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| 1.
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Shibutani, Takayuki ; Nakajima, Kenichi ; Wakabayashi, Hiroshi ; Mori, Hiroshi ; Matsuo, Shinro ; Yoneyama, Hiroto ; Konishi, Takahiro ; Okuda, Koichi ; Onoguchi, Masahisa ; Kinuya, Seigo ; 澁谷, 孝行 ; 中嶋, 憲一 ; 若林, 大志 ; 松尾, 信郎 ; 米山, 寛人 ; 小野口, 昌久 ; 絹谷, 清剛
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金沢大学医薬保健研究域保健学系<br />ObjectivesThe patient-based diagnosis with an artificial neural network (ANN) has shown potential u
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tility for the detection of coronary artery disease; however, the region-based accuracy of the detected regions has not been fully evaluated. The aim of this study was to demonstrate the accuracy of all detected regions compared with expert interpretation.\nMethodsA total of 109 abnormal regions including 33 regions with stress defects and 76 regions with ischemia were examined, which were derived from 21 patients who underwent myocardial perfusion SPECT within 45 days of coronary angiography. The gray and color scale images, a polar map of stress, rest and difference, and left ventricular function were displayed on the monitor to score the extent and severity of stress defect and ischemia. Two experienced nuclear medicine physicians (Observers A and B) scored the abnormality with a 4-point scale and draw abnormal regions on a polar map. The gold standard was determined by the final judgment of normal or abnormal by the consensus of two other independent expert nuclear cardiologists, and was compared with the stress defect and ischemia derived from ANN.\nResultsThe concordance rate of ANN to the gold standard was higher than that of two observers. Furthermore, the κ coefficient indicated moderate to substantial agreement for stress defect and slight to the fair agreement for ischemia. The area under the curve (AUC) of ANN was the highest for both stress defect and ischemia; in particular, the ANN of ischemia showed significantly higher AUC than Observer A (p = 0.005). The ANN of stress defect showed higher specificity compared with two observers, while the ANN of ischemia showed higher sensitivity. Consequently, the accuracy of ANN showed the highest in this study.\nConclusionThe ANN-based regional diagnosis showed a high concordance rate with the gold standard and comparable or even higher than the interpretation by nuclear medicine physicians.<br />Embargo Period 12 months
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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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Nakajima, Kenichi ; Inaki, Anri ; Hiramatsu, Takashi ; Hasegawa, Minoru ; Fujimoto, Manabu ; Takehara, Kazuhiko ; Kinuya, Seigo
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金沢大学医薬保健研究域医学系<br />Objectives: Esophageal complications are common in patients with systemic sclerosis (SSc). The relat
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ionship between gastroesophageal reflux (GER) symptoms and dysmotility was examined in endoscopically confirmed patients suspected of having reflux esophagitis. Methods: A total of 32 patients with limited and diffuse type SSc (lSSc, dSSc) were examined based on a structured questionnaire score (QS) of GER symptoms, retention fraction of esophageal scintigraphy at 90 s (R90) and gastric emptying time. Results: The QS was significantly higher in the reflux esophagitis group than in the non-esophagitis group (5.4 ± 3.5, 1.4 ± 2.9, P = 0.003). When the non-esophagitis group was further divided into lSSc and dSSc groups, R90 was higher in the reflux esophagitis group (31 ± 18%) and the non-esophagitis group with dSSc (34 ± 32%) than in the non-esophagitis group with lSSc (8 ± 3%, P = 0.02). Both high R90 ≥ 15% and QS ≥ 4 indicated reflux esophagitis. Conversely, both normal R90 and QS indicated no reflux esophagitis. Conclusion: A combination of esophageal scintigraphy and structured questionnaire demonstrated different aspects of esophageal dysfunction, namely dysmotility and GER. Patients with high QS and dysmotility may be indicated for further evaluation including endoscopic examination and medical treatment. © 2009 The Japanese Society of Nuclear Medicine.
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Okuda, Koichi ; Nakajima, Kenichi ; Motomura, Nobutoku ; Kubota, Masahiro ; Yamaki, Noriyasu ; Maeda, Hisato ; Matsuo, Shinro ; Kinuya, Seigo
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金沢大学医薬保健研究域<br />Objective: Segmentation with scatter and photopeak window data using attenuation correction (SSPAC) met
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hod can provide a patient-specific non-uniform attenuation coefficient map only by using photopeak and scatter images without X-ray computed tomography (CT). The purpose of this study is to evaluate the performance of attenuation correction (AC) by the SSPAC method on normal myocardial perfusion database. Methods: A total of 32 sets of exercise-rest myocardial images with Tc-99 m-sestamibi were acquired in both photopeak (140 keV ± 10%) and scatter (7% of lower side of the photopeak window) energy windows. Myocardial perfusion databases by the SSPAC method and non-AC (NC) were created from 15 female and 17 male subjects with low likelihood of cardiac disease using quantitative perfusion SPECT software. Segmental myocardial counts of a 17-segment model from these databases were compared on the basis of paired t test. Results: AC average myocardial perfusion count was significantly higher than that in NC in the septal and inferior regions (P < 0.02). On the contrary, AC average count was significantly lower in the anterolateral and apical regions (P < 0.01). Coefficient variation of the AC count in the mid, apical and apex regions was lower than that of NC. Conclusions: The SSPAC method can improve average myocardial perfusion uptake in the septal and inferior regions and provide uniform distribution of myocardial perfusion. The SSPAC method could be a practical method of attenuation correction without X-ray CT. © 2009 The Japanese Society of Nuclear Medicine.
