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Jungblut L, Euler A, Landsmann A, Englmaier V, Mergen V, Sefirovic M, Frauenfelder T. Pulmonary nodule visualization and evaluation of AI-based detection at various ultra-low-dose levels using photon-counting detector CT. Acta Radiol 2024:2841851241275289. [PMID: 39279297 DOI: 10.1177/02841851241275289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/18/2024]
Abstract
BACKGROUND Radiation dose should be as low as reasonably achievable. With the invention of photon-counting detector computed tomography (PCD-CT), the radiation dose may be considerably reduced. PURPOSE To evaluate the potential of PCD-CT for dose reduction in pulmonary nodule visualization for human readers as well as for computer-aided detection (CAD) studies. MATERIAL AND METHODS A chest phantom containing pulmonary nodules of different sizes/densities (range 3-12 mm and -800-100 HU) was scanned on a PCD-CT with standard low-dose protocol as well as with half, quarter, and 1/40 dose (CTDIvol 0.4-0.03 mGy). Dose-matched scans were performed on a third-generation energy-integrating detector CT (EID-CT). Evaluation of nodule visualization and detectability was performed by two blinded radiologists. Subjective image quality was rated on a 5-point Likert scale. Artificial intelligence (AI)-based nodule detection was performed using commercially available software. RESULTS Highest image noise was found at the lowest dose setting of 1/40 radiation dose (eff. dose = 0.01mSv) with 166.1 ± 18.5 HU for PCD-CT and 351.8 ± 53.0 HU for EID-CT. Overall sensitivity was 100% versus 93% at standard low-dose protocol (eff. dose = 0.2 mSv) for PCD-CT and EID-CT, respectively. At the half radiation dose, sensitivity remained 100% for human reader and CAD studies in PCD-CT. At the quarter radiation dose, PCD-CT achieved the same results as EID-CT at the standard radiation dose setting (93%, P = 1.00) in human reading studies. The AI-CAD system delivered a sensitivity of 93% at the lowest radiation dose level in PCD-CT. CONCLUSION At half dose, PCD CT showed pulmonary nodules similar to full-dose PCD, and at quarter dose, PCD CT performed comparably to standard low-dose EID CT. The CAD algorithm is effective even at ultra-low doses.
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Affiliation(s)
- Lisa Jungblut
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - André Euler
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Anna Landsmann
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Vanessa Englmaier
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Victor Mergen
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Medina Sefirovic
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Thomas Frauenfelder
- Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
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Bonatti M, Valletta R, Corato V, Oberhofer N, Piffer S, Vingiani V, Posteraro A, Proner B, Lombardo F, Avesani G, Cepurnaite R, Zamboni GA. Impact of different peak tube voltage settings on adrenal adenomas attenuation at unenhanced CT. Eur Radiol 2024:10.1007/s00330-024-10984-1. [PMID: 39068376 DOI: 10.1007/s00330-024-10984-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 06/14/2024] [Accepted: 07/10/2024] [Indexed: 07/30/2024]
Abstract
OBJECTIVES To assess the influence of peak tube voltage peak setting on adrenal adenomas (AA) attenuation on unenhanced abdominal CT. MATERIALS AND METHODS IRB-approved retrospective observational cohort study. We included 89 patients with imaging-defined AAs with shortest diameter > 6 mm who underwent two or more unenhanced abdominal CTs using at least two different peak tube voltage settings. Two readers independently measured adenoma attenuation on different CT acquisitions by drawing a round ROI on 3 mm thick axial MPR reconstructions encompassing at least 2/3 of the lesion's surface. The mean of the values measured by the two readers was used for further analysis. Interobserver variability was assessed (Intraclass Correlation Coefficient). Attenuation values measured on 100, 110 and 140 kVp acquisitions were compared with standard 120 kVp ones (Bland-Altman analysis). RESULTS We included 275 unenhanced abdominal CTs (3.1 ± 0.9/patient) in image analysis; 131 acquired at 120 kVp, 65 at 100 kVp, 59 at 110 kVp, and 20 at 140 kVp. 107 lesions were detected in 89 patients (1-4/patient), with a mean maximum diameter of 17 ± 6 mm. Interobserver agreement in attenuation measurement was excellent (ICC: 0.95, CI (92-97)). Median adenoma attenuation was significantly lower on 100 kVp images than on 120 kVp ones (-1 HU, IQR (-5 to 3.6), vs, 2.5 HU, IQR (-1.5 to 8.5); p < 0.001) whereas we didn't find statistically significant differences in adenoma attenuation between 110 kVp or 140 kVp and 120 kVp ones. CONCLUSION AA attenuation is significantly lower on unenhanced CT scans acquired at 100 kVp than on those acquired at "standard" 120 kVp. CLINICAL RELEVANCE STATEMENT AA attenuation is significantly lower at 100 kVp in comparison to 120 kVp. This might be exploited to increase unenhanced CT sensitivity in adenoma characterisation, but further studies including non-adenoma lesions are mandatory to confirm this hypothesis. KEY POINTS CT scans are often acquired using peak tube voltage settings different from the "standard" 120 kVp. AA attenuation varies if CT scans are acquired using different tube peak voltage settings. At 100 kVp AAs show a significantly lower attenuation than at 120 kVp.
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Affiliation(s)
- Matteo Bonatti
- Department of Radiology, Hospital of Bolzano (SABES-ASDAA), Teaching Hospital of Paracelsus Medical University (PMU), Bolzano, Italy
| | - Riccardo Valletta
- Department of Radiology, Hospital of Bolzano (SABES-ASDAA), Teaching Hospital of Paracelsus Medical University (PMU), Bolzano, Italy.
| | - Valentina Corato
- Department of Radiology, Hospital of Bolzano (SABES-ASDAA), Teaching Hospital of Paracelsus Medical University (PMU), Bolzano, Italy
| | - Nadia Oberhofer
- Deparment of Medical Physics, Hospital of Bolzano (SABES-ASDAA), Teaching Hospital of Paracelsus Medical University (PMU), Bolzano, Italy
| | - Stefano Piffer
- Deparment of Medical Physics, Hospital of Bolzano (SABES-ASDAA), Teaching Hospital of Paracelsus Medical University (PMU), Bolzano, Italy
| | - Vincenzo Vingiani
- Department of Radiology, Hospital of Bolzano (SABES-ASDAA), Teaching Hospital of Paracelsus Medical University (PMU), Bolzano, Italy
| | - Andrea Posteraro
- Department of Radiology, Hospital of Bolzano (SABES-ASDAA), Teaching Hospital of Paracelsus Medical University (PMU), Bolzano, Italy
| | - Bernardo Proner
- Department of Radiology, Hospital of Bolzano (SABES-ASDAA), Teaching Hospital of Paracelsus Medical University (PMU), Bolzano, Italy
| | - Fabio Lombardo
- Department of Radiology, IRCCS Ospedale Sacro Cuore - Don Calabria, Negrar, VR, Italy
| | - Giacomo Avesani
- Department of Radiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Rima Cepurnaite
- Department of Pathology, Hospital of Bolzano (SABES-ASDAA), Teaching Hospital of Paracelsus Medical University (PMU), Bolzano, Italy
| | - Giulia A Zamboni
- Radiology Unit, Pancreas Institute, University of Verona, Verona, Italy
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Grunz JP, Huflage H. Photon-Counting Computed Tomography: Experience in Musculoskeletal Imaging. Korean J Radiol 2024; 25:662-672. [PMID: 38942460 PMCID: PMC11214923 DOI: 10.3348/kjr.2024.0096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 03/28/2024] [Accepted: 04/19/2024] [Indexed: 06/30/2024] Open
Abstract
Since the emergence of the first photon-counting computed tomography (PCCT) system in late 2021, its advantages and a wide range of applications in all fields of radiology have been demonstrated. Compared to standard energy-integrating detector-CT, PCCT allows for superior geometric dose efficiency in every examination. While this aspect by itself is groundbreaking, the advantages do not stop there. PCCT facilitates an unprecedented combination of ultra-high-resolution imaging without dose penalty or field-of-view restrictions, detector-based elimination of electronic noise, and ubiquitous multi-energy spectral information. Considering the high demands of orthopedic imaging for the visualization of minuscule details while simultaneously covering large portions of skeletal and soft tissue anatomy, no subspecialty may benefit more from this novel detector technology than musculoskeletal radiology. Deeply rooted in experimental and clinical research, this review article aims to provide an introduction to the cosmos of PCCT, explain its technical basics, and highlight the most promising applications for patient care, while also mentioning current limitations that need to be overcome.
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Affiliation(s)
- Jan-Peter Grunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Würzburg, Germany.
| | - Henner Huflage
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Würzburg, Germany
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Tsalafoutas IA, AlKhazzam S, Kharita MH. The impact of automatic tube current modulation related settings of a modern GE CT scanner on image quality and patient dose; details do matter. J Appl Clin Med Phys 2024; 25:e14356. [PMID: 38659159 PMCID: PMC11163491 DOI: 10.1002/acm2.14356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 03/12/2024] [Accepted: 03/18/2024] [Indexed: 04/26/2024] Open
Abstract
PURPOSE To investigate the operation principles of the automatic tube current modulation (ATCM) of a modern GE healthcare CT scanner, and the impact of related settings on image quality and patient dose. MATERIAL & METHODS A dedicated phantom (Mercury 4.0) was scanned using two of the most frequently used clinical scanning protocols (chest and abdomen-pelvis). The preset protocol settings were used as starting points (reference conditions). Scan direction, scan mode (helical vs. axial), total beam width, tube potential (kVp), and ATCM settings were then modified individually to understand their impact on radiation dose and image quality. Regarding the ATCM settings, the SmartmA minimum and maximum mA limits, and the noise index (NI) values were varied. As surrogates of patient dose, the CTDIvol and DLP values of each scan were used. As surrogates of image quality were used the image noise and the detectability index (d') of five different materials (air, solid water, polystyrene, iodine, and bone) embedded in the Mercury phantom calculated with the ImQuest software. RESULTS The scanning direction did not have any effect on ATCM curves, unlike what has been observed in CT scanners from other manufacturers. Total beam width does matter, however, the SmartmA limit settings and kVp selection had the greatest impact on image quality and dose. It was seen that improper minimum mA limit settings practically invalidated the ATCM operation. In contrast, when full modulation was allowed without restrictions, noise standard deviation, and detectability index became much more consistent across the wide range of phantom diameters. For lower kVp settings an impressive dose reduction was observed that requires further investigation. CONCLUSION SmartmA is a tool that if not properly used may increase the patient doses considerably. Therefore, its settings should be carefully adjusted for each preset different clinical protocol.
