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Zhou Y, Eastman E, Lee C, Scott A. Optimal dose determination for coronary artery calcium scoring CT at standard tube voltage. Eur J Radiol 2023; 167:111029. [PMID: 37579562 DOI: 10.1016/j.ejrad.2023.111029] [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: 03/03/2023] [Revised: 05/31/2023] [Accepted: 08/08/2023] [Indexed: 08/16/2023]
Abstract
OBJECTIVES Coronary artery calcium scoring (CACs) at 120 kVp is the standard practice. It is an important tool for preventative management of asymptomatic patients. However, the current dose delivery, albeit patient-size dependent, does not connect the CACs specific noise requirement to the dose, causing significant dose variations. We propose a new approach for optimal dose determination by incorporating the patient-size dependent noise threshold. METHODS A polyethylene-based Mercury phantom of various diameters was scanned with a dual-source CT using CACs gating at different volume CT dose index (CTDIvol). The relationship of noise to the diameter and CTDIvol was obtained. The phantom diameter was then converted to the patient chest diameter through a retrospective analysis of a clinical cohort (N = 140). Finally, the patient-size dependent noise threshold was applied, and the optimal dose was derived. The prescribed doses were compared with those from a clinical CACs cohort (N = 262). RESULTS A power-exponential relationship was found for the noise versus CTDIvol and phantom diameter (R2 = 0.988). The phantom diameter versus the patient effective diameter was found to obey a linear relationship (R2 = 0.998). Two noise threshold settings were made for dose options: one for more dose saving, and another for tighter noise constraint. Retrospective comparisons with clinical CACs studies showed an average dose reduction of 23% in 80.5% of the cases with option 1. The average dose reduction is 23% in 77.9% of the cases with option 2. CONCLUSION A new optimal dose scheme dictated by the target noise was established for CACs at 120 kVp. The proposed dose modulation can serve as the baseline from which further dose reduction is possible.
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Affiliation(s)
- Yifang Zhou
- Department of Imaging, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, CA 90048, USA.
| | - Emi Eastman
- Department of Imaging, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, CA 90048, USA
| | - Christina Lee
- Department of Imaging, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, CA 90048, USA
| | - Alexander Scott
- Department of Imaging, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, CA 90048, USA
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Kim SY, Suh YJ, Lee HJ, Kim YJ. Progostic value of coronary artery calcium scores from 1.5 mm slice reconstructions of electrocardiogram-gated computed tomography scans in asymptomatic individuals. Sci Rep 2022; 12:7198. [PMID: 35504936 PMCID: PMC9064982 DOI: 10.1038/s41598-022-11332-3] [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] [Received: 01/30/2022] [Accepted: 04/22/2022] [Indexed: 11/18/2022] Open
Abstract
It is unknown whether the thinner slice reconstruction has added value relative to 3 mm reconstructions in predicting major adverse cardiac events (MACEs). This retrospective study included 550 asymptomatic individuals who underwent cardiac CT. Coronary artery calcium (CAC) scores and severity categories were assessed from 1.5 and 3 mm scans. CAC scores obtained from 1.5 and 3 mm scans were compared using Wilcoxon signed-rank tests. Cox proportional hazard models were developed to predict MACEs based on the degree of coronary artery stenosis on coronary CT angiography and the presence of CAC on both scans. Model performances were compared using the time-dependent ROC curve and integrated area under the curve (iAUC) methods. The CAC scores obtained from 1.5 mm scans were significantly higher than those from 3 mm scans (median, interquartile range 4.5[0–71] vs. 0[0–48.4]; p < 0.001). Models showed no difference in predictive accuracy of the presence of CAC between 1.5 and 3 mm scans (iAUC, 0.625 vs. 0.672). In conclusion, CAC scores obtained from 1.5 mm scans are significantly higher than those from 3 mm scans, but do not provide added prognostic value relative to 3 mm scans.
