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Almeida IP, Schyns LEJR, Öllers MC, van Elmpt W, Parodi K, Landry G, Verhaegen F. Dual-energy CT quantitative imaging: a comparison study between twin-beam and dual-source CT scanners. Med Phys 2017; 44:171-179. [DOI: 10.1002/mp.12000] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 08/25/2016] [Accepted: 11/04/2016] [Indexed: 11/08/2022] Open
Affiliation(s)
- Isabel P. Almeida
- Department of Radiation Oncology (MAASTRO); GROW - School for Oncology and Developmental Biology; Maastricht University Medical Centre; Maastricht The Netherlands
| | - Lotte E. J. R. Schyns
- Department of Radiation Oncology (MAASTRO); GROW - School for Oncology and Developmental Biology; Maastricht University Medical Centre; Maastricht The Netherlands
| | - Michel C. Öllers
- Department of Radiation Oncology (MAASTRO); GROW - School for Oncology and Developmental Biology; Maastricht University Medical Centre; Maastricht The Netherlands
| | - Wouter van Elmpt
- Department of Radiation Oncology (MAASTRO); GROW - School for Oncology and Developmental Biology; Maastricht University Medical Centre; Maastricht The Netherlands
| | - Katia Parodi
- Department of Medical Physics; Faculty of Physics; Ludwig-Maximilians-Universität München; Am Coulombwall 1 85748 Garching b. München Germany
| | - Guillaume Landry
- Department of Medical Physics; Faculty of Physics; Ludwig-Maximilians-Universität München; Am Coulombwall 1 85748 Garching b. München Germany
| | - Frank Verhaegen
- Department of Radiation Oncology (MAASTRO); GROW - School for Oncology and Developmental Biology; Maastricht University Medical Centre; Maastricht The Netherlands
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Power SP, Moloney F, Twomey M, James K, O’Connor OJ, Maher MM. Computed tomography and patient risk: Facts, perceptions and uncertainties. World J Radiol 2016; 8:902-915. [PMID: 28070242 PMCID: PMC5183924 DOI: 10.4329/wjr.v8.i12.902] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 08/29/2016] [Accepted: 10/24/2016] [Indexed: 02/06/2023] Open
Abstract
Since its introduction in the 1970s, computed tomography (CT) has revolutionized diagnostic decision-making. One of the major concerns associated with the widespread use of CT is the associated increased radiation exposure incurred by patients. The link between ionizing radiation and the subsequent development of neoplasia has been largely based on extrapolating data from studies of survivors of the atomic bombs dropped in Japan in 1945 and on assessments of the increased relative risk of neoplasia in those occupationally exposed to radiation within the nuclear industry. However, the association between exposure to low-dose radiation from diagnostic imaging examinations and oncogenesis remains unclear. With improved technology, significant advances have already been achieved with regards to radiation dose reduction. There are several dose optimization strategies available that may be readily employed including omitting unnecessary images at the ends of acquired series, minimizing the number of phases acquired, and the use of automated exposure control as opposed to fixed tube current techniques. In addition, new image reconstruction techniques that reduce radiation dose have been developed in recent years with promising results. These techniques use iterative reconstruction algorithms to attain diagnostic quality images with reduced image noise at lower radiation doses.
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Guberina N, Lechel U, Forsting M, Ringelstein A. Efficacy of high-pitch CT protocols for radiation dose reduction. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2016; 36:N57-N66. [PMID: 27642775 DOI: 10.1088/0952-4746/36/4/n57] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Various strategies have been developed to reduce radiation exposure of patients in CT examinations. The aim of this study was to evaluate the efficacy of high pitch in representative CT protocols examining lung embolism. We performed thermoluminescence measurements with an anthropomorphic phantom exposing it to CT algorithms for lung embolism in a 128-multislice, dual-source CT scanner: a standard CT protocol (sCT) and a CT protocol with a high pitch (+ F). Radiation doses for both CT algorithms were compared and the dose reduction potential of high pitch for individual organs was evaluated. As expected, the +F mode reduced the effective dose and organ doses in the primary beam of radiation (namely, lung, bone marrow, heart, breast, skin and skeleton) compared with sCT by up to 52% for an equivalent image quality. On the contrary, for organs at the margin of the primary beam (thymus, thyroid, liver, pancreas, kidneys, colon and small intestine), the +F mode reduced effective radiation doses by only 0-30%, compared with sCT. The dose reduction potential of the +F mode greatly depends on the position of the organ in the scan field. While for organs in the primary beam + F leads to a considerable dose reduction, it is less effective for tissues at the margin of the scanned area.
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Affiliation(s)
- N Guberina
- Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Hufelandstraße 55, 45147, Essen, Germany
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High-pitch Helical Dual-source Computed Tomographic Pulmonary Angiography: Comparing Image Quality in Inspiratory Breath-hold and During Free Breathing. J Thorac Imaging 2016; 31:56-62. [PMID: 26447868 DOI: 10.1097/rti.0000000000000173] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The purpose of this study was to compare qualitative and quantitative image parameters of dual-source high-pitch helical computed tomographic pulmonary angiography (CTPA) in breath-holding (BH) versus free-breathing (FB) patients. MATERIALS AND METHODS Ninety-nine consented patients (61 female individuals; mean age±SD, 49±18.7 y) were randomized into BH (n=45) versus FB (n=54) high-pitch helical CTPA. Patient characteristics and CTPA radiation doses were analyzed. Two readers assessed for pulmonary embolism (PE), transient interruption of contrast, and respiratory and cardiac motion. The readers used a subjective 3-point scale to rate the pulmonary artery opacification and lung parenchymal appearance. A single reader assessed mean pulmonary artery signal intensity, noise, contrast, signal to noise ratio, and contrast to noise ratio. RESULTS PE was diagnosed in 16% BH and 19% FB patients. CTPAs of both groups were of excellent or acceptable quality for PE evaluation and of similar mean radiation doses (1.3 mSv). Transient interruption of contrast was seen in 5/45 (11%) BH and 5/54 (9%) FB patients (not statistically significant, P=0.54). No statistically significant difference was noted in cardiac, diaphragmatic, and lung parenchymal motion. Lung parenchymal assessment was excellent in all cases, except for 5/54 (9%) motion-affected FB cases with acceptable quality (statistically significant, P=0.03). No CTPA was considered nondiagnostic by any of the readers. No objective image quality differences were noted between both groups (P>0.05). CONCLUSIONS High-pitch helical CTPA acquired during BH or in FB yields comparable image quality for the diagnosis of PE and lung pathology, with low radiation exposure. Only a modest increase in lung parenchymal artifacts is encountered in FB high-pitch helical CTPA.
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Sandfort V, Ahlman MA, Jones EC, Selwaness M, Y Chen M, R Folio L, Bluemke DA. High pitch third generation dual-source CT: Coronary and cardiac visualization on routine chest CT. J Cardiovasc Comput Tomogr 2016; 10:282-8. [PMID: 27133589 PMCID: PMC4958576 DOI: 10.1016/j.jcct.2016.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 03/21/2016] [Accepted: 03/25/2016] [Indexed: 12/21/2022]
Abstract
BACKGROUND Chest CT scans are frequently performed in radiology departments but have not previously contained detailed depiction of cardiac structures. OBJECTIVES To evaluate myocardial and coronary visualization on high-pitch non-gated CT of the chest using 3rd generation dual-source computed tomography (CT). METHODS Cardiac anatomy of patients who had 3rd generation, non-gated high pitch contrast enhanced chest CT and who also had prior conventional (low pitch) chest CT as part of a chest abdomen pelvis exam was evaluated. Cardiac image features were scored by reviewers blinded to diagnosis and pitch. Paired analysis was performed. RESULTS 3862 coronary segments and 2220 cardiac structures were evaluated by two readers in 222 CT scans. Most patients (97.2%) had chest CT for oncologic evaluation. The median pitch was 2.34 (IQR 2.05, 2.65) in high pitch and 0.8 (IQR 0.8, 0.8) in low pitch scans (p < 0.001). High pitch CT showed higher image visualization scores for all cardiovascular structures compared with conventional pitch scans (p < 0.0001). Coronary arteries were visualized in 9 coronary segments per exam in high pitch scans versus 2 segments for conventional pitch (p < 0.0001). Radiation exposure was lower in the high pitch group compared with the conventional pitch group (median CTDIvol 10.83 vs. 12.36 mGy and DLP 790 vs. 827 mGycm respectively, p < 0.01 for both) with comparable image noise (p = 0.43). CONCLUSION Myocardial structure and coronary arteries are frequently visualized on non-gated 3rd generation chest CT. These results raise the question of whether the heart and coronary arteries should be routinely interpreted on routine chest CT that is otherwise obtained for non-cardiac indications.
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Affiliation(s)
- Veit Sandfort
- Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD, USA
| | - Mark A Ahlman
- Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD, USA
| | - Elizabeth C Jones
- Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD, USA
| | - Mariana Selwaness
- Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD, USA
| | - Marcus Y Chen
- Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD, USA
| | - Les R Folio
- Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD, USA
| | - David A Bluemke
- Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD, USA.
