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Ichikawa S, Sofue K, Nakamura Y, Higaki T, Morisaka H, Hyodo T, Murakami T, Awai K, Jinzaki M, Goshima S. Single-Energy, Dual-Energy, and Photon-Counting Computed Tomography of the Liver: Current Development and Clinical Utility for the Assessment of Focal Liver Lesions. Invest Radiol 2025:00004424-990000000-00320. [PMID: 40203290 DOI: 10.1097/rli.0000000000001187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2025]
Abstract
ABSTRACT Advancements in computed tomography (CT) technology, particularly the emergence of dual-energy CT (DE-CT) and photon-counting detector CT (PCD-CT), can improve detection, characterization, and treatment monitoring of focal liver lesions. DE-CT, through its ability to differentiate tissues with similar densities and produce diverse datasets, has enhanced lesion visibility and diagnostic precision. PCD-CT further advances imaging with superior spatial resolution and material decomposition capabilities, offering potential for complex diagnostic scenarios. This review aimed to highlight the role of CT in hepatic imaging and its application to focal liver lesions.DE-CT improves lesion detectability using low-energy virtual monochromatic images, which enhance iodine contrast and reduce radiation and contrast agent doses. It also facilitates treatment response evaluation after locoregional therapies for hepatocellular carcinoma by quantifying biomarkers, such as the extracellular volume fraction. This review underscores the transformative impact of DE-CT and PCD-CT on liver imaging, emphasizing their complementary roles alongside magnetic resonance imaging. These innovations have paved the way for more precise diagnostics, improved treatment planning, and enhanced patient outcomes in the management of liver diseases.
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Affiliation(s)
- Shintaro Ichikawa
- Department of Radiology, Hamamatsu University School of Medicine, Shizuoka, Japan (S.I., S.G.) Department of Radiology, Kobe University Graduate School of Medicine, Hyogo, Japan (K.S., T.M.) Department of Diagnostic Radiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan (Y.N., T.H., K.A.) Graduate School of Advanced Science and Engineering, Hiroshima University, Hiroshima, Japan (T.H.) Department of Radiology, University of Yamanashi, Yamanashi, Japan (H.M.) Department of Radiology, Kindai University Faculty of Medicine, Osaka, Japan (T.H.) Department of Radiology, Keio University School of Medicine, Tokyo, Japan (M.J.)
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Dar G, Goldberg SN, Levy S, Nevo A, Daud M, Sosna J, Lev-Cohain N. Optimal CT windowing on low-monoenergetic images using a simplex algorithm-based approach for abdominal inflammatory processes. Eur J Radiol 2024; 170:111262. [PMID: 38141262 DOI: 10.1016/j.ejrad.2023.111262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/04/2023] [Accepted: 12/09/2023] [Indexed: 12/25/2023]
Abstract
BACKGROUND OBJECTIVES: To determine optimal window settings for conspicuity of abdominal inflammatory processes on 50 keV low-monoenergetic images derived from dual-energy spectral CT (DECT). METHODS A retrospective study of 30 patients with clinically proven pancreatitis (15/30) or pyelonephritis (15/30) with inflammatory lesions visible on DECT scans were selected to serve as reference populations. 50 keV low-monoenergetic images in the portal venous phase were iteratively evaluated by 6 abdominal radiologists in twenty-one different windows (7-350HU center; 120-580HU width), selected using a simplex optimization algorithm. Each reader graded the conspicuity of the parenchymal hypodense lesions and image background quality. Three-dimensional contour maps expressing the relationship between overall reader grade and window center and width were constructed and used to find the ideal window for inflammatory pancreatic and renal processes and the image background quality. Finally, 15 appendicitis cases were reviewed on optimal pancreas and kidney windows and the manufacturer recommended conventional abdominal window settings for conventional imaging. RESULTS Convergence to optimal windowing was achieved based upon a total of 3,780 reads (21 window settings × 6 readers × 15 cases for pancreas and kidney). Highest conspicuity grade (>4.5 ± 0.0) for pancreas inflammatory lesions was seen at 116HU/430HU, whereas hypodense pyelonephritis had highest conspicuity at 290HU/570HU. This rendered an ideal "compromise" window (>4 ± 0.2) of 150HU/450HU which differed substantially from conventional manufacturer recommended settings of 50HU/380HU (2.1 ± 1.0, p = 0.00001). Appendix mucosal enhancement was best visualized at manufacturer settings. CONCLUSIONS Optimal visualization of inflammatory processes in abdominal organs on 50 keV low-monoenergetic images may require tailored refinement of window settings.
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Affiliation(s)
- Gili Dar
- Department of Radiology, Hadassah Medical Organization and Faculty of Medicine, Hebrew University of Jerusalem, 19000 Ein Karem, Jerusalem, Israel
| | - S Nahum Goldberg
- Department of Radiology, Hadassah Medical Organization and Faculty of Medicine, Hebrew University of Jerusalem, 19000 Ein Karem, Jerusalem, Israel
| | - Shiran Levy
- Department of Radiology, Hadassah Medical Organization and Faculty of Medicine, Hebrew University of Jerusalem, 19000 Ein Karem, Jerusalem, Israel
| | - Adam Nevo
- Department of Radiology, Hadassah Medical Organization and Faculty of Medicine, Hebrew University of Jerusalem, 19000 Ein Karem, Jerusalem, Israel
| | - Marron Daud
- Department of Radiology, Hadassah Medical Organization and Faculty of Medicine, Hebrew University of Jerusalem, 19000 Ein Karem, Jerusalem, Israel
| | - Jacob Sosna
- Department of Radiology, Hadassah Medical Organization and Faculty of Medicine, Hebrew University of Jerusalem, 19000 Ein Karem, Jerusalem, Israel
| | - Naama Lev-Cohain
- Department of Radiology, Hadassah Medical Organization and Faculty of Medicine, Hebrew University of Jerusalem, 19000 Ein Karem, Jerusalem, Israel.
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Arao S, Masuda T, Oku T, Ono A, Okura Y. Utility of lower tube voltage scans in reducing exposure of healthcare workers within computed tomography room to scattered radiation. RADIATION PROTECTION DOSIMETRY 2023; 199:2338-2343. [PMID: 37646071 DOI: 10.1093/rpd/ncad240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 07/25/2023] [Accepted: 08/11/2023] [Indexed: 09/01/2023]
Abstract
The aim of this study was to estimate the effect of tube voltage on the scattered dose in a computed tomography (CT) room. To this end, we conducted experiments using anthropomorphic phantoms and a CT scanner at different tube voltages during CT. The scattered dose was measured using an electronic pocket dosemeter at 50-cm intervals from the centre of the gantry. The structure of the CT room was measured at 57 points (28 points in the front of the gantry (on the bed side), 6 points on the side of the gantry and 23 points behind the gantry) to be up to 200 cm. We compared the scattered dose distributions between 80 and 120 kVp at heights of 50, 100 and 150 cm above the floor surface. The scattered dose was reduced by ~30% when the tube voltage was reduced from 120 to 80 kVp.
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Affiliation(s)
- Shinichi Arao
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288 Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Takanori Masuda
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288 Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Takayuki Oku
- Department of Diagnostic Radiology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima, Hiroshima 730-8655, Japan
| | - Atsushi Ono
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288 Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Yasuhiko Okura
- Department of Clinical Radiology, Faculty of Health Sciences, Hiroshima International University, 555-36 Kurosegakuendai, Higashihiroshima, Hiroshima 739-2695, Japan
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Yuasa Y, Shiinoki T, Fujimoto K, Tanaka H. Pseudo dual-energy CT-derived iodine mapping using single-energy CT data based on a convolution neural network. BJR Open 2023; 5:20220059. [PMID: 37942496 PMCID: PMC10630979 DOI: 10.1259/bjro.20220059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 06/12/2023] [Accepted: 08/02/2023] [Indexed: 11/10/2023] Open
Abstract
Objective The objectives of this study are: (1) to develop a convolutional neural network model that yields pseudo high-energy CT (CTpseudo_high) from simple image processed low-energy CT (CTlow) images, and (2) to create a pseudo iodine map (IMpseudo) and pseudo virtual non-contrast (VNCpseudo) images for thoracic and abdominal regions. Methods Eighty patients who underwent dual-energy CT (DECT) examinations were enrolled. The data obtained from 55, 5, and 20 patients were used for training, validation, and testing, respectively. The ResUnet model was used for image generation model and was trained using CTlow and high-energy CT (CThigh) images. The proposed model performance was evaluated by calculating the CT values, image noise, mean absolute errors (MAEs), and histogram intersections (HIs). Results The mean difference in the CT values between CTpseudo_high and CThigh images were less than 6 Hounsfield unit (HU) for all evaluating patients. The image noise of CTpseudo_high was significantly lower than that of CThigh. The mean MAEs was less than 15 HU, and HIs were almost 1.000 for all the patients. The evaluation metrics of IM and VNC exhibited the same tendency as that of the comparison between CTpseudo_high and CThigh images. Conclusions Our results indicated that the proposed model enables to obtain the DECT images and material-specific images from only single-energy CT images. Advances in knowledges We constructed the CNN-based model which can generate pseudo DECT image and DECT-derived material-specific image using only simple image-processed CTlow images for the thoracic and abdominal regions.
