記述言語：英語   出版者・発行元：一般社団法人 日本循環器学会  

DOI： 10.1253/circj.cj-24-0386

PubMed

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：Applied Sciences (Switzerland)  

This study aimed to propose an automated prediction approach of the consolidation tumor ratios (CTRs) of part-solid tumors of patients treated with radiotherapy on treatment planning computed tomography images using deep learning segmentation (DLS) models. For training the DLS model for cancer regions, a total of 115 patients with non-small cell lung cancer (NSCLC) who underwent stereotactic body radiation therapy were selected as the training dataset, including solid, part-solid, and ground-glass opacity tumors. For testing the automated prediction approach of CTRs based on segmented tumor regions, 38 patients with part-solid tumors were selected as an internal test dataset A (IN) from a same institute as the training dataset, and 49 patients as an external test dataset (EX) from a public database. The CTRs for part-solid tumors were predicted as ratios of the maximum diameters of solid components to those of whole tumors. Pearson correlations between reference and predicted CTRs for the two test datasets were 0.953 (IN) and 0.926 (EX) for one of the DLS models (p < 0.01). Intraclass correlation coefficients between reference and predicted CTRs for the two test datasets were 0.943 (IN) and 0.904 (EX) for the same DLS models. The findings suggest that the automated prediction approach could be robust in calculating the CTRs of part-solid tumors.

DOI： 10.3390/app14083275

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Scopus

記述言語：英語   出版者・発行元：Japanese Journal of Radiology  

Dynamic chest radiography (DCR) is a novel functional radiographic imaging technique that can be used to visualize pulmonary perfusion without using contrast media. Although it has many advantages and clinical utility, most radiologists are unfamiliar with this technique because of its novelty. This review aims to (1) explain the basic principles of lung perfusion assessment using DCR, (2) discuss the advantages of DCR over other imaging modalities, and (3) review multiple specific clinical applications of DCR for pulmonary vascular diseases and compare them with other imaging modalities.

DOI： 10.1007/s11604-023-01483-2

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PubMed

記述言語：英語   出版者・発行元：Journal of Computer Assisted Tomography  

Objective The purpose of this study is to evaluate the efficacy of deep learning reconstruction (DLR) on low-Tube-voltage computed tomographic angiography (CTA) for transcatheter aortic valve implantation (TAVI). Methods We enrolled 30 patients who underwent TAVI-CT on a 320-row CT scanner. Electrocardiogram-gated coronary CTA (CCTA) was performed at 100 kV, followed by nongated aortoiliac CTA at 80 kV using a single bolus of contrast material. We used hybrid-iterative reconstruction (HIR), model-based IR (MBIR), and DLR to reconstruct these images. The contrast-To-noise ratios (CNRs) were calculated. Five-point scales were used for the overall image quality analysis. The diameter of the aortic annulus was measured in each reconstructed image, and we compared the interobserver and intraobserver agreements. Results In the CCTA, the CNR and image quality score for DLR were significantly higher than those for HIR and MBIR (P < 0.01). In the aortoiliac CTA, the CNR for DLR was significantly higher than that for HIR (P < 0.01) and significantly lower than that for MBIR (P ≤ 0.02). The image quality score for DLR was significantly higher than that for HIR (P < 0.01). No significant differences were observed between the image quality scores for DLR and MBIR. The measured aortic annulus diameter had high interobserver and intraobserver agreement regardless of the reconstruction method (all intraclass correlation coefficients, >0.89). Conclusions In low tube voltage TAVI-CT, DLR provides higher image quality than HIR, and DLR provides higher image quality than MBIR in CCTA and is visually comparable to MBIR in aortoiliac CTA.

DOI： 10.1097/RCT.0000000000001525

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PubMed

出版者・発行元：学研メディカル秀潤社  

DOI： 10.15105/gz.0000005005

CiNii Research

記述言語：英語   出版者・発行元：BMJ Open Respiratory Research  

Objective Few prospective cohort studies with relatively large numbers of patients with non-idiopathic pulmonary fibrosis (non-IPF) of idiopathic interstitial pneumonia (IIP) have been described. We aimed to assess disease progression and cause of death for patients with non-IPF IIPs or IPF under real-life conditions. Methods Data were analysed for a prospective multi-institutional cohort of 528 IIP patients enrolled in Japan between September 2013 and April 2016. Diagnosis of IPF versus non-IPF IIPs was based on central multidisciplinary discussion, and follow-up surveillance was performed for up to 5 years after patient registration. Survival and acute exacerbation (AE) were assessed. Results IPF was the most common diagnosis (58.0%), followed by unclassifiable IIPs (35.8%) and others (6.2%). The 5-year survival rate for non-IPF IIP and IPF groups was 72.8% and 53.7%, respectively, with chronic respiratory failure being the primary cause of death in both groups. AE was the second most common cause of death for both non-IPF IIP (24.1%) and IPF (23.5%) patients. The cumulative incidence of AE did not differ significantly between the two groups (p=0.36), with a 1-year incidence rate of 7.4% and 9.0% in non-IPF IIP and IPF patients, respectively. We found that 30.2% and 39.4% of non-IPF IIP and IPF patients, respectively, who experienced AE died within 3 months after an AE event, whereas 55.8% and 66.7% of such patients, respectively, died within 5 years after registration. Conclusion Closer monitoring of disease progression and palliative care interventions after AE are important for non-IPF IIP patients as well as for IPF patients.