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Temporal resolution measurement of 128-slice dual source and 320-row area detector computed tomography scanners in helical acquisition mode using the impulse method. Phys Med 2016; 32:625-30. [PMID: 27056437 DOI: 10.1016/j.ejmp.2016.02.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 01/09/2016] [Accepted: 02/29/2016] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To analyse the temporal resolution (TR) of modern computed tomography (CT) scanners using the impulse method, and assess the actual maximum TR at respective helical acquisition modes. METHODS To assess the actual TR of helical acquisition modes of a 128-slice dual source CT (DSCT) scanner and a 320-row area detector CT (ADCT) scanner, we assessed the TRs of various acquisition combinations of a pitch factor (P) and gantry rotation time (R). RESULTS The TR of the helical acquisition modes for the 128-slice DSCT scanner continuously improved with a shorter gantry rotation time and greater pitch factor. However, for the 320-row ADCT scanner, the TR with a pitch factor of <1.0 was almost equal to the gantry rotation time, whereas with pitch factor of >1.0, it was approximately one half of the gantry rotation time. The maximum TR values of single- and dual-source helical acquisition modes for the 128-slice DSCT scanner were 0.138 (R/P=0.285/1.5) and 0.074s (R/P=0.285/3.2), and the maximum TR values of the 64×0.5- and 160×0.5-mm detector configurations of the helical acquisition modes for the 320-row ADCT scanner were 0.120 (R/P=0.275/1.375) and 0.195s (R/P=0.3/0.6), respectively. CONCLUSION Because the TR of a CT scanner is not accurately depicted in the specifications of the individual scanner, appropriate acquisition conditions should be determined based on the actual TR measurement.
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Third-generation dual-source 70-kVp chest CT angiography with advanced iterative reconstruction in young children: image quality and radiation dose reduction. Pediatr Radiol 2016; 46:462-72. [PMID: 26739141 DOI: 10.1007/s00247-015-3510-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 09/27/2015] [Accepted: 11/12/2015] [Indexed: 12/19/2022]
Abstract
BACKGROUND Many technical updates have been made in multi-detector CT. OBJECTIVE To evaluate image quality and radiation dose of high-pitch second- and third-generation dual-source chest CT angiography and to assess the effects of different levels of advanced modeled iterative reconstruction (ADMIRE) in newborns and children. MATERIALS AND METHODS Chest CT angiography (70 kVp) was performed in 42 children (age 158 ± 267 days, range 1-1,194 days). We evaluated subjective and objective image quality, and radiation dose with filtered back projection (FBP) and different strength levels of ADMIRE. For comparison were 42 matched controls examined with a second-generation 128-slice dual-source CT-scanner (80 kVp). RESULTS ADMIRE demonstrated improved objective and subjective image quality (P < .01). Mean signal/noise, contrast/noise and subjective image quality were 11.9, 10.0 and 1.9, respectively, for the 80 kVp mode and 11.2, 10.0 and 1.9 for the 70 kVp mode. With ADMIRE, the corresponding values for the 70 kVp mode were 13.7, 12.1 and 1.4 at strength level 2 and 17.6, 15.6 and 1.2 at strength level 4. Mean CTDIvol, DLP and effective dose were significantly lower with the 70-kVp mode (0.31 mGy, 5.33 mGy*cm, 0.36 mSv) compared to the 80-kVp mode (0.46 mGy, 9.17 mGy*cm, 0.62 mSv; P < .01). CONCLUSION The third-generation dual-source CT at 70 kVp provided good objective and subjective image quality at lower radiation exposure. ADMIRE improved objective and subjective image quality.
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Vardhanabhuti V, Nicol E, Morgan-Hughes G, Roobottom CA, Roditi G, Hamilton MCK, Bull RK, Pugliese F, Williams MC, Stirrup J, Padley S, Taylor A, Davies LC, Bury R, Harden S. Recommendations for accurate CT diagnosis of suspected acute aortic syndrome (AAS)--on behalf of the British Society of Cardiovascular Imaging (BSCI)/British Society of Cardiovascular CT (BSCCT). Br J Radiol 2016; 89:20150705. [PMID: 26916280 PMCID: PMC4985448 DOI: 10.1259/bjr.20150705] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Accurate and timely assessment of suspected acute aortic syndrome is crucial in this life-threatening condition. Imaging with CT plays a central role in the diagnosis to allow expedited management. Diagnosis can be made using locally available expertise with optimized scanning parameters, making full use of recent advances in CT technology. Each imaging centre must optimize their protocols to allow accurate diagnosis, to optimize radiation dose and in particular to reduce the risk of false-positive diagnosis that may simulate disease. This document outlines the principles for the acquisition of motion-free imaging of the aorta in this context.
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Affiliation(s)
- Varut Vardhanabhuti
- 1 Plymouth University Peninsula Schools of Medicine and Dentistry, John Bull Building, Plymouth, UK.,2 Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong
| | - Edward Nicol
- 3 Radiology Department, Royal Brompton Hospital, London, UK
| | | | - Carl A Roobottom
- 1 Plymouth University Peninsula Schools of Medicine and Dentistry, John Bull Building, Plymouth, UK.,5 Department of Radiology, Derriford Hospital, Plymouth, UK
| | - Giles Roditi
- 6 Department of Radiology, Glasgow Royal Infirmary, Glasgow, UK
| | | | - Russell K Bull
- 8 Department of Radiology, Royal Bournemouth Hospital, Bournemouth, UK
| | - Franchesca Pugliese
- 9 Centre for Advanced Cardiovascular Imaging, NIHR Cardiovascular Biomedical Research Unit, Barts and The London School of Medicine & Barts Health NHS Trust, London, UK
| | - Michelle C Williams
- 10 University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Royal Infirmary of Edinburgh, Edinburgh, UK
| | - James Stirrup
- 3 Radiology Department, Royal Brompton Hospital, London, UK
| | - Simon Padley
- 3 Radiology Department, Royal Brompton Hospital, London, UK
| | - Andrew Taylor
- 11 Cardiothoracic Unit, Great Ormond Street Hospital for Children, London, UK
| | - L Ceri Davies
- 9 Centre for Advanced Cardiovascular Imaging, NIHR Cardiovascular Biomedical Research Unit, Barts and The London School of Medicine & Barts Health NHS Trust, London, UK
| | - Roger Bury
- 12 Radiology Department, Blackpool Teaching Hospitals, Blackpool, UK
| | - Stephen Harden
- 13 Department of Cardiothoracic Radiology, University Hospital Southampton NHS Trust, Southampton, UK
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Lim HK, Ha HI, Hwang HJ, Lee K. Feasibility of high-pitch dual-source low-dose chest CT: Reduction of radiation and cardiac artifacts. Diagn Interv Imaging 2016; 97:443-9. [PMID: 26896374 DOI: 10.1016/j.diii.2016.01.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 01/07/2016] [Accepted: 01/07/2016] [Indexed: 11/17/2022]
Abstract
PURPOSE To compare the radiation dose and image quality, focused mainly on cardiac pulsation artifact, between high-pitch low-dose chest computed tomography (HP-LDCT) and standard low-dose chest CT (LDCT). PATIENTS AND METHODS One hundred patients underwent HP-LDCT (50 patients) or LDCT (50 patients). Scan parameters were the same except for the pitch and gantry rotation time: 3.0 vs. 1.2 and 0.28s vs. 0.5s, respectively. Objective image noise at five regions and subjective image quality, such as noise, artifacts, cardiac pulsation artifacts, and overall diagnostic acceptability, were evaluated using a five-point scale. The significance level for all tests was set at P<0.05. RESULTS The dose-length products (DLPs) with HP-LDCT and LDCT were 90.2±4.3mGycm and 103.1±6.4mGycm, respectively (P<0.01). DLP of HP-LDCT showed a 13% reduction versus LDCT. Objective image noise was not significantly different. Cardiac pulsation artifacts showed a significant reduction on HP-LDCT (P<0.01). Other subjective image quality parameters of HP-LDCT were similar to those of LDCT. The overall diagnostic acceptability of HP-LDCT was better than that of LDCT (P<0.01). CONCLUSIONS HP-LDCT showed a 13% mean radiation dose reduction with no deterioration in image quality due to cardiac pulsation artifacts.
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Affiliation(s)
- H K Lim
- Department of Radiology, Soonchunhyang University Seoul Hospital, 59 Daesagwan-ro, Yongsan-gu, Seoul, 140-743, Republic of Korea.
| | - H I Ha
- Department of Radiology, Hallym University Medical Center, Hallym University Sacred Heart Hospital, 896 Pyeongchon-dong, Dongan-gu, Anyang-si, Gyeonggi-do, 431-070, Republic of Korea.
| | - H J Hwang
- Department of Radiology, Hallym University Medical Center, Hallym University Sacred Heart Hospital, 896 Pyeongchon-dong, Dongan-gu, Anyang-si, Gyeonggi-do, 431-070, Republic of Korea.
| | - K Lee
- Department of Radiology, Hallym University Medical Center, Hallym University Sacred Heart Hospital, 896 Pyeongchon-dong, Dongan-gu, Anyang-si, Gyeonggi-do, 431-070, Republic of Korea.
