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中嶋, 憲一 ; 澁谷, 孝行 ; 小野口, 昌久 ; 奥田, 光一 ; 米山, 寛人 ; 松尾, 信郎 ; 清水, 威志 ; Nakajima, Kenichi ; Shibuya, Takayuki ; Onoguchi, Masahisa ; Okuda, Koichi ; Yoneyama, Hiroto ; Matsuo, Shinro ; Shimizu, Takeshi
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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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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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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 ; Kawano, Masaya ; Matsumoto, Naoya ; Hashimoto, Jun ; Yoshinaga, Keiichiro ; Taki, Junichi ; Okuda, Koichi
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金沢大学医薬保健研究域医学系<br />Purpose The Japanese Society of Nuclear Medicine (JSNM) working group has created a myocardial perfu
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sion imaging database applicable to standard acquisition protocol. The aim of this study is to validate the diagnostic accuracy of the common normal database compared with the expert interpretation of each institute. Methods Five institutions participated in this study and used different acquisition settings which included 360°/ 180° rotation, camera configuration and camera orbits. The software and its version used in each institution also varied. The working group database was applied to detect the culprit coronary territory from a total of 166 patients with coronary artery disease (CAD) and 145 patients with lowlikelihood of CAD. Results When summed stress score C4 was defined as significant abnormality, overall sensitivity, specificity and accuracy of patient-based analysis were 77, 72 and 75%, respectively, based on quantitative analysis using the common database, whereas those by institutional visual expert reading were 72, 79 and 75%, respectively. Conclusion The common database, which was created by a multi-center working group and separated between male/ female with 180/360° acquisitions, demonstrated comparable diagnostic accuracy to expert interpretation by each institute, and it may be applicable to multi-center studies.
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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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Nakajima, Kenichi ; Matsuo, Shinro ; Okuda, Koichi ; Wakabayashi, Hiroshi ; Tsukamoto, Kazumasa ; Nishimura, Tsunehiko
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Background:Myocardial perfusion imaging (MPI) has been used to estimate cardiac event risk. The aim of the present study
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is to achieve stable risk estimation based on perfusion scoring and a multi-center prognostic database. Methods and Results:Multivariate logistic regression analysis was performed to estimate cardiac event risk based on a J-ACCESS study. A stress-MPI was performed in 45 patients with coronary artery disease (CAD) and in 25 non-CAD patients. Perfusion defect scoring of summed stress score (SSS) was performed by 5 methods: (1) visual scoring; (2) automatic scoring of 3 short-axis and 1 vertical long-axis slices; (3) visual modification of Method 2; (4) automatic polar map scoring based on a Japanese multi-center database; and (5) visual modification of Method 4. Agreement of SSS between 2 observers was good (r=0.87-0.97). Agreement of estimated cardiac event risk between observers and among 5 methods was very good (r=0.99-1.00). Regarding diagnostic accuracy for CAD, Method 5 showed optimal diagnostic yields (sensitivity 84%, accuracy 77%). Conclusions:Estimation of cardiac event risk in conjunction with polar map segmentation and common normal databases resulted in stable risk values, and might be used for risk stratification in patients suspected of having CAD. © All rights are reserved to the Japanese Circulation Society.
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Okuda, Koichi ; Nakajima, Kenichi ; Hosoya, Tetsuo ; Ishikawa, Takehiro ; Matsuo, Shinro ; Kawano, Masaya ; Taki, Junichi ; Kinuya, Seigo
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Objective: We have developed freeware package for automatically quantifying myocardial perfusion and 123I-labeled radiop
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harmaceutical single-photon emission computed tomography (SPECT), which is called "cardioBull". We aim to evaluate diagnostic performance of the detection of coronary artery disease (CAD) on the developed software in comparison with commercially available software package [Quantitative Perfusion SPECT (QPS)]. Methods: Stress-rest 99mTc-sestamibi myocardial perfusion SPECT was performed in 36 patients with CAD and 35 control patients. A ≥75% stenosis in the coronary artery was identified by coronary angiography in the CAD group. Segmental perfusion defect score was automatically calculated by both cardioBull and QPS software. Summed stress score (SSS) was obtained to detect CAD by the receiver operator characteristic (ROC) analysis. Areas under the ROC curves (AUC) were calculated in patient-based and coronary-based analyses. Results: Mean SSSs showed no significant difference between cardioBull and QPS (6.0 ± 7.1 vs. 5.6 ± 7.0). The AUC for cardioBull was equivalent to that for QPS (0.91 ± 0.04 vs. 0.87 ± 0.04, p = n.s.). Sensitivity, specificity, and accuracy for cardioBull were 89, 74, and 82%, respectively. For the regional detection of CAD, the AUC showed largest value in left anterior descending coronary artery (LAD) territory (0.86 ± 0.06 for cardioBull, 0.87 ± 0.06 for QPS, p = n.s.). Sensitivity, specificity and accuracy of cardioBull were 70, 88, and 83% for the LAD; 91, 62, and 66% for the left circumflex coronary artery (LCx); and 78, 69, and 70% for the right coronary artery (RCA), respectively. Conclusions: The AUC, sensitivity, specificity and accuracy for the detection of CAD showed high diagnostic performance on the developed software. In addition, the developed software provided comparable diagnostic performance to the commercially available software package. © 2011 The Japanese Society of Nuclear Medicine.
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