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Affiliation(s)
- Ioannis A. Tsalafoutas
- Medical Physics SectionOccupational Health and Safety DepartmentHamad Medical CorporationDohaQatar
| | - Shady AlKhazzam
- Medical Physics SectionOccupational Health and Safety DepartmentHamad Medical CorporationDohaQatar
| | - Mohammed Hassan Kharita
- Medical Physics SectionOccupational Health and Safety DepartmentHamad Medical CorporationDohaQatar
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Tonkopi E, Tetteh MA, Gunn C, Ashraf H, Rusten SL, Safi P, Tinsoe NS, Colford K, Ouellet O, Naimi S, Johansen S. A multi-institutional assessment of low-dose protocols in chest computed tomography: Dose and image quality. Acta Radiol Open 2024; 13:20584601241228220. [PMID: 38304118 PMCID: PMC10829498 DOI: 10.1177/20584601241228220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 01/09/2024] [Indexed: 02/03/2024] Open
Abstract
Background Low-dose CT (LDCT) chest protocols have widespread clinical applications for many indications; as a result, there is a need for protocol assessment prior to standardization. Dalhousie University and Oslo Metropolitan University have a formally established cooperative relationship. Purpose The purpose is to assess radiation dose and image quality for LDCT chest protocols in seven different hospital locations in Norway and Canada. Material and methods Retrospective dosimetry data, volumetric CT dose index (CTDIvol), and dose length product (DLP) from 240 average-sized patients as well as CT protocol parameters were included in the survey. Effective dose (ED) and size-specific dose estimate (SSDE) were calculated for each examination. For a quantitative image quality analysis, noise, CT number, and signal-to-noise ratio (SNR) were determined for three regions in the chest. The contrast-to-noise ratio (CNR) was calculated for lung parenchyma in comparison to the subcutaneous fat. Differences in dose and image quality were evaluated by a single-factor ANOVA test. A two-sample t-test was performed to determine differences in means between individual scanners. Results The ANOVA test revealed significant differences (p < .05) in dose values for all scanners, including identical scanner models. Statistically significant differences (p < .05) were determined in mean values of the SNR distributions between the scanners in all three measured regions in the chest, as well as the CNR values. Conclusion The observed variations in dose and image quality measurements, even within the same hospitals and between identical scanner models, indicate a potential for protocol optimization in the involved hospitals in both countries.
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Affiliation(s)
- Elena Tonkopi
- Department of Diagnostic Radiology, Dalhousie University, Halifax, NS, Canada
- Department of Radiation Oncology, Dalhousie University, Halifax, NS, Canada
- Department of Diagnostic Imaging, Nova Scotia Health Authority, Halifax, NS, Canada
| | - Mercy Afadzi Tetteh
- Department of Diagnostic Imaging, Akershus University Hospital, Loerenskog, Norway
| | - Catherine Gunn
- Department of Radiation Oncology, Dalhousie University, Halifax, NS, Canada
- School of Health Sciences, Dalhousie University, Halifax, NS, Canada
| | - Haseem Ashraf
- Department of Diagnostic Imaging, Akershus University Hospital, Loerenskog, Norway
- Medicine Faculty, University of Oslo, Oslo Norway
| | - Sigrid Lia Rusten
- Health Faculty, Department of Life Sciences and Health, Oslo Metropolitan University Oslo, Norway
| | - Perkhah Safi
- Health Faculty, Department of Life Sciences and Health, Oslo Metropolitan University Oslo, Norway
| | - Nora Suu Tinsoe
- Health Faculty, Department of Life Sciences and Health, Oslo Metropolitan University Oslo, Norway
| | - Kylie Colford
- School of Health Sciences, Dalhousie University, Halifax, NS, Canada
| | - Olivia Ouellet
- School of Health Sciences, Dalhousie University, Halifax, NS, Canada
| | - Salma Naimi
- Department of Diagnostic Imaging, Akershus University Hospital, Loerenskog, Norway
| | - Safora Johansen
- Health Faculty, Department of Life Sciences and Health, Oslo Metropolitan University Oslo, Norway
- Department of Cancer Treatment, Oslo University Hospital, Oslo, Norway
- Health and Social Science Cluster, Singapore Institute of Technology, Singapore
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Agostini A, Borgheresi A, Mariotti F, Ottaviani L, Carotti M, Valenti M, Giovagnoni A. New frontiers in oncological imaging with Computed Tomography: from morphology to function. Semin Ultrasound CT MR 2023; 44:214-227. [PMID: 37245886 DOI: 10.1053/j.sult.2023.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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Markart S, Fischer TS, Wildermuth S, Dietrich TJ, Alkadhi H, Leschka S, Guesewell S, Ditchfield MR, Oezden I, Lutters G, Waelti SL. Organ-based tube current modulation and bismuth eye shielding in pediatric head computed tomography. Pediatr Radiol 2022; 52:2584-2594. [PMID: 35836016 DOI: 10.1007/s00247-022-05410-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 12/23/2021] [Accepted: 05/30/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND Exposure of the eye lens to ionizing radiation results in cataract. Several dose optimization techniques to protect the lens are available for computed tomography (CT). OBJECTIVE The radiation dose to the eye lens, volume CT dose index (CTDIvol) and image quality of various methods of dose optimization were evaluated for pediatric head CT: automated tube current modulation (ATCM), automated tube voltage selection (ATVS), organ-based tube current modulation (OBTCM) and bismuth shielding. MATERIALS AND METHODS An anthropomorphic phantom of a 5-year-old child was scanned with nine protocols: no dose optimization technique and then adding different dose optimization techniques alone and in combination. Dose to the eye, thyroid and breast were estimated using metal oxide semiconductor field effect transistor (MOSFET) dosimetry. CTDIvol, influence of timing of shield placement, image noise and attenuation values in 13 regions of interest of the head and subjective image quality were compared. RESULTS The eye shield significantly reduced the eye lens dose when used alone, to a similar degree as when using all software-based techniques together. When used in combination with software-based techniques, the shield reduced the eye lens dose by up to 45% compared to the no dose optimization technique. Noise was significantly increased by the shield, most pronounced in the anterior portion of the eye. CONCLUSION The combination of ATCM, ATVS, OBTCM and a bismuth shield, with the shield placed after acquiring the localizer image, should be considered to reduce the radiation dose to the eye lens in pediatric head CT.
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Affiliation(s)
- Stefan Markart
- Department of Radiology and Nuclear Medicine, Children's Hospital of Eastern Switzerland, Claudiusstrasse 6, 9006, St. Gallen, Switzerland
- Department of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | - Tim S Fischer
- Department of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | - Simon Wildermuth
- Department of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | - Tobias J Dietrich
- Department of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
- Department of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Hatem Alkadhi
- Department of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Sebastian Leschka
- Department of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | - Sabine Guesewell
- Clinical Trials Unit, Biostatistics, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | - Michael R Ditchfield
- Department of Diagnostic Imaging, Monash Children's Hospital, Clayton, Australia
| | - Ismail Oezden
- Radiation Protection and Medical Physics, Cantonal Hospital Aarau, Aarau, Switzerland
| | - Gerd Lutters
- Radiation Protection and Medical Physics, Cantonal Hospital Aarau, Aarau, Switzerland
| | - Stephan L Waelti
- Department of Radiology and Nuclear Medicine, Children's Hospital of Eastern Switzerland, Claudiusstrasse 6, 9006, St. Gallen, Switzerland.
- Department of Radiology and Nuclear Medicine, Cantonal Hospital St. Gallen, St. Gallen, Switzerland.
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Wang K, Wang X, Zheng S, Li C, Jin L, Li M. Dedicated CCTA Followed by High-Pitch Scanning versus TRO-CT for Contrast Media and Radiation Dose Reduction: A Retrospective Study. Diagnostics (Basel) 2022; 12:diagnostics12112647. [PMID: 36359488 PMCID: PMC9688948 DOI: 10.3390/diagnostics12112647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/22/2022] [Accepted: 10/27/2022] [Indexed: 11/16/2022] Open
Abstract
We aimed to compare dedicated coronary computed tomography angiography (CCTA) followed by high-pitch scanning and triple-rule-out computed tomography angiography (TRO-CTA) in terms of radiation dose, contrast media (CM) use, and image quality. Patients with acute chest pain were retrospectively enrolled and assigned to group A (n = 55; scanned with dedicated CCTA followed by high-pitch scanning) or group B (n = 45; with TRO-CTA). Patient characteristics, radiation dose, CM use, and quantitative parameters (CT value, image noise, signal-to-noise ratio, contrast-to-noise ratio, and image quality score) of pulmonary arteries (PAs), thoracic aortae (TAs), and coronary arteries (CAs) were compared. The total effective dose was significantly lower in group A (6.25 ± 2.94 mSv) than B (8.93 ± 4.08 mSv; p < 0.001). CM volume was significantly lower in group A (75.7 ± 8.9 mL) than B (95.0 ± 0 mL; p < 0.001). PA and TA image quality were significantly better in group B, whereas that of CA was significantly better in group A. Qualitative image scores of PA and TA scans rated by radiologists were similar, whereas that of CA scans was significantly higher in group A than B (p < 0.001). Dedicated CCTA followed by high-pitch scanning demonstrated lower radiation doses and CM volume without debasing qualities of PA, TA, and CA scans than did TRO-CTA.