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Affiliation(s)
- Yuki Yuasa
- Department of Radiation Oncology, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan
| | - Takehiro Shiinoki
- Department of Radiation Oncology, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan
| | - Koya Fujimoto
- Department of Radiation Oncology, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan
| | - Hidekazu Tanaka
- Department of Radiation Oncology, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan
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Miyoshi K, Tanabe M, Ihara K, Tanabe M, Higashi M, Narikiyo K, Kawano Y, Inoue A, Ito K. Dual-Source Contrast-Enhanced Multiphasic CT of the Liver Using Low Voltage (70 kVp): Feasibility of a Reduced Radiation Dose and a 50% of Contrast Dose. Tomography 2023; 9:1568-1576. [PMID: 37736978 PMCID: PMC10514808 DOI: 10.3390/tomography9050125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/05/2023] [Accepted: 08/17/2023] [Indexed: 09/23/2023] Open
Abstract
This study investigated the feasibility of both a reduced radiation dose and a 50% of contrast dose in multiphasic CT of the liver with a 70 kVp protocol compared with a standard-tube-voltage protocol derived from dual-energy (DE) CT (blended DE protocol) with a full-dose contrast-agents in the same patient group. This study included 46 patients who underwent multiphasic contrast-enhanced dynamic CT of the liver with both a 70 kVp and a blended DE protocols. For quantitative analysis, median CT values for the liver, aorta, and portal vein, as well as signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), were measured and calculated. In addition, as a qualitative analysis, the contrast effect and overall image quality of the abdominal organs were evaluated on a five-point scale. CNR and SNR of the hepatic parenchyma were not significantly different between the 70kV protocol and the Blended DE protocol in all phases. The 70 kVp protocol showed significantly better image quality compared with the blended DE protocol in the arterial phase (p = 0.035) and the equilibrium layer phase (p = 0.016). A 70 kVp CT protocol in combination with a reduced radiation dose and half-dose iodine load is feasible for multiphasic dynamic CT of the liver by maintaining the contrast enhancement effects and image quality in comparison with the blended DE CT protocol.
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Affiliation(s)
- Keisuke Miyoshi
- Department of Radiology, Yamaguchi University Graduate School of Medicine, Ube 755-8505, Japan
| | - Masahiro Tanabe
- Department of Radiology, Yamaguchi University Graduate School of Medicine, Ube 755-8505, Japan
| | - Kenichiro Ihara
- Department of Radiology, Yamaguchi University Graduate School of Medicine, Ube 755-8505, Japan
| | - Masaya Tanabe
- Department of Radiology, Yamaguchi University Graduate School of Medicine, Ube 755-8505, Japan
| | - Mayumi Higashi
- Department of Radiology, Yamaguchi University Graduate School of Medicine, Ube 755-8505, Japan
| | - Koji Narikiyo
- Department of Radiology, Yamaguchi University Graduate School of Medicine, Ube 755-8505, Japan
| | - Yosuke Kawano
- Department of Radiology, Yamaguchi University Graduate School of Medicine, Ube 755-8505, Japan
| | - Atsuo Inoue
- Department of Radiology, Yamaguchi University Graduate School of Medicine, Ube 755-8505, Japan
| | - Katsuyoshi Ito
- Department of Radiology, Yamaguchi University Graduate School of Medicine, Ube 755-8505, Japan
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Chun M, Choi JH, Kim S, Ahn C, Kim JH. Fully automated image quality evaluation on patient CT: Multi-vendor and multi-reconstruction study. PLoS One 2022; 17:e0271724. [PMID: 35857804 PMCID: PMC9299323 DOI: 10.1371/journal.pone.0271724] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 07/06/2022] [Indexed: 12/21/2022] Open
Abstract
While the recent advancements of computed tomography (CT) technology have contributed in reducing radiation dose and image noise, an objective evaluation of image quality in patient scans has not yet been established. In this study, we present a patient-specific CT image quality evaluation method that includes fully automated measurements of noise level, structure sharpness, and alteration of structure. This study used the CT images of 120 patients from four different CT scanners reconstructed with three types of algorithm: filtered back projection (FBP), vendor-specific iterative reconstruction (IR), and a vendor-agnostic deep learning model (DLM, ClariCT.AI, ClariPi Inc.). The structure coherence feature (SCF) was used to divide an image into the homogeneous (RH) and structure edge (RS) regions, which in turn were used to localize the regions of interests (ROIs) for subsequent analysis of image quality indices. The noise level was calculated by averaging the standard deviations from five randomly selected ROIs on RH, and the mean SCFs on RS was used to estimate the structure sharpness. The structure alteration was defined by the standard deviation ratio between RS and RH on the subtraction image between FBP and IR or DLM, in which lower structure alterations indicate successful noise reduction without degradation of structure details. The estimated structure sharpness showed a high correlation of 0.793 with manually measured edge slopes. Compared to FBP, IR and DLM showed 34.38% and 51.30% noise reduction, 2.87% and 0.59% lower structure sharpness, and 2.20% and -12.03% structure alteration, respectively, on an average. DLM showed statistically superior performance to IR in all three image quality metrics. This study is expected to contribute to enhance the CT protocol optimization process by allowing a high throughput and quantitative image quality evaluation during the introduction or adjustment of lower-dose CT protocol into routine practice.
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Affiliation(s)
- Minsoo Chun
- Department of Radiation Oncology, Chung-Ang University Gwang Myeong Hospital, Gyeonggi-do, Republic of Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Jin Hwa Choi
- Department of Radiation Oncology, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - Sihwan Kim
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea
| | - Chulkyun Ahn
- Department of Transdisciplinary Studies, Program in Biomedical Radiation Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea
- ClariPi Research, Seoul, Republic of Korea
| | - Jong Hyo Kim
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea
- Department of Transdisciplinary Studies, Program in Biomedical Radiation Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea
- ClariPi Research, Seoul, Republic of Korea
- Department of Radiology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea
- Center for Medical-IT Convergence Technology Research, Advanced Institutes of Convergence Technology, Suwon, Republic of Korea
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Ichikawa S, Motosugi U, Shimizu T, Kromrey ML, Aikawa Y, Tamada D, Onishi H. Diagnostic performance and image quality of low-tube voltage and low-contrast medium dose protocol with hybrid iterative reconstruction for hepatic dynamic CT. Br J Radiol 2021; 94:20210601. [PMID: 34586900 DOI: 10.1259/bjr.20210601] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE To evaluate the diagnostic performance and image quality of the low-tube voltage and low-contrast medium dose protocol for hepatic dynamic CT. METHODS This retrospective study was conducted between January and May 2018. All patients underwent hepatic dynamic CT using one of the two protocols: tube voltage, 80 kVp and contrast dose, 370 mgI/kg with hybrid iterative reconstruction or tube voltage, 120 kVp and contrast dose, 600 mgI/kg with filtered back projection. Two radiologists independently scored lesion conspicuity and image quality. Another radiologist measured the CT numbers of abdominal organs, muscles, and hepatocellular carcinoma (HCC) in each phase. Lesion detectability, HCC diagnostic ability, and image quality of the arterial phase were compared between the two protocols using the non-inferiority test. CT numbers and HCC-to-liver contrast were compared between the protocols using the Mann-Whitney U test. RESULTS 424 patients (70.5 ± 10.1 years) were evaluated. The 80-kVp protocol showed non-inferiority in lesion detectability and diagnostic ability for HCC (sensitivity, 85.7-89.3%; specificity, 96.3-98.6%) compared with the 120-kVp protocol (sensitivity, 91.0-93.3%; specificity, 93.6-97.3%) (p < 0.001-0.038). The ratio of fair image quality in the 80-kVp protocol also showed non-inferiority compared with that in the 120-kVp protocol in assessments by both readers (p < 0.001). HCC-to-liver contrast showed no significant differences for all phases (p = 0.309-0.705) between the two protocols. CONCLUSION The 80-kVp protocol with hybrid iterative reconstruction for hepatic dynamic CT can decrease iodine doses while maintaining diagnostic performance and image quality compared with the 120-kVp protocol. ADVANCES IN KNOWLEDGE The 80- and 120-kVp protocols showed equivalent hepatic lesion detectability, diagnostic ability for HCC, image quality, and HCC-to-liver contrast.The 80-kVp protocol showed a 38.3% reduction in iodine dose compared with the 120-kVp protocol.
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Affiliation(s)
- Shintaro Ichikawa
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan
| | - Utaroh Motosugi
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan.,Department of Diagnostic Radiology, Kofu Kyoritsu Hospital, 1-9-1 Takara, Kofu, Yamanashi, Japan
| | - Tatsuya Shimizu
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan
| | - Marie Luise Kromrey
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan.,Department of Diagnostic Radiology and Neuroradiology, University Medicine Greifswald, Domstraße 11, Greifswald, Germany
| | - Yoshihito Aikawa
- Division of Radiology, University of Yamanashi Hospital, 1110 Shimokato, Chuo, Yamanashi, Japan
| | - Daiki Tamada
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan
| | - Hiroshi Onishi
- Department of Radiology, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, Japan
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Jiang J, Zhang M, Ji Y, Li C, Fang X, Zhang S, Wang W, Wang L, Liu A. An Individualized Contrast-Enhanced Liver Computed Tomography Imaging Protocol Based on Body Mass Index in 126 Patients Seen for Liver Cirrhosis. Med Sci Monit 2021; 27:e932109. [PMID: 34162827 PMCID: PMC8240488 DOI: 10.12659/msm.932109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Background Computed tomography (CT) imaging using iodinated contrast medium is associated with the radiation dose to the patient, which may require reduction in individual circumstances. This study aimed to evaluate an individualized liver CT protocol based on body mass index (BMI) in 126 patients investigated for liver cirrhosis. Material/Methods From November 2017 to December 2020, in this prospective study, 126 patients with known or suspected liver cirrhosis were recruited. Patients underwent liver CT using individualized protocols based on BMI, as follows. BMI ≤24.0 kg/m2: 80 kV, 352 mg I/kg; BMI 24.1–28.0 kg/m2: 100 kV, 440 mg I/kg; BMI ≥28.1 kg/m2: 120 kV, 550 mg I/kg. Figure of merit (FOM) and size-specific dose estimates (SSDEs) were calculated and compared using the Mann-Whitney U test. Subjective image quality and timing adequacy of the late arterial phase were evaluated with Likert scales. Results The SSDE was significantly lower in the 80 kV protocol, corresponding to a dose reduction of 36% and 50% compared with the others (all P<0.001). In the comparison of 80-, 100-, and 120-kV protocols, no statistically significant differences were found in FOMs (P=0.108~0.620). Of all the examinations, 95.2% (120 of 126) were considered as appropriate timing for the late arterial phase. In addition, overall image quality, hepatocellular carcinoma conspicuity, and detection rate did not differ significantly among the 3 protocols (P=0.383~0.737). Conclusions This study demonstrated the feasibility of using an individualized liver CT protocol based on BMI, and showed that patients with lower BMI should receive lower doses of iodinated contrast medium and significantly reduced radiation dose.