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Low-Voltage, High-Pitch Computerized Tomography Angiography of the Infrarenal Aorta and Lower Extremity Vessels: Assessment of Radiation Dose, Image Quality With Hybrid Iterative Reconstruction, and Efficacy of Test Injection Using a Monitoring Scan at Knee Level. J Comput Assist Tomogr 2016; 40:402-8. [PMID: 26854413 DOI: 10.1097/rct.0000000000000365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Our aim was to assess image quality and radiation dose of low-voltage high-pitch computed tomography angiography of the infrarenal aorta and lower extremities and evaluate the efficacy of test injection technique using a monitoring scan at knee level. METHODS A total of 60 patients with suspected peripheral arterial disease were divided into 2 groups: group 1 (30 patients, 80 kVp, high pitch [3.2], and hybrid iterative reconstruction [sinogram-affirmed iterative reconstruction]) and group 2 (30 patients, 120 kVp, low pitch [1.0], and filtered back projection reconstruction). The test injection technique at knee level was used to determine the scan delay time in group 1. The image quality and radiation exposure were compared. RESULTS There were significant differences between the 2 groups in mean (SD) arterial attenuation (80 vs 120 kVp: 507.78 [103.01] vs 317.54 [62.03] Hounsfield units, P < 0.001), mean (SD) signal-to-noise ratio (51.04 [20.29] vs 34.66 [9.94], P < 0.001), and contrast-to-noise ratio (44.83 [17.93] vs 28.26 [9.60], P < 0.001). No difference in subjective image quality was found between the 2 groups (all P > 0.05). The imaging time was significantly shorter in group 1 (2.70 [0.11] vs 14.65 [0.90s], P < 0.001). The mean (SD) effective dose was significantly lower in the 80 kVp group (0.76 [0.06] vs 4.29 [0.63] mSv, P < 0.001). CONCLUSIONS The 80-kVp high-pitch computed tomography angiography of the lower limbs using sinogram-affirmed iterative reconstruction yields reduction of radiation exposure as well as obtains acceptable image quality if acquisition protocols are used in conjunction with the test injection technique using monitoring scan at knee level to determine the delay time.
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Is bronchial wall imaging affected by temporal resolution? comparative evaluation at 140 and 75 ms in 90 patients. Eur Radiol 2016; 26:469-77. [DOI: 10.1007/s00330-015-3819-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 04/10/2015] [Accepted: 04/22/2015] [Indexed: 11/26/2022]
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Bridoux A, Hutt A, Faivre JB, Flohr T, Duhamel A, Pagniez J, Remy J, Remy-Jardin M. Coronary artery visibility in free-breathing young children on non-gated chest CT: impact of temporal resolution. Pediatr Radiol 2015; 45:1761-70. [PMID: 26293229 DOI: 10.1007/s00247-015-3401-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 04/08/2015] [Accepted: 06/01/2015] [Indexed: 12/01/2022]
Abstract
BACKGROUND Dual-source CT allows scanning of the chest with high pitch and high temporal resolution, which can improve the detection of proximal coronary arteries in infants and young children when scanned without general anesthesia, sedation or beta-blockade. OBJECTIVE To compare coronary artery visibility between higher and standard temporal resolution. MATERIALS AND METHODS We analyzed CT images in 93 children who underwent a standard chest CT angiographic examination with reconstruction of images with a temporal resolution of 75 ms (group 1) and 140 ms (group 2). RESULTS The percentage of detected coronary segments was higher in group 1 than in group 2 when considering all segments (group 1: 27%; group 2: 24%; P = 0.0004) and proximal segments (group 1: 37%; group 2: 32%; P = 0.0006). In both groups, the highest rates of detection were observed for the left main coronary artery (S1) (group 1: 65%; group 2: 58%) and proximal left anterior descending coronary artery (S2) (group 1: 43%; group 2: 42%). Higher rates of detection were seen in group 1 for the left main coronary artery (P = 0.03), proximal right coronary artery (P = 0.01), proximal segments of the left coronary artery (P = 0.02) and proximal segments of the left and right coronary arteries (P = 0.0006). CONCLUSION Higher temporal resolution improved the visibility of proximal coronary arteries in pediatric chest CT.
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Affiliation(s)
- Alexandre Bridoux
- Department of Thoracic Imaging, Hospital Calmette (EA 2694), CHRU et Université de Lille, Boulevard Jules Leclerq, 59037 Lille Cedex, France
| | - Antoine Hutt
- Department of Thoracic Imaging, Hospital Calmette (EA 2694), CHRU et Université de Lille, Boulevard Jules Leclerq, 59037 Lille Cedex, France
| | - Jean-Baptiste Faivre
- Department of Thoracic Imaging, Hospital Calmette (EA 2694), CHRU et Université de Lille, Boulevard Jules Leclerq, 59037 Lille Cedex, France
| | - Thomas Flohr
- Department of Research & Development in CT, Siemens Healthcare, Forchheim, Germany
| | - Alain Duhamel
- Department of Biostatistics, Université de Lille, Lille, France
| | - Julien Pagniez
- Department of Thoracic Imaging, Hospital Calmette (EA 2694), CHRU et Université de Lille, Boulevard Jules Leclerq, 59037 Lille Cedex, France
| | - Jacques Remy
- Department of Thoracic Imaging, Hospital Calmette (EA 2694), CHRU et Université de Lille, Boulevard Jules Leclerq, 59037 Lille Cedex, France
| | - Martine Remy-Jardin
- Department of Thoracic Imaging, Hospital Calmette (EA 2694), CHRU et Université de Lille, Boulevard Jules Leclerq, 59037 Lille Cedex, France.
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Computed Tomography Imaging in Patients with Congenital Heart Disease Part I: Rationale and Utility. An Expert Consensus Document of the Society of Cardiovascular Computed Tomography (SCCT). J Cardiovasc Comput Tomogr 2015; 9:475-92. [DOI: 10.1016/j.jcct.2015.07.004] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 07/17/2015] [Indexed: 12/16/2022]
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High-Pitch Dual-Source MDCT for Imaging of the Thoracoabdominal Aorta: Relationships Among Radiation Dose, Noise, Pitch, and Body Size in a Phantom Experiment and Clinical Study. AJR Am J Roentgenol 2015; 205:834-9. [DOI: 10.2214/ajr.15.14334] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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65
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66
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Utility of Low-dose High-pitch Scanning for Pediatric Cardiac Computed Tomographic Imaging. J Thorac Imaging 2015; 30:W36-40. [DOI: 10.1097/rti.0000000000000131] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Li HO, Huo R, Wang XM, Xu GQ, Duan YH, Nie P, Ji XP, Cheng ZP, Xu ZD. High-pitch spiral CT with 3D reformation: an alternative choice for imaging vascular anomalies with affluent blood flow in the head and neck of infants and children. Br J Radiol 2015; 88:20150005. [PMID: 26055504 DOI: 10.1259/bjr.20150005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVE To evaluate the feasibility of high-pitch spiral CT in imaging vascular anomalies (VAs) with affluent blood flow in the head and neck of infants and children. METHODS For patients with suspected VAs and affluent blood flow pre-detected by ultrasound, CT was performed with high-pitch mode, individualized low-dose scan protocol and three-dimensional (3D) reformation. A five-point scale was used for image quality evaluation. Diagnostic accuracy was calculated with clinical diagnosis with/without pathological results as the reference standard. Radiation exposure and single-phase scan time were recorded. Treatment strategies were formulated based on CT images and results and were monitored through follow-up results. RESULTS 20 lesions were identified in 15 patients (median age of 11 months). The mean score of image quality was 4.13 ± 0.74. 7 patients (7/15, 46.67%) were diagnosed with haemangiomas, 6 patients (6/15, 40%) were diagnosed with venous malformations and 2 patients (2/15, 13.33%) were diagnosed with arteriovenous malformations. The average effective radiation doses of a single phase and of the total procedure were 0.27 ± 0.08 and 0.86 ± 0.21 mSv. The average scanning time of a single phase was 0.46 ± 0.09 s. After treatment, 13 patients (13/15, 86.67%) achieved excellent results, and 2 patients (2/15, 13.33%) showed good results in follow-up visits. CONCLUSION High-pitch spiral CT with an individualized low-dose scan protocol and 3D reformation is an effective modality for imaging VAs with affluent blood flow in the head and neck of infants and children when vascular details are needed and ultrasound and MRI could not provide the complete information. ADVANCES IN KNOWLEDGE This study proposes an alternative modality for imaging VAs with affluent blood flow.
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Affiliation(s)
- H-O Li
- 1 Department of Radiology, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - R Huo
- 2 Department of Aesthetic, Plastic and Burn Surgery, Shandong Provincial Hospital, Jinan, Shandong, China
| | - X-M Wang
- 3 Department of CT, Shandong University, Shandong Medical Imaging Research Institute, Jinan, Shandong, China
| | - G-Q Xu
- 2 Department of Aesthetic, Plastic and Burn Surgery, Shandong Provincial Hospital, Jinan, Shandong, China
| | - Y-H Duan
- 3 Department of CT, Shandong University, Shandong Medical Imaging Research Institute, Jinan, Shandong, China
| | - P Nie
- 4 Department of Radiology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - X-P Ji
- 3 Department of CT, Shandong University, Shandong Medical Imaging Research Institute, Jinan, Shandong, China
| | - Z-P Cheng
- 3 Department of CT, Shandong University, Shandong Medical Imaging Research Institute, Jinan, Shandong, China
| | - Z-D Xu
- 3 Department of CT, Shandong University, Shandong Medical Imaging Research Institute, Jinan, Shandong, China
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Abstract
OBJECTIVE. In this article, we review the histopathologic classification of coronary atherosclerotic plaques and describe the possibilities and limitations of CT regarding the evaluation of coronary artery plaques. CONCLUSION. The composition of atherosclerotic plaques in the coronary arteries displays substantial variability and is associated with the likelihood for rupture and downstream ischemic events. Accurate identification and quantification of coronary plaque components on CT is challenging because of the limited temporal, spatial, and contrast resolutions of current scanners. Nonetheless, CT may provide valuable information that has potential for characterization of coronary plaques. For example, the extent of calcification can be determined, lipid-rich lesions can be separated from more fibrous ones, and positive remodeling can be identified.