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Affiliation(s)
- Kun Wang
- Radiology Department, Huadong Hospital Affiliated to Fudan University, Shanghai 200040, China
| | - Xiaodong Wang
- Shanghai Changfeng Community Health Service Center of Putuo District, Shanghai 200062, China
| | - Shaoqiang Zheng
- Department of Radiology, Tongji Hospital, School of Medicine, Tongji University, Shanghai 200065, China
| | - Cheng Li
- Radiology Department, Huadong Hospital Affiliated to Fudan University, Shanghai 200040, China
| | - Liang Jin
- Radiology Department, Huadong Hospital Affiliated to Fudan University, Shanghai 200040, China
- Correspondence: (L.J.); (M.L.); Tel.: +86-137-6114-8449 (L.J.); +86-138-1662-0371 (M.L.); Fax: +86-021-6248-3180 (L.J. & M.L.)
| | - Ming Li
- Radiology Department, Huadong Hospital Affiliated to Fudan University, Shanghai 200040, China
- Institute of Functional and Molecular Medical Imaging, Fudan University, Shanghai 200040, China
- Correspondence: (L.J.); (M.L.); Tel.: +86-137-6114-8449 (L.J.); +86-138-1662-0371 (M.L.); Fax: +86-021-6248-3180 (L.J. & M.L.)
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Mäkelä T, Kortesniemi M, Kaasalainen T. The impact of vertical off-centering on image noise and breast dose in chest CT with organ-based tube current modulation: A phantom study. Phys Med 2022; 100:153-163. [PMID: 35853275 DOI: 10.1016/j.ejmp.2022.06.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 06/11/2022] [Accepted: 06/28/2022] [Indexed: 10/17/2022] Open
Abstract
PURPOSE To determine the effects of patient vertical off-centering when using organ-based tube current modulation (OBTCM) in chest computed tomography (CT) with focus on breast dose. MATERIALS AND METHODS An anthropomorphic adult female phantom with two different breast attachment sizes was scanned on GE Revolution EVO and Siemens Definition Edge CT systems using clinical chest CT protocols and anterior-to-posterior scouts. Scans with and without OBTCM were performed at different table heights (GE: centered, ±6 cm, and ± 3 cm; Siemens: centered, -6 cm, and ± 3 cm). The dose effects were studied with metal-oxidesemiconductor field-effect transistor dosimeters with complementary Monte Carlo simulations to determine full dose maps. Changes in image noise were studied using standard deviations of subtraction images from repeated acquisitions without dosimeters. RESULTS Patient off-centering affected both the behavior of the normal tube current modulation as well as the extent of the OBTCM. Generally, both OBTCM techniques provided a substantial decrease in the breast doses (up to 30% local decrease). Lateral breast regions may, however, in some cases receive higher doses when OBTCM is enabled. This effect becomes more prominent when the patient is centered too low in the CT gantry. Changes in noise roughly followed the expected inverse of the change in dose. CONCLUSIONS Patient off-centering was shown to affect the outcome of OBTCM in chest CT examination, and on some occasions, resulting in higher exposure. The use of modern dose optimization tools such as OBTCM emphasizes the importance of proper centering when preparing patients to CT scans.
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Affiliation(s)
- Teemu Mäkelä
- HUS Diagnostic Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; Department of Physics, University of Helsinki, Finland.
| | - Mika Kortesniemi
- HUS Diagnostic Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Touko Kaasalainen
- HUS Diagnostic Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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Euler A, Taslimi T, Eberhard M, Kobe A, Reeve K, Zimmermann A, Krauss A, Gutjahr R, Schmidt B, Alkadhi H. Computed Tomography Angiography of the Aorta-Optimization of Automatic Tube Voltage Selection Settings to Reduce Radiation Dose or Contrast Medium in a Prospective Randomized Trial. Invest Radiol 2021; 56:283-291. [PMID: 33226202 DOI: 10.1097/rli.0000000000000740] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The aim of this study was to compare the image quality of low-kV protocols with optimized automatic tube voltage selection (ATVS) settings to reduce either radiation dose or contrast medium (CM) with that of a reference protocol for computed tomography angiography (CTA) of the thoracoabdominal aorta. MATERIALS AND METHODS In this institutional review board-approved, single-center, prospective randomized controlled trial, 126 patients receiving CTA of the aorta were allocated to one of three computed tomography protocols: (A) reference protocol at 120 kVp and standard weight-adapted CM dose; (B) protocol at 90 kVp, reduced radiation and standard CM dose; and (C) protocol at 90 kVp, standard radiation and reduced CM dose. All three protocols were performed on a third-generation dual-source computed tomography scanner using the semimode of the ATVS system. The image-task-dependent optimization settings of the ATVS (slider level) were adjusted to level 11 (high-contrast task) for protocols A and B and level 3 (low-contrast task) for protocol C. Radiation dose parameters were assessed. The contrast-to-noise ratios (CNRs) of protocols B and C were tested for noninferiority compared with A. Subjective image quality was assessed using a 5-point Likert scale. RESULTS Size-specific dose estimate was 34.3% lower for protocol B compared with A (P < 0.0001). Contrast medium was 20.2% lower for protocol C compared with A (P < 0.0001). Mean CNR in B and C was noninferior to protocol A (CNR of 30.2 ± 7, 33.4 ± 6.7, and 30.5 ± 8.9 for protocols A, B, and C, respectively). There was no significant difference in overall subjective image quality among protocols (4.09 ± 0.21, 4.03 ± 0.19, and 4.08 ± 0.17 for protocols A, B, and C, respectively; P = 0.4). CONCLUSIONS The slider settings of an ATVS system can be adjusted to optimize either radiation dose or CM at noninferior image quality in low-kV CTA of the aorta. This optimization could be used to extend future ATVS algorithms to take clinical risk factors like kidney function of individual patients into account.
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Affiliation(s)
- André Euler
- From the Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Tilo Taslimi
- From the Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Matthias Eberhard
- From the Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Adrian Kobe
- From the Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Kelly Reeve
- Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland
| | - Alexander Zimmermann
- Department of Vascular Surgery, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | | | | | | | - Hatem Alkadhi
- From the Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
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Jin L, Gao Y, Jiang A, Li Z, Wang P, Li M. Can the Coronary Artery Calcium Score Scan Reduce the Radiation Dose in Coronary Computed Tomography Angiography? Acad Radiol 2021; 28:364-369. [PMID: 32209277 DOI: 10.1016/j.acra.2020.02.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/13/2020] [Accepted: 02/20/2020] [Indexed: 02/05/2023]
Abstract
RATIONALE AND OBJECTIVES Radiation exposure from coronary computed tomography angiography (CCTA) remains a cause for concern. The objective of this study was to investigate whether using the coronary artery calcium score scan (CACS) would reduce the radiation dose for CCTA scanning and the overall radiation exposure (ORE). MATERIALS AND METHODS In total, 256 patients were examined with a third-generation dual-source CT (n = 200) or 256-row CT (n = 56), among whom 105 (Group A) and 28 patients (Group B), respectively, underwent CCTA with CACS for field of view planning. The remaining patients, with the scout view for field of view planning, constituted Group A1 and B1. The scanning parameter settings were standardized between groups. RESULTS Shorter scan lengths were observed in Group A (9.98 ± 0.79 cm) compared to Group A1 (13.64 ± 1.79 cm; p < 0.001), which also resulted in a lower dose-length product (DLP) in Group A (115.04 ± 64.13) relative to Group A1 (138.67 ± 68.87; p < 0.05). Similarly, shorter scan lengths were found in Group B (14.92 ± 1.17 cm) compared to Group B1 (15.79 ± 0.63 cm; p = 0.001); this resulted in a lower DLP (322.07 ± 45.39) compared to Group B1 (354.34 ± 65.27; p = 0.036). The CACS resulted in an increase in ORE in both groups. CONCLUSION CACS may have a critical role in the reduction of radiation dose in CCTA scanning, but the potential effectiveness of CACS in reducing ORE is weak.
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Affiliation(s)
- Liang Jin
- Radiology Department, Huadong Hospital, Affiliated to Fudan University, Shanghai, China
| | - Yiyi Gao
- Radiology Department, Huadong Hospital, Affiliated to Fudan University, Shanghai, China
| | - An'qi Jiang
- Radiology Department, Huadong Hospital, Affiliated to Fudan University, Shanghai, China
| | - Zhenlin Li
- Radiology Department, West China Hospital, Affiliated to SiChuan University, Chengdu, China
| | - Peijun Wang
- Radiology Department, Tongji Hospital, Affiliated to Tongji University, Shanghai, China
| | - Ming Li
- Radiology Department, Huadong Hospital, Affiliated to Fudan University, Shanghai, China; Institute of Functional and Molecular Medical Imaging, Fudan University, Shanghai, China.
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12
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Lin ZX, Zhou F, Schoepf UJ, Pillai B, Zhou CS, Quan W, Bao XQ, Lu GM, Zhang LJ. Tube Voltage, DNA Double-Strand Breaks, and Image Quality in Coronary CT Angiography. Korean J Radiol 2020; 21:967-977. [PMID: 32677381 PMCID: PMC7369208 DOI: 10.3348/kjr.2019.0932] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 02/16/2020] [Accepted: 03/05/2020] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVE To evaluate the effects of tube voltage on image quality in coronary CT angiography (CCTA), the estimated radiation dose, and DNA double-strand breaks (DSBs) in peripheral blood lymphocytes to optimize the use of CCTA in the era of low radiation doses. MATERIALS AND METHODS This study included 240 patients who were divided into 2 groups according to the DNA DSB analysis methods, i.e., immunofluorescence microscopy and flow cytometry. Each group was subdivided into 4 subgroups: those receiving CCTA only with different tube voltages of 120, 100, 80, or 70 kVp. Objective and subjective image quality was evaluated by analysis of variance. Radiation dosages were also recorded and compared. RESULTS There was no significant difference in demographic characteristics between the 2 groups and 4 subgroups in each group (all p > 0.05). As tube voltage decreased, both image quality and radiation dose decreased gradually and significantly. After CCTA, γ-H2AX foci and mean fluorescence intensity in the 120-, 100-, 80-, and 70-kVp groups increased by 0.14, 0.09, 0.07, and 0.06 foci per cell and 21.26, 9.13, 8.10, and 7.13 (all p < 0.05), respectively. The increase in the DNA DSB level in the 120-kVp group was higher than those in the other 3 groups (all p < 0.05), while there was no significant difference in the DSBs levels among these latter groups (all p > 0.05). CONCLUSION The 100-kVp tube voltage may be optimal for CCTA when weighing DNA DSBs against the estimated radiation dose and image quality, with further reductions in tube voltage being unnecessary for CCTA.