DOI： 10.1136/bmjresp-2023-001864

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記述言語：英語   出版者・発行元：Physical and Engineering Sciences in Medicine  

This study aimed to investigate the robustness of a deep learning (DL) fusion model for low training-to-test ratio (TTR) datasets in the segmentation of gross tumor volumes (GTVs) in three-dimensional planning computed tomography (CT) images for lung cancer stereotactic body radiotherapy (SBRT). A total of 192 patients with lung cancer (solid tumor, 118; part-solid tumor, 53; ground-glass opacity, 21) who underwent SBRT were included in this study. Regions of interest in the GTVs were cropped based on GTV centroids from planning CT images. Three DL models, 3D U-Net, V-Net, and dense V-Net, were trained to segment the GTV regions. Nine fusion models were constructed with logical AND, logical OR, and voting of the two or three outputs of the three DL models. TTR was defined as the ratio of the number of cases in a training dataset to that in a test dataset. The Dice similarity coefficients (DSCs) and Hausdorff distance (HD) of the 12 models were assessed with TTRs of 1.00 (training data: validation data: test data = 40:20:40), 0.791 (35:20:45), 0.531 (31:10:59), 0.291 (20:10:70), and 0.116 (10:5:85). The voting fusion model achieved the highest DSCs of 0.829 to 0.798 for all TTRs among the 12 models, whereas the other models showed DSCs of 0.818 to 0.804 for a TTR of 1.00 and 0.788 to 0.742 for a TTR of 0.116, and an HD of 5.40 ± 3.00 to 6.07 ± 3.26 mm better than any single DL models. The findings suggest that the proposed voting fusion model is a robust approach for low TTR datasets in segmenting GTVs in planning CT images of lung cancer SBRT.

DOI： 10.1007/s13246-023-01295-8

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記述言語：英語  

Dynamic chest radiography (DCR) is a novel functional radiographic imaging technique that can be used to visualize pulmonary perfusion without using contrast media. Although it has many advantages and clinical utility, most radiologists are unfamiliar with this technique because of its novelty. This review aims to (1) explain the basic principles of lung perfusion assessment using DCR, (2) discuss the advantages of DCR over other imaging modalities, and (3) review multiple specific clinical applications of DCR for pulmonary vascular diseases and compare them with other imaging modalities.

CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   出版者・発行元：(一社)日本医用画像工学会  

我々は深層学習(DL)を用いて体幹部定位放射線治療(SBRT)の治療計画CT画像において肺腫瘍の領域抽出法を研究している。SBRTにおいて領域抽出性能は訓練データ数に依存するが、その性能をある程度維持できる訓練データ数は研究されていない。本研究では、訓練データ数対テストデータ数比(training-to-test number ratio:TTR)の腫瘍領域抽出性能に対する影響を調査した。本研究は、非小細胞肺癌患者192名[solid:118名、part-solid:53名、ground-glass opacity(GGO):21名]を対象とした。3D U-Net、V-Net、およびDense V-Netの3つのDLモデルを5パターンのTTR(1.00、0.791、0.531、0.291および0.116)でトレーニングした。3つのモデルは、Dice係数、precision、およびrecallに基づいて評価された。V-Netは、TTR=0.116のとき、最も高い0.788のDice係数を達成し、precisionは0.826、recallは0.794であった。訓練症例が10%、検証症例が5%に削減されても、ある程度領域抽出性能を維持できる可能性を示した。(著者抄録)

記述言語：英語   出版者・発行元：(公社)日本医学放射線学会  

乳癌の乳管内播種の術前評価における仮想単色スペクトラルCTイメージング(VMI)の有用性について検討した。病理学的に2cm以上の非浸潤性乳管癌(DCIS)あるいは浸潤性乳管癌(IDC)と診断された女性患者24人(34～74歳)を対象に、従来の120kVp CTと40keVp VMIにおける病変のコントラストノイズ比(CNR)について後方視的に比較した。また、病理学的にDCISあるいは微小浸潤性乳管癌と診断された女性患者22人(37～82歳)を対象に2人の放射線科専門医が120kVp CT、40keV VMI及びMRIにおける病変サイズを測定し、病理組織学的サイズと比較した。40keV VMIにおけるCNRの平均は5.5±1.9で120kVp CTの3.6±1.5よりも有意に大きかった。120kVp CTにおける病変サイズは病理組織学的サイズと比べて有意に過小評価されていたが、40keV VMIにおける病変サイズは病理組織学的サイズと有意差がなかった。MRIとの比較にて、40keV VMIでは誤差範囲が10mm以内の測定値が120kVp CTよりも多く得られた。以上より、VMIは乳癌の乳管内播種に対する術前評価に有用であると考えられた。

