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| 1.
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Akhter, Nasima ; Nakajima, Kenichi ; Okuda, Koichi ; Matsuo, Shinro ; Yoneyama, Tatsuya ; Taki, Junichi ; Kinuya, Seigo
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金沢大学医薬保健研究域医学系<br />Purpose: Gated single-photon emission computed tomography (SPECT) imaging of myocardium by 99mTc and
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201Tl is used extensively to measure quantitative cardiac functional parameters. However, factors affecting normal values for myocardial functional parameters and population-specific standards have not yet been established. The aim of the study was to determine the effect of sex, radiotracer, rotation angles and frame rates on resting myocardial wall thickening (WT) and to develop a Japanese standard of normal values for WT. Methods: Data from a total of 202 patients with low possibility of having cardiac problems were collected from nine hospitals throughout Japan. Patients were divided into five groups according to study protocol, and WT was evaluated according to the 17-segment and four-region (basal, mid and apical regions and the apex) polar map distribution. Result: WT was generally higher in women than in men irrespective of the use of radiotracers, rotation angles or frame rates, and the difference was highly significant in the mid and apical regions. In any protocol used, resting myocardial thickening in the apex was higher than in the mid and apical regions, and thickening was lowest in the basal region, suggesting heterogeneous regional myocardial thickening (%) in normal subjects. Different rotation angles showed no significant change on WT, but different frame rates and tracers showed significant WT change in both sexes. Percent thickening of the myocardium was significantly higher in imaging by 99mTc-labelled tracers than in 201Tl. Conclusion: Sex, radiotracers and frame rates had a significant effect on myocardial thickening, and the importance of population-specific standards should be emphasized. A normal database can serve as a standard for gated SPECT evaluation of myocardial thickening in a Japanese population and might be applicable to Asian populations having a similar physique. © 2008 Springer-Verlag.<br />This article has not been published yet.
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| 2.
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Nakajima, Kenichi ; Kumita, Shinichiro ; Ishida, Yoshio ; Momose, Mitsuru ; Hashimoto, Jun ; Morita, Koichi ; Taki, Junichi ; Yamashina, Shohei ; Maruno, Hirotaka ; Ogawa, Masami ; Kubota, Masahiro ; Takahashi, Munehiro ; Odagawa, Tetsuro ; Yokozuka, Koichi
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金沢大学大学院医学系研究科がん制御学
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Nakajima, Kenichi ; Higuchi, Takahiro ; Taki, Junichi ; Kawano, Masaya ; Tonami, Norihisa
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金沢大学大学院医学系研究科<br />Gated myocardial perfusion SPECT has been used to calculate ejection fraction (EF) and end-diastolic
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volume (EDV) and has correlated well with conventional methods. However, the comparative accuracy of and correlations across various types of gated SPECT software are not well understood. Methods: Mathematic phantoms of cylindric-hemispheric hybrid models, ranging in volume from 34 to 266 mL, were generated. The clinical cases consisted of 30 patients who participated in a radionuclide angiography and gated blood-pool (GBP) study in addition to undergoing 99mTc-sestamibi gated SPECT. Four kinds of software, Quantitative Gated SPECT (QGS), the Emory Cardiac Toolbox (ECT), 4D-MSPECT, and Perfusion and Functional Analysis for Gated SPECT (pFAST) were used to compute EF and EDV, and the results were analyzed by multiple comparisons tests. Patients were classified into 4 groups (i.e., no defect, small defect, large defect, and small heart) so that factors affecting variation could be analyzed. Results: In mathematic models ≥74 mL, volume error was within ±15%, whereas for a small volume (34 mL), QGS and 4D-MSPECT underestimated the volume and pFAST overestimated it. The respective intra- and interobserver reproducibility of the results was good for QGS (r=0.99 and 1.00), ECT (r=0.98 and 0.98), and 4D-MSPECT (r=0.98 and 0.98) and fair for pFAST (r=0.88 and 0.85). The correlation coefficient for EF between gated SPECT and the GBP study was 0.82, 0.78, 0.69, and 0.84 for QGS, ECT, 4D-MSPECT, and pFAST, respectively. The correlation coefficient for EDV between gated SPECT and the GBP study was 0.88, 0.89, 0.85, and 0.90, respectively. Although good correlation was observed among the 4 software packages, QGS, ECT, and 4D-MSPECT overestimated EF in patients with small hearts, and pFAST overestimated the true volume in patients with large perfusion defects. Correlation coefficients among the 4 kinds of software were 0.80-0.95 for EF and 0.89-0.98 for EDV. Conclusion: All 4 software programs showed good correlation between EF or EDV and the GBP study. Good correlation was observed also between each pair of quantification methods. However, because each method has unique characteristics that depend on its specific algorithm and thus behaves differently in the various patient subgroups, the methods should not be used interchangeably.
