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| 1.
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論文
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Shibutani, Takayuki ; Onoguchi, Masahisa ; Yoneyama, Hiroto ; Konishi, Takahiro ; Matsuo, Shinro ; Nakajima, Kenichi ; 澁谷, 孝行 ; 松尾, 信郎 ; 中嶋, 憲一
概要:
金沢大学医薬保健研究域保健学系<br />ObjectivesAlthough the utility of IQ-SPECT imaging using 99mTc and 201Tl myocardial perfusion SPECT
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has been reported, 123I-labeled myocardial SPECT has not been fully evaluated. We determined the characteristics and utility of 123I IQ-SPECT imaging compared with conventional SPECT (C-SPECT).MethodsTwo myocardial phantom patterns were used to simulate normal myocardium and myocardial infarction. SPECT acquisition was performed using a hybrid dual-head SPECT/CT system equipped with a SMARTZOOM collimator for IQ-SPECT or a low-medium energy general purpose collimator for C-SPECT. Projection data were reconstructed using ordered subset expectation maximization with depth-dependent 3-dimensional resolution recovery for C-SPECT and ordered subset conjugate gradient minimizer method for IQ-SPECT. Three types of myocardial image were created; namely, no correction (NC), with attenuation correction (AC), and with both attenuation and scatter corrections (ACSC). Five observers visually scored the homogeneity of normal myocardium and defect severity of the myocardium with inferior defects by a five-point scale: homogeneity scores (5 = homogeneous to 1 = inhomogeneous) and defect scores (5 = excellent to 1 = poor). We also created a 17-segment polar map and quantitatively assessed segmental %uptake using a myocardial phantom with normal findings and defects.ResultsThe average visual homogeneity scores of the IQ-SPECT with NC and ACSC were significantly higher than that of C-SPECT, whereas the average visual defect scores of IQ-SPECT with AC and ACSC were significantly lower. The %uptake of all segments for IQ-SPECT with NC was significantly higher than that of C-SPECT. Furthermore, the subtraction of %uptake for C-SPECT and IQ-SPECT was the largest in inferior wall, which was approximately 10.1%, 14.7% and 14.4% for NC, AC and ACSC, respectively. The median % uptake values of the inferior wall with defect areas for C-SPECT and IQ-SPECT were 46.9% and 50.7% with NC, 59.8% and 69.2% with AC, and 54.7% and 66.5% with ACSC, respectively.Conclusion123I IQ-SPECT imaging significantly improved the attenuation artifact compared with C-SPECT imaging. Although the defect detectability of IQ-SPECT was inferior to that of C-SPECT, 123I IQ-SPECT images with NC and ACSC met the criteria for defect detectability. Use of 123I IQ-SPECT is suitable for routine examinations.<br />Embargo Period 12 months
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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
概要:
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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Okuda, Koichi ; Nakajima, Kenichi ; Hosoya, Tetsuo ; Ishikawa, Takehiro ; Konishi, Takahiro ; Matsubara, Kosuke ; Matsuo, Shinro ; Kinuya, Seigo
概要:
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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Yoneyama, Hiroto ; Tsushima, Hiroyuki ; Onoguchi, Masahisa ; Konishi, Takahiro ; Nakajima, Kenichi ; Matsuo, Shinro ; Kayano, Daiki ; Wakabayashi, Hiroshi ; Inaki, Anri ; Kinuya, Seigo
概要:
Objective: Although SPECT/CT systems have been used for sentinel lymph node (SLN) imaging, few studies have focused on o
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ptimization of attenuation correction (AC) and scatter correction (SC). While SLNs could be detected in conventional planar images, they sometimes do not appear in SPECT/CT images. The purpose of this study was to investigate the optimal AC and SC and to improve the detectability of SLNs in examinations using SPECT/CT systems.Materials and methods: The study group consisted of 56 female patients with breast cancer. In SPECT/CT imaging, four kinds of images were created with and without AC and SC; namely, AC−SC−, AC+SC−, AC−SC+ and AC+SC+. Five nuclear medicine physicians interpreted the planar and SPECT/CT images with five grades of confidence levels (1–5). The detection rate was calculated as the number of patients whose average confidence levels of interpretation were more than 4, divided by the total number of patients.Results: The confidence level of interpretation and the detection rate provided by the planar images were 4.76 ± 0.49 and 94.6 %, respectively. In SPECT/CT imaging, the AC+SC− provided the best detection rate (confidence level of interpretation, 4.81 ± 0.38; detection rate, 98.2 %), followed by the AC−SC− (4.70 ± 0.55, 89.3 %), and the AC−SC+ (4.39 ± 1.2, 78.6 %). The lowest values were obtained for the AC+SC+ (4.36 ± 1.22, 78.6 %). Regarding the confidence levels of interpretation, significant differences were observed between AC+SC− and AC−SC−, AC+SC− and AC+SC+, AC+SC− and AC−SC+, and between planar images and AC+SC+ (P = 0.0021, 0.0009, 0.0013, and 0.0056, respectively).Conclusions: When SPECT/CT was used, AC improved the detection of SLNs. SC caused disappearance of a faint SLN in some cases and should not be performed.
