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Masuda T, Nakaura T, Funama Y, Sato T, Masuda S, Gotanda R, Arao K, Imaizumi H, Arao S, Ono A, Hiratsuka J, Awai K. RADIATION DOSE REDUCTION AT LOW TUBE VOLTAGE WITH CORONARY ARTERY BYPASS GRAFT COMPUTED TOMOGRAPHY ANGIOGRAPHY BASED ON THE CONTRAST NOISE RATIO INDEX. RADIATION PROTECTION DOSIMETRY 2023; 199:527-532. [PMID: 36881907 DOI: 10.1093/rpd/ncad049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 02/08/2023] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
To compare the radiation dose and diagnostic ability of the 100-kVp protocol, based on the contrast noise ratio (CNR) index, during coronary artery bypass graft (CABG) vessels with those of the 120-kVp protocol. For the 120-kVp scans (150 patients), the targeted image level was set at 25 Hounsfield units (HU) (CNR120 = iodine contrast/25 HU). For the 100-kVp scans (150 patients), the targeted noise level was set at 30 HU to obtain the same CNR as in the 120-kVp scans (i.e. using 1.2-fold higher iodine contrast, CNR100 = 1.2 × iodine contrast/(1.2 × 25 HU) = CNR120). We compared the CNRs, radiation doses, detection of CABG vessels and visualisation scores of the scans acquired at 120 and 100 kVp, respectively. At the same CNR, the 100-kVp protocol may help reduce the radiation dose by ⁓30% compared with the 120-kVp protocol, without degradation of diagnostic ability during CABG.
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Affiliation(s)
- Takanori Masuda
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Takeshi Nakaura
- Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan
| | - Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Tomoyasu Sato
- Department of Diagnostic Radiology, Tsuchiya General Hospital, Nakajima-cho 3-30, Naka-ku, Hiroshima 730-8655, Japan
| | - Shouko Masuda
- Department of Radiological Technology, Kawamura clinic Otemachi, Naka-ku, Hiroshima 730-0051, Japan
| | - Rumi Gotanda
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Keiko Arao
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Hiromasa Imaizumi
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Shinichi Arao
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, 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
| | - Junichi Hiratsuka
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
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Jovin DG, Katlaps GJ, Sumption KF. Coronary artery bypass graft markers: history, usage, and effects. Gen Thorac Cardiovasc Surg 2020; 68:453-458. [DOI: 10.1007/s11748-020-01325-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 02/21/2020] [Indexed: 01/09/2023]
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Ippolito D, Fior D, Franzesi CT, Riva L, Casiraghi A, Sironi S. Diagnostic accuracy of 256-row multidetector CT coronary angiography with prospective ECG-gating combined with fourth-generation iterative reconstruction algorithm in the assessment of coronary artery bypass: evaluation of dose reduction and image quality. LA RADIOLOGIA MEDICA 2017; 122:893-901. [PMID: 28849537 DOI: 10.1007/s11547-017-0800-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 08/10/2017] [Indexed: 02/05/2023]
Abstract
BACKGROUND Effective radiation dose in coronary CT angiography (CTCA) for coronary artery bypass graft (CABG) evaluation is remarkably high because of long scan lengths. Prospective electrocardiographic gating with iterative reconstruction can reduce effective radiation dose. OBJECTIVES To evaluate the diagnostic performance of low-kV CT angiography protocol with prospective ecg-gating technique and iterative reconstruction (IR) algorithm in follow-up of CABG patients compared with standard retrospective protocol. METHODS Seventy-four non-obese patients with known coronary disease treated with artery bypass grafting were prospectively enrolled. All the patients underwent 256 MDCT (Brilliance iCT, Philips) CTCA using low-dose protocol (100 kV; 800 mAs; rotation time: 0.275 s) combined with prospective ECG-triggering acquisition and fourth-generation IR technique (iDose4; Philips); all the lengths of the bypass graft were included in the evaluation. A control group of 42 similar patients was evaluated with a standard retrospective ECG-gated CTCA (100 kV; 800 mAs).On both CT examinations, ROIs were placed to calculate standard deviation of pixel values and intra-vessel density. Diagnostic quality was also evaluated using a 4-point quality scale. RESULTS Despite the statistically significant reduction of radiation dose evaluated with DLP (study group mean DLP: 274 mGy cm; control group mean DLP: 1224 mGy cm; P value < 0.001). No statistical differences were found between PGA group and RGH group regarding intra-vessel density absolute values and SNR. Qualitative analysis, evaluated by two radiologists in "double blind", did not reveal any significant difference in diagnostic quality of the two groups. CONCLUSIONS The development of high-speed MDCT scans combined with modern IR allows an accurate evaluation of CABG with prospective ECG-gating protocols in a single breath hold, obtaining a significant reduction in radiation dose.