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Affiliation(s)
- Jian Jiang
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China (mainland)
| | - Maowei Zhang
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China (mainland)
| | - Yuan Ji
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China (mainland)
| | - Chunfeng Li
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China (mainland)
| | - Xin Fang
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China (mainland)
| | - Shuyuan Zhang
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China (mainland)
| | - Wei Wang
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, China (mainland)
| | - Lijun Wang
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China (mainland)
| | - Ailian Liu
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China (mainland)
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Hosogoshi S, Tada K, Iijima J, Kajitani T, Yoshida R, Kitagaki H. Double Dose Reduction in the Equilibrium Phase of Chest-Pelvic CT With Low Tube Voltage and Forward-Projected Model-Based Iterative Reconstruction Solution. Cureus 2020; 12:e10545. [PMID: 33101793 PMCID: PMC7575314 DOI: 10.7759/cureus.10545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Objectives This study aimed to examine whether a new imaging method (80-kV forward-projected model-based iterative reconstruction solution [FIRST] protocol) that uses a combination of low tube voltage and FIRST can reduce radiation dose and contrast medium volume by comparing the quality of the resulting image with that of the image obtained by 120-kV adaptive iterative dose reduction 3D protocol in the equilibrium phase of chest-pelvic computed tomography (CT). Subjects and methods Twenty-seven patients underwent CT by both protocols on different days. Two radiologists subjectively assessed image quality by scoring axial images for sharpness, contrast enhancement, noise, artifacts, and overall quality. The mean CT values, standard deviations, contrast-to-noise ratios, and signal-to-noise ratios in the liver, aorta, and erector spinae muscles were used for objective assessment. Radiation dose parameters included the CT dose index volume, dose-length product, effective dose, and size-specific dose estimate. Results were compared for different body mass index categories. Results The 80-kV FIRST protocol helped achieve mean reductions of 36.3%, 35.7%, and 36.6% in CT dose index volume, effective dose, and size-specific dose estimate, respectively (p < 0.01). Therefore, this protocol was regarded as comparable to the conventional protocol in image quality, except for visual sharpness. Conclusions The 80-kV FIRST protocol is capable of reducing radiation dose and contrast medium volume compared to the adaptive iterative dose reduction 3D protocol in the equilibrium phase of chest-pelvic CT.
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Tanaka H, Igami T, Shimoyama Y, Ebata T, Yokoyama Y, Mori K, Nagino M. New method for the assessment of perineural invasion from perihilar cholangiocarcinoma. Surg Today 2020; 51:136-143. [PMID: 32623582 DOI: 10.1007/s00595-020-02071-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 06/19/2020] [Indexed: 01/01/2023]
Abstract
PURPOSE Perineural invasion (PN) is often found in perihilar cholangiocarcinoma. New procedure was developed to assess PN around the right hepatic artery (RHA) using dual-energy computed tomography (DECT). METHODS Thirty patients with perihilar cholangiocarcinoma who underwent DECT before biliary drainage were retrospectively reviewed. Mask images, i.e., the periarterial layer (PAL) around the RHA and superior mesenteric artery (SMA), were made from late arterial phase DECT. The mean CT number of the PAL was measured. RESULTS Twenty patients with PN around the RHA were classified into the PN (+) group. The remaining 10 patients without PN and other 26 patients with other diseases that are never accompanied with PN were classified into the PN (-) group. The PAL ratio (the CT number of the PAL around the RHA relative to that around the SMA) was calculated. Both the mean CT number of the PAL around the RHA and the PAL ratio were significantly higher in the PN (+) group than in the PN (-) group. According to an ROC analysis, the predictive ability of the PAL ratio was superior. Using the cutoff value of the PAL ratio 1.009, a diagnosis of PN around the RHA was made with approximately 75% accuracy. CONCLUSIONS Assessment with CT number of the PAL reconstructed from DECT images is an easy and objective method to diagnose PN.
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Affiliation(s)
- Hiroshi Tanaka
- Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Tsuyoshi Igami
- Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
| | - Yoshie Shimoyama
- Department of Pathology and Clinical Laboratories, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tomoki Ebata
- Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Yukihiro Yokoyama
- Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Kensaku Mori
- Graduate School of Informatics, Nagoya University, Nagoya, Japan.,Information Strategy Office, Information and Communications, Nagoya University, Nagoya, Japan
| | - Masato Nagino
- Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
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Tamura A, Nakayama M, Ota Y, Kamata M, Hirota Y, Sone M, Hamano M, Tanaka R, Yoshioka K. Feasibility of thin-slice abdominal CT in overweight patients using a vendor neutral image-based denoising algorithm: Assessment of image noise, contrast, and quality. PLoS One 2019; 14:e0226521. [PMID: 31846490 PMCID: PMC6917298 DOI: 10.1371/journal.pone.0226521] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 11/26/2019] [Indexed: 11/19/2022] Open
Abstract
The purpose of this study was to investigate whether the novel image-based noise reduction software (NRS) improves image quality, and to assess the feasibility of using this software in combination with hybrid iterative reconstruction (IR) in image quality on thin-slice abdominal CT. In this retrospective study, 54 patients who underwent dynamic liver CT between April and July 2017 and had a body mass index higher than 25 kg/m2 were included. Three image sets of each patient were reconstructed as follows: hybrid IR images with 1-mm slice thickness (group A), hybrid IR images with 5-mm slice thickness (group B), and hybrid IR images with 1-mm slice thickness denoised using NRS (group C). The mean image noise and contrast-to-noise ratio relative to the muscle of the aorta and liver were assessed. Subjective image quality was evaluated by two radiologists for sharpness, noise, contrast, and overall quality using 5-point scales. The mean image noise was significantly lower in group C than in group A (p < 0.01), but no significant difference was observed between groups B and C. The contrast-to-noise ratio was significantly higher in group C than in group A (p < 0.01 and p = 0.01, respectively). Subjective image quality was also significantly higher in group C than in group A (p < 0.01), in terms of noise and overall quality, but not in terms of sharpness and contrast (p = 0.65 and 0.07, respectively). The contrast of images in group C was greater than that in group A, but this difference was not significant. Compared with hybrid IR alone, the novel NRS combined with a hybrid IR could result in significant noise reduction without sacrificing image quality on CT. This combined approach will likely be particularly useful for thin-slice abdominal CT examinations of overweight patients.
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Affiliation(s)
- Akio Tamura
- Department of Radiology, Iwate Medical University School of Medicine, Morioka, Japan
- * E-mail:
| | - Manabu Nakayama
- Department of Radiology, Iwate Medical University School of Medicine, Morioka, Japan
| | - Yoshitaka Ota
- Division of Central Radiology, Iwate Medical University Hospital, Morioka, Japan
| | - Masayoshi Kamata
- Division of Central Radiology, Iwate Medical University Hospital, Morioka, Japan
| | - Yasuyuki Hirota
- Division of Central Radiology, Iwate Medical University Hospital, Morioka, Japan
| | - Misato Sone
- Department of Radiology, Iwate Medical University School of Medicine, Morioka, Japan
| | - Makoto Hamano
- Department of Radiology, Iwate Medical University School of Medicine, Morioka, Japan
| | - Ryoichi Tanaka
- Division of Dental Radiology, Department of General Dentistry, Iwate Medical University School of Dentistry, Morioka, Japan
| | - Kunihiro Yoshioka
- Department of Radiology, Iwate Medical University School of Medicine, Morioka, Japan
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Masuda T, Nakaura T, Funama Y, Sato T, Higaki T, Matsumoto Y, Yamashita Y, Imada N, Kiguchi M, Baba Y, Yamashita Y, Awai K. Contrast enhancement on 100- and 120 kVp hepatic CT scans at thin adults in a retrospective cohort study: Bayesian inference of the optimal enhancement probability. Medicine (Baltimore) 2019; 98:e17902. [PMID: 31764788 PMCID: PMC6882564 DOI: 10.1097/md.0000000000017902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To assess the probability of achieving optimal contrast enhancement in 100 kVp and 120 kVp-protocol on hepatic computed tomography (CT) scans. MATERIALS AND METHODS We enrolled 200 patients in a retrospective cohort study. Hundred patients were scanned with 120 kVp setting, and other 100 patients were scanned with 100 kVp setting. We measured the CT number in the abdominal aorta and hepatic parenchyma on unenhanced scans and hepatic arterial phase (HAP)-, and portal venous phase (PVP). The aortic enhancement at HAP and the hepatic parenchymal enhancement at PVP were compared between the two scanning protocols. Bayesian inference was used to assess the probability of achieving optimal contrast enhancement in each protocol. RESULTS The Bayesian analysis indicated that when 100 kVp-rotocol was used, the probability of achieving optimal aortic enhancement (>280 HU) was 98.8% ± 0.6%, whereas it was 88.7% ± 2.5% when 120 kVp-protocol was used. Also, the probability of achieving optimal hepatic parenchymal enhancement (>50 HU) was 95.3% ± 1.5%, whereas it was 64.7% ± 3.8% when 120 kVp-protocol was used. CONCLUSION Bayesian inference suggested that the post-test probability of optimal contrast enhancement at hepatic dynamic CT was lower under the 120 kVp than the 100 kVp-protocol.