記述言語：英語   出版者・発行元：Japanese Journal of Radiology  

Purpose: To investigate the efficacy of virtual monochromatic spectral computed tomography imaging (VMI) in the preoperative evaluation for intraductal spread of breast cancer. Materials and methods: Twenty-four women who underwent spectral CT and were pathologically diagnosed with ductal carcinoma with a ≥ 2-cm noninvasive component were retrospectively enrolled in Group 1. Twenty-two women with 22 lesions pathologically diagnosed with ductal carcinoma in situ or microinvasive carcinoma were enrolled in Group 2. We compared the contrast-to-noise ratios (CNRs) of the lesions on conventional 120-kVp CT images and 40-keV VMIs in Group 1. Two board-certified radiologists measured the maximum diameters of enhancing areas on 120-kVp CT, 40-keV VMI, and MRI in Group 2 and compared with histopathological sizes. Results: The quantitative assessment of Group 1 revealed that the mean ± SD of the CNRs in the 40-keV images were significantly greater than those in the 120-kVp images (5.5 ± 1.9 vs. 3.6 ± 1.5, p < 0.0001). The quantitative assessment of Group 2 demonstrated that the lesion size observed in the conventional 120-kVp CT images by both readers was significantly underestimated as compared to the histopathological size (p = 0.017, 0.048), whereas both readers identified no significant differences between the lesion size measured on 40-keV VMI and the histopathological data. In a comparison with MRI, 40-keV VMI provided measurement within a 10-mm error range in more lesions as compared to the conventional 120-kVp CT. Conclusion: VMI improves the evaluation of intraductal spread and is useful for the preoperative evaluations of breast cancer.

DOI： 10.1007/s11604-023-01392-4

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記述言語：英語   出版者・発行元：Computer Methods and Programs in Biomedicine  

Background and objectives: Suspended respirable airborne particles are associated with human health risks and especially particles within the range of ultrafine (< 0.1 μm) or fine (< 2.5 μm) have a high possibility of penetrating the lung region, which is concerned to be closely related to the bronchial or alveoli tissue dosimetry. Nature complex structure of the respiratory system requires much effort to explore and comprehend the flow and the inhaled particle dynamics for precise health risk assessment. Therefore, this study applied the computational fluid-particle dynamics (CFPD) method to elucidate the deposition characteristics of ultrafine-to-coarse particles in the human respiratory tract from nostrils to the 16th generation of terminal bronchi. Methods: The realistic bronchi up to the 8th generation are precisely and perfectly generated from computed tomography (CT) images, and an artificial model compensates for the 9th-16th bronchioles. Herein, the steady airflow is simulated at constant breathing flow rates of 7.5, 15, and 30 L/min, reproducing human resting-intense activity. Then, trajectories of the particle size ranging from 0.002 – 10 μm are tracked using a discrete phase model. Results: Here, we report reliable results of airflow patterns and particle deposition efficiency in the human respiratory system validated against experimental data. The individual-related focal point of ultrafine and fine particles deposition rates was actualized at the 8th generation; whilst the hot-spot of the deposited coarse particles was found in the 6th generation. Lobar deposition characterizes the dominance of coarse particles deposited in the right lower lobe, whereas the left upper-lower and right lower lobes simultaneously occupy high deposition rates for ultrafine particles. Finally, the results indicate a higher deposition in the right lung compared to its counterpart. Conclusions: From the results, the developed realistic human respiratory system down to the terminal bronchiole in this study, in coupling with the CFPD method, delivers the accurate prediction of a wide range of particles in terms of particle dosimetry and visualization of site-specific in the consecutive respiratory system. In addition, the series of CFPD analyses and their results are to offer in-depth information on particle behavior in human bronchioles, which may benefit health risk assessment or drug delivery studies

DOI： 10.1016/j.cmpb.2023.107589

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記述言語：英語   出版者・発行元：Clinical Imaging  

Purpose: To assess the usefulness of amide proton transfer (APT) imaging to predict the biological status of breast cancers. Method: Sixty-six patients (age range 31–85 years, mean 58.9 years) with histopathologically proven invasive ductal carcinomas of 2 cm or larger in diameter were included in this study. 3D APT weighted imaging was conducted on a 3 T scanner. Mean APT signal intensity (SI) was analyzed in relation to biological subtypes, Ki-67 labeling index, and nuclear grades (NGs). Results: The triple-negative (TN) cancers (n = 10; 2.75 ± 0.42%) showed significantly higher APT SI than the luminal type cancers (n = 48; 1.74 ± 0.83) and HER2 cancers (n = 8; 1.83 ± 0.21) (P = 0.0007, 0.03). APT SI had weakly positive correlation with the Ki-67 labeling index (r = 0.38, P = 0.002). The mean APT SIs were significantly higher for high-Ki-67 (>30%) (n = 31; 2.25 ± 0.70) than low-Ki-67 (≤30%) cancers (n = 35; 1.60 ± 0.79) (P = 0.0007). There was no significant difference in the APT SIs between NG 1–2 (n = 31; 1.71 ± 0.84) and NG 3 (n = 35; 2.08 ± 0.76%) cancers (P = 0.06). Conclusions: TN and high-Ki-67 breast cancers showed high APT SIs. APT imaging can help to predict the biological status of breast cancers.