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Terai, Hidenobu ; Shimizu, Masami ; Ino, Hidekazu ; Yamaguchi, Masato ; Uchiyama, Katsuharu ; Oe, Kotaro ; Nakajima, Kenichi ; Taki, Junichi ; Kawano, Masaya ; Mabuchi, Hiroshi
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金沢大学大学院医学系研究科<br />Left ventricular (LV) systolic function in hypertrophic cardiomyopathy (HCM) is usually normal. Late
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in the disease, however, LV systolic dysfunction and dilatation are recognized. Although abnormalities in cardiac sympathetic nerve activity in patients with HCM have been demonstrated using 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy, the changes of cardiac sympathetic nerve activity throughout the clinical course from typical to end-stage HCM are unclear. The objective of this study was to evaluate the relationship between abnormalities on 123I-MIBG myocardial scintigraphy and pathophysiologic changes in patients with HCM. Methods: We performed 123I-MIBG scintigraphy on 46 patients with HCM and 18 age-matched control subjects. The patients were categorized into 3 groups: 28 patients with normal LV systolic function (group A), 9 patients with LV systolic dysfunction (group B), and 9 patients with LV systolic dysfunction and dilatation (group C). With planar 123I-MIBG imaging, the heart-to-mediastinum ratio for early and delayed acquisitions and the washout rate were calculated. With SPECT, polar maps of the LV myocardium were divided into 20 segments. The regional uptake and washout rate were calculated from semiquantitative 20-segment bull's-eye analysis. Results: The early uptake was significantly lower in group C than in the control group (P < 0.01). The washout rate was progressively higher in group A, group B, and group C (P < 0.01). Reduced regional early uptake was found in 2.9 ± 3.4 (group A), 4.1 ± 4.7 (group B), and 7.4 ± 4.3 (group C) segments, respectively. In group C, regional early uptake was significantly reduced, predominantly in the interventricular septal wall, and regional washout rate was increased in the apex and lateral wall. Conclusion: These results suggest that cardiac sympathetic nerve abnormalities in patients with HCM may advance with development of LV systolic dysfunction and dilatation and that 123I-MIBG myocardial scintigraphy may be a useful tool for the evaluation of pathophysiologic changes in HCM.
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| 5.
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Shimizu, Masami ; Ino, Hidekazu ; Yamaguchi, Masato ; Terai, Hidenobu ; Hayashi, Kenshi ; Nakajima, Kenichi ; Taki, Junichi ; Mabuchi, Hiroshi
概要:
金沢大学大学院医学系研究科<br />Cardiac sympathetic nerve activity is changed in patients with hypertrophic cardiomyopathy (HCM). How
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ever, the relationship between heterogeneity of this activity and systolic left ventricular dysfunction in patients with HCM is not well established. This study was performed to evaluate the sympathetic nerve activity in various cardiac regions and to investigate the relationship between cardiac dysfunction and heterogeneity of the cardiac sympathetic nerve activity in patients with HCM. Methods: Cardiac sympathetic nerve activity was evaluated in 25 patients with HCM and 10 control subjects using planar imaging and SPECT by 123l-metaiodobenzylguanidine (MIBG) myocardial scintigraphy. With planar 123I-MIBG imaging, the heart-to-mediastinum activity ratios (H/M), at early (20 min) and delayed (3 h) acquisition, and the washout rate were calculated. Polar maps of the left ventricular myocardium were divided into 20 segments, and the dispersion (maximal to minimal values) and SD of uptake and the washout rate in 20 segments were calculated. Results: The early H/M did not differ between the 2 groups. The delayed H/M was significantly lower and the washout rate of the whole heart was significantly higher in the HCM group than those in the control group. In patients with HCM, the delayed H/M, early uptake dispersion, and SD of early uptake showed good correlation with the left ventricular end-diastolic and end-systolic dimensions and the percentage of fractional shortening. A stepwise regression analysis revealed that the SD of early uptake was a powerful determinant for the percentage of fractional shortening in patients with HCM. Conclusion: These results suggest that the heterogeneity of regional cardiac sympathetic nerve activity may be correlated with cardiac dysfunction in patients with HCM.