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Affiliation(s)
- Suh Young Kim
- Department of Medicine, College of Medicine, Yonsei University Graduate School, Seoul, Korea.,Department of Radiology, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, Korea
| | - Young Joo Suh
- Department of Radiology, Severance Hospital, Research Institute of Radiological Science, Center for Clinical Imaging Data Science, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea.
| | - Hye-Jeong Lee
- Department of Radiology, Severance Hospital, Research Institute of Radiological Science, Center for Clinical Imaging Data Science, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea
| | - Young Jin Kim
- Department of Radiology, Severance Hospital, Research Institute of Radiological Science, Center for Clinical Imaging Data Science, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea
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Hou KY, Tsujioka K, Yang CC. Optimization of HU threshold for coronary artery calcium scans reconstructed at 0.5-mm slice thickness using iterative reconstruction. J Appl Clin Med Phys 2020; 21:111-120. [PMID: 31889419 PMCID: PMC7021007 DOI: 10.1002/acm2.12806] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/30/2019] [Accepted: 12/13/2019] [Indexed: 12/22/2022] Open
Abstract
PURPOSE This work investigated the simultaneous influence of tube voltage, tube current, body size, and HU threshold on calcium scoring reconstructed at 0.5-mm slice thickness using iterative reconstruction (IR) through multivariate analysis. Regression results were used to optimize the HU threshold to calibrate the resulting Agatston scores to be consistent with those obtained from the conventional protocol. METHODS A thorax phantom set simulating three different body sizes was used in this study. A total of 14 coronary artery calcium (CAC) protocols were studied, including 1 conventional protocol reconstructed at 3-mm slice thickness, 1 FBP protocol, and 12 statistical IR protocols (3 kVp values*4 SD values) reconstructed at 0.5-mm slice thickness. Three HU thresholds were applied for calcium identification, including 130, 150, and 170 HU. A multiple linear regression method was used to analyze the impact of kVp, SD, body size, and HU threshold on the Agatston scores of three calcification densities for IR-reconstructed CAC scans acquired with 0.5-mm slice thickness. RESULTS Each regression relationship has R2 larger than 0.80, indicating a good fit to the data. Based on the regression models, the HU thresholds as a function of SD estimated to ensure the quantification accuracy of calcium scores for 120-, 100-, and 80-kVp CAC scans reconstructed at 0.5-mm slice thickness using IR for three different body sizes were proposed. Our results indicate that the HU threshold should be adjusted according to the imaging condition, whereas a 130-HU threshold is appropriate for 120-kVp CAC scans acquired with SD = 55 for body size of 24.5 cm. CONCLUSION The optimized HU thresholds were proposed for CAC scans reconstructed at 0.5-mm slice thickness using IR. Our study results may provide a potential strategy to improve the reliability of calcium scoring by reducing partial volume effect while keeping radiation dose as low as reasonably achievable.
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Affiliation(s)
- Kuei-Yuan Hou
- Department of Radiology, Cathay General Hospital, Taipei, Taiwan
| | - Katsumi Tsujioka
- Faculty of Radiological Technology, Fujita Health University, Aichi, Japan
| | - Ching-Ching Yang
- Department of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan
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Li Q, Berman BP, Hagio T, Gavrielides MA, Zeng R, Sahiner B, Gong Q, Fang Y, Liu S, Petrick N. Coronary artery calcium quantification using contrast-enhanced dual-energy computed tomography scans in comparison with unenhanced single-energy scans. Phys Med Biol 2018; 63:175006. [PMID: 30101756 PMCID: PMC6183065 DOI: 10.1088/1361-6560/aad9be] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Extracting coronary artery calcium (CAC) scores from contrast-enhanced computed tomography (CT) images using dual-energy (DE) based material decomposition has been shown feasible, mainly through patient studies. However, the quantitative performance of such DE-based CAC scores, particularly per stenosis, is underexamined due to lack of reference standard and repeated scans. In this work we conducted a comprehensive quantitative comparative analysis of CAC scores obtained with DE and compare to conventional unenhanced single-energy (SE) CT scans through phantom studies. Synthetic vessels filled with iodinated blood mimicking material and containing calcium stenoses of different sizes and densities were scanned with a third generation dual-source CT scanner in a chest phantom using a DE coronary CT angiography protocol with three