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Affiliation(s)
- Zhu Xiao Lin
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China.,Department of Medical Imaging, Yantaishan Hospital, Yantai, China
| | - Fan Zhou
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - U Joseph Schoepf
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China.,Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA
| | - Balakrishnan Pillai
- Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA
| | - Chang Sheng Zhou
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Wei Quan
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Xue Qin Bao
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Guang Ming Lu
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Long Jiang Zhang
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, China.
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Evaluation of a Tube Voltage-Tailored Contrast Medium Injection Protocol for Coronary CT Angiography: Results From the Prospective VOLCANIC Study. AJR Am J Roentgenol 2020; 215:1049-1056. [PMID: 32960669 DOI: 10.2214/ajr.20.22777] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE. The purpose of this study was to prospectively evaluate, using software support, the feasibility and the quantitative and qualitative image quality parameters of a tube voltage-tailored contrast medium (CM) application protocol for patient-specific injection during coronary CT angiography (CCTA). SUBJECTS AND METHODS. In the Voltage-Based Contrast Media Adaptation in Coronary Computed Tomography Angiography (VOLCANIC-CTA) study, a single-center trial, 120 patients referred for CCTA were prospectively assigned to a tube voltage-tailored CM injection protocol. Automated tube voltage levels were selected in 10-kV intervals and ranged from 70 to 130 kV, and the iodine delivery rate (IDR) was adapted to the tube voltage level using dedicated software. The administered CM volume (370 mg I/mL) ranged from 33 mL at 70 kV (IDR, 0.7 g I/s) to 65 mL at 130 kV (IDR, 1.7 g I/s). Attenuation was measured in the aorta and coronary arteries to calculate quantitative signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), and 5-point scales were used to evaluate overall image quality. Radiation metrics were also assessed and compared among the protocols. RESULTS. The mean age of the study patients was 62.5 ± 11.9 (SD) years. Image quality was rated as diagnostic in all patients. Contrast attenuation peaked at 70 kV (p < 0.001), whereas SNR and CNR parameters showed no significant differences between tube voltage levels (p ≥ 0.085). Additionally, no significant differences in subjective image quality parameters were found among the different protocols (p ≥ 0.139). The lowest radiation dose values were observed in the group assigned to the 70-kV protocol, which had a median radiation effective dose of 2.0 mSv (p < 0.001). CONCLUSION. The proposed tube voltage-tailored injection protocol allows individualized scanning of patients undergoing CCTA and significantly reduces CM and radiation dose while maintaining a high diagnostic image quality.
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14
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Martini K, Moon JW, Revel MP, Dangeard S, Ruan C, Chassagnon G. Optimization of acquisition parameters for reduced-dose thoracic CT: A phantom study. Diagn Interv Imaging 2020; 101:269-279. [PMID: 32107196 DOI: 10.1016/j.diii.2020.01.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/23/2020] [Accepted: 01/28/2020] [Indexed: 02/06/2023]
Abstract
PURPOSE The purpose of this study was to analyze the impact of different options for reduced-dose computed tomography (CT) on image noise and visibility of pulmonary structures in order to define the best choice of parameters when performing ultra-low dose acquisitions of the chest in clinical routine. MATERIALS AND METHODS Using an anthropomorphic chest phantom, CT images were acquired at four defined low dose levels (computed tomography dose index [CTDIvol]=0.15, 0.20, 0.30 and 0.40mGy), by changing tube voltage, pitch factor, or rotation time and adapting tube current to reach the predefined CTDIvol-values. Images were reconstructed using two different levels of iteration (adaptive statistical iterative reconstruction [ASIR®]-v70% and ASIR®-v100%). Signal-to-noise ratio (SNR) as well as contrast-to-noise ratio (CNR) was calculated. Visibility of pulmonary structures (bronchi/vessels) were assessed by two readers on a 5-point-Likert scale. RESULTS Best visual image assessments and CNR/SNR were obtained with high tube voltage, while lowest scores were reached with lower pitch factor followed by high tube current. Protocols favoring lower pitch factor resulted in decreased visibility of bronchi/vessels, especially in the periphery. Decreasing radiation dose from 0.40 to 0.30mGy was not associated with a significant decrease in visual scores (P<0.05), however decreasing radiation dose from 0.30mGy to 0.15mGy was associated with a lower visibility of most of the evaluated structures (P<0.001). While image noise could be significantly reduced when ASIR®-v100% instead of ASIR®-v70% was used, the visibility-scores of pulmonary structures did not change significantly. CONCLUSION Favoring high tube voltage is the best option for reduced-dose protocols. A decrease of SNR and CNR does not necessarily go along with reduced visibility of pulmonary structures.
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Affiliation(s)
- K Martini
- Department of Radiology, Cochin Hospital, AP-HP Centre, 75014 Paris, France; Diagnostic and Interventional Radiology, University Hospital Zurich, 8008 Zurich, Switzerland
| | - J W Moon
- Department of Radiology, Cochin Hospital, AP-HP Centre, 75014 Paris, France
| | - M P Revel
- Department of Radiology, Cochin Hospital, AP-HP Centre, 75014 Paris, France; Université de Paris, Descartes-Paris 5, 75006 Paris, France
| | - S Dangeard
- Department of Radiology, Cochin Hospital, AP-HP Centre, 75014 Paris, France
| | - C Ruan
- General Electric Healthcare, 78530 Buc, France
| | - G Chassagnon
- Department of Radiology, Cochin Hospital, AP-HP Centre, 75014 Paris, France; Université de Paris, Descartes-Paris 5, 75006 Paris, France; Center for Visual Computing, École Centrale Supelec, 91190 Gif-sur-Yvette, France.
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15
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Jin L, Gao Y, Shan Y, Sun Y, Li M, Wang Z. Qualitative and quantitative image analysis of 16 cm wide-coverage computed tomography compared to new-generation dual-source CT. JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2020; 28:527-539. [PMID: 32333574 DOI: 10.3233/xst-190624] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
BACKGROUND Diagnostic quality of computed tomography (CT) images depends on numerous factors. Recently, two different modalities were introduced for coronary CT angiography (CCTA). OBJECTIVE This study aims to compare the performance of 16 cm wide-coverage detector CT (WDCT) using the snapshot freeze technique with a new-generation dual-source CT (DSCT) with 66 ms temporal resolution for CCTA. METHODS Total 101 patients with suspected coronary heart disease were enrolled. Of these, 50 and 51 patients were examined on WDCT and DSCT, respectively. CT values, image noise, signal-to-noise ratio, and contrast-to-noise ratio were measured. The image processing efficiency was recorded, followed by statistical comparison of diagnostic accuracy and radiation dose. RESULTS Ninety-nine patients (98.02%) had satisfactory diagnostic image quality. DSCT was significantly better than WDCT in terms of quantitative image quality, image processing efficiency, and qualitative analysis (P < 0.05). However, radiation dose was significantly lower on WDCT (P < 0.05) as compared to DSCT. CONCLUSIONS Image processing efficiency and image quality of CCTA was higher on DSCT compared to WDCT due to the limitation of maximal tube current of WDCT.
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Affiliation(s)
- Liang Jin
- Department of Radiology, Huadong Hospital (Affiliated to Fudan University), Shanghai, China
| | - Yiyi Gao
- Department of Radiology, Huadong Hospital (Affiliated to Fudan University), Shanghai, China
| | - Yuqing Shan
- Department of Radiology, Rizhao People's Hospital, Rizhao, China
| | - Yingli Sun
- Department of Radiology, Huadong Hospital (Affiliated to Fudan University), Shanghai, China
| | - Ming Li
- Department of Radiology, Huadong Hospital (Affiliated to Fudan University), Shanghai, China
- Institute of Functional and Molecular Medical Imaging, Fudan University, Shanghai, China
| | - Zhizhong Wang
- Department of Radiology, Caoxian People's Hospital, Fumin Avenue, Caoxian Development Zone, Heze, China
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Automatic Tube Current Modulation and Tube Voltage Selection in Pediatric Computed Tomography: A Phantom Study on Radiation Dose and Image Quality. Invest Radiol 2019; 54:265-272. [PMID: 30562273 PMCID: PMC6484681 DOI: 10.1097/rli.0000000000000537] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVES The aim of this study was to investigate the effects of a modern automatic tube current modulation (ATCM) and automatic tube voltage selection (ATVS) system on radiation dose and image quality in pediatric head, and torso computed tomography (CT) examinations for various clinical indications. MATERIALS AND METHODS Four physical anthropomorphic phantoms that represent the average individual as neonate, 1-year-old, 5-year-old, and 10-year-old child were used. Standard head, thorax, and abdomen/pelvis acquisitions were performed with (1) fixed tube current, (2) ATCM, and (3) ATVS. Acquisitions were performed at various radiation dose levels to generate images at different levels of quality. Reference volume CT dose index (CTDIvol), reference image noise, and reference contrast-to-noise ratios were determined. The potential dose reductions with ATCM and ATVS were assessed. RESULTS The percent reduction of CTDIvol with ATCM ranged from 8% to 24% for head, 16% to 39% for thorax, and 25% to 41% for abdomen/pelvis. The percent reduction of CTDIvol with ATVS varied on the clinical indication. In CT angiography, ATVS resulted to the highest dose reduction, which was up to 70% for head, 77% for thorax, and 34% for abdomen/pelvis. In noncontrast examinations, ATVS increased dose by up to 21% for head, whereas reduced dose by up to 34% for thorax and 48% for abdomen/pelvis. CONCLUSIONS In pediatric CT, the use of ATCM significantly reduces radiation dose and maintains image noise. The additional use of ATVS reduces further the radiation dose for thorax and abdomen/pelvis, and maintains contrast-to-noise ratio for the specified clinical diagnostic task.