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Affiliation(s)
- Davide Ippolito
- Department of Diagnostic Radiology, "San Gerardo" Hospital, Via Pergolesi 33, 20900, Monza, MB, Italy.
- School of Medicine, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, MB, Italy.
| | - Davide Fior
- Department of Diagnostic Radiology, "San Gerardo" Hospital, Via Pergolesi 33, 20900, Monza, MB, Italy
- School of Medicine, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, MB, Italy
| | - Cammillo Talei Franzesi
- Department of Diagnostic Radiology, "San Gerardo" Hospital, Via Pergolesi 33, 20900, Monza, MB, Italy
- School of Medicine, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, MB, Italy
| | - Luca Riva
- Department of Diagnostic Radiology, "San Gerardo" Hospital, Via Pergolesi 33, 20900, Monza, MB, Italy
- School of Medicine, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, MB, Italy
| | - Alessandra Casiraghi
- Department of Diagnostic Radiology, "San Gerardo" Hospital, Via Pergolesi 33, 20900, Monza, MB, Italy
- School of Medicine, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, MB, Italy
| | - Sandro Sironi
- School of Medicine, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, MB, Italy
- Department of Diagnostic Radiology, "Papa Giovanni XXIII" Hospital, Bergamo, Italy
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Heye T, Kauczor HU, Szabo G, Hosch W. Computed tomography angiography of coronary artery bypass grafts: robustness in emergency and clinical routine settings. Acta Radiol 2014; 55:161-70. [PMID: 23908242 DOI: 10.1177/0284185113494977] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND There is a high probability for presence of irregular heart rates and artifacts in patients with previous coronary artery bypass graft (CABG) surgery. Previously reported diagnostic performance of ECG-gated 64-slice dual-source computer tomography angiography (CTA) in this patient group is based on pre-selection for normal heart rate and routine clinical setting. PURPOSE To investigate image quality and diagnostic performance of CTA in patients with previous CABG surgery in various clinical settings. MATERIAL AND METHODS Fifty-six non-selected, consecutive patients (110 grafts, 44 arterial, 66 venous) with previous CABG surgery were prospectively examined using a dual-source 64-slice CT (Siemens Definition, Forchheim, Germany) without utilization of CT-related pharmaceutical heart rate control. Patients were stratified according to the clinical setting: planned redo-cardiac surgery; emergency CTA within 30 days after CABG surgery; routine follow-up after CABG surgery. A reference standard was available for 30 patients (53.6%; 67/110 grafts). Image quality, artifacts, and graft patency were independently assessed by two observers. RESULTS All CTAs were diagnostic despite the presence of irregular heart rhythm (25% of cases) and artifacts (72.7% of grafts). CTA was accurate in all patient groups in assessing graft patency (97.9% sensitivity; 100% specificity; 98.5% accuracy) but artifacts decreased diagnostic performance for stenosis detection (60% sensitivity; 88.6% specificity; 84.1% accuracy). Arterial grafts exhibited more surgical clip artifacts compared to venous grafts, which predominantly showed motion artifacts. Overall diagnostic quality was rated excellent in 70.9%/56.4%, good in 23.4%/39.1%, and sufficient in 5.5%/4.5% by each observer, respectively. CTA detected acute findings in 10 cases (graft bleeding, graft occlusion, pericardial hematoma, sternal instability with retrosternal abscess formation, pericardial effusion, left ventricle thrombus) in the emergency group; seven cases required surgical revision. CONCLUSION Dual-source CTA is a robust and accurate method for assessment of graft patency and detection of relevant extra-cardiac pathologies in a non-selected patient population after CABG surgery in routine as well as emergency clinical settings. Artifacts caused by irregular heart rhythm or surgical clips do not impair graft patency evaluation but limit stenosis assessment.