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| 6.
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Taki, Junichi ; Fujino, Susumu ; Nakajima, Kenichi ; Matsunari, Ichiro ; Okazaki, Hideaki ; Saga, Takashi ; Bunko, Hisashi ; Tonami, Norihisa
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金沢大学大学院医学系研究科<br />The aim of the study was to investigate the increase in myocardial 99mTc-methoxyisobutylisonitrile (s
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estamibi) retention in humans during pharmacologic vasodilation. Methods: For calculation of the increase in 99mTc-sestamibi retention during hyperemia, baseline and adenosine triphosphate (ATP)-induced hyperemic stress sestamibi studies were performed using a same-day rest-stress protocol. On the injection of sestamibi, left ventricular dynamic data were obtained for 90 s. The increase in sestamibi retention from baseline to hyperemia was calculated by the formula Cmh(t) ∫01 Cbb(τ)dτ/Cmb(t) ∫01 Cbh(τ)dτ, where Cmh(t) and Cmb(t) are myocardial counts on the tomographic image, and Cbb(τ) and Cbh(τ) are the left ventricular blood-pool counts during the first transit of sestamibi at baseline and during hyperemia, respectively. Coronary flow increase during intravenous ATP stress was measured using intracoronary Doppler flow guide wire and compared with the scintigraphic results of 28 measurements in 22 patients. Results: Sestamibi retention increased as coronary flow velocity increased but plateaued at >2.5-3 times baseline flow velocity. The relationship between the increase in sestamibi retention (Y) and the increase in flow (X) is expressed as follows: Y = 0.44 + 0.60X - 0.068X2 (r = 0.82). Conclusion: In humans, the increase in 99mTc-sestamibi myocardial retention underestimates coronary flow reserve, particularly at high flow rates. Knowledge of these tracer retention characteristics will contribute to a more comprehensive understanding of the manner and interpretation of stress sestamibi imaging.
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| 7.
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Taki, Junichi ; Higuchi, Takahiro ; Kawashima, Atsuhiro ; Tait, Jonathan F. ; Kinuya, Seigo ; Muramori, Akira ; Matsunari, Ichiro ; Nakajima, Kenichi ; Tonami, Norihisa ; Strauss, H. William
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金沢大学大学院医学系研究科<br />There is increasing evidence that cell death after myocardial ischemia and reperfusion may begin as a
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poptosis rather than necrosis. To determine the time course, location, and extent of this process, we studied groups of rats after a 20-min interval of coronary occlusion and reperfusion. METHODS: After thoracotomy, the left coronary artery was occluded for 20 min. After release and before study, groups of animals were allowed to recover for various intervals: 0.5 h (n = 6), 1.5 h (n = 7), 6 h (n = 7), 1 d (n = 8), 3 d (n = 8), or 2 wk (n = 5). At the time of study, the rats were injected with 99mTc-annexin V (80-150 MBq). One hour later, to verify the area at risk, 201Tl (0.74 MBq) was injected intravenously just after the left coronary artery reocclusion and the rats were sacrificed 1 min later. Dual-tracer autoradiography was performed to assess 99mTc-annexin V uptake and the area at risk. RESULTS: Extensive 99mTc-annexin V uptake was observed in the mid myocardium after 0.5-1.5 h of reperfusion. The area of annexin uptake had expanded in the subendocardial and subepicardial layers at 6 h after reperfusion and then gradually lessened over 3 d. At 0.5 and 1.5 h of reperfusion, 99mTc-annexin V uptake ratios were 7.36 +/- 2.95 and 6.34 +/- 2.24 (mean +/- SD), respectively. The uptake ratios gradually decreased at 6 h, 1 d, 3 d, and 2 wk after reperfusion (4.65 +/- 1.93, 3.27 +/- 0.92 [P < 0.01 vs. 0.5 h], 1.84 +/- 0.55 [P < 0.001 vs. 0.5 h, P < 0.005 vs. 1.5 h], and 1.65 +/- 0.31 [P < 0.001 vs. 0.5 h, P < 0.005 vs. 1.5 h], respectively). CONCLUSION: These data indicate that annexin binding commences soon after ischemia and reperfusion in the mid myocardium within the area at risk and expands to include the subendocardial and subepicardial layers at 6 h after reperfusion, followed by gradual reduction of activity over 3 d.
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| 8.