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17
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Forbrig R, Ingrisch M, Stahl R, Winter KS, Reiser M, Trumm CG. Radiation dose and image quality of high-pitch emergency abdominal CT in obese patients using third-generation dual-source CT (DSCT). Sci Rep 2019; 9:15877. [PMID: 31685902 PMCID: PMC6828752 DOI: 10.1038/s41598-019-52454-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 10/17/2019] [Indexed: 01/01/2023] Open
Abstract
In this third-generation dual-source CT (DSCT) study, we retrospectively investigated radiation dose and image quality of portal-venous high-pitch emergency CT in 60 patients (28 female, mean age 56 years) with a body mass index (BMI) ≥ 30 kg/m2. Patients were dichotomized in groups A (median BMI 31.5 kg/m2; n = 33) and B (36.8 kg/m2; n = 27). Volumetric CT dose index (CTDIvol), size-specific dose estimate (SSDE), dose length product (DLP) and effective dose (ED) were assessed. Contrast-to-noise ratio (CNR) and dose-independent figure-of-merit (FOM) CNR were calculated. Subjective image quality was assessed using a five-point scale. Mean values of CTDIvol, SSDE as well as normalized DLP and ED were 7.6 ± 1.8 mGy, 8.0 ± 1.8 mGy, 304 ± 74 mGy * cm and 5.2 ± 1.3 mSv for group A, and 12.6 ± 3.7 mGy, 11.0 ± 2.6 mGy, 521 ± 157 mGy * cm and 8.9 ± 2.7 mSv for group B (p < 0.001). CNR of the liver and spleen as well as each calculated FOM CNR were significantly higher in group A (p < 0.001). Subjective image quality was good in both groups. In conclusion, third-generation abdominal high-pitch emergency DSCT yields good image quality in obese patients. Radiation dose increases in patients with a BMI > 36.8 kg/m2.
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Affiliation(s)
- Robert Forbrig
- Institute of Neuroradiology, University Hospital, LMU Munich, Munich, Germany.
| | - Michael Ingrisch
- Department of Radiology, University Hospital, LMU Munich, Munich, Germany
| | - Robert Stahl
- Institute of Neuroradiology, University Hospital, LMU Munich, Munich, Germany
- Department of Radiology, University Hospital, LMU Munich, Munich, Germany
| | | | - Maximilian Reiser
- Department of Radiology, University Hospital, LMU Munich, Munich, Germany
| | - Christoph G Trumm
- Institute of Neuroradiology, University Hospital, LMU Munich, Munich, Germany
- Institute for Diagnostic and Interventional Radiology, Neuroradiology and Nuclear Medicine, München Klinik Harlaching, Munich, Germany
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18
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Eller A, Wiesmüller M, Wüst W, Heiss R, Kopp M, Saake M, Brand M, Uder M, May MM. Carotid CTA at the Lowest Tube Voltage (70 kV) in Comparison with Automated Tube Voltage Adaption. AJNR Am J Neuroradiol 2019; 40:1374-1382. [PMID: 31296525 DOI: 10.3174/ajnr.a6108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 05/26/2019] [Indexed: 12/28/2022]
Abstract
BACKGROUND AND PURPOSE CTA is the imaging modality of choice in many institutions for the evaluation of the supraaortic vessels, but radiation exposure remains a matter of concern. Our aim was to evaluate a 70-kV protocol for CT angiography of the carotid arteries with respect to image quality and radiation exposure compared with automated tube voltage adaption. MATERIALS AND METHODS A total of 90 consecutive patients were included in this prospective study and randomized to the study group (n = 45, 70 kV) or control group (n = 45, automated tube voltage adaptation). Volume CT dose indices and dose-length products were recorded in the examination protocol. Image quality was assessed as arterial vessel contrast, signal-to-noise ratio, contrast-to-noise ratio, and contrast-to-noise ratio in reference to the radiation dose. Subjective overall image-quality analysis, image-artifact analysis, and diagnostic evaluation were performed by 2 observers by using a 4-point Likert scale. RESULTS Radiation exposure was significantly lower in the study group (volume CT dose index reduced by 22%, dose-length product reduction by 20%; each P < .001). Contrast (P = .15), SNR (P = .4), and contrast-to-noise ratio (P = .5) did not show significant differences between the groups. The contrast-to-noise ratio in reference to the radiation dose was not significantly increased using the study protocol (P = .2). Subjective image quality and visualization of pathologic findings did not differ significantly between the groups. CONCLUSIONS Carotid CTA using the lowest available voltage (70 kV) is feasible at very-low-dose levels, while overall image quality is comparable with protocols using automated tube voltage selection.
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Affiliation(s)
- A Eller
- From the Department of Radiology (A.E., M.W., W.W., R.H., M.K., M.S., M.B., M.U., M.M.M.), University Hospital Erlangen, Erlangen, Germany
| | - M Wiesmüller
- From the Department of Radiology (A.E., M.W., W.W., R.H., M.K., M.S., M.B., M.U., M.M.M.), University Hospital Erlangen, Erlangen, Germany
| | - W Wüst
- From the Department of Radiology (A.E., M.W., W.W., R.H., M.K., M.S., M.B., M.U., M.M.M.), University Hospital Erlangen, Erlangen, Germany
| | - R Heiss
- From the Department of Radiology (A.E., M.W., W.W., R.H., M.K., M.S., M.B., M.U., M.M.M.), University Hospital Erlangen, Erlangen, Germany
| | - M Kopp
- From the Department of Radiology (A.E., M.W., W.W., R.H., M.K., M.S., M.B., M.U., M.M.M.), University Hospital Erlangen, Erlangen, Germany
| | - M Saake
- From the Department of Radiology (A.E., M.W., W.W., R.H., M.K., M.S., M.B., M.U., M.M.M.), University Hospital Erlangen, Erlangen, Germany
| | - M Brand
- From the Department of Radiology (A.E., M.W., W.W., R.H., M.K., M.S., M.B., M.U., M.M.M.), University Hospital Erlangen, Erlangen, Germany
| | - M Uder
- From the Department of Radiology (A.E., M.W., W.W., R.H., M.K., M.S., M.B., M.U., M.M.M.), University Hospital Erlangen, Erlangen, Germany
- Imaging Science Institute (M.U., M.M.M.), Erlangen, Germany
| | - M M May
- From the Department of Radiology (A.E., M.W., W.W., R.H., M.K., M.S., M.B., M.U., M.M.M.), University Hospital Erlangen, Erlangen, Germany
- Imaging Science Institute (M.U., M.M.M.), Erlangen, Germany
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Optimizing Pulmonary Embolism Computed Tomography in the Age of Individualized Medicine: A Prospective Clinical Study. Invest Radiol 2019; 53:306-312. [PMID: 29438139 DOI: 10.1097/rli.0000000000000443] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
PURPOSE The aim of the study was to simultaneously optimize contrast media (CM) injection and scan parameters for the individual patient during computed tomography pulmonary angiography (CTPA). METHODS In this study (NCT02611115), 235 consecutive patients suspected of having pulmonary embolism were prospectively enrolled. Automated kV selection software on a third-generation multidetector computed tomography adapted tube voltage to the individual patient, based on scout scans. The contrast injection protocol was adapted to both patient body weight and kV-setting selection via a predefined formula, based on previous research. Injection data were collected from a contrast media and radiation dose monitoring software. Attenuation was measured in Hounsfield units (HU) in the pulmonary trunk (PT); attenuation values 200 HU or greater were considered diagnostic. Subjective image quality was assessed by using a 4-point Likert scale at the level of the PT, lobar, segmental, and subsegmental arteries. Results between groups were reported as mean ± SD. RESULTS Two hundred twenty-two patients (94%) were scanned at a kV setting below 100 kV: n = 108 for 70 kV, n = 82 for 80 kV, and n = 32 for 90 kV. Mean CM bolus volume (in milliliters) and total iodine load (in grams of iodine) for 70 to 90 kV were as follows: 24 ± 3 mL and 7 ± 1 g I, 29 ± 4 mL and 9 ± 2 g I, and 38 ± 4 mL and 11 ± 1 g I, respectively. Mean flow rates (in milliliters per second) and iodine delivery rates (in grams of iodine per second) were 3.0 ± 0.4 mL/s and 0.9 ± 0.1 g I/s (70 kV), 3.6 ± 0.4 mL/s and 1.0 ± 0.1 g I/s (80 kV), and 4.7 ± 0.5 mL/s and 1.3 ± 0.1 g I/s (90 kV). Mean radiation doses were 1.3 ± 0.3 mSv at 70 kV, 1.7 ± 0.4 mSv at 80 kV, and 2.2 ± 0.6 mSv at 90 kV. Mean vascular attenuation in the PT for each kV group was as follows: 397 ± 101 HU for 70 kV, 398 ± 96 HU for 80 kV, and 378 ± 100 HU for 90 kV, P = 0.59. Forty-six patients (21%) showed pulmonary embolism on the CTPA. One scan (90 kV) showed nondiagnostic segmental pulmonary arteries, and 5% of subsegmental arteries were of nondiagnostic image quality. All other segments were considered diagnostic-excellent subjective image quality. CONCLUSIONS Simultaneously optimizing both CM injections and kV settings to the individual patient in CTPA results in diagnostic attenuation with on average 24 to 38 mL of CM volume and a low radiation dose for most patients. This individualized protocol may help overcome attenuation-variation problems between patients and kV settings in CTPA.