DOI： 10.1016/j.clinimag.2023.02.002

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出版者・発行元：学研メディカル秀潤社  

DOI： 10.15105/gz.0000004455

CiNii Research

記述言語：英語   出版者・発行元：Radiology  

Background: While current guidelines require lung ventilation-perfusion (V/Q) scanning as the first step to diagnose chronic pulmonary embolism in pulmonary hypertension (PH), its use may be limited by low availability and/or exposure to ionizing radiation. Purpose: To compare the performance of dynamic chest radiography (DCR) and lung V/Q scanning for detection of chronic thromboembolic PH (CTEPH). Materials and Methods: Patients with PH who underwent DCR and V/Q scanning in the supine position from December 2019 to July 2021 were retrospectively screened. The diagnosis of CTEPH was confirmed with right heart catheterization and invasive pulmonary angiography. Observer tests were conducted to evaluate the diagnostic accuracy of DCR and V/Q scanning. The lungs were divided into six areas (upper, middle, and lower for both) in the anteroposterior image, and the number of lung areas with thromboembolic perfusion defects was scored. Diagnostic performance was compared between DCR and V/Q scanning using the area under the receiver operating characteristic curve. Agreement between the interpretation of DCR and that of V/Q scanning was assessed using the Cohen kappa coefficient and percent agreement. Results: A total of 50 patients with PH were analyzed: 29 with CTEPH (mean age, 64 years ± 15 [SD]; 19 women) and 21 without CTEPH (mean age, 61 years ± 22; 14 women). The sensitivity, specificity, and accuracy of DCR were 97%, 86%, and 92%, respectively, and those of V/Q scanning were 100%, 86%, and 94%, respectively. Areas under the receiver operating characteristic curve for DCR and V/Q scanning were 0.92 (95% CI: 0.79, 0.97) and 0.93 (95% CI: 0.78, 0.98). Agreement between the consensus interpretation of DCR and that of V/Q scanning was substantial (κ = 0.79 [95% CI: 0.61, 0.96], percent agreement = 0.9 [95% CI: 0.79, 0.95]). Conclusion: Dynamic chest radiography had similar efficacy to ventilation-perfusion scanning in the detection of chronic thromboembolic pulmonary hypertension.

DOI： 10.1148/radiol.220908

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   出版者・発行元：European Journal of Radiology  

Purpose: We evaluated the usefulness of three-dimensional (3D) chemical exchange saturation transfer (CEST) imaging with compressed sensing and sensitivity encoding (CS-SENSE) for differentiating low-grade gliomas (LGGs) from high-grade gliomas (HGGs). Methods: We evaluated 28 patients (mean age 51.0 ± 13.9 years, 13 males, 15 females) including 12 with LGGs and 16 with HGGs, all acquired using a 3 T magnetic resonance (MR) scanner. Nine slices were acquired for 3D CEST imaging, and one slice was acquired for two-dimensional (2D) CEST imaging. Two radiological technologists each drew a region of interest (ROI) surrounding the high-signal-intensity area(s) on the fluid-attenuated inversion recovery image of each patient. We compared the magnetization transfer ratio asymmetry (MTRasym) at 3.5 ppm in the tumors among the (i) single-slice 2D CEST imaging (“2D”), (ii) all tumor slices of the 3D CEST imaging (3Dall), and (iii) a representative tumor slice of 3D CEST imaging (maximum signal intensity [3Dmax]). The relationship between the MTRasym at 3.5 ppm values measured by these three methods and the Ki-67 labeling index (LI) of the tumors was assessed. Diagnostic performance was evaluated with a receiver operating characteristic analysis. The Ki-67LI and MTRasym at 3.5 ppm values were compared between the LGGs and HGGs. Results: A moderate positive correlation between the MTRasym at 3.5 ppm and the Ki-67LI was observed with all three methods. All methods proved a significantly larger MTRasym at 3.5 ppm for the HGGs compared to the LGGs. All methods showed equivalent diagnostic performance. The signal intensity varied depending on the slice position in each case. Conclusions: The 3D CEST imaging provided the MTRasym at 3.5 ppm for each slice cross-section; its diagnostic performance was also equivalent to that of 2D CEST imaging.

DOI： 10.1016/j.ejrad.2022.110654

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記述言語：英語   出版者・発行元：福岡医学会  

【目的】本研究は，head-mounted display（HMD）装着下でバーチャルリアリティ（VR）空間に表現 したVR 解剖モデルの直接的な計測評価が可能なデジタルノギスを利用した長さ計測システムのプロトタイプを開発し，計測の正確さと再現性を評価することで，医学・医療分野での活用の可能性と意義を考察することを目的とした．【方法】実物体と仮想物体の位置・動きを同期するセンサで，現実空間のデジタルノギスのjawとVR 空間の仮想jaw とを紐付け，VR 空間で使用できる長さの計測システムを開発した．この計測システムの評価は，一辺が5，10，25，50，100 mmの仮想キューブと，VR で表現した三つのVR 解剖モデ ル（血管，骨格，臓器）に対して行った．キューブは1名の被験者による計測，VR解剖モデルは2名の被験者による計測を行い，結果は，キューブとVR 解剖モデルに対する計測誤差とその統計的分析により評価した．また，被験者内の計測の信頼性と被験者間の計測の信頼性を，級内相関係数（intraclass correlation coefficients：ICC）を求め評価した． 【結果】開発した計測システムは，現実空間のデジタルノギスのjaw とVR 空間の仮想jaw が連動し，HMD 装着下でVR 空間上に表現した物体の長さを計測できた．キューブの計測誤差は，すべてのキューブサイズで0.5 mm以内であった．また，各キューブサイズの計測誤差間には統計的有意差を 認めなかった．VR 解剖モデルの計測誤差は，すべての解剖部位で0.3mm以内で，各VR 解剖モデ ルの計測誤差の間にも統計的有意差を認めなかった．被験者内および被験者間の計測の信頼性（ICC）はともに0.99 と十分に高い値を示した．【結論】HMD装着下でVR 解剖モデルの直接的な計測評価が可能な長さ計測システムのプロトタイプ を開発でき，医学・医療分野での活用の可能性がある．