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Taki, Junichi ; Higuchi, Takahiro ; Nakajima, Kenichi ; Matsunari, Ichiro ; Hwang, Eui-Hyo ; Bunko, Hisashi ; Kawasuji, Michio ; Watanabe, Go ; Tonami, Norihisa
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金沢大学大学院医学系研究科<br />Abnormal septal motion after coronary artery bypass graft surgery (CABG) is a common finding. This st
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udy was undertaken to investigate the change in various global and regional ventricular function parameters measured by gated myocardial perfusion SPECT after surgery and to determine which quantitative parameter of WT and WM is more appropriate for the evaluation of regional cardiac function, especially in the septum of patients with CABG. Methods: Before and 3 to 5 wk after CABG (all patients underwent at least 1 bypass grafting to the left anterior descending coronary artery), 35 patients (28 men, 7 women) underwent gated SPECT using 99mTc-methoxyisobutylisonitrile. Quantitative global and regional ventricular functional analysis was performed using quantitative gated SPECT software. Results: Global ejection fraction did not change (59.3% ± 16.0% to 60.5% ± 14.5%, P = 0.24). However, end-diastolic and end-systolic volumes lessened significantly after CABG (81.4 ± 37.3 mL to 68.9 ± 28.9 mL, P < 0.0001, and 38.1 ± 33.1 mL to 30.4 ± 23.0 mL, P < 0.005, respectively). As global function parameters, the changes in both total WM (r = 0.88) and WT (r = 0.86) correlated well with the change in ejection fraction after surgery. Segmental analysis showed a significant postoperative increase in relative tracer uptake in the anterior, anteroseptal, inferoseptal, and inferior walls and in the apex. Segmental wall motion (WM) deteriorated in the anteroseptal, inferoseptal, and mid anterior walls. On the other hand, anterolateral, inferolateral, and inferior WM increased. As a whole, these WM changes showed a reduction in septal motion associated with a concomitant increase in lateral motion after surgery. Segmental wall thickening, however, did not decrease in septal areas and did not increase in the lateral wall and correlated with percentage tracer uptake (r = 0.69) better than WM did (r = 0.30) after CABG. Conclusion: In patients with CABG, postoperative WM analysis by gated SPECT underestimated septal motion and overestimated lateral motion because of exaggerated systolic anteromedial cardiac translation. Therefore, wall thickening analysis would be recommended for the evaluation of postoperative cardiac function
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9. Time course of discordant BMIPP and thallium uptake after ischemia and reperfusion in a rat model
Higuchi, Takahiro ; Taki, Junichi ; Nakajima, Kenichi ; Kinuya, Seigo ; Namura, Masanobu ; Tonami, Norihisa
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金沢大学大学院医学系研究科<br />Serial changes in fatty acid metabolism or use associated with acute ischemia and reperfusion were ex
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amined in rat hearts. Methods: Male Wistar rats were subjected to occlusion of the left coronary artery for 20 min followed by reperfusion. After release of the occlusion, groups of animals were allowed to recover for intervals of 20 min (n = 9), 1 d (n = 9), 3 d (n = 6), 7 d (n = 6), or 30 d (n = 6). Hearts were excised 15-20 min after injection of 0.74 MBq of 125I-15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) and 14.8 MBq of 201TI. One minute before resection, the left coronary artery was reoccluded and 185 MBq of 99mTc-sestamibi were injected to document the area at risk. Triple-tracer autoradiography was performed to assess tracer uptake. Uptake ratios of BMIPP and 201TI in the area at risk were calculated on the basis of the count density in the lesion divided by that in the normally perfused area. Results: 201TI uptake did not change throughout the observation period (P = 0.25). In contrast, BMIPP uptake increased early in the acute phase (20 min and 1 d), decreased during the sub-acute phase (7 d), and subsequently recovered in the chronic phase (30 d). Conclusion: The present investigation clearly illustrated that BMIPP uptake is higher than 201TI uptake in the acute phase, that BMIPP uptake is lower than 201TI uptake in the subacute phase, and that BMIPP uptake and 201TI uptake are similar in the chronic phase. These results yield data essential to the precise interpretation of BMIPP images.
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Nakajima, Kenichi ; Matsubara, Kosuke ; Ishikawa, Takahiro ; Motomura, Nobutoku ; Maeda, Ryo ; Akhter, Nasima ; Okuda, Koichi ; Taki, Junichi ; Kinuya, Seigo
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金沢大学大学院医学系研究科がん制御学
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