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Forbrig R, Geyer LL, Stahl R, Thorsteinsdottir J, Schichor C, Kreth FW, Patzig M, Herzberg M, Liebig T, Dorn F, Trumm CG. Radiation dose and image quality in intraoperative CT (iCT) angiography of the brain with stereotactic head frames. Eur Radiol 2019; 29:2859-2867. [PMID: 30635759 DOI: 10.1007/s00330-018-5930-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 11/06/2018] [Accepted: 11/28/2018] [Indexed: 01/04/2023]
Abstract
OBJECTIVES Intraoperative CT (iCT) angiography of the brain with stereotactic frames is an integral part of navigated neurosurgery. Validated data regarding radiation dose and image quality in these special examinations are not available. We therefore investigated two iCT protocols in this IRB-approved study. METHODS Retrospective analysis of patients, who received a cerebral stereotactic iCT angiography on a 128 slice CT scanner between February 2016 and December 2017. In group A, automated tube current modulation (ATCM; reference value 410 mAs) and automated tube voltage selection (reference value 120 kV) were enabled, and only examinations with a selected voltage of 120 kV were included. In group B, fixed parameters were applied (300 mAs, 120 kV). Radiation dose was measured by assessing the volumetric CT dose index (CTDIvol), dose length product (DLP) and effective dose (ED). Signal-to-noise ratio (SNR) and image noise were assessed for objective image quality, visibility of arteries and grey-white differentiation for subjective image quality. RESULTS Two hundred patients (n = 100 in each group) were included. In group A, median selected tube current was 643 mAs (group B, 300 mAs; p < 0.001). Median values of CTDIvol, DLP and ED were 91.54 mGy, 1561 mGy cm and 2.97 mSv in group A, and 43.15 mGy, 769 mGy cm and 1.46 mSv in group B (p < 0.001). Image quality did not significantly differ between groups (p > 0.05). CONCLUSIONS ATCM yielded disproportionally high radiation dose due to substantial tube current increase at the frame level, while image quality did not improve. Thus, ATCM should preferentially be disabled. KEY POINTS • Automated tube current modulation (ATCM) yields disproportionally high radiation dose in intraoperative CT angiography of the brain with stereotactic head frames. • ATCM does not improve overall image quality in these special examinations. • ATCM is not yet optimised for CT angiography of the brain with major extracorporeal foreign materials within the scan range.
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Affiliation(s)
- Robert Forbrig
- Institute of Neuroradiology, University Hospital, LMU Munich, Marchioninistrasse 15, 81377, Munich, Germany.
| | - Lucas L Geyer
- Center of Radiology and Neuroradiology, Klinikum Ingolstadt, Ingolstadt, Germany
| | - Robert Stahl
- Department of Radiology, University Hospital, LMU Munich, Munich, Germany
| | | | - Christian Schichor
- Department of Neurosurgery, University Hospital, LMU Munich, Munich, Germany
| | | | - Maximilian Patzig
- Institute of Neuroradiology, University Hospital, LMU Munich, Marchioninistrasse 15, 81377, Munich, Germany
| | - Moriz Herzberg
- Institute of Neuroradiology, University Hospital, LMU Munich, Marchioninistrasse 15, 81377, Munich, Germany
| | - Thomas Liebig
- Institute of Neuroradiology, University Hospital, LMU Munich, Marchioninistrasse 15, 81377, Munich, Germany
| | - Franziska Dorn
- Institute of Neuroradiology, University Hospital, LMU Munich, Marchioninistrasse 15, 81377, Munich, Germany
| | - Christoph G Trumm
- Institute for Diagnostic and Interventional Radiology, Neuroradiology and Nuclear Medicine, Städtisches Klinikum München Harlaching, Munich, Germany
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Kaasalainen T, Mäkelä T, Kortesniemi M. The effect of vertical centering and scout direction on automatic tube voltage selection in chest CT: a preliminary phantom study on two different CT equipments. Eur J Radiol Open 2018; 6:24-32. [PMID: 30619916 PMCID: PMC6298908 DOI: 10.1016/j.ejro.2018.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 12/11/2018] [Accepted: 12/11/2018] [Indexed: 12/11/2022] Open
Abstract
Purpose To determine the effect of patient's vertical off-centering and scout direction on the function of automatic tube voltage selection (ATVS) and tube current modulation (TCM) in chest computed tomography (CT). Methods Chest phantom was scanned with Siemens and GE CT systems using three clinical chest CT protocols exploiting ATVS and a fixed 120 kVp chest protocol. The scans were performed at five vertical positions of the phantom (-6 to +6 cm from the scanner isocenter). The effects of scout direction (posterior-to-anterior, anterior-to-posterior, and lateral) and vertical off-centering on the function of ATVS and TCM were studied by examining changes in selected voltage, radiation dose (volume CT dose index, CTDIvol), and image noise and contrast. Results Both scout direction and vertical off-centering affected ATVS. The effect differed between the vendors for the studied geometry, demonstrating differences in technical approaches. The greatest observed increase in CTDIvol due to off-centering was 91%. Anterior-to-posterior scout produced highest doses at the uppermost table position, whereas posterior-to-anterior scout produced highest doses at the lowermost table position. Dose varied least using lateral scouts. Vertical off-centering impacted image noise and contrast due to the combined effect of ATVS, TCM, structural noise, and bowtie filters. Conclusions Patient vertical off-centering and scout direction affected substantially the CTDIvol and image quality in chest CT examinations. Vertical off-centering caused variation also in the selected tube voltage. The function of ATVS and TCM methods differ significantly between the CT vendors, resulting in differences in CTDIvol and image noise characteristics.
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Affiliation(s)
- Touko Kaasalainen
- HUS Medical Imaging Center, Helsinki University Central Hospital, Finland.,Department of Physics, University of Helsinki, Finland
| | - Teemu Mäkelä
- HUS Medical Imaging Center, Helsinki University Central Hospital, Finland.,Department of Physics, University of Helsinki, Finland
| | - Mika Kortesniemi
- HUS Medical Imaging Center, Helsinki University Central Hospital, Finland.,Department of Physics, University of Helsinki, Finland
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22
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Hojreh A, Homolka P, Gamper J, Unterhumer S, Kienzl-Palma D, Balassy C, Wrba T, Prosch H. Automated tube voltage selection in pediatric non-contrast chest CT. PLoS One 2018; 13:e0204794. [PMID: 30281614 PMCID: PMC6169939 DOI: 10.1371/journal.pone.0204794] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 09/15/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Modern CT scanners provide automatic dose adjustment systems, which are promising options for reducing radiation dose in pediatric CT scans. Their impact on patient dose, however, has not been investigated sufficiently thus far. OBJECTIVE To evaluate automated tube voltage selection (ATVS) in combination with automated tube current modulation (ATCM) in non-contrast pediatric chest CT, with regard to the diagnostic image quality. MATERIALS AND METHODS There were 160 non-contrast pediatric chest CT scans (8.7±5.4 years) analyzed retrospectively without and with ATVS. Correlations of volume CT Dose Index (CTDIvol) and effective diameter, with and without ATVS, were compared using Fisher's z-transformation. Image quality was assessed by mean signal-difference-to-noise ratios (SDNR) in the aorta and in the left main bronchus using the independent samples t-test. Two pediatric radiologists and a general radiologist rated overall subjective Image quality. Readers' agreement was assessed using weighted kappa coefficients. A p value <0.05 was considered significant. RESULTS CTDIvol correlation with the effective diameter was r = 0.62 without and r = 0.80 with ATVS (CI: -0.04 to -0.60; p = 0.025). Mean SDNR was 10.88 without and 10.03 with ATVS (p = 0.0089). Readers' agreement improved with ATVS (weighted kappa between pediatric radiologists from 0.1 (0.03-0.16) to 0.27 (0.09-0.45) with ATVS; between general and each pediatric radiologist from 0.1 (0.06-0.14) to 0.12 (0.05-0.20), and from 0.22 (0.11-0.34) to 0.36 (0.24-0.49)). CONCLUSION ATVS, combined with ATCM, results in a radiation dose reduction for pediatric non-contrast chest CT without a loss of diagnostic image quality and prevents errors in manual tube voltage setting, and thus protecting larger children against an unnecessarily high radiation exposure.
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Affiliation(s)
- Azadeh Hojreh
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
- * E-mail:
| | - Peter Homolka
- Centre for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Jutta Gamper
- Centre for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Sylvia Unterhumer
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Daniela Kienzl-Palma
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Csilla Balassy
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Thomas Wrba
- IT-Systems & Communications, IT4Science, Medical University of Vienna, Vienna, Austria
| | - Helmut Prosch
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
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Body size and tube voltage-dependent guiding equations for optimal selection of image acquisition parameters in clinical X-ray imaging. Radiol Phys Technol 2018; 11:212-218. [PMID: 29667102 DOI: 10.1007/s12194-018-0457-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 03/31/2018] [Accepted: 04/11/2018] [Indexed: 10/17/2022]
Abstract
The purpose of this work was to present body size and tube voltage-dependent equations for optimal selection of image acquisition parameters in guiding clinical X-ray imaging. The dose output of X-ray tubes was expressed as a function of the image acquisition parameters of tube voltage (kVp), tube current-exposure time product (mAs), and body size (d). Dose power (n) to kVp was determined to be a linear function of body size in an earlier phantom study. Tube voltage-dependent attenuation coefficients of water were used to determine the kVp effect on the depth dose of X-rays from the body's entrance surface. The new expression for the dose output of X-ray tubes in patients was then employed for image quality and radiation dose optimization, assuming that image quality is a logistic function of the radiation dose to patients. For constant kVp, the percentage of mAs increase for a 1-cm increase in body size d is dependent on the kVp applied. For constant mAs, the percentage of kVp increase for a 1-cm increase in body size is dependent on both body size d and the kVp applied. For constant body size, the percentage of kVp increase should be a fraction of the percentage of decrease in the mAs, where the fraction is dependent on the body size. The improved body size and tube voltage-dependent governing equations for variations in X-ray imaging parameters should be more accurate in guiding optimal selection of the kVp and mAs image acquisition parameters in medical X-ray imaging.