DOI： 10.15017/6788286

CiNii Research

記述言語：英語   出版者・発行元：福岡医学会  

【目的】本研究は,head-mounted display(HMD)装着下でバーチャルリアリティ(VR)空間に表現したVR解剖モデルの直接的な計測評価が可能なデジタルノギスを利用した長さ計測システムのプロトタイプを開発し,計測の正確さと再現性を評価することで,医学・医療分野での活用の可能性と意義を考察することを目的とした.【方法】実物体と仮想物体の位置・動きを同期するセンサで,現実空間のデジタルノギスのjawとVR空間の仮想jawとを紐付け,VR空間で使用できる長さの計測システムを開発した.この計測システムの評価は,一辺が5,10,25,50,100mmの仮想キューブと,VRで表現した三つのVR解剖モデル(血管,骨格,臓器)に対して行った.キューブは1名の被験者による計測,VR解剖モデルは2名の被験者による計測を行い,結果は,キューブとVR解剖モデルに対する計測誤差とその統計的分析により評価した.また,被験者内の計測の信頼性と被験者間の計測の信頼性を,級内相関係数(intraclass correlation coefficients:ICC)を求め評価した.【結果】開発した計測システムは,現実空間のデジタルノギスのjawとVR空間の仮想jawが連動し,HMD装着下でVR空間上に表現した物体の長さを計測できた.キューブの計測誤差は,すべてのキューブサイズで0.5mm以内であった.また,各キューブサイズの計測誤差間には統計的有意差を認めなかった.VR解剖モデルの計測誤差は,すべての解剖部位で0.3mm以内で,各VR解剖モデルの計測誤差の間にも統計的有意差を認めなかった.被験者内および被験者間の計測の信頼性(ICC)はともに0.99と十分に高い値を示した.【結論】HMD装着下でVR解剖モデルの直接的な計測評価が可能な長さ計測システムのプロトタイプを開発でき,医学・医療分野での活用の可能性がある.(著者抄録)

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   出版者・発行元：Magnetic Resonance Imaging  

Purpose: To evaluate the accuracy of three-dimensional (3D) chemical exchange saturation transfer (CEST) imaging with a compressed sensing (CS) and sensitivity encoding (SENSE) technique (CS-SENSE) for full z-spectrum acquisition. Methods: All images were acquired on 3-T magnetic resonance imaging (MRI) scanner. In the phantom study, we used the acidoCEST imaging. The phantoms were prepared in seven vials containing different concentrations of iopamidol mixed in phosphate-buffered solution with different pH values. The CEST ratios were calculated from the two CEST effects. We compared the CEST ratios obtained with three different 3D CEST imaging protocols (CS-SENSE factor 5, 7, 9) with those obtained with the 2D CEST imaging as a reference standard. In the clinical study, 21 intracranial tumor patients (mean 49.7 ± 17.2 years, 7 males and 14 females) were scanned. We compared the intratumor magnetization transfer ratio asymmetry (MTRasym) obtained with 3D CEST imaging with those obtained with 2D CEST imaging as a reference standard. Results: A smaller CS-SENSE factor resulted in higher agreement and better correlations with the 2D CEST imaging in the phantom study (CS-SENSE 5; ICC = 0.977, R2 = 0.8943, P < 0.0001: CS-SENSE 7; ICC = 0.970, R2 = 0.9013, P < 0.0001: CS-SENSE 9; ICC = 0.934, R2 = 0.8156 P < 0.0001). In the brain tumors, the means and percentile values of MTRasym at 2.0 and 3.5 ppm showed high linear correlations (R2 = 0.7325–0.8328, P < 0.0001) and high ICCs (0.859–0.907), which enabled successful multi-slice CEST imaging. Conclusions: The 3D CEST imaging with CS-SENSE provided equivalent contrast to 2D CEST imaging; moreover, a z-spectrum with a wide scan range could be obtained.