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Affiliation(s)
- Takanori Masuda
- Department of Radiological Technology, Tsuchiya General Hospital, 3-30 Nakajima-cho, Naka-ku, Hiroshima
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Takeshi Nakaura
- Department of Diagnostic Radiology, Graduate School of Medical Sciences
| | - Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto
| | - Tomoyasu Sato
- Department of Diagnostic Radiology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku
| | - Toru Higaki
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Yoriaki Matsumoto
- Department of Radiological Technology, Tsuchiya General Hospital, 3-30 Nakajima-cho, Naka-ku, Hiroshima
| | - Yukari Yamashita
- Department of Radiological Technology, Tsuchiya General Hospital, 3-30 Nakajima-cho, Naka-ku, Hiroshima
| | - Naoyuki Imada
- Department of Radiological Technology, Tsuchiya General Hospital, 3-30 Nakajima-cho, Naka-ku, Hiroshima
| | - Masao Kiguchi
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Yasutaka Baba
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | | | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
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Watanabe R, Funama Y, Takaki T, Oda S, Nakaura T, Murakami S, Aoki T. Additive value of split-bolus single-phase CT scan protocol for preoperative assessment of lung cancer patients referred for video-assisted thoracic surgery. Radiol Phys Technol 2019; 12:409-416. [PMID: 31654374 DOI: 10.1007/s12194-019-00541-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 10/16/2019] [Accepted: 10/17/2019] [Indexed: 10/25/2022]
Abstract
We aimed to assess the additive value of the split-bolus single-phase computed tomography (CT) scan protocol to preoperatively assess patients with lung cancer, who were referred for video-assisted thoracic surgery, when compared to a standard staging CT protocol. We included 160 patients with lung cancer who underwent a split-bolus single-phase CT scan protocol (split-bolus protocol), which can acquire whole-body staging CT and pulmonary artery-vein separation CT angiography (PA-PV CTA) in a single acquisition and 160 patients who underwent whole-body staging CT (standard protocol). We compared the quality of the staging CT images of hepatic parenchyma, portal vein, and hepatic vein between both protocols. We also investigated image quality on PA-PV CTA images in the split-bolus protocol and recorded the number of patients that underwent the 3D PA-PV CTA imaging process. The split-bolus protocol for staging CT images demonstrated a slightly higher enhancement with regard to the hepatic parenchyma (p = 0.007) and hepatic vein (p = 0.006) than the standard protocol. There was no significant difference in the quality of the staging CT images between both protocols (p = 0.067). The mean CT number for the main pulmonary artery and the left atrium for the PA-PV CTA images in the split-bolus protocol were 289.1 HU and 172.8 HU, respectively. Among the images associated with the split-bolus protocol, 98.1% were of appropriate quality for 3D PA-PV CTA imaging. The split-bolus protocol is a dose-efficient protocol to acquire the staging CT and PA-PV CTA images in a single session and provides sufficient image quality for preoperative assessment in patients with lung cancer.
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Affiliation(s)
- Ryo Watanabe
- Graduate School of Health Sciences, Kumamoto University, 1-1-1, Honjo, Chuo-ku, Kumamoto, 860-8556, Japan.,Department of Radiology, Hospital of the University of Occupational and Environmental Health, Iseigaoka 1-1, Yahatanishi-ku, Kitakyushu-shi, Fukuoka, 807-8555, Japan
| | - Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, 1-1-1, Honjo, Chuo-ku, Kumamoto, 860-8556, Japan.
| | - Takeshi Takaki
- Department of Radiology, Hospital of the University of Occupational and Environmental Health, Iseigaoka 1-1, Yahatanishi-ku, Kitakyushu-shi, Fukuoka, 807-8555, Japan
| | - Seitaro Oda
- Department of Radiology, Kumamoto University Hospital, 1-1-1, Honjo, Chuo-ku, Kumamoto, 860-8556, Japan
| | - Takeshi Nakaura
- Department of Radiology, Kumamoto University Hospital, 1-1-1, Honjo, Chuo-ku, Kumamoto, 860-8556, Japan
| | - Seiichi Murakami
- Department of Radiology, Hospital of the University of Occupational and Environmental Health, Iseigaoka 1-1, Yahatanishi-ku, Kitakyushu-shi, Fukuoka, 807-8555, Japan
| | - Takatoshi Aoki
- Department of Radiology, University of Occupational and Environmental Health School of Medicine, Iseigaoka 1-1, Yahatanishi-ku, Kitakyushu-shi, Fukuoka, 807-8555, Japan
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Nakamoto A, Yamamoto K, Sakane M, Nakai G, Higashiyama A, Juri H, Yoshikawa S, Narumi Y. Reduction of the radiation dose and the amount of contrast material in hepatic dynamic CT using low tube voltage and adaptive iterative dose reduction 3-dimensional. Medicine (Baltimore) 2018; 97:e11857. [PMID: 30142778 PMCID: PMC6113013 DOI: 10.1097/md.0000000000011857] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The purpose of this study was to prospectively evaluate the image quality and the diagnostic ability of low tube voltage and reduced contrast material dose hepatic dynamic computed tomography (CT) reconstructed with adaptive iterative dose reduction 3-dimensional (AIDR 3D).Eighty-nine patients underwent hepatic dynamic CT using one of the 2 protocols: tube voltage of 120 kVp, contrast dose of 600 mgI/kg, and filtered back projection in Protocol A (n = 46), and tube voltage of 100 kVp, contrast dose of 500 mgI/kg, and AIDR 3D in Protocol B (n = 43). The volume CT dose index (CTDIvol) and size-specific dose estimates (SSDEs) were compared between the 2 groups. Objective image noise and tumor to liver contrast-to-noise ratio (CNR) were also compared. Three radiologists independently reviewed image quality. The jackknife alternative free-response receiver-operating characteristic (JAFROC) analysis was performed to compare diagnostic performance.The mean CTDIvol and SSDE of Protocol B (14.3 and 20.2, respectively) were significantly lower than those of Protocol A (22.1 and 31.4, P < .001). There were no significant differences in either objective image noise or CNR. In the qualitative analysis, 2 readers assigned significant lower scores to images of Protocol B for at least one of the 3 phases regarding overall image quality (P < .05). There was no significant difference in the JAFROC1 figure of merit between protocols.Low tube voltage CT with AIDR 3D yielded a reduction in radiation dose and in the amount of contrast material while maintaining diagnostic performance.
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Affiliation(s)
- Atsushi Nakamoto
- Department of Radiology, Osaka Medical College, Takatsuki
- Department of Radiology, Osaka University Graduate School of Medicine, Suita
| | | | - Makoto Sakane
- Department of Radiology, Osaka Medical College, Takatsuki
| | - Go Nakai
- Department of Radiology, Osaka Medical College, Takatsuki
| | | | - Hiroshi Juri
- Department of Radiology, Osaka Medical College, Takatsuki
| | - Shushi Yoshikawa
- Central Radiology Department, Osaka Medical College Hospital, Takatsuki, Osaka, Japan
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Kawashima H, Ichikawa K, Hanaoka S, Matsubara K, Takata T. Relationship between size-specific dose estimates and image quality in computed tomography depending on patient size. J Appl Clin Med Phys 2018; 19:246-251. [PMID: 29729075 PMCID: PMC6036365 DOI: 10.1002/acm2.12340] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 03/04/2018] [Accepted: 03/27/2018] [Indexed: 11/08/2022] Open
Abstract
This study investigates the relationship between contrast-to-noise ratio (CNR) and size-specific dose estimate (SSDE) in computed tomography (CT) depending on patient size. In addition, the relationship to the auto exposure control (AEC) techniques is examined. A tissue-equivalent material having human-liver energy dependence is developed and used to evaluate these relationships. Three exposure dose levels (constant CT dose index, constant SSDE, and with AEC) are tested using four different phantom sizes (diameter: 15, 20, 25 and 30 cm) in two different CT scanners (SOMATOM Definition Flash, Siemens, and LightSpeed VCT, GE). The contrast-to-noise ratios (CNRs) are measured using the developed phantom. It is found that the CNR increases with decreasing phantom size at constant SSDE, although the increase ratio is smaller than that of the constant CT dose index. This result indicates that the image characteristics differ even when the patient dose received from the CT examination is equivalent for each patient size. In the case of AEC use, the CNR results of the Siemens scanner exhibit a similar trend to those obtained for constant SSDE, for each phantom size. This suggests that the AEC technique that maintains a constant image quality (CARE Dose 4D) for each patient size corresponds well to the image quality obtained for constant SSDE. These findings facilitate further understanding of the relationship between image quality and exposure CT dose depending on patient size.
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Affiliation(s)
- Hiroki Kawashima
- Faculty of Health SciencesInstitute of Medical, Pharmaceutical and Health SciencesKanazawa UniversityKanazawaJapan
| | - Katsuhiro Ichikawa
- Faculty of Health SciencesInstitute of Medical, Pharmaceutical and Health SciencesKanazawa UniversityKanazawaJapan
| | | | - Kosuke Matsubara
- Faculty of Health SciencesInstitute of Medical, Pharmaceutical and Health SciencesKanazawa UniversityKanazawaJapan
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16
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Shimoyama S, Nishii T, Watanabe Y, Kono AK, Kagawa K, Takahashi S, Sugimura K. Advantages of 70-kV CT Angiography for the Visualization of the Adamkiewicz Artery: Comparison with 120-kV Imaging. AJNR Am J Neuroradiol 2017; 38:2399-2405. [PMID: 28912277 DOI: 10.3174/ajnr.a5372] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Accepted: 07/07/2017] [Indexed: 02/02/2023]
Abstract
BACKGROUND AND PURPOSE Preprocedural identification of the Adamkiewicz artery is crucial in patients with aortic diseases. This study aimed to compare 70-kV CTA with conventional 120-kV CTA for the identification of the Adamkiewicz artery, examining differences in radiation dose and image quality. MATERIALS AND METHODS We retrospectively analyzed 2 equal groups of 60 patients who had undergone 70-kV or 120-kV CTA to detect the Adamkiewicz artery before aortic repair. Size-specific dose estimate, the CT number of the aorta, and the contrast-to-noise ratio of the anterior spinal artery to the spinal cord were recorded. Furthermore, detectability of the Adamkiewicz artery was evaluated by using a 4-point continuity score (3, definite to 0, undetectable). RESULTS There was significantly lower radiation exposure with 70-kV CTA than 120-kV CTA (median size-specific dose estimate, 23.1 versus 61.3 mGy, respectively; P < .001). CT number and contrast-to-noise ratio were both significantly higher in the 70-kV CTA group than the 120-kV group (999.1 HU compared with 508.7 HU, and 5.6 compared with 3.4, respectively; P < .001 for both). Detectability of the Adamkiewicz artery was not impaired in the 70-kV CTA group (90.0% versus 83.3% in the 120-kV group, P = .28). Moreover, the Adamkiewicz artery was detected with greater confidence with 70-kV CTA, reflected by a significantly superior continuity score (median, 3) compared with 120-kV CTA (median, 2; P = .001). CONCLUSIONS Seventy-kilovolt CTA has substantial advantages for the identification of the Adamkiewicz artery before aortic repair, with a significantly lower radiation exposure and superior image quality than 120-kV CTA.