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Beeres M, Bauer RW, Kerl JM, Vogl TJ, Lee C. Energy Limits in Second Generation High-pitch Dual Source CT - Comparison in an Upper Abdominal Phantom. J Clin Imaging Sci 2015; 5:2. [PMID: 25806137 PMCID: PMC4322381 DOI: 10.4103/2156-7514.150441] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 01/22/2015] [Indexed: 11/18/2022] Open
Abstract
Objectives: The aim of our study was to find out how much energy is applicable in second-generation dual source high-pitch computed tomography (CT) in imaging of the abdomen. Materials and Methods: We examined an upper abdominal phantom using a Somatom Definition Flash CT-Scanner (Siemens, Forchheim, Germany). The study protocol consisted of a scan-series at 100 kV and 120 kV. In each scan series we started with a pitch of 3.2 and reduced it in steps of 0.2, until a pitch of 1.6 was reached. The current was adjusted to the maximum the scanner could achieve. Energy values, image noise, image quality, and radiation exposure were evaluated. Results: For a pitch of 3.2 the maximum applicable current was 142 mAs at 120 kV and in 100 kV the maximum applicable current was 114 mAs. For conventional abdominal imaging, current levels of 200 to 260 mAs are generally used. To achieve similar current levels, we had to decrease the pitch to 1.8 at 100 kV — at this pitch we could perform our imaging at 204 mAs. At a pitch of 2.2 in 120 kV we could apply a current of 206 mAs. Conclusion: We conclude our study by stating that if there is a need for a higher current, we have to reduce the pitch. In a high-pitch dual source CT, we always have to remember where our main focus is, so we can adjust the pitch to the energy we need in the area of the body that has to be imaged, to find answers to the clinical question being raised.
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Affiliation(s)
- Martin Beeres
- Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt, Germany
| | - Ralf W Bauer
- Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt, Germany
| | - Josef M Kerl
- Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt, Germany
| | - Thomas J Vogl
- Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt, Germany
| | - Clara Lee
- Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt, Germany
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Leng S, Hruska CB, McCollough CH. Use of ionizing radiation in screening examinations for coronary artery calcium and cancers of the lung, colon, and breast. Semin Roentgenol 2015; 50:148-60. [PMID: 25770345 DOI: 10.1053/j.ro.2014.10.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Shuai Leng
- Department of Radiology, Mayo Clinic, Rochester, MN.
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72
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Feasibility of discriminating uric acid from non-uric acid renal stones using consecutive spatially registered low- and high-energy scans obtained on a conventional CT scanner. AJR Am J Roentgenol 2015; 204:92-7. [PMID: 25539242 DOI: 10.2214/ajr.13.11911] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The objective of our study was to show the feasibility of distinguishing between uric acid (UA) and non-UA renal stones using two consecutive spatially registered low- and high-energy scans acquired on a conventional CT system. SUBJECTS AND METHODS A total of 33 patients undergoing clinically indicated dual-source dual-energy CT examinations to differentiate UA from non-UA renal stones were enrolled in this study. Immediately after patients underwent clinically indicated dual-source dual-energy CT, two consecutive scans (one at 80 kV and one at 140 kV) were obtained on a conventional CT scanner over the region limited to the stones identified on the dual-source scans. After 3D deformable registration of the 80- and 140-kV images, UA and non-UA stones were identified using commercial software. The sensitivity, specificity, and accuracy of stone classification were calculated using the dual-source results as the reference standard. RESULTS A total of 469 stones were identified in the dual-source examinations (26 UA and 443 non-UA stones). The average in-plane stone diameter was 4.4 ± 2.5 (SD) mm (range, 2.0-18.9 mm). The overall sensitivity, specificity, and accuracy for identifying UA stones were 73.1%, 90.1%, and 89.1%, respectively. The sensitivity, specificity, and accuracy were 94.7%, 96.9%, and 96.8% for stones 3 mm or larger (n = 341 [19 UA and 322 non-UA]). CONCLUSION Accurate differentiation of UA from non-UA renal stones is feasible using two consecutively acquired and spatially registered conventional CT scans.
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Ramirez-Giraldo JC, Fuld M, Grant K, Primak AN, Flohr T. New Approaches to Reduce Radiation While Maintaining Image Quality in Multi-Detector-Computed Tomography. CURRENT RADIOLOGY REPORTS 2015. [DOI: 10.1007/s40134-014-0084-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Nie P, Yang G, Wang X, Duan Y, Xu W, Li H, Cao T, Liu X, Ji X, Cheng Z, Wang A. Application of prospective ECG-gated high-pitch 128-slice dual-source CT angiography in the diagnosis of congenital extracardiac vascular anomalies in infants and children. PLoS One 2014; 9:e115793. [PMID: 25546178 PMCID: PMC4278836 DOI: 10.1371/journal.pone.0115793] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 11/26/2014] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To investigate the value of prospective ECG-gated high-pitch 128-slice dual-source CT (DSCT) angiography in the diagnosis of congenital extracardiac vascular anomalies in infants and children in comparison with transthoracic echocardiography (TTE). METHODS Eighty consecutive infants or children clinically diagnosed of congenital heart disease and suspected with extracardiac vascular anomaly were enrolled, and 75 patients were finally included in this prospective study. All patients underwent prospective ECG-gated high-pitch DSCT angiography after TTE with an interval of 1-7 days. The diagnostic accuracy and sensitivity of high-pitch DSCT angiography and TTE were compared according to the surgical/CCA findings. The image quality of DSCT was assessed using a five-point scale. The effective radiation dose (ED) was calculated. RESULTS A total of 17 congenital heart diseases and 162 separate extracardiac vascular anomalies were confirmed by surgical/CCA findings in 75 patients. The diagnostic accuracy of high-pitch DSCT angiography and TTE was 99.67% and 97.89%, respectively. The sensitivity of high-pitch DSCT angiography and TTE was 97.53% and 79.62%, respectively. There was significant difference regarding to the diagnostic accuracy and the sensitivity between high-pitch DSCT angiography and TTE (χ2 = 23.561 and 28.013, P<0.05). The agreement on the image quality scoring of DSCT between the two observers was excellent (κ = 0.81), and the mean score of image quality was 4.1±0.7. The mean ED of DSCT was 0.29±0.08 mSv. CONCLUSIONS Prospective ECG-gated high-pitch 128-slice DSCT angiography with low radiation dose and high diagnostic accuracy has higher sensitivity compared to TTE in the detection of congenital extracardiac vascular anomalies in infants and children.
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Affiliation(s)
- Pei Nie
- Department of Radiology, the Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Guangjie Yang
- Department of Nuclear Medicine, Qilu Hospital, Shandong University, Jinan, Shandong, China
| | - Ximing Wang
- Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Diseases, Shandong Medical Imaging Research Institute, Jinan, Shandong, China
- * E-mail:
| | - Yanhua Duan
- Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Diseases, Shandong Medical Imaging Research Institute, Jinan, Shandong, China
| | - Wenjian Xu
- Department of Radiology, the Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Haiou Li
- Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Diseases, Shandong Medical Imaging Research Institute, Jinan, Shandong, China
| | - Ting Cao
- Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Diseases, Shandong Medical Imaging Research Institute, Jinan, Shandong, China
| | - Xuejun Liu
- Department of Radiology, the Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Xiaopeng Ji
- Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Diseases, Shandong Medical Imaging Research Institute, Jinan, Shandong, China
| | - Zhaoping Cheng
- Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-Cerebral Vascular Diseases, Shandong Medical Imaging Research Institute, Jinan, Shandong, China
| | - Anbiao Wang
- Department of Cardiovascular Surgery, Shandong Provincial Hospital, Jinan, Shandong, China
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Niwa S, Hara T, Kato H, Wada Y. [Performance evaluation of CT automatic exposure control on fast dual spiral scan]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2014; 70:1273-1279. [PMID: 25410334 DOI: 10.6009/jjrt.2014_jsrt_70.11.1273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The performance of individual computed tomography automatic exposure control (CT-AEC) is very important for radiation dose reduction and image quality equalization in CT examinations. The purpose of this study was to evaluate the performance of CT-AEC in conventional pitch mode (Normal spiral) and fast dual spiral scan (Flash spiral) in a 128-slice dual-source CT scanner. To evaluate the response properties of CT-AEC in the 128-slice DSCT scanner, a chest phantom was placed on the patient table and was fixed at the center of the field of view (FOV). The phantom scan was performed using Normal spiral and Flash spiral scanning. We measured the effective tube current time product (Eff. mAs) of simulated organs in the chest phantom along the longitudinal (z) direction, and the dose dependence (distribution) of in-plane locations for the respective scan modes was also evaluated by using a 100-mm-long pencil-type ionization chamber. The dose length product (DLP) was evaluated using the value displayed on the console after scanning. It was revealed that the response properties of CT-AEC in Normal spiral scanning depend on the respective pitches and Flash spiral scanning is independent of the respective pitches. In-plane radiation dose of Flash spiral was lower than that of Normal spiral. The DLP values showed a difference of approximately 1.7 times at the maximum. The results of our experiments provide information for adjustments for appropriate scanning parameters using CT-AEC in a 128-slice DSCT scanner.