DOI： 10.1016/j.mri.2022.05.014

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PubMed

記述言語：英語   出版者・発行元：Magnetic Resonance Imaging  

Background: A magnetic resonance imaging (MRI)-specific objective image quality assessment (IQA) algorithm, the quality evaluation using multidirectional filters for MRI (QEMDIM), was previously reported. QEMDIM requires a set of reference images to calculate the quality score (SQ) for an assessed image. SQ may be affected by the quality of the reference set owing to the calculation procedure. Purpose: To propose a modified version of the IQA algorithm and compare the IQA performance of the original and modified algorithms. Assessment: Brain axial T1- and T2-weighted spin-echo images of varying quality levels (noise and blurring) were acquired from seven healthy men. Subjective IQA (paired comparisons) was conducted on the images, and subjective quality scores were obtained. With reference sets of various quality levels, QEMDIM and modified IQA were applied to the same images that underwent the subjective IQA. The correlation of each SQ and modified score (Smod) with the subjective scores was evaluated for content-related subsets of assessed images and for each reference set. The effect of the reference-set quality on the distribution of the correlation coefficients (CCs) was statistically evaluated for SQ and Smod using a one-way analysis of variance test with a significance level of 0.05. We also evaluated the variation in Smod for images with almost the same qualities using the standard deviation (SD). Results: The CCs of SQ varied significantly with the quality of the reference set, whereas that of Smod did not. The SD of Smod for almost-same-quality images was less than that corresponding to the confidence interval of the subjective scores. Conclusion: Our modified algorithm was superior to QEMDIM in terms of IQA performance in clinical practice, especially in terms of accuracy, robustness, and reproducibility.

DOI： 10.1016/j.mri.2022.07.010

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Scopus

PubMed

記述言語：英語   出版者・発行元：(公社)日本医学放射線学会  

超高精細CT(U-HRCT)による冠動脈CT造影(CCTA)で、モーションアーチファクトに対し、心拍数(HR)が及ぼす影響について検討した。模擬冠動脈が付随した模擬心臓動態ファントムと、CCTA受診患者でU-HRCTと従来のCT(CRCT)画像を比較し、U-HRCT CCTAにおける最適なHRの上限を決定した。安静下およびHRシミュレーション(10bpm間隔で40-90bpm)下で、心臓動態ファントムを両CTで走査し、模擬冠動脈モデルのシャープネスと血管内腔径を定量的に評価した。また、U-HRCTによるCCTAの臨床画像に関しては、視覚評価も行った。その結果、HR≦60bpmではU-HRCTの血管内腔径の誤差はCRCTよりも小さい傾向だったが、HR>60bpmでは逆に大きく、モーションアーチファクトに強く影響されていた。なお、画像シャープネスでは、U-HRCTではCRCTに比べ有意に優れており、視覚評価のスコアでは患者のHRと負に相関した(Spearman r=-0.71、p<0.01)。一方、ROC解析では最終診断が得られなかった画質のHR最適カットオフ値で61bpmが得られ、AUCは0.87、感度95%、特異度71%であった。以上より、HR≦60bpmの場合には、U-HRCTが冠動脈造影ではCRCTよりも診断精度が高く、U-HRCTによるCCTAにより、最適なHRの上限値が約60bpmであることが示唆された。

記述言語：英語   出版者・発行元：Japanese Journal of Radiology  

Purpose: We investigated the effects of the heart rate (HR) on the motion artifact in coronary computed tomography angiography (CCTA) with ultra-high-resolution-CT (U-HRCT), and we clarified the upper limit of optimal HR in CCTA with U-HRCT in a comparison with conventional-resolution-CT (CRCT) on a cardiac phantom and in patients with CCTA. Materials and methods: A pulsating cardiac phantom equipped with coronary models was scanned at static and HR simulations of 40–90 beats/min (bpm) at 10-bpm intervals using U-HRCT and CRCT, respectively. The sharpness and lumen diameter of the coronary model were quantitatively compared between U-HRCT and CRCT stratified by HR in the phantom study. We also assessed the visual inspections of clinical images in CCTA with U-HRCT. Results: At the HRs ≤ 60 bpm, the error of the lumen diameter of the U-HRCT tended to be smaller than that of the CRCT. However, at the HRs > 60 bpm, the inverse was shown. For the image sharpness, the U-HRCT was significantly superior to the CRCT (p < 0.05). In the visual assessment, the scores were negatively correlated with HRs in patients (Spearman r = − 0.71, p < 0.01). A receiver-operating characteristic analysis revealed the HR of 61 bpm as the optimal cutoff of the non-diagnostic image quality, with an area under the curve of 0.87, 95% sensitivity, and 71% specificity. Conclusion: At HRs ≤ 60 bpm, U-HRCT was more accurate in the imaging of coronary arteries than CRCT. The upper limit of the optimal HR in CCTA with U-HRCT was approx. 60 bpm.

DOI： 10.1007/s11604-022-01265-2

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Scopus

PubMed

記述言語：日本語   出版者・発行元：(一社)日本医用画像工学会  

本研究では,免疫チェックポイント阻害剤(ICI)により治療された非小細胞肺癌(NSCLC)患者のCT画像を用いて,腫瘍細胞数の経時変化曲線(TGT)を推定する方法を研究した.ICI治療(atezolizumab)を受けたNSCLC患者6人を用い,腫瘍輪郭を抽出し腫瘍細胞数を計算した.腫瘍輪郭は治療前CTとフォローアップCT画像で抽出した.腫瘍細胞はICI感受性,耐性,persister細胞から成ると仮定し,Bertalanffy-Putterモデルを用いてTGTを予測した.焼きなまし法を用いてTGTモデルの14個のパラメータを最適化した.各CT撮影時点における腫瘍細胞数と予測値の関係を,スピアマン順位相関係数を用いて評価した.スピアマン順位相関係数の二乗平均平方根は0.758であった.本手法はICI治療患者のTGTを推定できる可能性がある.(著者抄録)