exposures/CTDIvol: auto-mAs/8 mGy (automatic exposure), 160 mAs/20 mGy and 260 mAs/34 mGy and 10 repeats. As a control, a set of vessel phantoms without iodine was scanned using a standard SE CAC score protocol (3 mGy). Calcium volume, mass and Agatston scores were estimated for each stenosis. For DE dataset, image-based three-material decomposition was applied to remove iodine before scoring. Performance of DE-based calcium scores were analyzed on a per-stenosis level and compared to SE-based scores. There was excellent correlation between the DE- and SE-based scores (correlation coefficient r: 0.92-0.98). Percent bias for the calcium volume and mass scores varied as a function of stenosis size and density for both modalities. Precision (coefficient of variation) improved with larger and denser stenoses for both DE- and SE-based calcium scores. DE-based scores (20 mGy and 34 mGy) provided comparable per-stenosis precision to SE-based (3 mGy). Our findings suggest that on a per-stenosis level, DE-based CAC scores from contrast-enhanced CT images can achieve comparable quantification performance to conventional SE-based scores. However, DE-based CAC scoring required more dose compared with SE for high per-stenosis precision so some caution is necessary with clinical DE-based CAC scoring.
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Affiliation(s)
- Qin Li
- US Food and Drug Administration, CDRH/OSEL/DIDSR, Silver Spring, MD, United States of America
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Vonder M, van der Aalst CM, Vliegenthart R, van Ooijen PMA, Kuijpers D, Gratama JW, de Koning HJ, Oudkerk M. Coronary Artery Calcium Imaging in the ROBINSCA Trial: Rationale, Design, and Technical Background. Acad Radiol 2018; 25:118-128. [PMID: 28843465 DOI: 10.1016/j.acra.2017.07.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/18/2017] [Accepted: 07/20/2017] [Indexed: 01/20/2023]
Abstract
RATIONALE AND OBJECTIVES To describe the rationale, design, and technical background of coronary artery calcium (CAC) imaging in the large-scale population-based cardiovascular disease screening trial (Risk Or Benefit IN Screening for CArdiovascular Diseases [ROBINSCA]). MATERIALS AND METHODS First, literature search was performed to review the logistics, setup, and settings of previously performed CAC imaging studies, and current clinical CAC imaging protocols of participating centers in the ROBINSCA trial were evaluated. A second literature search was performed to evaluate the impact of computed tomography parameter settings on CAC score. RESULTS Based on literature reviews and experts opinion an imaging protocol accompanied by data management protocol was created for ROBINSCA. The imaging protocol should consist of a fixed tube voltage, individually tailored tube current setting, mid-diastolic electrocardiography-triggering, fixed field-of-view, fixed reconstruction kernel, fixed slice thickness, overlapping reconstruction and without iterative reconstruction. The analysis of scans is performed with one type and version of CAC scoring software, by two dedicated and experienced researchers. The data management protocol describes the organization of data handling between the coordinating center, participating centers, and core analysis center. CONCLUSION In this paper we describe the rationale and technical considerations to be taken in developing CAC imaging protocol, and we present a detailed protocol that can be implemented for CAC screening purposes.
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Affiliation(s)
- Marleen Vonder
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging North-East Netherlands (CMI-NEN), Groningen, The Netherlands
| | - Carlijn M van der Aalst
- Erasmus MC-University Medical Centre, Department of Public Health, Rotterdam, The Netherlands
| | - Rozemarijn Vliegenthart
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging North-East Netherlands (CMI-NEN), Groningen, The Netherlands
| | - Peter M A van Ooijen
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging North-East Netherlands (CMI-NEN), Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, Department of Radiology, Groningen, The Netherlands
| | - Dirkjan Kuijpers
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging North-East Netherlands (CMI-NEN), Groningen, The Netherlands; Department of Radiology, Haaglanden Medical Center Bronovo, The Hague, The Netherlands
| | - Jan Willem Gratama
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging North-East Netherlands (CMI-NEN), Groningen, The Netherlands; Department of Radiology, Gelre Hospital, Apeldoorn, The Netherlands
| | - Harry J de Koning
- Erasmus MC-University Medical Centre, Department of Public Health, Rotterdam, The Netherlands
| | - Matthijs Oudkerk
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging North-East Netherlands (CMI-NEN), Groningen, The Netherlands.