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Affiliation(s)
- S Shimoyama
- From the Department of Radiology (S.S., T.N., Y.W., A.K.K., S.T., K.S.), Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - T Nishii
- From the Department of Radiology (S.S., T.N., Y.W., A.K.K., S.T., K.S.), Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Y Watanabe
- From the Department of Radiology (S.S., T.N., Y.W., A.K.K., S.T., K.S.), Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
- Department of Radiology (Y.W., A.K.K.), National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
| | - A K Kono
- From the Department of Radiology (S.S., T.N., Y.W., A.K.K., S.T., K.S.), Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
- Department of Radiology (Y.W., A.K.K.), National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
| | - K Kagawa
- Division of Radiology (K.K.), Center for Radiology and Radiation Oncology, Kobe University Hospital, Kobe, Hyogo, Japan
| | - S Takahashi
- From the Department of Radiology (S.S., T.N., Y.W., A.K.K., S.T., K.S.), Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - K Sugimura
- From the Department of Radiology (S.S., T.N., Y.W., A.K.K., S.T., K.S.), Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
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Computed Tomographic Angiography of the Abdomen and Pelvis in Azotemic Patients Utilizing 80-kV(p) Technique and Reduced Dose Iodinated Contrast. J Comput Assist Tomogr 2017; 41:141-147. [DOI: 10.1097/rct.0000000000000478] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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18
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Low-Tube Voltage Computed Tomography During Hepatic Arterial Phase: The Effect of Body Habitus on Image Quality. J Comput Assist Tomogr 2016; 41:401-406. [PMID: 27879528 DOI: 10.1097/rct.0000000000000519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE This study aimed to evaluate the impact of body habitus factors on image quality of low-tube voltage computed tomography (CT) during the hepatic arterial phase. MATERIALS AND METHODS Ninety-seven patients (66 men, 31 women; age range, 26-78 years) who underwent clinically indicated liver dynamic CT examination were enrolled in the study. Analysis with 80-kVp CT and intermediate tube current (277-337 mA) was performed in the late hepatic arterial phase using a 320-detector row scanner with adaptive iterative dose reduction 3-dimensional reconstruction. Patient body habitus was measured using body weight (BW), body mass index (BMI), lateral width (LW) of the abdomen, and muscle volume (MV) of the abdominal wall. On hepatic arterial phase, the mean image noise and contrast-to-noise ratio (CNR) for the aorta and liver were assessed. The correlations between body habitus factors and image quality parameters were evaluated. RESULTS In all patients, MV showed the strongest correlation with image noise, followed by BW and LW (r = 0.684, 0.570, and 0.555, respectively). The BMI showed the fourth strongest correlation with image noise among all body habitus factors (r = 0.377). With respect to CNR of the aorta, MV and BW showed the strongest inverse correlation (r = -0.590 and -0.600, respectively), followed by LW and BMI (r = -0.557 and -0.423, respectively). Regarding the CNR of the liver, MV showed the strongest inverse correlation (r = -0.279), although the correlation efficiency was weak compared with other correlations. CONCLUSIONS Among various body habitus factors, MV showed the strongest association with image noise and CNR in the hepatic arterial phase using 80-kVp CT.
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Matsumoto Y, Masuda T, Yamashita Y, Oku T, Uyama H, Sato T, Imada N. Vessel Visibility Assessment of Low Tube Voltage Coronary Computed Tomography Angiography Determined with Contrast-to-Noise Ratio. Nihon Hoshasen Gijutsu Gakkai Zasshi 2016; 72:999-1006. [PMID: 27760911 DOI: 10.6009/jjrt.2016_jsrt_72.10.999] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE The purpose of this study was to investigate the association of vessel visibility and radiation dose using contrast-to-noise ratio (CNR) method with low tube voltage in coronary computed tomography angiography (c-CTA). METHODS We performed electrocardiogram-gated scan of 2.0-mm diameter simulated vessel in the center of the cardiac phantom by the use of a 64-detector CT scanner. Reference CNR was calculated from the target coronary CT number (CTnumberA; 350 Hounsfield units [HU]), epicardial fat CT number (CTnumberB; -100 HU), and target epicardial fat standard deviation (SD) number (SDB; 25 HU) at the 120 kV. We obtained the tube current at low tube voltage (100 and 80 kV) to perform the similar reference CNR at 120 kV. The full widths at half maximum from axial images were evaluated with quantitative evaluation and three types of visualizations of the vessel phantom were evaluated with the qualitative evaluations. RESULTS CTnumberA of 100 and 80 kV were increased by 26% and 50%, respectively, compared with 120 kV (P<0.01). SDB was also increased by a similar ratio (P<0.01). CTDIvol of 100 and 80 kV were decreased by 39% and 51%, respectively, compared with 120 kV (P<0.05). There were no significant voltage differences among three tubes in quantitative and qualitative evaluations at the same CNR (P> 0.05). CONCLUSION In this phantom study, these results show that the CNR method with low tube voltage achieves radiation dose reduction without decreasing the image quality.
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Optimizing CT technique to reduce radiation dose: effect of changes in kVp, iterative reconstruction, and noise index on dose and noise in a human cadaver. Radiol Phys Technol 2016; 10:180-188. [DOI: 10.1007/s12194-016-0382-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 09/21/2016] [Accepted: 09/25/2016] [Indexed: 10/20/2022]
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Aw-Zoretic J, Collins JD. Considerations for Imaging the Inferior Vena Cava (IVC) with/without IVC Filters. Semin Intervent Radiol 2016; 33:109-21. [PMID: 27247480 DOI: 10.1055/s-0036-1583207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Deep venous thrombosis (DVT), thrombosis of the inferior vena cava, and pulmonary embolism (PE) constitute a continuum that includes venous thromboembolic (VTE) disease. VTE is the third most common cardiovascular disorder that affects all races, ethnicities, gender, and ages. VTE predominantly affects the elderly population, exponentially increasing in incidence with increasing age. Venous thromboembolism is not only a singular event but a chronic disease and has been found to have a rate of recurrence approaching 40% among all patients after 10 years. Whether symptomatic or asymptomatic, once thromboembolism is suspected, objective methods are required for the accurate and confirmatory presence of a thrombus with imaging as the next step in the diagnostic algorithm. Imaging also allows for the determination of the extent of clot burden, clot propagation, occlusive versus nonocclusive thrombus, acute versus chronic thrombus, or in some cases thrombus recurrence versus thrombophlebitis. Vena caval filter placement is, in some instances, required to prevent a significant subsequent VTE event. Placement of these therapeutic devices paradoxically promotes thrombus formation, and other sequelae may arise from the placement of inferior vena cava filters. In this article, the authors provide an overview of available techniques for imaging the vena cava with or without a filter and discuss advantages and drawbacks for each.
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Affiliation(s)
- Jessie Aw-Zoretic
- Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Jeremy D Collins
- Northwestern University Feinberg School of Medicine, Chicago, Illinois
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22
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Effect of various environments and computed tomography scanning parameters on renal volume measurements in vitro: A phantom study. Exp Ther Med 2016; 12:753-758. [PMID: 27446271 DOI: 10.3892/etm.2016.3414] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 04/19/2016] [Indexed: 01/21/2023] Open
Abstract
Kidney volume is an important parameter in clinical practice, and accurate assessment of kidney volume is vital. The aim of the present study was to evaluate the effect of various environments, tube voltages, tube currents and slice thicknesses on the accuracy of a novel segmentation software in determining renal volume on computed tomography (CT) images. The volumes of potatoes and porcine kidneys were measured on CT images and compared with the actual volumes, which were determined by a water displacement method. CT scans were performed under various situations, including different environments (air or oil); tube voltages/tube currents (80 kVp/200 mAs, 120 kVp/200 mAs, 120 kVp/100 mAs); and reconstructed slice thicknesses (0.75 or 1.5 mm). Percentage errors (PEs) relative to the reference standards were calculated. In addition, attenuation and image noise under different CT scanning parameters were compared. Student's t-test was also used to analyze the effect of various conditions on image quality and volume measurements. The results indicated that the volumes measured in oil were closer to the actual volumes (P<0.05). Furthermore, attenuation and image noise significantly increased when using a tube voltage of 80 kVp, while the mean PEs between 120 and 80 kVp voltages were not significantly different. The mean PEs were greater when using a tube current of 100 mAs compared with a current of 200 mAs (P<0.05). In addition, the volumes measured on 1.5 mm slice thickness were closer to the actual volumes (P<0.05). In conclusion, different environments, tube currents and slice thicknesses may affect the volume measurements. In the present study, the most accurate volume measurements were obtained at 120 kVp/200 mAs and a slice thickness of 1.5 mm.
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Manual adjustment of tube voltage from 120 to 100 kVp during abdominal CT in patients with body weights ≤75 kg: assessment of image quality and radiation dose in a prospective, randomised trial. Clin Radiol 2016; 71:615.e1-6. [DOI: 10.1016/j.crad.2016.02.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 02/05/2016] [Accepted: 02/14/2016] [Indexed: 11/22/2022]
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Saade C, Deeb IA, Mohamad M, Al-Mohiy H, El-Merhi F. Contrast medium administration and image acquisition parameters in renal CT angiography: what radiologists need to know. Diagn Interv Radiol 2016; 22:116-24. [PMID: 26728701 PMCID: PMC4790062 DOI: 10.5152/dir.2015.15219] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 07/06/2015] [Accepted: 07/20/2015] [Indexed: 12/12/2022]
Abstract
Over the last decade, exponential advances in computed tomography (CT) technology have resulted in improved spatial and temporal resolution. Faster image acquisition enabled renal CT angiography to become a viable and effective noninvasive alternative in diagnosing renal vascular pathologies. However, with these advances, new challenges in contrast media administration have emerged. Poor synchronization between scanner and contrast media administration have reduced the consistency in image quality with poor spatial and contrast resolution. Comprehensive understanding of contrast media dynamics is essential in the design and implementation of contrast administration and image acquisition protocols. This review includes an overview of the parameters affecting renal artery opacification and current protocol strategies to achieve optimal image quality during renal CT angiography with iodinated contrast media, with current safety issues highlighted.