記述言語：英語   出版者・発行元：Radiological Physics and Technology  

To determine the optimal display conditions for ultra-high-resolution computed tomography (UHRCT) images in clinical practice, this study investigated the effects of liquid–crystal display (LCD) resolution and displayed image size on the spatial resolution of phantom images acquired using a UHRCT system. A phantom designed to evaluate the high-contrast resolution was scanned. The scan data were reconstructed into four types of UHRCT image series consisting of the following possible combinations: two types of reconstruction kernels on the filtered back-projection method (for the lung and mediastinum) and two types of matrix sizes (10242 and 20482). These images were displayed under eight types of display conditions: three image sizes displayed on a 2-megapixel (MP) and 3-MP color LCD and two image sizes on an 8-MP color LCD. A total of 32 samples (four image series × eight display conditions) were evaluated by eight observers for high-contrast resolution. The high-contrast resolution of the displayed UHRCT images was significantly affected by the displayed image size, although the largest (full-screen) displayed image size did not necessarily show the maximum high-contrast resolution. When the images were displayed in the full-screen size, LCD resolution affected the high-contrast resolution of only the 20482-matrix-size images reconstructed using the lung kernel. In conclusion, the spatial resolution of UHRCT images may be affected by LCD resolution and displayed image size. To optimize the clinical display conditions for UHRCT images, it is necessary to adopt an LCD with an adequate resolution for each viewing situation.

DOI： 10.1007/s12194-022-00656-4

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PubMed

記述言語：英語   出版者・発行元：(公社)日本放射線技術学会  

超高精細CT(UHRCT)装置で取得した画像の空間分解能に、液晶ディスプレイ(LCD)の解像度と表示画像サイズが及ぼす影響について調べた。本報では、まず始めに高コントラスト分解能の評価用にデザインされたファントムをスキャンし、スキャンデータをフィルタ補正逆投影法により画像再構成を行った。次に、2種類の画像再構成関数(カーネル)と2種類のマトリックスサイズを組み合わせ、4種類のUHRCT画像の再構成処理をした後、解像度の異なるカラーLCD上に表示させた。その結果、1024^2および2048^2のマトリックスサイズのUHRCT画像での高コントラスト分解能は、LCDの解像度と表示画像サイズの影響を受けることが確認された。また、画像をフルサイズで表示させると、肺カーネルで再構成処理した、マトリックスサイズ2048^2のUHRCT画像の高コントラスト分解能のみが、LCD解像度の影響を受けることが明らかにされた。以上より、UHRCT画像の空間分解能は、LCDの解像度と表示画像サイズの影響を受けることが示唆されたことから、UHRCT画像の表示条件を最適化するには、観察状況ごとに十分な解像度のLCDを適用することが不可欠と考えられた。

記述言語：英語   出版者・発行元：Polish Journal of Radiology  

Purpose: To examine the optimal number and combination of b-values in intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) of the major salivary glands. Material and methods: IVIM-DWI was performed on 10 healthy volunteers using 13 b-values (low b-values: 0-100 s/mm2; high b-values: 200-1000 s/mm2). The IVIM parameters and apparent diffusion coefficient of the bilateral major salivary glands were calculated using 13 b-values and were considered the standard values. We sequentially reduced the number of b-values to 10, 8, 6, and 5. The parameters in each combination were calculated. The standard values were compared with the parameters from each reduced b-value in IVIM-DWI. The Wilcoxon signed-rank test was used to determine whether there were any differences between the parameters in each combination. Bonferroni correction was conducted for multiple comparisons. Results: There were no significant differences between the standard values and parameters from the 2 combinations of 6 b-values. However, significant differences were observed between the standard values and parameters from some combinations of only 2 low or only 2 high b-values. Conclusions: IVIM-DWI of the major salivary glands could be performed using a minimum of 6 b-values. However, they should contain 3 low and 3 high b-values.

DOI： 10.5114/pjr.2022.116167

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   出版者・発行元：European Journal of Radiology  

Purpose: To evaluate the optimal sequence for high-resolution magnetic resonance imaging (MRI) of the triangular fibrocartilage complex (TFCC) using compressed sensing-sensitivity encoding (CS-SENSE). Methods: Three-dimensional fast field echo T2-weighted images were obtained from 13 healthy volunteers using the original, high spatial resolution sequence with CS-SENSE [HR (CS-SENSE)] and without CS-SENSE (HR) and super-high spatial resolution sequence with CS-SENSE [S-HR (CS-SENSE)] and without CS-SENSE (S-HR). For qualitative analysis, the number of patients affected by motion artifacts in each sequence was counted, and the visualization of the TFCC anatomic structures and overall image quality were categorized. For the quantitative analysis, relative signal intensity (SI) and relative contrast of the lunate bone marrow, lunate cartilage, and disk proper in the wrist joint were all calculated. Results: The HR (CS-SENSE) sequence showed better visualization scores than the original sequence in the triangular ligament at the ulnar styloid tip, dorsal radioulnar ligament, and ulnotriquetral ligament. Similarly, the S-HR (CS-SENSE) sequence showed better visualization scores than the original sequence in the triangular ligament at the ulnar styloid tip and dorsal radioulnar ligament. Overall image quality scores were not significantly different, and motion artifacts in the HR and S-HR sequences were observed in 3 of the 13 patients. In contrast, the original sequence showed higher values than those in the HR (CS-SENSE) and S-HR (CS-SENSE) sequences in relative SI of the bone marrow and relative contrast of the cartilage-bone marrow and cartilage-disk proper. Conclusions: Out of the three sequences, the HR (CS-SENSE) sequence provided the highest visualization score and diagnostically sufficient image quality score, although relative SI and relative contrast were low. The HR (CS-SENSE) sequence may be clinically useful for imaging TFCCs.