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Yoneyama, Hiroto ; Tsushima, Hiroyuki ; Onoguchi, Masahisa ; Konishi, Takahiro ; Nakajima, Kenichi ; Matsuo, Shinro ; Kayano, Daiki ; Wakabayashi, Hiroshi ; Inaki, Anri ; Kinuya, Seigo
概要:
Objective: Although SPECT/CT systems have been used for sentinel lymph node (SLN) imaging, few studies have focused on o
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ptimization of attenuation correction (AC) and scatter correction (SC). While SLNs could be detected in conventional planar images, they sometimes do not appear in SPECT/CT images. The purpose of this study was to investigate the optimal AC and SC and to improve the detectability of SLNs in examinations using SPECT/CT systems. Materials and methods: The study group consisted of 56 female patients with breast cancer. In SPECT/CT imaging, four kinds of images were created with and without AC and SC; namely, AC−SC−, AC+SC−, AC−SC+ and AC+SC+. Five nuclear medicine physicians interpreted the planar and SPECT/CT images with five grades of confidence levels (1–5). The detection rate was calculated as the number of patients whose average confidence levels of interpretation were more than 4, divided by the total number of patients. Results: The confidence level of interpretation and the detection rate provided by the planar images were 4.76 ± 0.49 and 94.6 %, respectively. In SPECT/CT imaging, the AC+SC− provided the best detection rate (confidence level of interpretation, 4.81 ± 0.38; detection rate, 98.2 %), followed by the AC−SC− (4.70 ± 0.55, 89.3 %), and the AC−SC+ (4.39 ± 1.2, 78.6 %). The lowest values were obtained for the AC+SC+ (4.36 ± 1.22, 78.6 %). Regarding the confidence levels of interpretation, significant differences were observed between AC+SC− and AC−SC−, AC+SC− and AC+SC+, AC+SC− and AC−SC+, and between planar images and AC+SC+ (P = 0.0021, 0.0009, 0.0013, and 0.0056, respectively). Conclusions: When SPECT/CT was used, AC improved the detection of SLNs. SC caused disappearance of a faint SLN in some cases and should not be performed. © 2014, The Japanese Society of Nuclear Medicine.
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Yoneyama, Hiroto ; Tsushima, Hiroyuki ; Onoguchi, Masahisa ; Konishi, Takahiro ; Nakajima, Kenichi ; Kinuya, Seigo
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Objective: The identification of sentinel lymph nodes (SLNs) near injection sites is difficult because of scattered gamm
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a rays. The purpose of this study was to investigate the optimal energy windows for elimination of scattered gamma rays in order to improve the detection of SLNs. Methods: The clinical study group consisted of 56 female patients with breast cancer. While the energy was centred at 140 keV with a 20% window for Tc-99m, this energy window was divided into five subwindows with every 4% in planar imaging. Regions of interest were placed on SLNs and the background, and contrast was calculated using a standard equation. The confidence levels of interpretations were evaluated using a five-grade scale. Results: The contrast provided by 145.6 keV ± 2% was the best, followed by 140 keV ± 2%, 151.2 keV ± 2%, 134.4 keV ± 2% and 128.8 keV ± 2% in that order. When 128.8 keV ± 2% and 134.4 keV ± 2% were eliminated from 140 keV ± 10% (145.6 keV ± 6%), the contrast of SLNs improved significantly. The confidence levels of interpretation and detection rate provided by the planar images with 140 keV ± 10% were 4.74 ± 0.58 and 94.8%, respectively, and those provided by 145.6 keV ± 6% were 4.94 ± 0.20 and 100%. Conclusion: Because lower energy windows contain many scattered gamma rays, upper offset energy windows, which exclude lower energy windows, improve the image contrast of SLNs near injection sites. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
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