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Affiliation(s)
- Tobias Heye
- Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany
- Department of Radiology and Nuclear Medicine, University Hospital Basel, Basel, Switzerland
| | - Hans-Ulrich Kauczor
- Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany
| | - Gabor Szabo
- Department of Cardiothoracic Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Waldemar Hosch
- Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany
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Sun Z, Ng KH. Prospective versus retrospective ECG-gated multislice CT coronary angiography: A systematic review of radiation dose and diagnostic accuracy. Eur J Radiol 2012; 81:e94-100. [DOI: 10.1016/j.ejrad.2011.01.070] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 01/11/2011] [Accepted: 01/17/2011] [Indexed: 12/28/2022]
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Lee JH, Chun EJ, Choi SI, Vembar M, Lim C, Park KH, Choi DJ. Prospective versus retrospective ECG-gated 64-detector coronary CT angiography for evaluation of coronary artery bypass graft patency: comparison of image quality, radiation dose and diagnostic accuracy. Int J Cardiovasc Imaging 2011; 27:657-67. [PMID: 21678128 DOI: 10.1007/s10554-011-9904-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 05/27/2011] [Indexed: 01/21/2023]
Abstract
We aimed to evaluate image quality, radiation dose and diagnostic accuracy of coronary CT angiography (CCTA) with a prospectively gated transverse-axial scan (PGT) compared with a retrospectively gated helical scan (RGH), using a 64-slice scanner in patients who underwent coronary artery bypass graft (CABG). Of the 131 consecutive patients that underwent CABG using 64-slice multidetector row computed tomography during 2008, patients with heart rate (HR) of <75 beats/minute (bpm), and HR variation <10 bpm were included in the study. PGT was performed on 39 patients with 93 grafts, with RGH performed on 43 patients with 102 grafts. Image quality (1: excellent-4: poor) and estimated radiation dose were compared between the two groups. Of these, a total of 64 segments in 26 patients were subjected to invasive coronary angiography (ICA) for clinical reasons. Diagnostic accuracy of CCTA for evaluation of graft was performed between the two groups with ICA as a reference standard in terms of significant stenosis (≥ 50% of luminal stenosis). The image quality was not statistically different in the two groups. Mean effective radiation dose was 6.5 mSv in PGT-group, which was significantly lower than that in the RGH-group (21.2 mSv; P < 0.001). There was no statistically significant difference in diagnostic accuracy between the two groups (PGT-group versus RGH-group; 93.1% versus 91.4%). PGT can achieve dose reductions of up to 70% compared to RGH while maintaining image quality and high diagnostic accuracy in patients undergoing CABG.
