Japanese
Title核聴診器を用いた左室駆出率測定におけるバックグラウンドの検討
Subtitle技術報告
Authors土肥まゆみ*, 伊東春樹**, 谷口興一***, 広江道昭*, 丸茂文昭*
Authors(kana)
Organization*東京医科歯科大学第二内科, **心臓血管研究所, ***群馬県立前橋病院
Journal核医学
Volume30
Number6
Page681-686
Year/Month1993/6
Article報告
Publisher日本核医学会
Abstract「要旨」 携帯用RI心機能連続測定装置(核聴診器)の至適バックグラウンドについて, 心プール法と比較して検討した. 対象は健常成人男性20例(23.2歳)で, 三段階坐位自転車エルゴメータ負荷試験を二回行い, 安静時, stage I, II, IIIの心駆出率(ejection fraction EF)を心プール法と核聴診器法で測定した. 核聴診器法で除去レベル(cut-off level)を左室拡張末期カウントの70%, 75%に固定して算出したEF(EF70, EF75)は, どちらも心プール法EFと一致しなかった. 心プール法EF値と一致するようにcut-off level値を回帰的に求めると, 症例個々で変動が大きく規則性がなかった. すなわち, cut-off levelは各症例で異なりしかも運動で変化し, その変化量は肺野カウントの変化量と必ずしも比例しないことが示唆された. そこでバックグラウンドの変化が反映されるように, バックグラウンド測定用検出器のカウント数をそのままcut-off levelとして用いEFを算出したところ(EFB), 安静時, 各stageとも心プール法とEFの絶対値は一致しないが, 各stage間のEF変化量はcut-off level固定法よりもよく一致した. さらに, 心プール法で測定した安静時EFをEFB安静時として代入しstage I, II, IIIの各EFを算出すると, 心プール法EFとの相関はstage I r=0.91, stage II r=0.82, stage III r=0.69であった. EF70安静時に代入すると, stage I r=0.82, stage II r=0.77, stage III r=0.61で, EFBの方が相関がよかった. 以上より, 核聴診器でEFを測定する場合には, バックグラウンド用検出器を用いて, バックグラウンドカウント数を測定し, cut-off levelとするべきであると考えられた.
Practice臨床医学：一般
KeywordsNuclear stethoscope, Blood pool study, Left ventricular ejection fraction, Background.
English
TitleAssessment of the Background Count to Measure the Left Ventricular Ejection Fraction with a Nuclear Stethoscope
Subtitle
AuthorsMayumi DOI*, Haruki ITOH**, Michiaki HIROE*, Koichi TANIGUCHI***, Fumiaki MARUMO*
Authors(kana)
Organization*Second Department of Internal Medicine, Tokyo Medical and Dental University, **Internal Medicine, The Cardiovascular Institute, ***Internal Medicine, Gunma Maebashi Hospital
JournalThe Japanese Journal of nuclear medicine
Volume30
Number6
Page681-686
Year/Month1993/6
ArticleReport
PublisherTHE JAPANESE SOCIETY OF NUCLEAR MEDICINE
Abstract[Summary] The nuclear stethoscope is a newly developed device for monitoring left ventricular ejection fraction (EF) with a pair of cadmium telluride detector for both left ventricular count (first channel) and background count (second channel). Although it is useful for evaluating the cardiac function during exercise, the methodology of the calculation for distinguishing the net ventricular blood count from the background count has not been established yet. In order to establish a reasonable method to calculate EF, we measured EF using a nuclear stethoscope and conventional gated blood pool scintigraphy in 20 healthy volunteers. All subjects underwent two supine ergometer exercise tests consisting of the 3 stages for the nuclear stethoscope and blood pool scintigraphy. The EF was determined with the following three method for the nuclear stethoscope; 1) Cut-off level was fixed at 70% of first channel, 2) Cut-off level at 75%, 3) Cut-off level was determined by the background count obtained from second channel. There was a poor relationship between the EFs obtained from gated blood scintigraphy and the EFs from the nuclear stethoscope calculated by any of these method. Regarding the EF calculated using the background count, however, the delta values of EF between rest and any of the 3 stages during exercise correlated closely to those EF from blood scintigraphy. When we apply the EF-at-rest value obtained from blood pool scintigraphy to analysis with the nuclear stethoscope, the EFs of 3 stages indicated good correlation (Stage I r=0.91, Stage II r=0.82, Stage III r=0.69). These results suggest that detecting the background count is useful in order to measure the left ventricular EF with the nuclear stethoscope. Since the absolute value of EF doesn't necessarily correlate to that from blood pool scintigraphy in this method, it is recommended to evaluate only the changing values of the EF.
PracticeClinical medicine
KeywordsNuclear stethoscope, Blood pool study, Left ventricular ejection fraction, Background.

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