研究者詳細 - 後藤　佐知子

論文 - 後藤　佐知子

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Investigating the Effects of Reconstruction Conditions on Image Quality and Radiomic Analysis in Photon-counting Computed Tomography. 査読国際誌

Miyu Ohata, Ryohei Fukui, Yusuke Morimitsu, Daichi Kobayashi, Takatsugu Yamauchi, Noriaki Akagi, Mitsugi Honda, Aiko Hayashi, Koshi Hasegawa, Katsuhiro Kida, Sachiko Goto, Takao Hiraki

Journal of medical physics 50 ( 1 ) 100 - 107 2025年5月

記述言語：英語掲載種別：研究論文（学術雑誌）

INTRODUCTION: Photon-counting computed tomography (CT) is equipped with an adaptive iterative reconstruction method called quantum iterative reconstruction (QIR), which allows the intensity to be changed during image reconstruction. It is known that the reconstruction conditions of CT images affect the analysis results when performing radiomic analysis. The aim of this study is to investigate the effect of QIR intensity on image quality and radiomic analysis of renal cell carcinoma (RCC). MATERIALS AND METHODS: The QIR intensities were selected as off, 2 and 4. The image quality evaluation items considered were task-based transfer function (TTF), noise power spectrum (NPS), and low-contrast object specific contrast-to-noise ratio (CNRLO). The influence on radiomic analysis was assessed using the discrimination accuracy of clear cell RCC. RESULTS: For image quality evaluation, TTF and NPS values were lower and CNRLO values were higher with increasing QIR intensity; for radiomic analysis, sensitivity, specificity, and accuracy were higher with increasing QIR intensity. Principal component analysis and receiver operating characteristics analysis also showed higher values with increasing QIR intensity. CONCLUSION: It was confirmed that the intensity of the QIR intensity affects both the image quality and the radiomic analysis.

DOI： 10.4103/jmp.jmp_114_24

PubMed

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Accuracy of deep learning-based attenuation correction in 99mTc-GSA SPECT/CT hepatic imaging 査読

M. Miyai, R. Fukui, M. Nakashima, D. Hasegawa, S. Goto

Radiography 31 ( 1 ) 112 - 117 2025年1月

Backside Irradiation of Ultraviolet-A for Correcting Nonuniformity Error of Gafchromic XR-QA2 Films 査読

Nobuyoshi Tanki, Sachiko Goto, Toshizo Katsuda, Rumi Gotanda, Tatsuhiro Gotanda, Tadao Kuwano

Journal of Medical Physics 49 ( 4 ) 563 - 567 2024年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Ovid Technologies (Wolters Kluwer Health)

Purpose:

Radiochromic film is used for quality assurance and quality control of X-ray equipment in the diagnostic radiology. In addition, three-dimensional dose distribution of computed tomography (CT) is measured. To correct the nonuniformity and uncertainty of radiochromic films for dose measurement of CT, the films are preirradiated ultraviolet (UV)-A rays. There is a difference in the UV protection strength of radiochromic films. A concern exists about the effects of the UV-A irradiation intensity. We thus irradiated with UV-A rays from the backsides of the films to assess if backside irradiation was possible.

Materials and Methods:

Gafchromic XR-QA2 and RTQA2 were used in this study. The UV-A rays were simultaneously irradiated on the front and backsides of each film for 12 h. The yellow layer of each film was scanned and imaged. The average pixel values ± standard deviations (SDs) were compared. In the statistical analysis, a paired t-test was performed. To compare, the active-layer densities engendered by the UV-A rays. Calibration curve was created with 48 h of preirradiation of UV-A.

Results:

The mean pixel values ± SD for Gafchromic XR-QA2 on the front and backsides were 130.776 ± 0.812 and 81.015 ± 1.128, respectively. On the other hand, the mean pixel values ± SD for Gafchromic RTQA2 on the front and backsides were 62.299 ± 1.077 and 133.761 ± 1.365, respectively. The statistical results of the paired t-test were significantly different (P < 0.01) between both films. Fitting equation of the calibration curve is shown below. y = -390.47 ± 200 + (443.45 ± 10x80).5068 ± 0.0434.

Conclusion:

Based on the relationship between the sensitivity of the active layer to UV-A rays and the strength of UV protection on the surface, we concluded that backside irradiation is recommended for Gafchromic XR-QA2, and frontside irradiation is recommended for Gafchromic RTQA2.