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Affiliation(s)
- Jae Hwan Lee
- Divison of Cardiovascular Imaging, Department of Radiology, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do 463-707, Korea
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Choi TY, Malpeso J, Li D, Sourayanezhad S, Budoff MJ. Radiation dose reduction with increasing utilization of prospective gating in 64-multidetector cardiac computed tomography angiography. J Cardiovasc Comput Tomogr 2011; 5:264-70. [PMID: 21723518 DOI: 10.1016/j.jcct.2011.06.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2011] [Revised: 05/13/2011] [Accepted: 06/04/2011] [Indexed: 10/18/2022]
Abstract
BACKGROUND Medical radiation exposure is a major concern, and several methods have been proposed to reduce radiation doses in multidetector cardiac computed tomography (CT). OBJECTIVE The purpose of this study was to review radiation doses of clinical cardiac CT performed at our center and to evaluate the effect of radiation dose reduction strategies on the median dose delivered to patients over time. METHODS This study included 623 consecutive clinical patients (male, 58%) who were referred for imaging. The effective dose (mSv) was derived from the product of the dose-length-product (DLP) and a conversion coefficient for the chest (0.014). RESULTS The median radiation dose of all patients was 3.0 mSv (interquartile range [IQR], 1.9-8.1 mSv). A significant difference was observed in radiation dose between the prospective (n = 384) and retrospective (n = 239) gating groups (2.0 vs 9.6 mSv; P < 0.0001). Compared with patients with coronary artery bypass grafting (CABG; n = 52), patients without CABG had significantly lower median radiation dose (prospective gating: 2.0 vs 3.4 mSv, P < 0.0001; retrospective gating: 9.3 vs 10.3 mSv, P < 0.0001). In patients with CABG, a significant difference was observed in radiation dose between prospective and retrospective gating (3.4 vs 10.3; P < 0.0001). The median radiation doses per month at our center decreased from 6.2 to 2.1 mSv over time with increasing use of prospective gating (≤91%). CONCLUSION Radiation reduction techniques have led to progressive decreases in radiation exposure over time, primarily because of prospective gating.
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Affiliation(s)
- Tae-Young Choi
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, 1124 W Carson St, RB-2, Torrance, CA 90502, USA
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Law WY, Yang CC, Chen LK, Huang TC, Lu KM, Wu TH, Mok GS. Retrospective gating vs. prospective triggering for noninvasive coronary angiography: Assessment of image quality and radiation dose using a 256-slice CT scanner with 270 ms gantry rotation. Acad Radiol 2011; 18:31-9. [PMID: 21145027 DOI: 10.1016/j.acra.2010.07.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 07/23/2010] [Accepted: 07/28/2010] [Indexed: 10/18/2022]
Abstract
OBJECTIVE To report our clinical experience with a 256-slice multidetector computed tomography (MDCT) with a 270-ms gantry rotation system in performing CT coronary angiograms (CTCA) using both prospectively gated step and shoot (PGSS) and retrospectively gated helical (RGH) techniques. MATERIALS AND METHODS We studied 252 patients who received CTCA; 126 patients having mean heart rate (HR) of 72.1 were imaged with RGH CTCA and 126 patients having mean HR of 58.7 were imaged with PGSS CTCA. For patients with a prescan HR ≤70 beats/min, a PGSS acquisitions trigger was used, whereas patients whose prescan HR was >70 beats/min were imaged using an RGH acquisition. The blood vessel accessibility of both PGSS and RGH techniques was evaluated by grading the image quality score from 1 (no motion artifacts) to 4 (severe motion artifacts preventing diagnosis) for each coronary artery segment. Radiation doses of the techniques were also compared. RESULTS In both groups, more than 50% of segments received the best imaging score. The overall image quality scores for RGH and PGSS groups were 1.522 ± 0.317 and 1.500 ± 0.374, respectively. There was no significant difference in right coronary artery, left anterior descending artery, and left circumflex artery image quality between the two groups. Only 0.1% of segments were nonevaluative with the PGSS technique and all segments were evaluative with RGH. PGSS was associated with a 62% reduction in effective radiation dose as compared to RGH (PGSS, 5.1 mSv; RGH, 13.2 mSv). CONCLUSIONS There is no significant difference in image quality between PGSS and RGH in this study. Although providing similar image quality as RGH, PGSS was associated with a 62% reduction in effective radiation dose. Further study to confirm the diagnostic accuracy as compared to coronary artery angiography is warranted.
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