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Affiliation(s)
- Charbel Saade
- From the Department of Radiology (C.S., I.A.D., M.M., F.E.M. ), American University of Beirut, Beirut, Lebanon; the Department of Radiology (H.A.M.), King Khalid University, Abha, Saudi Arabia
| | - Ibrahim Alsheikh Deeb
- From the Department of Radiology (C.S., I.A.D., M.M., F.E.M. ), American University of Beirut, Beirut, Lebanon; the Department of Radiology (H.A.M.), King Khalid University, Abha, Saudi Arabia
| | - Maha Mohamad
- From the Department of Radiology (C.S., I.A.D., M.M., F.E.M. ), American University of Beirut, Beirut, Lebanon; the Department of Radiology (H.A.M.), King Khalid University, Abha, Saudi Arabia
| | - Hussain Al-Mohiy
- From the Department of Radiology (C.S., I.A.D., M.M., F.E.M. ), American University of Beirut, Beirut, Lebanon; the Department of Radiology (H.A.M.), King Khalid University, Abha, Saudi Arabia
| | - Fadi El-Merhi
- From the Department of Radiology (C.S., I.A.D., M.M., F.E.M. ), American University of Beirut, Beirut, Lebanon; the Department of Radiology (H.A.M.), King Khalid University, Abha, Saudi Arabia
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Chang K, Heisler M, Mahesh M, Baird G, Mayo-Smith W. CT colonography at low tube potential: using iterative reconstruction to decrease noise. Clin Radiol 2015; 70:981-8. [DOI: 10.1016/j.crad.2015.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 03/24/2015] [Accepted: 05/12/2015] [Indexed: 01/15/2023]
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Evaluation of image quality and dose reduction of 80 kVp neck computed tomography in patients with suspected peritonsillar abscess. Clin Radiol 2015; 70:e67-73. [DOI: 10.1016/j.crad.2015.04.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 04/09/2015] [Accepted: 04/20/2015] [Indexed: 12/12/2022]
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Low contrast dose protocol involving a 100 kVp tube voltage for hypervascular hepatocellular carcinoma in patients with renal dysfunction. Jpn J Radiol 2015; 33:566-76. [PMID: 26162707 DOI: 10.1007/s11604-015-0457-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 07/02/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE To evaluate the feasibility of a 20 % reduced contrast dose hepatic arterial phase (HAP) CT for hypervascular hepatocellular carcinoma (HCC) with 100 kVp. MATERIALS AND METHODS The study included 97 patients with hypervascular HCC who underwent dynamic CT, including HAP scanning. The 54 patients had an estimated glomerular filtration rate (eGFR) of ≥60 were scanned with our conventional 120 kVp protocol. The other 43 patients (eGFR < 60) underwent scans using a tube voltage of 100 kVp and a 20 % reduced contrast dose. We compared the estimated effective dose, image noise, tumor-liver contrast (TLC), and contrast-to-noise ratio (CNR) in the hepatic arterial phase between the two groups using the Student's t test. RESULTS Estimated effective dose and image noise were not significantly different between these groups (p = 0.67 and p = 0.20, respectively). The TLC and CNR were significantly higher for the 100 kVp protocol than for the 120 kVp protocol (52.2 HU ± 17.4 vs 40.8 HU ± 18.6, p < 0.01 and 6.8 ± 2.6 vs 5.5 ± 2.4, p = 0.01, respectively). CONCLUSION For hepatic arterial phase CT of hypervascular HCC, 100 kVp scan allows a 20 % reduction in the contrast dose without reduction in image quality compared with a standard 120 kVp CT protocol.
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Al Mahrooqi KMS, Ng CKC, Sun Z. Pediatric Computed Tomography Dose Optimization Strategies: A Literature Review. J Med Imaging Radiat Sci 2015; 46:241-249. [PMID: 31052099 DOI: 10.1016/j.jmir.2015.03.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 02/20/2015] [Accepted: 03/23/2015] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Computed tomography (CT) dose optimization is an important issue in radiography because CT is the largest contributor to medical radiation dose and its use is increasing. However, CT dose optimization for pediatric patients could be more challenging than their adult counterparts. The purpose of this literature review was to identify and discuss the current pediatric CT dose saving techniques. Optimized pediatric protocols were also proposed. METHODS A comprehensive literature search was conducted using the Medline, ProQuest Health and Medical Complete, PubMed, ScienceDirect, Scopus, Springer Link, and Web of Science databases and the keywords CT, pediatric, optimization, protocol, and radiation dose to identify articles focusing on pediatric CT dose optimization strategies published between 2004 and 2014. RESULTS AND SUMMARY Seventy-seven articles were identified in the literature search. Strategies for optimizing a range of scan parameters and technical considerations including tube voltage and current, iterative reconstruction, diagnostic reference levels, bowtie filters, scout view, pitch, scan collimation and time, overscanning, and overbeaming for pediatric patients with different ages and body sizes and compositions were discussed. An example of optimized pediatric protocols specific to age and body size for the 64-slice CT scanners was devised. It is expected that this example could provide medical radiation technologists, radiologists, and medical physicists with ideas to optimize their pediatric protocols.
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Affiliation(s)
| | - Curtise Kin Cheung Ng
- Department of Medical Radiation Sciences, Curtin University, Perth, Western Australia, Australia.
| | - Zhonghua Sun
- Department of Medical Radiation Sciences, Curtin University, Perth, Western Australia, Australia
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Lv P, Liu J, Zhang R, Jia Y, Gao J. Combined Use of Automatic Tube Voltage Selection and Current Modulation with Iterative Reconstruction for CT Evaluation of Small Hypervascular Hepatocellular Carcinomas: Effect on Lesion Conspicuity and Image Quality. Korean J Radiol 2015; 16:531-40. [PMID: 25995682 PMCID: PMC4435983 DOI: 10.3348/kjr.2015.16.3.531] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 01/15/2015] [Indexed: 11/15/2022] Open
Abstract
Objective To assess the lesion conspicuity and image quality in CT evaluation of small (≤ 3 cm) hepatocellular carcinomas (HCCs) using automatic tube voltage selection (ATVS) and automatic tube current modulation (ATCM) with or without iterative reconstruction. Materials and Methods One hundred and five patients with 123 HCC lesions were included. Fifty-seven patients were scanned using both ATVS and ATCM and images were reconstructed using either filtered back-projection (FBP) (group A1) or sinogram-affirmed iterative reconstruction (SAFIRE) (group A2). Forty-eight patients were imaged using only ATCM, with a fixed tube potential of 120 kVp and FBP reconstruction (group B). Quantitative parameters (image noise in Hounsfield unit and contrast-to-noise ratio of the aorta, the liver, and the hepatic tumors) and qualitative visual parameters (image noise, overall image quality, and lesion conspicuity as graded on a 5-point scale) were compared among the groups. Results Group A2 scanned with the automatically chosen 80 kVp and 100 kVp tube voltages ranked the best in lesion conspicuity and subjective and objective image quality (p values ranging from < 0.001 to 0.004) among the three groups, except for overall image quality between group A2 and group B (p = 0.022). Group A1 showed higher image noise (p = 0.005) but similar lesion conspicuity and overall image quality as compared with group B. The radiation dose in group A was 19% lower than that in group B (p = 0.022). Conclusion CT scanning with combined use of ATVS and ATCM and image reconstruction with SAFIRE algorithm provides higher lesion conspicuity and better image quality for evaluating small hepatic HCCs with radiation dose reduction.
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Affiliation(s)
- Peijie Lv
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province 450052, China
| | - Jie Liu
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province 450052, China
| | - Rui Zhang
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province 450052, China
| | - Yan Jia
- Siemens Healthcare China, Beijing 100102, China
| | - Jianbo Gao
- Department of Radiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province 450052, China
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Objective and subjective image quality of primary and recurrent squamous cell carcinoma on head and neck low-tube-voltage 80-kVp computed tomography. Neuroradiology 2015; 57:645-51. [DOI: 10.1007/s00234-015-1512-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 03/13/2015] [Indexed: 11/24/2022]
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Non-linear image blending improves visualization of head and neck primary squamous cell carcinoma compared to linear blending in dual-energy CT. Clin Radiol 2015; 70:168-75. [DOI: 10.1016/j.crad.2014.10.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 10/26/2014] [Accepted: 10/30/2014] [Indexed: 11/20/2022]
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Wichmann JL, Kraft J, Nöske EM, Bodelle B, Burck I, Scholtz JE, Frellesen C, Wagenblast J, Kerl JM, Bauer RW, Lehnert T, Vogl TJ, Schulz B. Low-tube-voltage 80-kVp neck CT: evaluation of diagnostic accuracy and interobserver agreement. AJNR Am J Neuroradiol 2014; 35:2376-81. [PMID: 25104285 DOI: 10.3174/ajnr.a4052] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND AND PURPOSE Low-tube-voltage acquisition has been shown to facilitate substantial dose savings for neck CT with similar image contrast compared with standard 120-kVp acquisition. However, its potential for the detection of neck pathologies is uncertain. Our aim was to evaluate the effects of low-tube-voltage 80-kV(peak) acquisitions for neck CT on diagnostic accuracy and interobserver agreement. MATERIALS AND METHODS Three radiologists individually analyzed 80-kVp and linearly blended 120-kVp image series of 170 patients with a variety of pathologies who underwent dual-energy neck CT. Reviewers were unblinded to the clinical indication for CT but were otherwise blinded to any other data or images and were asked to state a final main diagnosis. Findings were compared with medical record charts, CT reports, and pathology results. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for each observer. Interobserver agreement was evaluated by using intraclass correlation coefficients. RESULTS Diagnoses were grouped as squamous cell carcinoma-related (n = 107, presence/absence of primary/recurrent squamous cell carcinoma), lymphoma-related (n = 40, presence/absence of primary/recurrent lymphoma), and benign (n = 23, eg, abscess). Cumulative sensitivity, specificity, positive predictive value, and negative predictive value for 80-kVp and blended 120-kVp images were 94.8%, 93.0%, 95.9%, and 91.1%, respectively. Results were also consistently high for squamous cell carcinoma-related (94.8%/95.3%, 89.1%/89.1%, 94.3%/94.4%, 90.1%/91.0%) and lymphoma-related (95.0%, 100.0%, 100.0%, 95.2%) 80-kVp/120-kVp image series. Global interobserver agreement was almost perfect (intraclass correlation coefficient, 0.82, 0.80; 95% CI, 0.76-0.74, 0.86-0.85). Calculated dose-length product was reduced by 48% with 80-kVp acquisitions compared with the standard 120-kVp scans (135.5 versus 282.2 mGy × cm). CONCLUSIONS Low-tube-voltage 80-kVp CT of the neck provides sufficient image quality with high diagnostic accuracy in routine clinical practice and has the potential to substantially decrease radiation exposure.