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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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6. 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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Okuda, Koichi ; Nakajima, Kenichi ; Hosoya, Tetsuo ; Ishikawa, Takehiro ; Konishi, Takahiro ; Matsubara, Kosuke ; Matsuo, Shinro ; Kinuya, Seigo
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金沢大学医薬保健研究域医学系<br />Background: We have developed novel software for semi-automatically measuring heart-to-mediastinum (
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H/M) ratio in cardiac Iodine-123 (123I)-labeled meta-iodobenzylguanidine (MIBG) imaging. Our aim is to improve the reproducibility of the H/M ratio using the semi-automated method as opposed to the manual method. Methods and Results: The software algorithm automatically determined the mediastinal region of interest (ROI) using information from 123I-MIBG uptake of the heart, lung, liver, and thyroid after a cardiac circular ROI was manually set. A total of 37 patients who underwent both early and delayed 123I-MIBG imaging was retrospectively selected. The heart-to-mediastinum (H/M) ratios were calculated by both semi-automated and manual methods and assessed for the intra- and inter-observer variability. All H/M ratios were classified into three groups: normal, slight abnormality, and severe abnormality. The H/M ratios with the new method were higher than those obtained manually (P<.001). In the test-retest reliability, the intra-class correlation coefficient from the semi-automated method showed excellent reproducibility for early (0.99) and delayed (0.99) imaging. The Bland-Altman plots demonstrated better agreement using the semi-automated method (a range of 95% limits -0.11 to 0.10) than that in the manual method (-0.34 to 0.27). The inter-observer agreement was also good using the semi-automated method (κ = 0.866). Conclusions: The H/M ratio using the semi-automated method showed high reproducibility in both early and delayed imaging. © 2010 American Society of Nuclear Cardiology.
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Nakajima, Kenichi ; Matsuo, Shinro ; Hasegawa, Minoru ; Kinuya, Seigo ; Takehara, Kazuhiko
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金沢大学医薬保健研究域医学系<br />Myocardial involvement is an important prognostic factor in patients with systemic sclerosis, and ea
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rly diagnosis and staging of the disease have been sought after. Since myocardial damage is characterized by connective tissue disease, including fibrosis and diffuse vascular lesions or microcirculation, nuclear myocardial perfusion imaging has been a promising option for evaluating myocardial damages in early stages. In addition to the conventional stress-rest perfusion imaging, the current use of quantitative electrocardiographic gated imaging has contributed to more precise evaluation of cardiac perfusion, ventricular wall motion, and diastolic function, all of which have enhanced diagnostic ability of evaluating myocardial dysfunction. Abnormal sympathetic imaging with Iodine-123 metaiodobenzylguanidine might be another option for identifying myocardial damage. This paper deals with approaches from nuclear cardiology to detect perfusion and functional abnormality as an early sign of myocardial involvement as well as possible prognostic values in patients with abnormal imaging results. The role of nuclear cardiology in the era of multiple imaging modalities is discussed.
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Nakajima, Kenichi ; Okuda, Koichi ; Nyström, Karin ; Richter, Jens ; Minarik, David ; Wakabayashi, Hiroshi ; Matsuo, Shinro ; Kinuya, Seigo ; Edenbrandt, Lars
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Purpose In patients with a small heart, defined as an end-systolic volume (ESV) of ≤20 mL calculated using the Quantitat
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ive Gated SPECT (QGS) program, underestimation of ESV and overestimation of ejection fraction (EF) using gated myocardial perfusion imaging are considered errors caused by inappropriate delineation of the left ventricle (LV). The aim of this study was to develop a new method for delineation of the LV and to evaluate it in studies using a digital phantom, normal subjects and patients. Methods The active shape-based method for LV delineation, EXINI heart (ExH), was adjusted to more accurately process small hearts. In small hearts, due to the partial volume effect and the short distance to the opposite ventricular wall, the endocardial and the epicardial surfaces are shifted in the epicardial direction depending on the midventricular volume. The adjusted method was evaluated using digital XCAT phantoms with Monte Carlo simulation (8 virtual patients), a Japanese multicentre normal database (69 patients) and consecutive Japanese patients (116 patients). The LV volumes, EF and diastolic parameters derived from ExH and QGS were compared. Results The digital phantom studies showed a mean ESV of 87 %±9 % of the true volume calculated using ExH and 22 %±18 % calculated using QGS. In the normal database, QGS gave higher EFs in women than in men (71.4±6.0 % vs. 67.2±6.0 %, p=0.0058), but ExH gave comparable EFs (70.7±4.9 % and 71.4±5 % in men and women, respectively, p=ns). QGS gave higher EFs in subjects with a small heart than in those with a normal-sized heart (74.5±5.1 % vs. 66.1±4.9 %), but ExH gave comparable values (70.0±5.9 % vs. 71.6±4.2 %, respectively, p=ns). In consecutive patients, the average EFs with QGS in patients with ESV >20 mL, 11–20 mL and ≤10 mL were 57.9 %, 71.9 % and 83.2 %, but with ExH the differences among these groups were smaller (65.2 %, 67.8 % and 71.5 %, respectively). Conclusion The volume-dependent edge correction algorithm was able to effectively reduce the effects on ESV and EF of a small heart. The uniform normal values might be applicable to both men and women and to both small and normal-sized hearts.
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