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24
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Albrecht MH, Bickford MW, Schoepf UJ, Tesche C, De Santis D, Eid M, Jacobs BE, Duguay TM, Schmidt BT, Canstein C, Varga-Szemes A, Leithner D, Martin S, Vogl TJ, De Cecco CN. Beam-hardening in 70-kV Coronary CT angiography: Artifact reduction using an advanced post-processing algorithm. Eur J Radiol 2018; 101:111-117. [DOI: 10.1016/j.ejrad.2018.02.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 09/27/2017] [Accepted: 02/12/2018] [Indexed: 10/18/2022]
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Lee HS, Suh YJ, Han K, Kim JY, Chang S, Im DJ, Hong YJ, Lee HJ, Hur J, Kim YJ, Choi BW. Effectiveness of automatic tube potential selection with tube current modulation in coronary CT angiography for obese patients: Comparison with a body mass index-based protocol using the propensity score matching method. PLoS One 2018; 13:e0190584. [PMID: 29304060 PMCID: PMC5755873 DOI: 10.1371/journal.pone.0190584] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 11/21/2017] [Indexed: 01/09/2023] Open
Abstract
Background Reduced image quality from increased X-ray scatter and image noise can be problematic when coronary computed tomography angiography (CCTA) imaging is performed in obese patients. The aim of this study was to compare the image quality and radiation dose obtained using automatic tube potential selection with tube current modulation (APSCM) with those obtained using a body mass index (BMI)-based protocol for CCTA in obese patients. Methods A total of 203 consecutive obese (BMI > 30 kg/m2) patients were retrospectively enrolled, of whom 96 underwent CCTA with APSCM and 107 underwent a BMI-based protocol. After applying the propensity score matching method, the clinical parameters, subjective and objective image quality, and radiation dose were compared between the APSCM group and the matched BMI-based group. These parameters were also compared among different tube potential subgroups. Results No significant differences were observed between the APSCM group and the BMI-based group with respect to image quality or radiation dose assessment (p > 0.05). Twenty patients (21%) examined with 140 kV in the APSCM group were exposed to significantly more radiation (p < 0.05) than patients in the BMI-based group or patients in the other APSCM kV subgroups; significant improvement in image quality was not observed in the 140 kV subgroup. Patients with a high BMI and a large effective diameter tended to be examined with 140 kV (p < 0.05). Conclusion The use of APSCM for CCTA in obese patients did not significantly reduce the radiation dose or improve image quality compared with those in the matched BMI-based group. Our data indicate that it is better to avoid using APSCM when 140 kV is automatically selected, due to increased radiation dose and lack of significant improvement in image quality.
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Affiliation(s)
- Hong Seon Lee
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Young Joo Suh
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
- * E-mail:
| | - Kyunghwa Han
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Jin Young Kim
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Suyon Chang
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Dong Jin Im
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Yoo Jin Hong
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Hye-Jeong Lee
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Jin Hur
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Young Jin Kim
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
| | - Byoung Wook Choi
- Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Korea
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Othman AE, Bongers MN, Zinsser D, Schabel C, Wichmann JL, Arshid R, Notohamiprodjo M, Nikolaou K, Bamberg F. Evaluation of reduced-dose CT for acute non-traumatic abdominal pain: evaluation of diagnostic accuracy in comparison to standard-dose CT. Acta Radiol 2018; 59:4-12. [PMID: 28406049 DOI: 10.1177/0284185117703152] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Background Patients with acute non-traumatic abdominal pain often undergo abdominal computed tomography (CT). However, abdominal CT is associated with high radiation exposure. Purpose To evaluate diagnostic performance of a reduced-dose 100 kVp CT protocol with advanced modeled iterative reconstruction as compared to a linearly blended 120 kVp protocol for assessment of acute, non-traumatic abdominal pain. Material and Methods Two radiologists assessed 100 kVp and linearly blended 120 kVp series of 112 consecutive patients with acute non-traumatic pain (onset < 48 h) regarding image quality, noise, and artifacts on a five-point Likert scale. Both radiologists assessed both series for abdominal pathologies and for diagnostic confidence. Both 100 kVp and linearly blended 120 kVp series were quantitatively evaluated regarding radiation dose and image noise. Comparative statistics and diagnostic accuracy was calculated using receiver operating curve (ROC) statistics, with final clinical diagnosis/clinical follow-up as reference standard. Results Image quality was high for both series without detectable significant differences ( P = 0.157). Image noise and artifacts were rated low for both series but significantly higher for 100 kVp ( P ≤ 0.021). Diagnostic accuracy was high for both series (120 kVp: area under the curve [AUC] = 0.950, sensitivity = 0.958, specificity = 0.941; 100 kVp: AUC ≥ 0.910, sensitivity ≥ 0.937, specificity = 0.882; P ≥ 0.516) with almost perfect inter-rater agreement (Kappa = 0.939). Diagnostic confidence was high for both dose levels without significant differences (100 kVp 5, range 4-5; 120 kVp 5, range 3-5; P = 0.134). The 100 kVp series yielded 26.1% lower radiation dose compared with the 120 kVp series (5.72 ± 2.23 mSv versus 7.75 ± 3.02 mSv, P < 0.001). Image noise was significantly higher in reduced-dose CT (13.3 ± 2.4 HU versus 10.6 ± 2.1 HU; P < 0.001). Conclusion Reduced-dose abdominal CT using 100 kVp yields excellent image quality and high diagnostic accuracy for the assessment of acute non-traumatic abdominal pain.
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Affiliation(s)
- Ahmed E Othman
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - Malte Niklas Bongers
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - Dominik Zinsser
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - Christoph Schabel
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - Julian L Wichmann
- Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Frankfurt, Germany
| | - Rami Arshid
- Department of General, Visceral and Transplantation Surgery, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - Mike Notohamiprodjo
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - Konstantin Nikolaou
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
| | - Fabian Bamberg
- Department for Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, University Hospital Tuebingen, 72076, Tübingen, Germany
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Diagnostic accuracy of low and high tube voltage coronary CT angiography using an X-ray tube potential-tailored contrast medium injection protocol. Eur Radiol 2017; 28:2134-2142. [PMID: 29181587 DOI: 10.1007/s00330-017-5150-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 09/07/2017] [Accepted: 10/18/2017] [Indexed: 12/12/2022]
Abstract
OBJECTIVES To compare the diagnostic accuracy between low-kilovolt peak (kVp) (≤ 100) and high-kVp (> 100) third-generation dual-source coronary CT angiography (CCTA) using a kVp-tailored contrast media injection protocol. METHODS One hundred twenty patients (mean age = 62.6 years, BMI = 29.0 kg/m2) who underwent catheter angiography and CCTA with automated kVp selection were separated into two cohorts (each n = 60, mean kVp = 84 and 117). Contrast media dose was tailored to the kVp level: 70 = 40 ml, 80 = 50 ml, 90 = 60 ml, 100 = 70 ml, 110 = 80 ml, and 120 = 90 ml. Contrast-to-noise ratio (CNR) was measured. Two observers evaluated image quality and the presence of significant coronary stenosis (> 50% luminal narrowing). RESULTS Diagnostic accuracy (sensitivity/specificity) with ≤ 100 vs. > 100 kVp CCTA was comparable: per patient = 93.9/92.6% vs. 90.9/92.6%, per vessel = 91.5/97.8% vs. 94.0/96.8%, and per segment = 90.0/96.7% vs. 90.7/95.2% (all P > 0.64). CNR was similar (P > 0.18) in the low-kVp vs. high-kVp group (12.0 vs. 11.1), as ws subjective image quality (P = 0.38). Contrast media requirements were reduced by 38.1% in the low- vs. high-kVp cohort (53.6 vs. 86.6 ml, P < 0.001) and radiation dose by 59.6% (4.3 vs. 10.6 mSv, P < 0.001). CONCLUSIONS Automated tube voltage selection with a tailored contrast media injection protocol allows CCTA to be performed at ≤ 100 kVp with substantial dose reductions and equivalent diagnostic accuracy for coronary stenosis detection compared to acquisitions at > 100 kVp. KEY POINTS • Low-kVp coronary CT angiography (CCTA) enables reduced contrast and radiation dose. • Diagnostic accuracy is comparable between ≤ 100 and > 100 kVp CCTA. • Image quality is similar for low- and high-kVp CCTA. • Low-kVp image acquisition is facilitated by automated tube voltage selection. • Tailoring contrast injection protocols to the automatically selected kVp-level is feasible.
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Renapurkar RD, Primak A, Azok J, Lempel J, Tandon Y, Bullen J, Dong F, Karim W, Graham R. Attenuation-based kV pair selection in dual source dual energy computed tomography angiography of the chest: impact on radiation dose and image quality. Eur Radiol 2017; 27:3283-3289. [PMID: 28091793 DOI: 10.1007/s00330-016-4714-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 11/09/2016] [Accepted: 12/15/2016] [Indexed: 01/22/2023]
Abstract
OBJECTIVES The purpose of this study was to evaluate the impact of attenuation-based kilovoltage (kV) pair selection in dual source dual energy (DSDE)-pulmonary embolism (PE) protocol examinations on radiation dose savings and image quality. METHODS A prospective study was carried out on 118 patients with suspected PE. In patients in whom attenuation-based kV pair selection selected the 80/140Sn kV pair, the pre-scan 100/140Sn CTDIvol (computed tomography dose index volume) values were compared with the pre-scan 80/140Sn CTDIvol values. Subjective and objective image quality parameters were assessed. RESULTS Attenuation-based kV pair selection switched to the 80/140Sn kV pair ("switched" cohort) in 63 out of 118 patients (53%). The mean 100/140Sn pre-scan CTDIvol was 8.8 mGy, while the mean 80/140Sn pre-scan CTDIvol was 7.5 mGy. The average estimated dose reduction for the "switched" cohort was 1.3 mGy (95% CI 1.2, 1.4; p < 0.001), representing a 15% reduction in dose. After adjusting for patient weight, mean attenuation was significantly higher in the "switched" vs. "non-switched" cohorts in all five pulmonary arteries and in all lobes on iodine maps. CONCLUSIONS This study demonstrates that attenuation-based kV pair selection in DSDE examination is feasible and can offer radiation dose reduction without compromising image quality. KEY POINTS • Attenuation-based kV pair selection in dual energy examination is feasible. • It can offer radiation dose reduction to approximately 50% of patients. • Approximate 15% reduction in radiation dose was achieved using this technique. • The image quality is not compromised by use of attenuation-based kV pair selection.