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Affiliation(s)
- J L Wichmann
- From the Departments of Diagnostic and Interventional Radiology (J.L.W., J.K., E.-M.N., B.B., I.B., J.-E.S, C.F., J.M.K., R.W.B., T.L., T.J.V., B.S.)
| | - J Kraft
- From the Departments of Diagnostic and Interventional Radiology (J.L.W., J.K., E.-M.N., B.B., I.B., J.-E.S, C.F., J.M.K., R.W.B., T.L., T.J.V., B.S.)
| | - E-M Nöske
- From the Departments of Diagnostic and Interventional Radiology (J.L.W., J.K., E.-M.N., B.B., I.B., J.-E.S, C.F., J.M.K., R.W.B., T.L., T.J.V., B.S.)
| | - B Bodelle
- From the Departments of Diagnostic and Interventional Radiology (J.L.W., J.K., E.-M.N., B.B., I.B., J.-E.S, C.F., J.M.K., R.W.B., T.L., T.J.V., B.S.)
| | - I Burck
- From the Departments of Diagnostic and Interventional Radiology (J.L.W., J.K., E.-M.N., B.B., I.B., J.-E.S, C.F., J.M.K., R.W.B., T.L., T.J.V., B.S.)
| | - J-E Scholtz
- From the Departments of Diagnostic and Interventional Radiology (J.L.W., J.K., E.-M.N., B.B., I.B., J.-E.S, C.F., J.M.K., R.W.B., T.L., T.J.V., B.S.)
| | - C Frellesen
- From the Departments of Diagnostic and Interventional Radiology (J.L.W., J.K., E.-M.N., B.B., I.B., J.-E.S, C.F., J.M.K., R.W.B., T.L., T.J.V., B.S.)
| | - J Wagenblast
- Otolaryngology, Head and Neck Surgery (J.W.), University Hospital Frankfurt, Frankfurt, Germany
| | - J M Kerl
- From the Departments of Diagnostic and Interventional Radiology (J.L.W., J.K., E.-M.N., B.B., I.B., J.-E.S, C.F., J.M.K., R.W.B., T.L., T.J.V., B.S.)
| | - R W Bauer
- From the Departments of Diagnostic and Interventional Radiology (J.L.W., J.K., E.-M.N., B.B., I.B., J.-E.S, C.F., J.M.K., R.W.B., T.L., T.J.V., B.S.)
| | - T Lehnert
- From the Departments of Diagnostic and Interventional Radiology (J.L.W., J.K., E.-M.N., B.B., I.B., J.-E.S, C.F., J.M.K., R.W.B., T.L., T.J.V., B.S.)
| | - T J Vogl
- From the Departments of Diagnostic and Interventional Radiology (J.L.W., J.K., E.-M.N., B.B., I.B., J.-E.S, C.F., J.M.K., R.W.B., T.L., T.J.V., B.S.)
| | - B Schulz
- From the Departments of Diagnostic and Interventional Radiology (J.L.W., J.K., E.-M.N., B.B., I.B., J.-E.S, C.F., J.M.K., R.W.B., T.L., T.J.V., B.S.)
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Low-dose abdominal CT protocols with a tube voltage setting of 100 kVp or 80 kVp: Performance of radiation dose reduction and influence on visual contrast. Clin Radiol 2014; 69:804-11. [DOI: 10.1016/j.crad.2014.03.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 03/10/2014] [Accepted: 03/20/2014] [Indexed: 11/18/2022]
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Dubourg B, Caudron J, Lestrat JP, Bubenheim M, Lefebvre V, Godin M, Tron C, Eltchaninoff H, Bauer F, Dacher JN. Single-source dual-energy CT angiography with reduced iodine load in patients referred for aortoiliofemoral evaluation before transcatheter aortic valve implantation: impact on image quality and radiation dose. Eur Radiol 2014; 24:2659-68. [DOI: 10.1007/s00330-014-3263-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 04/01/2014] [Accepted: 05/22/2014] [Indexed: 01/25/2023]
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Diagnostic efficiency of low-dose CT angiography compared with conventional angiography in peripheral arterial occlusions. AJR Am J Roentgenol 2014; 201:W906-14. [PMID: 24261398 DOI: 10.2214/ajr.12.10209] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study was to assess the diagnostic efficiency and radiation dose of peripheral arterial CT angiography (CTA) performed at a low tube voltage of 70 kV in comparison with conventional angiography. SUBJECTS AND METHODS Thirty consecutive patients (body mass index ≤ 25 kg/m(2)) with known or suspected peripheral arterial occlusion diseases underwent both CTA at a low tube voltage of 70 kV and conventional angiography. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of peripheral arterial CTA were evaluated. The radiation dose was recorded. RESULTS Diagnostic CTA images were obtained in all patients. CTA allowed accurate identification, characterization, and measurement of all peripheral arterial occlusive diseases. In conventional angiography, 360 diseased segments were found among the 810 segments evaluated. The sensitivity, specificity, PPV, NPV, and accuracy of CTA were 100% (95% CI, 98.81-100%), 93.5% (90.96-95.36%), 90.86% (87.38-93.45%), 100% (99.17-100%), and 96.05% (94.48-97.19%), respectively, with a kappa value of 0.92 (excellent agreement). The mean CT dose index was 3.71 ± 0.8 mGy, and the dose-length product was 446.6 ± 35.7 mGy × cm. The effective dose was 1.94 ± 0.21 mSv for CTA and 4.41 ± 0.64 mSv for conventional angiography. CONCLUSION CTA of peripheral arteries with a low tube voltage of 70 kV provides reliable information and serves as a rapidly performed and easily available "one-stop-shop" imaging modality in the diagnosis of peripheral arterial occlusion diseases.
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Kidoh M, Nakaura T, Nakamura S, Oda S, Utsunomiya D, Sakai Y, Harada K, Yamashita Y. Low-dose abdominal CT: Comparison of low tube voltage with moderate-level iterative reconstruction and standard tube voltage, low tube current with high-level iterative reconstruction. Clin Radiol 2013; 68:1008-15. [DOI: 10.1016/j.crad.2013.04.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 04/18/2013] [Accepted: 04/22/2013] [Indexed: 01/29/2023]
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Low tube voltage intermediate tube current liver MDCT: sinogram-affirmed iterative reconstruction algorithm for detection of hypervascular hepatocellular carcinoma. AJR Am J Roentgenol 2013; 201:23-32. [PMID: 23789655 DOI: 10.2214/ajr.12.10000] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE The purpose of this study was to compare image quality and lesion detectability in the evaluation of hypervascular hepatocellular carcinoma (HCC) on low-tube-voltage half-dose liver CT scans subjected to sinogram-affirmed iterative reconstruction (SAFIRE) with the quality and detectability on full-dose scans reconstructed with filtered back projection (FBP). MATERIALS AND METHODS A total of 126 patients with suspected HCC who underwent liver CT including arterial phase scanning at 80 kVp in the dual-source mode (300 mAs for each tube) were included in the study. The half-dose arterial scans were reconstructed with FBP, iterative reconstruction in image space (IRIS), and five SAFIRE strengths (S1-S5) and were compared with full-dose virtual scans (600 mA) reconstructed with FBP. We assessed image noise, contrast-to-noise ratio (CNR) of the liver and blood vessels, and lesionto-liver CNR. Two radiologists evaluated image quality and lesion detectability attained with the different imaging sets. RESULTS Image noise on SAFIRE images was significantly lower than that on the other images, and the CNRs on SAFIRE images were higher than those on half-dose FBP images (p < 0.001). In addition, lesion-to-liver CNR on the half-dose S5 SAFIRE images was higher than on IRIS and full-dose FBP images (p < 0.05). Among the half-dose scans, SAFIRE images had significantly better image quality than FBP images (p < 0.05). Regarding lesion detection, half-dose SAFIRE images were better than half-dose FBP images and were comparable with full-dose FBP images (observer 1, 91.8% vs 96%; observer 2, 98% vs 98%; p > 0.05). CONCLUSION Performing half-dose 80-kVp liver CT with SAFIRE technique may increase image quality and afford comparable lesion detectability of hypervascular HCC at a reduced radiation dose compared with full-dose CT with FBP.
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Abstract
Patients, referring physicians, the media, and government agencies have all expressed concern over the risks of medical radiation, particularly as it relates to CT. This concern is particularly paramount when associated with a screening examination such as CT colonography. These theoretical risks must be weighed realistically against the substantial benefits of colon cancer screening as well as against the risks inherent in the major alternative screening option, optical colonoscopy. When put into perspective, the risk-benefit ratio is highly in favor of the performance of CT colonography. Nevertheless, in following the ALARA principle, there is an ever increasing armamentarium of options that can be employed in the pursuit of CT radiation dose reduction, all of which can be used in many synergistic combinations allowing for dose reduction while simultaneously preserving image quality and minimizing image noise. After a brief tutorial on estimating radiation dose, various strategies will be discussed including reductions in tube current and tube voltage as well as the use of automatic dose modulation and iterative reconstruction. Other practical considerations will also be reviewed including proper patient isocentering, optimization of colonic insufflation to minimize additional decubitus scans, proper choice of scan volumes to avoid overranging, and variation of slice thickness and window width to minimize perceived image noise. Finally, a strategy for how to incrementally introduce these methods as well as a way to compare dose reduction efforts across institutions throughout the country will be offered.