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Accuracy, image quality, and radiation dose of prospectively ECG-triggered high-pitch dual-source CT angiography in infants and children with complex coarctation of the aorta. Acad Radiol 2014; 21:1248-54. [PMID: 25097011 DOI: 10.1016/j.acra.2014.04.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 04/23/2014] [Accepted: 04/24/2014] [Indexed: 11/24/2022]
Abstract
RATIONALE AND OBJECTIVES To evaluate the diagnostic accuracy, image quality, and radiation dose of prospective electrocardiogram (ECG)-triggered high-pitch dual-source computed tomography (DSCT) in infants and young children with complex coarctation of the aorta (CoA). MATERIALS AND METHODS Forty pediatric patients aged < 4 years with suspected CoA underwent prospective ECG-triggered high-pitch DSCT angiography and transthoracic echocardiography (TTE). Surgery and/or conventional cardiac angiography (CCA) were performed in all patients. The diagnostic accuracy of DSCT angiography and TTE was compared to the surgical and/or CCA findings. The causes of misdiagnosis and miss were analyzed, and the advantages and limitation of both imaging modalities were evaluated. Image quality of DSCT was evaluated, and effective radiation dose was calculated. RESULTS The sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy of DSCT in evaluation of complex CoA were 92.37%, 98.51%, 97.32%, 93.57%, and 96.25%, respectively. There was a significant difference in the accuracy between DSCT and TTE (χ² = 9.9, P<.05). For a total of 80 extracardiac anomalies, the sensitivity (98.8%, 79/80) of DSCT was greater than that of TTE (62.5%; 50 of 80). On the contrary, for 38 cardiac anomalies, the sensitivity (78.9%, 30 of 38) of DSCT was lesser than that of TTE (100%; 38 of 38). The mean score of image quality was 4.27 ± 0.73. The mean effective radiation dose was 0.20 ± 0.09 mSv. CONCLUSIONS Prospective ECG-triggered high-pitch DSCT may be a clinical feasible modality in the evaluation of pediatric patients with complex CoA, providing adequate image quality, high diagnostic accuracy, and low radiation dose.
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Penzkofer T, Donandt E, Isfort P, Allmendinger T, Kuhl CK, Mahnken AH, Bruners P. Influence of trigger type, tube voltage and heart rate on calcified plaque imaging in dual source cardiac computed tomography: phantom study. BMC Med Imaging 2014; 14:30. [PMID: 25178653 PMCID: PMC4174388 DOI: 10.1186/1471-2342-14-30] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 08/03/2014] [Indexed: 11/10/2022] Open
Abstract
Background To investigate the impact of high pitch cardiac CT vs. retrospective ECG gated CT on the quantification of calcified vessel stenoses, with assessment of the influence of tube voltage, reconstruction kernel and heart rate. Methods A 4D cardiac movement phantom equipped with three different plaque phantoms (12.5%, 25% and 50% stenosis at different calcification levels), was scanned with a 128-row dual source CT scanner, applying different trigger types (gated vs. prospectively triggered high pitch), tube voltages (100-120 kV) and heart rates (50–90 beats per minute, bpm). Images were reconstructed using different standard (B26f, B46f, B70f) and iterative (I26f, I70f) convolution kernels. Absolute and relative plaque sizes were measured and statistically compared. Radiation dose associated with the different methods (gated vs. high pitch, 100 kV vs. 120 kV) were compared. Results Compared to the known diameters of the phantom plaques and vessels both CT-examination techniques overestimated the degrees of stenoses. Using the high pitch CT-protocol plaques appeared larger (0.09 ± 0.31 mm, 2 ± 8 percent points, PP) in comparison to the ECG-gated CT-scans. Reducing tube voltage had a similar effect, resulting in higher grading of the same stenoses by 3 ± 8 PP. In turn, sharper convolution kernels lead to a lower grading of stenoses (differences of up to 5%). Pairwise comparison of B26f and I26f, B46f and B70f, and B70f and I70f showed differences of 0–1 ± 6–8 PP of the plaque depiction. Motion artifacts were present only at 90 bpm high pitch experiments. High-pitch protocols were associated with significantly lower radiation doses compared with the ECG-gated protocols (258.0 mGy vs. 2829.8 mGy CTDIvol, p ≤ 0.0001). Conclusion Prospectively triggered high-pitch cardiac CT led to an overestimation of plaque diameter and degree of stenoses in a coronary phantom. This overestimation is only slight and probably negligible in a clinical situation. Even at higher heart rates high pitch CT-scanning allowed reliable measurements of plaque and vessel diameters with only slight differences compared ECG-gated protocols, although motion artifacts were present at 90 bpm using the high pitch protocols.
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Affiliation(s)
- Tobias Penzkofer
- Department of Diagnostic and Interventional Radiology, Aachen University Hospital, RWTH Aachen University, Pauwelsstr, 30, 52074 Aachen, Germany.
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McLaughlin PD, Liang T, Homiedan M, Louis LJ, O'Connell TW, Krzymyk K, Nicolaou S, Mayo JR. High pitch, low voltage dual source CT pulmonary angiography: assessment of image quality and diagnostic acceptability with hybrid iterative reconstruction. Emerg Radiol 2014; 22:117-23. [PMID: 24993583 DOI: 10.1007/s10140-014-1230-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 04/23/2014] [Indexed: 12/20/2022]
Abstract
Increased use of CT Pulmonary angiography in suspected pulmonary embolism (PE) has driven research to minimize radiation dose while maintaining image quality and diagnostic accuracy. Following institutional review board approval, we performed a retrospective comparison study in patients with suspected PE. Patients were scanned using an ultra high pitch dual source technique (pitch = 2.6) using 120 kV (SVCTPA) (n = 54) or 100 kV (RV-CTPA) (n = 52). SV-CTPA images were reconstructed using filtered back projection (SV-wFBP) and RV-CTPA images were reconstructed using both FBP (RV-wFBP) and Iterative Reconstruction (RV-IR). Comparison of radiation dose, diagnostic ability, subjective image noise, quality, and sharpness, diagnostic agreement, signal to noise (SNR) and contrast to noise ratios (CNR) were performed. Mean effective dose was 2.56 ± 0.19 mSv for the RV protocol compared to 5.36 ± 0.60 mSv for the SV. The RV-CTPA protocol resulted in a mean DLP reduction of 52 % and mean CTDI reduction of 51 %. Pulmonary artery SNR and CNR were significantly higher on RV-IR images than SV-wFBP (p = 0.007, p = 0.003). Mean subjective image noise, quality and sharpness scores did not differ significantly between the SV-wFBP and RVIR images (p > 0.05). Subjective quality scores were significantly better for the RV-IR group compared to the RV-wFBP group (p < 0.001). Agreement between readers for presence or absence of pulmonary emboli on RV-IR images was almost perfect (κ = 0.891, p < 0.001). Iterative reconstruction complements ultra high pitch dual source CTPA examinations acquired using a reduced voltage resulting in higher mean pulmonary artery SNR and CNR when compared to both RV-wFBP and SV-CTPA.
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Affiliation(s)
- Patrick D McLaughlin
- Department of Radiology, Vancouver General Hospital, Vancouver, BC, Canada, V5Z 1M9,
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Beitzke D, Nolz R, Unterhumer S, Plank C, Weber M, Schernthaner R, Schöpf V, Wolf F, Loewe C. Low-dose high-pitch CT angiography of the supraaortic arteries using sinogram-affirmed iterative reconstruction. PLoS One 2014; 9:e99832. [PMID: 24919195 PMCID: PMC4053523 DOI: 10.1371/journal.pone.0099832] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 05/19/2014] [Indexed: 11/18/2022] Open
Abstract
Objective To prospectively evaluate image quality and radiation dose using a low-dose computed tomography angiography protocol and iterative image reconstruction for high-pitch dual-source CT-angiography (DSCTA) of the supraaortic arteries. Material and Methods DSCTA was performed in 42 patients, using either 120 kVp tube voltage, 120 mAS tube current, 2.4 pitch and filtered back projection, or 100 kVp tube voltage, 100 mAs tube current, 3.2 pitch, and sinogram affirmed iterative reconstruction. Measurements of vessel attenuation, of the contrast-to-noise ratio (CNR) and the signal-to-noise ratio (SNR) were performed to objectively evaluate image quality. Two readers evaluated subjective image quality and image noise, using a four-point scale. Effective dose was used to compare the differences in radiation dose. Results Low-dose protocol application showed significantly higher vessel opacification (p = 0.013), and non-significantly higher CNR and SNR values. There was no difference in the subjective image quality and image noise reading between the protocols. Effective dose was significantly lower using the low-dose protocol (1.29±0.21 mSv vs. 2.92±0.72 mSv; p<0.001). Conclusion The combined use of reduced tube voltage, reduced tube current, and iterative reconstruction reduces radiation dose by 55.4% in high-pitch DSCTA of the supraaortic arteries without impairment of image quality.