DOI： 10.1016/j.ejrad.2022.110191

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   出版者・発行元：一般社団法人日本インターベンショナルラジオロジー学会  

DOI： 10.11407/ivr.36.119

CiNii Research

記述言語：英語   出版者・発行元：British Journal of Radiology  

Objectives The lung nodule volume determined by CT is used for nodule diagnoses and monitoring tumor responses to therapy. Increased image noise on low-dose CT degrades the measurement accuracy of the lung nodule volume. We compared the volumetric accuracy among deep-learning reconstruction (DLR), model-based iterative reconstruction (MBIR), and hybrid iterative reconstruction (HIR) at an ultra-low-dose setting. Methods Artificial ground-glass nodules (6 mm and 10 mm diameters, −660 HU) placed at the lung-apex and the middle-lung field in chest phantom were scanned by 320-row CT with the ultra-low-dose setting of 6.3 mAs. Each scan data set was reconstructed by DLR, MBIR, and HIR. The volumes of nodules were measured semi-automatically, and the absolute percent volumetric error (APEvol) was calculated. The APEvol provided by each reconstruction were compared by the Tukey-Kramer method. Inter- and intraobserver variabilities were evaluated by a Bland-Altman analysis with limits of agreements. Results DLR provided a lower APEvol compared to MBIR and HIR. The APEvol of DLR (1.36%) was significantly lower than those of the HIR (8.01%, p = 0.0022) and MBIR (7.30%, p = 0.0053) on a 10-mm-diameter middle-lung nodule. DLR showed narrower limits of agreement compared to MBIR and HIR in the inter- and intraobserver agreement of the volumetric measurement. Conclusions DLR showed higher accuracy compared to MBIR and HIR for the volumetric measurement of artificial ground-glass nodules by ultra-low-dose CT. Advances in knowledge DLR with ultra-low-dose setting allows a reduction of dose exposure, maintaining accuracy for the volumetry of lung nodule, especially in patients which deserve a long-term follow-up.

DOI： 10.1259/bjr.20210915

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s10334-019-00823-6.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s10334-019-00776-w.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.ejrad.2018.08.021.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1177/0284185114544244

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1148/radiol.2331030779

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1053/crad.2001.0731

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1080/028418502127347637

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1097/00005382-199904000-00007

記述言語：日本語   著書種別：学術書

リポジトリ公開URL： http://hdl.handle.net/2324/1001459607

記述言語：日本語   著書種別：学術書

記述言語：日本語   著書種別：学術書

開催年月日： 2014年11月 - 2014年12月

記述言語：英語  

国名：アメリカ合衆国  

開催年月日： 2014年4月

記述言語：日本語  

開催地：横浜市   国名：日本国  

開催年月日： 2013年6月

記述言語：英語  

国名：大韓民国  

開催年月日： 2011年3月

国名：オーストリア共和国  

開催年月日： 2010年11月

開催地：東京都   国名：日本国  

開催年月日： 2010年9月

会議種別：口頭発表（一般）  

開催地：横浜市   国名：日本国  

開催年月日： 2009年11月 - 2010年12月

国名：アメリカ合衆国  

開催年月日： 2008年9月

会議種別：口頭発表（一般）  

開催地：旭川市   国名：日本国  

国名：日本国  

会議種別：口頭発表（一般）  

国名：アメリカ合衆国  

会議種別：口頭発表（一般）  

国名：アメリカ合衆国  

会議種別：口頭発表（一般）  

開催地：横浜市  

会議種別：口頭発表（一般）  

開催地：つくば市   国名：日本国  

会議種別：口頭発表（一般）  

開催地：Chicago   国名：アメリカ合衆国  

国名：日本国  

国名：アメリカ合衆国  

記述言語：日本語  

記述言語：日本語  

記述言語：英語  

記述言語：英語  

記述言語：日本語  

記述言語：英語  

記述言語：日本語  

記述言語：日本語  

記述言語：日本語  

記述言語：日本語  

記述言語：英語  

記述言語：日本語  

記述言語：日本語  

記述言語：日本語  

記述言語：日本語  

記述言語：日本語  

記述言語：日本語  

記述言語：日本語  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

記述言語：日本語   掲載種別：記事・総説・解説・論説等（学術雑誌）  

種別：査読等 

外国語雑誌　査読論文数：20

日本語雑誌　査読論文数：1

国際会議録　査読論文数：0

国内会議録　査読論文数：10

種別：大会・シンポジウム等 

種別：査読等 

外国語雑誌　査読論文数：15

日本語雑誌　査読論文数：1

国際会議録　査読論文数：0

国内会議録　査読論文数：10

種別：大会・シンポジウム等 

種別：大会・シンポジウム等 

種別：大会・シンポジウム等