算イメージ容積曲線の第1フレームを平行移動して規格化する. 減算の不十分な容積曲線は完全に重複し, 減算が過大になるにつれ重複曲線から分離する. この境界にある容積曲線が真のBGカウントを除去したものとなる. 本法は左室に大まかなROIを設けるのみで, 自動的に短時間に実行できるソフトウェアが可能である. |
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| Practice | 臨床医学：一般 |
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| Keywords | Gated cardiac blood pool image, Background count elimination, Iterative constant subtraction. |
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| English |
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| Title | A New Approach to Eliminate Background Count from Gated Blood Pool Image (Iterative Constant Subtraction Method) Part 1: Principle and Technique |
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| Subtitle | - Original Articles - |
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| Authors | Masamichi MATSUDAIRA*, Kenichi NAKAJIMA** |
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| Organization | *Department of Radiology, Kanazawa University Hospital, **Department of Nuclear Medicine, Kanazawa University School of Medicine |
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| Journal | The Japanese Journal of nuclear medicine |
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| Volume | 33 |
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| Number | 10 |
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| Page | 1053-1063 |
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| Year/Month | 1996/10 |
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| Article | Original article |
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| Publisher | THE JAPANESE SOCIETY OF NUCLEAR MEDICINE |
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| Abstract | It is important for obtaining a left ventricular volume curve and ejection fraction from a multigated blood pool image (MGBP image) to accurately subtract the background (BG) from the image. We devised a new method of accurately subtracting the BG with good reproducibility. This method (tentatively called the ICS method) is as follows. An image, on which n times (n=0, 1, 2, 3, ..., N-1) an adequately low constant (k) is subtracted from the MGBP image at every pixel of the image matrix, is prepared. When n equale 0, constant is not subtracted from the image, therefore it is original MGBP image. Then the original (n=0) and constant (nk: n=1, 2, 3, ..., N-1) subtraction MGBP images were prepared. The constant was defined as about 5% of the maximum pixel count in the end-diastole of the left ventricle. Rough region of interest (ROI) were set at the left ventricle on these MGBP images, and time activity curves (TACs, left ventricular volume curves) on each image were prepared. These N kinds of curves are shifted in parallel for normalization in the first frame (end-diastole). The first frame count on the original MGBP image is normalized. As a result, TACs obtained by inadequate subtraction in which subtraction of the constant does not reach the BG count, overlap completely, while TACs obtained by subtraction over the BG gradually separate from the overlapping curves. The MGBP image including a curve located in the border between the overlapping curve and the separated curve is regarded as the image accurately subtracting the BG, and the constant of subtraction (nk) as the BG count for each pixel. The border is obtained by analyzing changes in count of the end-systolic frame of each TAC normalized. The ICS method provides computer software that is performed automatically within a short time by setting a rough ROI at the left ventricle on the end-diastolic MGBP image. |
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| Practice | Clinical medicine |
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| Keywords | Gated cardiac blood pool image, Background count elimination, Iterative constant subtraction. |
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