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Affiliation(s)
- Dietrich Beitzke
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Vienna, Austria
- * E-mail:
| | - Richard Nolz
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Vienna, Austria
| | - Sylvia Unterhumer
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Vienna, Austria
| | - Christina Plank
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Vienna, Austria
| | - Michael Weber
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Vienna, Austria
| | - Rüdiger Schernthaner
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Vienna, Austria
| | - Veronika Schöpf
- Department of Biomedical Imaging and Image-guided Therapy, Division of Neuroradiology and Musculoskeletal Radiology, Medical University Vienna, Vienna, Austria
| | - Florian Wolf
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Vienna, Austria
| | - Christian Loewe
- Department of Biomedical Imaging and Image-guided Therapy, Division of Cardiovascular and Interventional Radiology, Medical University Vienna, Vienna, Austria
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Fukuda A, Lin PJP, Matsubara K, Miyati T. Measurement of table feed speed in modern CT. J Appl Clin Med Phys 2014; 15:275–281. [PMID: 24892343 PMCID: PMC5711061 DOI: 10.1120/jacmp.v15i3.4703] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 01/04/2014] [Accepted: 12/31/2013] [Indexed: 11/23/2022] Open
Abstract
The purpose of this study was to develop and evaluate a noninvasive method to assess table feed speed (mm/s) in modern commercial computed tomography (CT) systems. The table feed (mm/rotation) was measured at selected nominal table feed speeds, given as low (26.67 mm/s), intermediate (48.00 mm/s), and high (64.00 mm/s), by utilizing a computed radiography (CR) cassette installed with a photostimulable phosphor plate. The cassette was placed on the examination table to travel through the isocenter longitudinally, with a total scan length of over 430 mm. The distance travelled was employed to determine the total table feed length. To calculate the table feed speed, gantry rotation time was measured concurrently at a preselected nominal rotation time of 750 ms. Upon completion of data acquisition, the table feed and gantry rotation time were analyzed and used to calculate the actual table feed speed (mm/s). Under the low table feed speed setting, the table feed speed was found to be 26.67 mm/s. Similarly, under the intermediate and high table feed speed settings, the table feed speed was found to be 48.10 and 64.07 mm/s, respectively. Measurements of the table feed speed can be accomplished with a CR system and solid-state detector, and the table feed speed results were in excellent agreement with the nominal preset values.
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Christensen JD, Seaman DM, Lungren MP, Hurwitz LM, Boll DT. Assessment of vascular contrast and wall motion of the aortic root and ascending aorta on MDCT angiography: dual-source high-pitch vs non-gated single-source acquisition schemes. Eur Radiol 2014; 24:990-7. [PMID: 24573567 DOI: 10.1007/s00330-014-3120-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 01/31/2014] [Accepted: 02/10/2014] [Indexed: 12/18/2022]
Abstract
OBJECTIVES This retrospective study assessed whether dual-source high-pitch computed tomographic angiography (CTA) offered advantages over single-source standard-pitch techniques in the evaluation of the ascending aorta. METHODS Twenty patients who received both thoracic dual-source high-pitch and single-source standard-pitch CTAs within 1 year were assessed. Dual-source CTAs were performed; standard-pitch imaging used dose-modulated 120 kVp/150 mAs and 0.8 pitch compared with high-pitch protocols employing dose-modulated 120 kVp/250 mAs and 2.4 target pitch. Radiation dose was documented. Contrast-to-noise ratios (CNRs) at sinuses of the Valsalva (CNRValsalva) and ascending aorta (CNRAorta) were calculated. Dose/CNR for each technique was compared with paired t-tests. Motion at aortic valve, aortic root and ascending aorta were assessed with four-point scales and Mann-Whitney U tests; longitudinal extension of motion was compared with paired t-tests. RESULTS Significantly lower motion scores for high-pitch, compared with standard-pitch acquisitions for aortic annulus, 0 vs. 2, aortic root, 0 vs. 3, and ascending aorta, 0 vs. 2, were achieved. Significantly reduced longitudinal extension of motion at aortic root, 4.9 mm vs 15.7 mm, and ascending aorta, 4.9 mm vs 21.6 mm, was observed. Contrast was not impacted: CNRValsalva, 45.6 vs 46.3, and CNRAorta, 45.3 vs 47.1. CTDIvol was significantly decreased for high-pitch acquisitions, 13.9 mGy vs 15.8 mGy. CONCLUSIONS Dual-source high-pitch CTAs significantly decreased motion artefact without negatively impacting vascular contrast and radiation dose. KEY POINTS • Dual-source high-pitch CTA significantly decreased motion artefact of the ascending aorta. • Dual-source high-pitch CTA did not negatively impact on vascular contrast. • Dual-source high-pitch CTA significantly decreased radiation dose compared with single-source standard-pitch acquisitions.
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Affiliation(s)
- Jared D Christensen
- Department of Radiology, Duke University Medical Center, Durham, NC, 27710, USA
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Weininger M, Renker M, Rowe GW, Abro JA, Costello P, Schoepf UJ. Integrative computed tomographic imaging of coronary artery disease. Expert Rev Cardiovasc Ther 2014; 9:27-43. [DOI: 10.1586/erc.10.166] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Radiation dose reduction in pediatric cardiac computed tomography: experience from a tertiary medical center. Pediatr Cardiol 2014; 35:171-9. [PMID: 23872908 DOI: 10.1007/s00246-013-0758-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 06/20/2013] [Indexed: 10/26/2022]
Abstract
Cardiac CT angiography (cCTA) has become an established method for the assessment of congenital heart disease. However, the potential harmful effects of ionizing radiation must be considered, particularly in younger, more radiosensitive patients. In this study, we sought to assess the temporal change in radiation doses from pediatric cCTA during an 8-year period at a tertiary medical center. This retrospective study included all patients ≤18 years old who were referred to electrocardiography (ECG)-gated cCTA for the assessment of congenital heart disease or inflammatory disease (Kawasaki disease) from November 2004 to September 2012. During the study period, 95 patients were scanned using 3 different scanner models-64-slice multidetector CT (64-MDCT) and first- (64-DSCT) and second-generation (128-DSCT) dual-source CT-and 3 scan protocols-retrospective ECG-gated helical scanning (RG), prospective ECG-triggered axial scanning (PT), or prospective ECG-triggered high-pitch helical scanning (HPH). Effective dose (ED) was calculated with the dose length product method with a conversion factor (k) adjusted for age. ED was then compared among scan protocols. Image quality was extracted from clinical cCTA reports when available. Overall, 94 % of scans were diagnostic (80 % for 64-slice MDCT, 93 % for 64-slice DSCT, and 97 % for 128-slice DSCT).With 128-DSCT, median ED (1.0 [range 0.6-2.0] mSv) decreased by 85.8 % and 66.8 % compared with 64-MDCT (6.8 [range 2.9-13.6] mSv) and 64-DSCT (2.9 [range 0.9-4.1] mSv), respectively. With HPH, median ED (0.9 [range 0.6-1.8] mSv) decreased by 59.4 % and 85.4 % compared with PT (2.2 [range 0.9-3.4] mSv) and RG (6.1 [range 2.5-10.6] mSv). cCTA can now be obtained at very low radiation doses in pediatric patients using the latest dual-source CT technology in combination with prospective ECG-triggered HPH acquisition.
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CT signs of right ventricular dysfunction correlated with echocardiography-derived pulmonary arterial systolic pressure: incremental value of the pulmonary arterial diameter index. Int J Cardiovasc Imaging 2013; 29 Suppl 2:109-18. [DOI: 10.1007/s10554-013-0322-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 10/29/2013] [Indexed: 10/26/2022]
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Mobberley SD, Fuld MK, Sieren JP, Primak AN, Hoffman EA. Scatter correction associated with dedicated dual-source CT hardware improves accuracy of lung air measures. Acad Radiol 2013; 20:1334-43. [PMID: 24119345 DOI: 10.1016/j.acra.2013.04.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 04/09/2013] [Accepted: 04/09/2013] [Indexed: 11/17/2022]
Abstract
RATIONALE AND OBJECTIVES Accurate assessment of air density used to quantitatively characterize amount and distribution of emphysema in chronic obstructive pulmonary disease (COPD) subjects has remained challenging. Hounsfield units (HU) within tracheal air can be considerably less negative than -1000 HU. This study has sought to characterize the effects of improved scatter correction used in dual-source pulmonary computed tomography (CT). MATERIALS AND METHODS Dual-source dual-energy (DSDE) and single-source (SS) scans taken at multiple energy levels and scan settings were acquired for quantitative comparison using anesthetized ovine (n = 6), swine (n = 13), and a lung phantom. Data were evaluated for the lung, inferior vena cava, and tracheal segments. To minimize the effect of cross-scatter, the phantom scans in the DSDE mode were obtained by reducing the current of one of the tubes to near zero. RESULTS A significant shift in mean HU values in the tracheal regions of animals and the phantom is observed, with values consistently closer to -1000 HU in DSDE mode. HU values associated with SS mode demonstrated a positive shift of up to 32 HU. In vivo tracheal air measurements demonstrated considerable variability with SS scanning, whereas these values were more consistent with DSDE imaging. Scatter effects in the lung parenchyma differed from adjacent tracheal measures. CONCLUSION Data suggest that the scatter correction introduced into the dual-energy mode of imaging has served to provide more accurate CT lung density measures sought to quantitatively assess the presence and distribution of emphysema in COPD subjects. Data further suggest that CT images, acquired without adequate scatter correction, cannot be corrected by linear algorithms given the variability in tracheal air HU values and the independent scatter effects on lung parenchyma.