DOI： 10.4103/jmp.jmp_87_24

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Effect of segmentation dimension on radiomics analysis for MGMT promoter methylation status in gliomas. 査読

Ryohei Fukui, Masataka Onishi, Koshi Hasegawa, Miyu Ohata, Katsuhiro Kida, Sachiko Goto

Aktualności Neurologiczne 24 ( 1 ) 8 - 14 2024年7月

Assessment of a New Elbow Joint Positioning Method Using Area Detector Computed Tomography 査読

Takuya AKAGAWA, Ryohei FUKUI, Katsuhiro KIDA, Ryutaro MATSUURA, Makoto SHIMADA, Mitsuhiro KINOSHITA, Yoko AKAGAWA, Sachiko GOTO

Acta Medica Okayama 78 ( 3 ) 215 - 225 2024年6月

Native myocardial T1 mapping using inversion recovery T1-weighted turbo field echo sequence. 査読

Katsuhiro Kida, Takamasa Kurosaki, Ryohei Fukui, Ryutaro Matsuura, Sachiko Goto

Radiological physics and technology 2024年3月

担当区分：最終著者記述言語：英語掲載種別：研究論文（学術雑誌）

This study proposes the use of the inversion recovery T1-weighted turbo field echo (IR-T1TFE) sequence for myocardial T1 mapping and compares the results obtained with those of the modified Look-Locker inversion recovery (MOLLI) method for accuracy, precision, and reproducibility. A phantom containing seven vials with different T1 values was imaged, thereby comparing the T1 measurements between the inversion recovery spin-echo (IR-SE) technique, MOLLI, and the IR-T1TFE. The accuracy, precision, and reproducibility of the T1-mapping sequences were analyzed in a phantom study. Fifteen healthy subjects were recruited for the in vivo comparison of native myocardial T1 mapping using MOLLI and IR-T1TFE sequences. After myocardium segmentation, the T1 value of the entire myocardium was calculated. In the phantom study, excellent accuracy was achieved using IR-T1TFE for all T1 ranges. MOLLI displayed lower accuracy than IR-T1TFE (p =0.016), substantially underestimating T1 at large T1 values (> 1000 ms). In the in vivo study, the first mean myocardial T1 values ± SD using MOLLI and IR-T1TFE were 1306 ± 70 ms and 1484 ± 28 ms, respectively, and the second were 1297 ± 68 ms and 1474 ± 43 ms, respectively. The native myocardial T1 obtained with MOLLI was lower than that of IR-T1TFE (p < 0.001). The reproducibility of native myocardial T1 mapping within the same sequence was not statistically significant (p = 0.11). This study demonstrates the utility and validity of myocardial T1 mapping using IR-T1TFE, which is a common sequence. This method was found to have high accuracy and reproducibility.

DOI： 10.1007/s12194-024-00795-w

PubMed

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Deep learning-based attenuation correction method in 99mTc-GSA SPECT/CT hepatic imaging: a phantom study 査読

Masahiro Miyai, Ryohei Fukui, Masahiro Nakashima, Sachiko Goto

Radiological Physics and Technology 2023年11月

担当区分：最終著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Springer Science and Business Media LLC

DOI： 10.1007/s12194-023-00762-x

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その他リンク： https://link.springer.com/article/10.1007/s12194-023-00762-x/fulltext.html

Proposal for diagnosis using FLAIR image aimed for pediatric MELAS with recurrent stroke-like episodes on MRI system cannot take ASL imaging 査読

Makoto Shimada, Tae Ikeda, Ryohei Fukui, Katsuhiro Kida, Ryutaro Matsuura, Takuya Akagawa, Sachiko Goto

Egyptian Pediatric Association Gazette 71 ( 1 ) 2023年11月

担当区分：最終著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Springer Science and Business Media LLC

Abstract

Background

Arterial spin-labeling (ASL) imaging is currently the most useful method for diagnosing mitochondrial encephalomyopathy, lactic acidosis, and stroke-like attack syndrome (MELAS). However, ASL is often an optional feature of standard MRI systems. Therefore, not all MRI systems can perform ASL imaging. In contrast, fluid-attenuated inversion recovery (FLAIR) imaging is one of the common sequences in brain MRI because FLAIR imaging can be performed regardless of the specifications of the equipment. This study aimed to compare the diagnostic performance of quantitative analysis of signal intensity obtained from fluid-attenuated inversion recovery (FLAIR) images with ASL images for MELAS with recurrent stroke-like episodes (SLEs). A total of 68 cases with normal magnetic resonance imaging findings and 25 cases diagnosed MELAS with recurrent SLEs were included. We evaluated the frontal lobe and cuneus as target areas and compared the regional cerebral blood flow (rCBF) values obtained from ASL images with the normalized signal intensity (nSI) obtained from FLAIR images.

Results

The sensitivity and specificity for diagnosing MELAS from linear discriminant analysis (LDA) obtained from the rCBF values were 0.84 and 0.941, respectively, and those of nSI were 0.8 and 0.897, respectively. The area under the ROC curves (AUC) calculated from the receiver operating characteristic (ROC) curve analysis using rCBF values and nSI were 0.889 and 0.804, respectively.