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Siegel MJ, Hildebolt C, Bradley D. Effects of Automated Kilovoltage Selection Technology on Contrast-enhanced Pediatric CT and CT Angiography. Radiology 2013; 268:538-47. [PMID: 23564712 DOI: 10.1148/radiol.13122438] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Marilyn J Siegel
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, St Louis, MO 63110, USA.
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Abstract
OBJECTIVE The purpose of this study was to determine the effect of lowering tube voltage on dose and noise in cylindric water phantoms to optimize quality and decrease the radiation dose for body CT. MATERIALS AND METHODS We performed CT on cylindric water phantoms with diameters of 10, 20, 25, and 30 cm, simulating the abdomen of an infant, child, adolescent, and adult. We used tube voltages of 120, 100, and 80 kVp. The CT dose index (32-cm reference) ranged from 1 to 10 mGy in 10- and 20-cm phantoms and from 2 to 20 mGy in the 25- and 30-cm phantoms. The noise was measured at the center and periphery of the scans. Central and peripheral doses were measured in 16- and 32-cm CT dose index phantoms, and the ratio of central to peripheral doses was calculated. RESULTS At the same noise levels, there was no significant increase in dose in 10-cm cylindric water phantoms when tube voltage was decreased to either 80 or 100 kVp. In 20-, 25-, and 30-cm phantoms, there was a 1-6% increase in dose when tube voltage was decreased to 100 kVp. Central-to-peripheral noise ratios increased 7-37% with increased phantom size. The measured peripheral dose increased as much as 5%. CONCLUSION Our findings support the practice of lowering tube voltage to 80 kVp for imaging of infants and to 100 kVp for imaging of older children. The increase in peripheral dose with decreased tube voltage is minimal and is unlikely to cause substantial change in the effective dose.
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Low radiation dose protocol in cardiac CT with 100 kVp: usefulness of display preset optimization. Int J Cardiovasc Imaging 2013; 29:1381-9. [DOI: 10.1007/s10554-013-0214-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 04/02/2013] [Indexed: 12/13/2022]
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Kuramochi K, Ogawa Y, Chikaraishi K, Tateishi K, Yoshikawa T. [Usefulness of low kilovoltage settings in computed tomography venography of lower limbs]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2013; 69:85-91. [PMID: 23358342 DOI: 10.6009/jjrt.2013_jsrt_69.1.85] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
It has been reported that a reduction in tube kilovoltage during computed tomography (CT) angiography results in an average reduction of the effective radiation dose. Furthermore, a lower kilovoltage has been shown as a technique dose. However, there is no fundamental data in a low-kilovoltage protocol for CT venography. Thus, the purpose of this study was to investigate contrast enhancement, image noise, and radiation exposure with lower kilovoltage on CT images scanned using phantom of lower limbs and clinical CT images. In order to grasp the effective energy in each tube voltage of the equipment used, we determined the half-value layer using aluminum attenuation coefficient. The phantom of the lower was sealed with contrast agent that was adjusted in various CT values. We scanned this phantom at 80 kVp, 100 kVp, and 120 kVp settings, and evaluated the changes in CT value. We also compared CT values, CTDIvol, contrast enhancement, and radiation exposure with 100 kVp and 120 kVp in patients with suspected pulmonary embolism or deep venous thrombosis. We found the CT value increased 30 HU with 100 kVp settings, and contrast was also improved. A reduction of radiation exposure without deterioration of image quality would be possible by lowering the kilovoltage setting in CT venography.
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Affiliation(s)
- Kenji Kuramochi
- Imaging Center, St. Marianna University School of Medicine Hospital
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Optimal Contrast of Computed Tomography Portal Venography Using Dual-Energy Computed Tomography. J Comput Assist Tomogr 2013; 37:142-8. [DOI: 10.1097/rct.0b013e31827cd656] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Chang KJ, Caovan DB, Grand DJ, Huda W, Mayo-Smith WW. Reducing radiation dose at CT colonography: decreasing tube voltage to 100 kVp. Radiology 2012; 266:791-800. [PMID: 23264348 DOI: 10.1148/radiol.12120134] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To assess the effect of a decrease in tube voltage from 120 kVp to 100 kVp on dose, contrast-to-noise ratio (CNR), and three-dimensional (3D) image quality in patients undergoing computed tomographic (CT) colonography as well as to determine how these changes are affected by patient size. MATERIALS AND METHODS This HIPAA-compliant and institutional review board-approved retrospective study included 63 consecutive patients who underwent CT colonography and who waived informed consent. Scanning was performed with patients in the supine (120 kVp) and prone (100 kVp) positions, with other parameters unchanged. Volume CT dose index (CTDI(vol)), dose-length product (DLP), image noise, attenuation of selected materials, and CNR were compared with the Wilcoxon matched-pairs signed rank test. Two readers blinded to tube voltage independently assessed 3D endoluminal image quality. The k coefficients were calculated for interobserver agreement. Average image quality ratings were compared with the Wilcoxon signed rank test. All recorded data were stratified by patient anteroposterior diameter to determine effects of patient size. RESULTS Decreasing tube voltage from 120 to 100 kVp resulted in a 20% decrease in CTDI(vol) (P < .001) and a 16% decrease in DLP (P < .001). Image noise increased by 32% (P < .001). Mean attenuation of tagged fluid increased from 395 to 487 HU (P < .001). There was no change in mean CNR of tagged fluid (17.1 at 120 kVp, 16.8 at 100 kVp; P = .37), regardless of patient size. The 3D image quality decreased slightly from a median score of 5 out of 5 to 4 out of 5 (P < .001). There was substantial interobserver agreement. CONCLUSION A decrease in tube voltage from 120 to 100 kVp results in a significant decrease in radiation dose but only a minimal decrease in 3D image quality at all patient sizes. © RSNA, 2012.
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Affiliation(s)
- Kevin J Chang
- Department of Diagnostic Imaging, Warren Alpert Medical School of Brown University, Rhode Island Hospital, 593 Eddy St, Providence, RI 02903, USA.
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Lee KH, Lee JM, Moon SK, Baek JH, Park JH, Flohr TG, Kim KW, Kim SJ, Han JK, Choi BI. Attenuation-based Automatic Tube Voltage Selection and Tube Current Modulation for Dose Reduction at Contrast-enhanced Liver CT. Radiology 2012; 265:437-447. [DOI: 10.1148/radiol.12112434] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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CT enterography at 80 kVp with adaptive statistical iterative reconstruction versus at 120 kVp with standard reconstruction: image quality, diagnostic adequacy, and dose reduction. AJR Am J Roentgenol 2012; 198:1084-92. [PMID: 22528897 DOI: 10.2214/ajr.11.6597] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVE The objective of our study was to evaluate the image quality and diagnostic adequacy of the following two CT enterography protocols in patients weighing less than 160 lb (72 kg): 80-kVp imaging with the adaptive statistical iterative reconstruction (ASIR) in comparison with 120-kVp imaging with the filtered back projection reconstruction. MATERIALS AND METHODS We retrospectively reviewed 133 CT enterography examinations of 127 patients weighing less than 160 lb, 64 80-kVp examinations, and 69 120-kVp examinations. Image quality for evaluation of the bowel wall, mesenteric vessels, and hepatic parenchyma and the overall image quality were graded on a scale of 1-5 (1 = poor, 2 = acceptable, 3 = good, 4 = very good, 5 = excellent). Diagnostic accuracy for the detection of inflammatory bowel disease was evaluated. The volume CT dose index (CTDI(vol)) was recorded and effective dose was calculated from scanner-generated dose-length product. RESULTS There was a statistically significant decrease in the mean image quality scores for 80-kVp examinations compared with 120-kVp examinations for evaluation of the bowel wall (3.19 vs 3.70, respectively) and liver (3.12 vs 3.81) and for overall image quality (3.23 vs 3.68), but there was no significant decrease in score for evaluation of the mesenteric vessels (3.63 vs 3.67). None of the 80-kVp examinations was graded as poor, and all were considered to be of acceptable quality. Both techniques had comparable diagnostic accuracy for the detection of inflammatory bowel disease. Interobserver agreement was fair to moderate for qualitative image grading and was substantial for the detection of features of inflammatory bowel disease. The mean CTDI(vol) and effective dose for the 80-kVp examinations were 6.15 mGy and 4.60 mSv, respectively, and for the 120-kVp examinations, 20.79 mGy and 15.81 mSv. CONCLUSION In patients weighing less than 160 lb, CT enterography examinations at 80 kVp with 30% ASIR produce diagnostically acceptable image quality with an average CTDI(vol) of 6.15 mGy and an average effective dose of 4.60 mSv.
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Noise Reduction to Decrease Radiation Dose and Improve Conspicuity of Hepatic Lesions at Contrast-Enhanced 80-kV Hepatic CT Using Projection Space Denoising. AJR Am J Roentgenol 2012; 198:405-11. [DOI: 10.2214/ajr.11.6987] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Improvement of Image Quality at Low–Radiation Dose and Low–Contrast Material Dose Abdominal CT in Patients With Cirrhosis. J Comput Assist Tomogr 2012; 36:495-501. [DOI: 10.1097/rct.0b013e31825b821f] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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High-pitch dual-source CT angiography of the whole aorta without ECG synchronisation: Initial experience. Eur Radiol 2011; 22:129-37. [DOI: 10.1007/s00330-011-2257-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 08/02/2011] [Accepted: 08/24/2011] [Indexed: 11/25/2022]
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Abdominal CT at low peak tube potential settings brings promises, but new rules apply. AJR Am J Roentgenol 2011; 196:1322-3. [PMID: 21606295 DOI: 10.2214/ajr.11.6924] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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