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Affiliation(s)
- Sean D Mobberley
- Department of Radiology, Division of Physiological Imaging, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, CC 701 GH, University of Iowa Carver College of Medicine, Iowa City, IA 52241; Department of Biomedical Engineering, University of Iowa, Iowa City, IA
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Zheng M, Zhao H, Xu J, Wu Y, Li J. Image quality of ultra-low-dose dual-source CT angiography using high-pitch spiral acquisition and iterative reconstruction in young children with congenital heart disease. J Cardiovasc Comput Tomogr 2013; 7:376-82. [DOI: 10.1016/j.jcct.2013.11.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 10/15/2013] [Accepted: 11/03/2013] [Indexed: 10/26/2022]
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Farshad-Amacker NA, Alkadhi H, Leschka S, Frauenfelder T. Effect of high-pitch dual-source CT to compensate motion artifacts: a phantom study. Acad Radiol 2013; 20:1234-9. [PMID: 24029055 DOI: 10.1016/j.acra.2013.07.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/24/2013] [Accepted: 07/02/2013] [Indexed: 11/19/2022]
Abstract
RATIONALE AND OBJECTIVES To evaluate the potential of high-pitch, dual-source computed tomography (DSCT) for compensation of motion artifacts. MATERIALS AND METHODS Motion artifacts were created using a moving chest/cardiac phantom with integrated stents at different velocities (from 0 to 4-6 cm/s) parallel (z direction), transverse (x direction), and diagonal (x and z direction combined) to the scanning direction using standard-pitch (SP) (pitch = 1) and high-pitch (HP) (pitch = 3.2) 128-detector DSCT (Siemens, Healthcare, Forchheim, Germany). The scanning parameters were (SP/HP): tube voltage, 120 kV/120 kV; effective tube current time product, 300 mAs/500 mAs; and a pitch of 1/3.2. Motion artifacts were analyzed in terms of subjective image quality and object distortion. Image quality was rated by two blinded, independent observers using a 4-point scoring system (1, excellent; 2, good with minor object distortion or blurring; 3, diagnostically partially not acceptable; and 4, diagnostically not acceptable image quality). Object distortion was assessed by the measured changes of the object's outer diameter (x) and length (z) and a corresponding calculated distortion vector (d) (d = √(x(2) + z(2))). RESULTS The interobserver agreement was excellent (k = 0.91). Image quality using SP was diagnostically not acceptable with any motion in x direction (scores 3 and 4), in contrast to HP DSCT where it remained diagnostic up to 2 cm/s (scores 1 and 2). For motion in the z direction only, image quality remained diagnostic for SP and HP DSCT (scores 1 and 2). Changes of the object's diameter (x), length (z), and distortion vectors (d) were significantly greater with SP (overall: x = 1.9 cm ± 1.7 cm, z = 0.6 cm ± 0.8 cm, and d = 1.4 cm ± 1.5 cm) compared to HP DSCT (overall: x = 0.1 cm ± 0.1 cm, z = 0.0 cm ± 0.1 cm, and d = 0.1 cm ± 0.1 cm; each P < .05). CONCLUSION High-pitch DSCT significantly decreases motion artifacts in various directions and improves image quality.
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Affiliation(s)
- Nadja A Farshad-Amacker
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 101, 8091 Zurich, Switzerland.
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Leng S, Zhao K, Qu M, An KN, Berger R, McCollough CH. Dynamic CT technique for assessment of wrist joint instabilities. Med Phys 2013; 38 Suppl 1:S50. [PMID: 21978117 DOI: 10.1118/1.3577759] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To develop a 4D [three-dimensional (3D) + time] CT technique to capture high spatial and temporal resolution images of wrist joint motion so that dynamic joint instabilities can be detected before the development of static joint instability and onset of osteoarthritis (OA). METHODS A cadaveric wrist was mounted onto a custom motion simulator and scanned with a dual source CT scanner during radial-ulnar deviation. A dynamic 4D CT technique was utilized to reconstruct images at 20 equidistant time points from one motion cycle. 3D images of carpal bones were generated using volume rendering techniques (VRT) at each of the 20 time points and then 4D movies were generated to depict the dynamic joint motion. The same cadaveric wrist was also scanned after cutting all portions of the scapholunate interosseus ligament to simulate scapholunate joint instability. Image quality were assessed on an ordinal scale (1-4, 4 being excellent) by three experienced orthopedic surgeons (specialized in hand surgery) by scoring 2D axial images. Dynamic instability was evaluated by the same surgeons by comparing the two 4D movies of joint motion. Finally, dose reduction was investigated using the cadaveric wrist by scanning at different dose levels to determine the lowest radiation dose that did not substantially alter diagnostic image quality. RESULTS The mean image quality scores for dynamic and static CT images were 3.7 and 4.0, respectively. The carpal bones, distal radius and ulna, and joint spaces were clearly delineated in the 3D VRT images, without motion blurring or banding artifacts, at all time points during the motion cycle. Appropriate viewing angles could be interactively selected to view any articulating structure using different 3D processing techniques. The motion of each carpal bone and the relative motion among the carpal bones were easily observed in the 4D movies. Joint instability was correctly and easily detected in the scan performed after the ligament was cut by observing the relative motion between the scaphoid and lunate bones. Diagnostic capability was not sacrificed with a volume CT dose index (CTDI(vol)) as low as 18 mGy for the whole scan, with estimated skin dose of approximately 33 mGy, which is much lower than the threshold for transient skin erythema (2000 mGy). CONCLUSIONS The proposed dynamic 4D CT imaging technique generated high spatial and high temporal resolution images without requiring periodic joint motion. Preliminary results from this cadaveric study demonstrate the feasibility of detecting joint instability using this technique.
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Affiliation(s)
- Shuai Leng
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA.
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Landry G, Seco J, Gaudreault M, Verhaegen F. Deriving effective atomic numbers from DECT based on a parameterization of the ratio of high and low linear attenuation coefficients. Phys Med Biol 2013; 58:6851-66. [DOI: 10.1088/0031-9155/58/19/6851] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Schmidt B, Saltybaeva N, Kolditz D, Kalender WA. Assessment of patient dose from CT localizer radiographs. Med Phys 2013; 40:084301. [DOI: 10.1118/1.4813296] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Ghetti C, Palleri F, Serreli G, Ortenzia O, Ruffini L. Physical characterization of a new CT iterative reconstruction method operating in sinogram space. J Appl Clin Med Phys 2013; 14:4347. [PMID: 23835395 PMCID: PMC5714520 DOI: 10.1120/jacmp.v14i4.4347] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 03/13/2013] [Accepted: 03/04/2013] [Indexed: 11/23/2022] Open
Abstract
Recently a new iterative reconstruction algorithm named Sinogram Affirmed Iterative Reconstruction (SAFIRE) has been released by Siemens. This algorithm works in the raw data domain with noise reduction as main purpose, providing five different strengths. In this study, the effect of SAFIRE on image quality has been investigated using selected phantoms and a comparison with standard filtered back projection (FBP) has been carried out. The following quantitative parameters have been evaluated: image noise, impact of different reconstruction kernels on noise reduction, noise power spectrum (NPS), contrast‐to‐noise ratio (CNR), spatial resolution, and linearity and accuracy of CT numbers. The influence of strengths on image quality parameters has also been examined. Results show that image noise reduction is independent of reconstruction kernel and strongly related to the strength of SAFIRE applied. The peak of NPS curve for SAFIRE reconstructions is shifted towards low frequencies; this effect is more marked at higher levels of strength. Contrast‐to‐noise ratio is always improved in SAFIRE reconstruction and increases with higher strength. At different dose levels SAFIRE preserves CT number accuracy, linearity, and spatial resolution, both in transversal and coronal planes. These results confirm that SAFIRE allows for image noise reduction with preserved image quality. First clinical data to validate this phantom analysis and confirm that commercially available iterative algorithms can play an effective role in dose containment. PACS number: 87.57.Q
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Affiliation(s)
- Caterina Ghetti
- Servizio di Fisica Sanitaria, Azienda Ospedaliero-Universitaria, Parma, Italy.
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Quantitative analysis of motion artifacts in high-pitch dual-source computed tomography of the thorax. J Thorac Imaging 2013; 27:382-6. [PMID: 22627616 DOI: 10.1097/rti.0b013e3182575729] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
PURPOSE The purpose of this study was to objectively analyze motion artifacts on thoracic computed tomography (CT) with dual-source high-pitch and single-source techniques when using a no-breath-hold technique to examine patients who have difficulty complying with breath-holding instructions. MATERIALS AND METHODS A total of 120 patients who received CT of the thorax with a free-breathing technique in single-source (16 slices and 128 slices; pitch = 1.2) and dual-source (pitch = 3.0) manners were evaluated retrospectively. In each of the 3 study groups, movements of the diaphragm and pulsations of the aortic root and main pulmonary artery were analyzed for their number and severity (blurred distance). RESULTS No motion artifacts of the diaphragm were identified using a pitch of 3.0 (compared with n = 14 for single-source CT using 128 slices and n = 24 using 16-slice CT). In single-source examinations, the severity of artifacts was similar between 128-slice CT and 16-slice CT: blurring distance of the lung parenchyma due to diaphragm movements was 14 versus 16 mm, and double contours of the aorta were measured as 8 and 9 mm, respectively. CONCLUSIONS A high-pitch, dual-source mode is potentially advantageous for evaluating the lung parenchyma and vascular structures in patients who have difficulty complying with breath-holding instructions. Increasing from 16 to 128 slices can significantly reduce the number and severity of motion artifacts.