Conclusion

Quantitative analysis using the signal intensity of the FLAIR image could have a diagnostic performance equivalent to that of rCBF values obtained from ASL images.

DOI： 10.1186/s43054-023-00232-4

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その他リンク： https://link.springer.com/article/10.1186/s43054-023-00232-4/fulltext.html

3D phase-sensitive inversion recovery sequence for intracranial vertebrobasilar artery dissection. 査読国際誌

Takuya Enoki, Katsuhiro Kida, Wataru Jomoto, Yusuke Kawanaka, Manabu Shirakawa, Masataka Miyama, Noriko Kotoura, Sachiko Goto

Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia 118 52 - 57 2023年10月

担当区分：最終著者記述言語：英語掲載種別：研究論文（学術雑誌）

BACKGROUND: T1-weighted 3D turbo spin echo (T1W-3D-TSE) sequences with variable refocusing flip angle are commonly used to diagnose intracranial vertebrobasilar artery dissection (iVAD). However, magnetic susceptibility artifacts of the cavernous sinus may cause loss of the basilar and vertebral arteries. This study investigated the effectiveness of a 3D phase-sensitive inversion recovery (3D-PSIR) sequence in reducing magnetic susceptibility artifacts in the cavernous sinus, and its imaging findings for iVAD. METHODS: Twelve volunteers and eleven patients with iVAD were included. Magnetic resonance imaging (MRI) was performed using a 3.0-T MRI system. 3D-PSIR and T1W-3D-TSE sequences were used. Vessel wall defects and contrast-to-noise ratio (CNR) were evaluated. The MRI findings were visually evaluated. RESULTS: In the 3D-PSIR images, one volunteer (8 %) had vessel wall defects, and five (42 %) had vessel wall defects (p = 0.046) in the T1W-3D-TSE images. CNR was higher in 3D-PSIR images for vessel wall-to-lumen, whereas it was higher in T1W-3D-TSE images for vessel wall-to-CSF (p < 0.001). Visual evaluation revealed similar MRI findings between the two sequences. CONCLUSIONS: The 3D-PSIR sequence may be able to improve the vessel wall defects and achieve MRI findings comparable to those of the T1W-3D-TSE sequence in iVAD. The 3D-PSIR sequence can be a useful tool for the imaging-based diagnosis of iVAD.

DOI： 10.1016/j.jocn.2023.10.008

PubMed

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Influence of Two-Dimensional and Three-Dimensional Acquisitions of Radiomic Features for Prediction Accuracy 査読

Ryohei Fukui, Ryutarou Matsuura, Katsuhiro Kida, Sachiko Goto

Progress in Medical Physics 34 ( 3 ) 23 - 32 2023年9月

Fundamental study for application of 3D phase-sensitive inversion recovery sequence to multiple sclerosis 査読

Takuya Enoki, Wataru Jomoto, Katsuhiro Kida, Sachiko Goto, Noriko Kotoura

Journal of the Japan Association of Radiologic Technologists 70 ( 6 ) 580 - 587 2023年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：(公社)日本診療放射線技師会

本研究の目的は,3D PSIRを多発性硬化症へ応用するために,撮像パラメーターと脳組織コントラストの関係を明らかにすることである.ファントム実験で,TFE factor,shot interval,TIがコントラストに与える影響を検討した.TFE factorは30,shot intervalは1000msが採用された.健常ボランティアでTI(300-800ms)を変化させ,脳組織コントラストについて視覚評価を行った。TIを長くするとコントラストは向上した.3D-PSIRを多発性硬化症へ応用するには,TFE factorが30,shot intervalが1000msの場合,TIは700msが最適である.(著者抄録)

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Image Quality Assessment of Deep Learning Image Reconstruction in Torso Computed Tomography Using Tube Current Modulation 査読

Kazuhiro Takeuchi, Yasuhiro Ide, Yuichiro Mori, Yusuke Uehara, Hiroshi Sukeishi, Sachiko Goto

Acta Medica Okayama 77 ( 1 ) 45 - 55 2023年2月

Effect of Bead Device Diameter on Z-Resolution Measurement in Tomosynthesis Images: A Simulation Study 査読

Ryohei Fukui, Miho Numata, Saki Nishioka, Ryutarou Matsuura, Katsuhiro Kida, Sachiko Goto

Progress in Medical Physics 33 ( 4 ) 1 - 9 2022年12月

Effect of Median Filter Processing on Measurement of Presampled Modulation Transfer Function using Edge Method in Digital Radiographic Systems 査読