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van der Werf NR, Willemink MJ, Willems TP, Greuter MJW, Leiner T. Influence of iterative reconstruction on coronary calcium scores at multiple heart rates: a multivendor phantom study on state-of-the-art CT systems. Int J Cardiovasc Imaging 2017; 34:947-957. [DOI: 10.1007/s10554-017-1292-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 12/19/2017] [Indexed: 10/18/2022]
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Gassenmaier T, Allmendinger T, Kunz AS, Veyhl-Wichmann M, Ergün S, Bley TA, Petritsch B. In vitro evaluation of a new iterative reconstruction algorithm for dose reduction in coronary artery calcium scoring. Acta Radiol Open 2017; 6:2058460117710682. [PMID: 28607763 PMCID: PMC5453409 DOI: 10.1177/2058460117710682] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 04/27/2017] [Indexed: 11/17/2022] Open
Abstract
Background Coronary artery calcium (CAC) scoring is a widespread tool for cardiac risk assessment in asymptomatic patients and accompanying possible adverse effects, i.e. radiation exposure, should be as low as reasonably achievable. Purpose To evaluate a new iterative reconstruction (IR) algorithm for dose reduction of in vitro coronary artery calcium scoring at different tube currents. Material and Methods An anthropomorphic calcium scoring phantom was scanned in different configurations simulating slim, average-sized, and large patients. A standard calcium scoring protocol was performed on a third-generation dual-source CT at 120 kVp tube voltage. Reference tube current was 80 mAs as standard and stepwise reduced to 60, 40, 20, and 10 mAs. Images were reconstructed with weighted filtered back projection (wFBP) and a new version of an established IR kernel at different strength levels. Calcifications were quantified calculating Agatston and volume scores. Subjective image quality was visualized with scans of an ex vivo human heart. Results In general, Agatston and volume scores remained relatively stable between 80 and 40 mAs and increased at lower tube currents, particularly in the medium and large phantom. IR reduced this effect, as both Agatston and volume scores decreased with increasing levels of IR compared to wFBP (P < 0.001). Depending on selected parameters, radiation dose could be lowered by up to 86% in the large size phantom when selecting a reference tube current of 10 mAs with resulting Agatston levels close to the reference settings. Conclusion New iterative reconstruction kernels may allow for reduction in tube current for established Agatston scoring protocols and consequently for substantial reduction in radiation exposure.
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Affiliation(s)
- Tobias Gassenmaier
- Department of Diagnostic and Interventional Radiology, University Hospital of Würzburg, Würzburg, Germany
| | | | - Andreas S Kunz
- Department of Diagnostic and Interventional Radiology, University Hospital of Würzburg, Würzburg, Germany
| | - Maike Veyhl-Wichmann
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Süleyman Ergün
- Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany
| | - Thorsten A Bley
- Department of Diagnostic and Interventional Radiology, University Hospital of Würzburg, Würzburg, Germany
| | - Bernhard Petritsch
- Department of Diagnostic and Interventional Radiology, University Hospital of Würzburg, Würzburg, Germany
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Fuchs A, Groen JM, Arnold BA, Nikolovski S, Knudsen AD, Kühl JT, Nordestgaard BG, Greuter MJ, Kofoed KF. Assessment of coronary calcification using calibrated mass score with two different multidetector computed tomography scanners in the Copenhagen General Population Study. Eur J Radiol 2017; 88:21-25. [DOI: 10.1016/j.ejrad.2016.12.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 11/16/2016] [Accepted: 12/28/2016] [Indexed: 01/07/2023]
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