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Entezari P, Kino A, Honarmand AR, Galizia MS, Yang Y, Collins J, Yaghmai V, Carr JC. Analysis of the thoracic aorta using a semi-automated post processing tool. Eur J Radiol 2013; 82:1558-64. [PMID: 23680155 DOI: 10.1016/j.ejrad.2013.03.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 03/21/2013] [Accepted: 03/24/2013] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To evaluates a semi-automated method for Thoracic Aortic Aneurysm (TAA) measurement using ECG-gated Dual Source CT Angiogram (DSCTA). METHODS This retrospective HIPAA compliant study was approved by our IRB. Transaxial maximum diameters of outer wall to outer wall were studied in fifty patients at seven anatomic locations of the thoracic aorta: annulus, sinus, sinotubular junction (STJ), mid ascending aorta (MAA) at the level of right pulmonary artery, proximal aortic arch (PROX) immediately proximal to innominate artery, distal aortic arch (DIST) immediately distal to left subclavian artery, and descending aorta (DESC) at the level of diaphragm. Measurements were performed using a manual method and semi-automated software. All readers repeated their measurements. Inter-method, intra-observer and inter-observer agreements were evaluated according to intraclass correlation coefficient (ICC) and Bland-Altman plot. The number of cases with manual contouring or center line adjustment for the semi-automated method and also the post-processing time for each method were recorded. RESULTS The mean difference between semi-automated and manual methods was less than 1.3mm at all seven points. Strong inter-method, inter-observer and intra-observer agreement was recorded at all levels (ICC ≥ 0.9). The maximum rate of manual adjustment of center line and contour was at the level of annulus. The average time for manual post-processing of the aorta was 19 ± 0.3 min, while it took 8.26 ± 2.1 min to do the measurements with the semi-automated tool (Vitrea version 6.0.0.1 software). The center line was edited manually at all levels, with most corrections at the level of annulus (60%), while the contour was adjusted at all levels with highest and lowest number of corrections at the levels of annulus and DESC (75% and 0.07% of the cases), respectively. CONCLUSION Compared to the commonly used manual method, semi-automated measurement of vessel dimensions is feasible in the thoracic aorta with the advantage of reduced post-processing time.
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Affiliation(s)
- Pegah Entezari
- Department of Radiology, Cardiovascular Imaging, Northwestern University, Chicago, IL, United States.
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Wang Q, Qin J, He B, Zhou Y, Yang JJ, Hou XL, Yang XB, Chen JH, Chen YD. Computed tomography coronary angiography with a consistent dose below 2 mSv using double prospectively ECG-triggered high-pitch spiral acquisition in patients with atrial fibrillation: initial experience. Int J Cardiovasc Imaging 2013; 29:1341-9. [PMID: 23471682 DOI: 10.1007/s10554-013-0203-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 03/01/2013] [Indexed: 02/03/2023]
Abstract
To evaluate the feasibility and imaging quality of double prospectively ECG-triggered high-pitch spiral acquisition mode (double flash mode) for coronary computed tomography angiography (CTCA) in patients with atrial fibrillation (AF). 47 patients (11 women, 36 men; mean age 64.5 ± 12.1 years) were enrolled for CTCA examinations using a dual-source CT with 2 × 128 × 0.6 mm collimation, 0.28 s rotation time and a pitch of 3.4. Double flash mode was prospectively triggered first at 60 % and later at 30 % of the R-R interval within two cardiac cycles. Image quality was evaluated using a four-point scale (1 = excellent, 4 = non-assessable). From 672 coronary artery segments, 77.5 % (521/672) was rated as score of 1, 20.8 % (140/672) as score of 2, 1.2 % (8/672) as score of 3 and 0.4 % (3/672) was rated as 'non-assessable'. The average image quality score was 1.25 ± 0.38 on a per segment basis. Mean dose-length product for CTCA was 92.6 ± 28.2 mGy cm, the effective dose was 1.30 ± 0.39 mSv (0.64-1.97 mSv). In patients with AF, double prospectively ECG-triggered high-pitch spiral acquisition mode could be a feasible and valuable scan mode for CTCA with a consistent dose below 2 mSv as well as diagnostic imaging quality.
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Affiliation(s)
- Qi Wang
- Department of Cardiology, Chinese PLA General Hospital, Beijing, 100853, China.
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Kalra MK, Quick P, Singh S, Sandborg M, Persson A. Whole spine CT for evaluation of scoliosis in children: feasibility of sub-milliSievert scanning protocol. Acta Radiol 2013; 54:226-30. [PMID: 23138023 DOI: 10.1258/ar.2012.110625] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Optimization of CT radiation dose is important for children due to their higher risk of radiation-induced adverse effects. Anatomical structures with high inherent contrast, such as bones can be imaged at very low radiation doses by optimizing scan parameters. PURPOSE To assess feasibility of sub-milliSievert whole spine CT scanning protocol for evaluation of scoliosis in children. MATERIAL AND METHODS With approval of the ethical board, we performed whole spine CT for evaluation of scoliosis in 22 children (age range, 3-18 years; mean age, 13 years; 13 girls, 9 boys) on a 128-slice dual source multidetector-row CT scanner. Lowest possible quality reference mAs value (image quality factor for xy-z automatic exposure control or xyz-AEC, CARE Dose 4D) was selected on a per patient basis. Remaining parameters were held constant at 3.0:1 pitch, 128 × 0.6 mm detector collimation, 115.2 mm table feed per gantry rotation, 100 kVp, and 1 and 3 mm reconstructed sections. Average mAs, projected estimated dose savings with AEC, computed tomography dose index volume (CTDI vol), and dose length product (DLP) were recorded. Artifacts were graded on a four-point scale (1, no artifacts; 4, severe artifacts). Ability to identify vertebral and pedicular contours, and measure pedicular width and degree of vertebral rotation was graded on a three-point scale (1, unacceptable; 3, excellent). RESULTS All CT examinations were deemed as reliable for identifying vertebral and pedicular contours as well as for measuring pedicular width (5.9 ± 1.6 mm) and degree of vertebral rotation (28.7 ± 23.4°). Mean objective image noise and signal to noise ratio (SNR) were 57.5 ± 21.5 and 4.7 ± 2.3, respectively. With a mean quality reference mAs of 13, the scanner employed an average actual effective mAs of 10 ± 3.8 (range, 6-18 mAs) with an estimated radiation dose saving of 43.5 ± 16.3% with xyz-AEC compared with fixed mAs. The mean CTDI, DLP, and estimated effective doses were 0.4 ± 0.1 mGy (0.2-0.7 mGy), 21 ± 10 mGy.cm (8-41 mGy.cm), and 0.3 ± 0.1 mSv (0.12-0.64 mSv), respectively. CONCLUSION Radiation dose for whole spine CT for evaluation of scoliosis in children can be minimized to less than one-third of a milliSievert while maintaining diagnostic image quality.
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Affiliation(s)
- Mannudeep K Kalra
- Center for Medical Image Science and Visualization (CMIV), Linkoping University, Linkoping University Hospital, Linkoping, Sweden
- Massachusetts General Hospital Imaging, Massachusetts General Hospital, Boston, MA, USA
| | - Petter Quick
- Center for Medical Image Science and Visualization (CMIV), Linkoping University, Linkoping University Hospital, Linkoping, Sweden
| | - Sarabjeet Singh
- Massachusetts General Hospital Imaging, Massachusetts General Hospital, Boston, MA, USA
| | - Michael Sandborg
- Center for Medical Image Science and Visualization (CMIV), Linkoping University, Linkoping University Hospital, Linkoping, Sweden
- Department of Radiophysics, Linkoping University Hospital, Linkoping, Sweden
| | - Anders Persson
- Center for Medical Image Science and Visualization (CMIV), Linkoping University, Linkoping University Hospital, Linkoping, Sweden
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Bodelle B, Bauer RW, Holthaus L, Schulz B, Al-Butmeh F, Wichmann JL, Beeres M, Vogl TJ, Kerl JM. Dose and image quality of high-pitch dual source computed tomography for the evaluation of cervical lymph node status - comparison to regular 128-slice single source computed tomography. Eur J Radiol 2013; 82:e281-5. [PMID: 23414716 DOI: 10.1016/j.ejrad.2013.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Revised: 12/31/2012] [Accepted: 01/09/2013] [Indexed: 02/06/2023]
Abstract
PURPOSE A high-pitch dual-source CT (DSCT) was compared to a standard single-source CT protocol in terms of dose and image quality for malignant lymphoma staging. MATERIALS AND METHODS Data from 43 patients who underwent DSCT (group 1) of the neck for staging of malignant lymphoma and 40 patients who underwent regular single source CT (group 2) were investigated retrospectively. Volume CT dose index (CTDIvol), dose length product (DLP), background noise (BN), attenuation values, signal-to-noise-ratio (SNR), scan time, effective tube current-time product (eff. mAs), subjective diagnostic image quality and artifact burden were compared. RESULTS CTDIvol (5.5 ± 0.8 mGy vs. 12.4 ± 1.4 mGy), DLP (172 ± 27 mGycm vs. 344 ± 60 mGycm, p<0.0001), eff. mAs (98 ± 15 mAs vs. 183 ± 20 mAs, p<0.0001) and scan time (0.64 ± 0.05 s vs. 8.21 ± 0.72 s) were lower for group 1. BN was higher (p<0.001) for group 1 with a mean difference of 2.6 HU. SNR for sternocleidomastoid and pectoral muscle was lower (6.6-12.3 vs. 7.8-19.1) for group 1. Subjective image quality (1.55 ± 0.6 vs. 1.42 ± 0.5) and artifact burden (1.62 ± 1.0 vs. 1.57 ± 0.9) were not rated significantly different (p=0.47 and p=0.80) with a good inter-observer agreement (κ=0.59-0.90). CONCLUSION High-pitch DSCT allows reduction of patient dose for cervical lymphoma staging while diagnostic image quality is preserved.
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Affiliation(s)
- Boris Bodelle
- Goethe University of Frankfurt, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
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