Kazuhiro Takeuchi, Masaki Asahara, Masatoshi Morimoto, Sachiko Goto

医用画像情報学会雑誌 39 ( 2 ) 30 - 37 2022年6月

システム平面感度法における収集条件が定量値に与える影響査読

田中杏佳, 中嶋真大, 後藤佐知子, 竹田芳弘

核医学技術 42 ( 2 ) 139 - 145 2022年2月

Effect of the Number of Projected Images on the Noise Characteristics in Tomosynthesis Imaging 査読

Ryohei Fukui, Ryutaro Matsuura, Katsuhiro Kida, Sachiko Goto

Progress in Medical Physics 32 ( 2 ) 50 - 58 2021年6月

Image Evaluation of Free-breathing Navigator Echo and Triggered Cardiac-gated Delayed 査読

Ryutaro Matsuura, Sachiko Goto, Shuhei Sato, Noriaki Akagi, Seiji Tahara

Acta Med Okayama 72 ( 3 ) 267 - 273 2018年6月

High spatial resolution MRA of renal arteries using contrast behavior between fat and water during transient phase before reaching a steady state 査読

Katsuhiro Kida, Sachiko Goto, Yoshiharu Azuma

EUROPEAN JOURNAL OF RADIOLOGY 81 ( 5 ) 846 - 850 2012年5月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER IRELAND LTD

Purpose: Our aim is high spatial resolution imaging of maximum intensity projection (MIP) images in renal magnetic resonance angiography (MRA) by constructing a protocol for acquiring three-dimensional volume data with isotropic voxels.
Materials and methods: We eliminated water-selective excitation (WATS) and utilized effective contrast behavior between fat and water before reaching a steady state-that is, during the transient phase-to cover fat suppression by WATS. In a phantom study, the optimal flip angle was investigated under the "low-high Y" profile order using distilled water and baby oil to construct a protocol with isotropic voxels. Signal intensity, contrast, noise and signal-to-noise ratio were investigated to compare image qualities between the conventional and the constructed isotropic protocols. In a clinical study, three radiologists and two radiological technologists visually evaluated clinical images of 20 volunteers for spatial resolution, contrast and overall reader confidence in two protocols.
Results: We constructed an isotropic protocol with voxel dimensions of 0.78 mm x 0.78 mm x 0.78 mm at a flip angle of 90 degrees. We maintained the scan time but enlarged the x-y pixel dimensions from 0.59 mm x 0.59 mm to 0.78 mm x 0.78 mm and shortened image height from 48 mm to 42.9 mm. Data from the phantom study were worse in the isotropic protocol than in the conventional protocol. However, overall reader confidence in the clinical images was significantly better in the isotropic protocol than in the conventional protocol (p < .001).
Conclusion: Our study indicated the value of addressing high spatial resolution imaging of MIP images for renal MRA by constructing an isotropic protocol. (C) 2011 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.ejrad.2011.02.031

Web of Science

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頭部MRIのT1強調画像における各種Contrast to Noise Ratio (CNR) 算出法の比較査読

木田勝博, 後藤佐知子, 東義晴, 梶谷努

日本放射線技師会雑誌 59 ( 702 ) 81 - 86 2012年

Computed Radiography（CR）マンモグラフィにおける乳腺含有率の推定査読

辻田直子, 後藤佐知子, 東義晴, 白石順

日本放射線技術学会雑誌 67 ( 12 ) 1540 - 1547 2011年

記述言語：日本語出版者・発行元：Japanese Society of Radiological Technology

Measurement of a percent glandular tissue composition (%GTC) is important in terms of the estimation of individual patient exposure dose and the prediction of malignancy, and thus a number of reports for estimating %GTC by use of a mammogram have been published. In this study, we propose a method for estimating individual %GTC by use of computed radiography (CR) mammograms. By employing breast-equivalent phantoms that are able to create breast phantom images with various combinations of fat and glandular tissue, as well as the thickness of whole breast, we determined a reference table for converting an each pixel value on CR mammography to the glandular tissue ratio. Therefore, the %GTC for individual breast was estimated by averaging glandular tissue ratio for a whole region. The clinical image data set that consisted of 49 CR mammograms were used for estimating %GTC. A paired comparison method for determining subjective ranking of the degree of breast density was employed in order to demonstrate the validity of our method. The results indicate that the average estimated %GTC was 35.0% (ranged from 12.0% to 67.0%) and they had a increased correlation with the ranking of those obtained by observer test. Therefore, it was suggested that our proposed method would be utilized for estimating the %GTC in objective manner.

DOI： 10.6009/jjrt.67.1540

CiNii Article

CiNii Books

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その他リンク： https://jlc.jst.go.jp/DN/JALC/00384818611?from=CiNii

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