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Affiliation(s)
- Rahul D Renapurkar
- Thoracic Imaging, L10, Imaging Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA.
| | | | - Joseph Azok
- Thoracic Imaging, L10, Imaging Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA
| | - Jason Lempel
- Thoracic Imaging, L10, Imaging Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA
| | - Yasmeen Tandon
- Department of Radiology, Case Western Reserve University-Metro Health Medical Center, Cleveland, OH, 44109, USA
| | - Jennifer Bullen
- Quantitative Health Sciences, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA
| | - Frank Dong
- Section of Medical Physics, Cleveland Clinic, Cleveland, OH, USA
| | - Wadih Karim
- Thoracic Imaging, L10, Imaging Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA
| | - Ruffin Graham
- Thoracic Imaging, L10, Imaging Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA
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Optimizing Contrast Media Injection Protocols in Computed Tomography Angiography at Different Tube Voltages. J Comput Assist Tomogr 2017; 41:804-810. [DOI: 10.1097/rct.0000000000000613] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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30
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Mangold S, De Cecco CN, Schoepf UJ, Kuhlman TS, Varga-Szemes A, Caruso D, Duguay TM, Tesche C, Vogl TJ, Nikolaou K, Steinberg DH, Wichmann JL. CT angiography for planning transcatheter aortic valve replacement using automated tube voltage selection: Image quality and radiation exposure. Eur J Radiol 2017; 86:276-283. [DOI: 10.1016/j.ejrad.2016.11.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 09/19/2016] [Accepted: 11/22/2016] [Indexed: 11/30/2022]
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Mangold S, Wichmann JL, Schoepf UJ, Caruso D, Tesche C, Steinberg DH, Varga-Szemes A, Stubenrauch AC, Bayer RR, Biancalana M, Nikolaou K, De Cecco CN. Diagnostic accuracy of coronary CT angiography using 3 rd-generation dual-source CT and automated tube voltage selection: Clinical application in a non-obese and obese patient population. Eur Radiol 2016; 27:2298-2308. [PMID: 27682312 DOI: 10.1007/s00330-016-4601-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 08/15/2016] [Accepted: 09/07/2016] [Indexed: 12/19/2022]
Abstract
PURPOSE To investigate diagnostic accuracy of 3rd-generation dual-source CT (DSCT) coronary angiography in obese and non-obese patients. METHODS We retrospectively analyzed 76 patients who underwent coronary CT angiography (CCTA) and invasive coronary angiography. Prospectively ECG-triggered acquisition was performed with automated tube voltage selection (ATVS). Patients were dichotomized based on body mass index in groups A (<30 kg/m2, n = 37) and B (≥30 kg/m2, n = 39) and based on tube voltage in groups C (<120 kV, n = 46) and D (120 kV, n = 30). Coronary arteries were assessed for significant stenoses (≥50 % luminal narrowing) and diagnostic accuracy was calculated. RESULTS Per-patient overall sensitivity, specificity, positive predictive value, negative predictive value (NPV) and accuracy were 96.9 %, 95.5 %, 93.9 %, 97.7 % and 96.1 %, respectively. Sensitivity and NPV were lower in groups B and D compared to groups A and C, but no statistically significant differences were observed (group A vs. B: sensitivity, 100.0 % vs. 93.3 %, p = 0.9493; NPV, 100 % vs. 95.5 %, p = 0.9812; group C vs. D: sensitivity, 100.0 % vs. 92.3 %, p = 0.8462; NPV, 100.0 % vs. 94.1 %, p = 0.8285). CONCLUSION CCTA using 3rd-generation DSCT and (ATVS) provides high diagnostic accuracy in both non-obese and obese patients. KEY POINTS • Coronary CTA provides high diagnostic accuracy in non-obese and obese patients. • Diagnostic accuracy between obese and non-obese patients showed no significant difference. • <120 kV studies were performed in 44 % of obese patients. • Current radiation dose-saving approaches can be applied independent of body habitus.
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Affiliation(s)
- Stefanie Mangold
- Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260, USA.,Department of Diagnostic and Interventional Radiology, Eberhard-Karls University Tuebingen, Tuebingen, Germany
| | - Julian L Wichmann
- Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260, USA.,Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Frankfurt, Germany
| | - U Joseph Schoepf
- Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260, USA. .,Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, SC, USA.
| | - Damiano Caruso
- Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260, USA.,Department of Radiological Sciences, Oncology and Pathology, University of Rome "Sapienza", Rome, Italy
| | - Christian Tesche
- Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260, USA.,Department of Cardiology, Heart Centre Munich-Bogenhausen, Munich, Germany
| | - Daniel H Steinberg
- Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Akos Varga-Szemes
- Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260, USA
| | - Andrew C Stubenrauch
- Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260, USA
| | - Richard R Bayer
- Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, SC, USA
| | - Matthew Biancalana
- Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260, USA
| | - Konstantin Nikolaou
- Department of Diagnostic and Interventional Radiology, Eberhard-Karls University Tuebingen, Tuebingen, Germany
| | - Carlo N De Cecco
- Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC, 29425-2260, USA
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The changing use of pediatric CT in Australia. Pediatr Radiol 2016; 46:1199-208. [PMID: 26952101 DOI: 10.1007/s00247-016-3563-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 12/16/2015] [Accepted: 01/26/2016] [Indexed: 10/22/2022]
Abstract
BACKGROUND Despite the medical benefits of CT, there are concerns about increased cancer risks following CT scans in childhood. OBJECTIVE To assess Australian temporal trends in pediatric CT scans funded through Medicare over the period 1985 to 2005, as well as changes in the types of CT scanners used. MATERIALS AND METHODS We studied de-identified electronic records of Medicare-funded services, including CT scans, that were available for children and adults younger than 20 years between 1985 and 2005. We assessed temporal trends using CT imaging rates by age, gender and anatomical region. Regulators provided CT scanner registration lists to identify new models installed in Australia and to date the introduction of new technologies. RESULTS Between 1985 and 2005, 896,306 Medicare-funded CT services were performed on 688,260 individuals younger than 20 years. The imaging rate more than doubled during that time period. There were more than 1,000 CT scanners on registration lists during the study period. There were both a sharp increase in the availability of helical scanning capabilities from 1994 and significant growth in multi-detector CT scanners from 2000. CONCLUSION Significant increases in the rate of pediatric CT scanning have occurred in Australia. This rate has stabilized since 2000, possibly a result of better understanding of cancer risks.
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Sabel BO, Buric K, Karara N, Thierfelder KM, Dinkel J, Sommer WH, Meinel FG. High-Pitch CT Pulmonary Angiography in Third Generation Dual-Source CT: Image Quality in an Unselected Patient Population. PLoS One 2016; 11:e0146949. [PMID: 26872262 PMCID: PMC4752234 DOI: 10.1371/journal.pone.0146949] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 12/22/2015] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES To investigate the feasibility of high-pitch CT pulmonary angiography (CTPA) in 3rd generation dual-source CT (DSCT) in unselected patients. METHODS Forty-seven patients with suspected pulmonary embolism underwent high-pitch CTPA on a 3rd generation dual-source CT scanner. CT dose index (CTDIvol) and dose length product (DLP) were obtained. Objective image quality was analyzed by calculating signal-to-noise-ratio (SNR) and contrast-to-noise ratio (CNR). Subjective image quality on the central, lobar, segmental and subsegmental level was rated by two experienced radiologists. RESULTS Median CTDI was 8.1 mGy and median DLP was 274 mGy*cm. Median SNR was 32.9 in the central and 31.9 in the segmental pulmonary arteries. CNR was 29.2 in the central and 28.2 in the segmental pulmonary arteries. Median image quality was "excellent" in central and lobar arteries and "good" in subsegmental arteries according to both readers. Segmental arteries varied between "excellent" and "good". Image quality was non-diagnostic in one case (2%), beginning in the lobar arteries. Thirteen patients (28%) showed minor motion artifacts. CONCLUSIONS In third-generation dual-source CT, high-pitch CTPA is feasible for unselected patients. It yields excellent image quality with minimal motion artifacts. However, compared to standard-pitch cohorts, no distinct decrease in radiation dose was observed.
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Affiliation(s)
- Bastian O. Sabel
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Kristijan Buric
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Nora Karara
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Kolja M. Thierfelder
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Julien Dinkel
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Wieland H. Sommer
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Felix G. Meinel
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
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Automated tube voltage selection for radiation dose and contrast medium reduction at coronary CT angiography using 3(rd) generation dual-source CT. Eur Radiol 2016; 26:3608-16. [PMID: 26847044 DOI: 10.1007/s00330-015-4191-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 12/09/2015] [Accepted: 12/22/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVES To investigate the relationship between automated tube voltage selection (ATVS) and body mass index (BMI) and its effect on image quality and radiation dose of coronary CT angiography (CCTA). METHODS We evaluated 272 patients who underwent CCTA with 3(rd) generation dual-source CT (DSCT). Prospectively ECG-triggered spiral acquisition was performed with automated tube current selection and advanced iterative reconstruction. Tube voltages were selected by ATVS (70-120 kV). BMI, effective dose (ED), and vascular attenuation in the coronary arteries were recorded. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Five-point scales were used for subjective image quality analysis. RESULTS Image quality was rated good to excellent in 98.9 % of examinations without significant differences for proximal and distal attenuation (all p ≥ .0516), whereas image noise was rated significantly higher at 70 kV compared to ≥100 kV (all p < .0266). However, no significant differences were observed in SNR or CNR at 70-120 kV (all p ≥ .0829). Mean ED at 70-120 kV was 1.5 ± 1.2 mSv, 2.4 ± 1.5 mSv, 3.6 ± 2.7 mSv, 5.9 ± 4.0 mSv, 7.9 ± 4.2 mSv, and 10.7 ± 4.1 mSv, respectively (all p ≤ .0414). Correlation analysis showed a moderate association between tube voltage and BMI (r = .639). CONCLUSION ATVS allows individual tube voltage adaptation for CCTA performed with 3(rd) generation DSCT, resulting in significantly decreased radiation exposure while maintaining image quality. KEY POINTS • Automated tube voltage selection allows an individual tube voltage adaption in CCTA. • A tube voltage-based reduction of contrast medium volume is feasible. • Image quality was maintained while radiation exposure was significantly decreased. • A moderate association between tube voltage and body mass index was found.
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