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Feldle P, Grunz JP, Kunz AS, Pannenbecker P, Patzer TS, Pichlmeier S, Sauer ST, Hendel R, Ergün S, Bley TA, Huflage H. Influence of spectral shaping and tube voltage modulation in ultralow-dose computed tomography of the abdomen. BMC Med Imaging 2024; 24:49. [PMID: 38395772 PMCID: PMC10893640 DOI: 10.1186/s12880-024-01228-1] [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: 05/10/2023] [Accepted: 02/14/2024] [Indexed: 02/25/2024] Open
Abstract
PURPOSE Unenhanced abdominal CT constitutes the diagnostic standard of care in suspected urolithiasis. Aiming to identify potential for radiation dose reduction in this frequent imaging task, this experimental study compares the effect of spectral shaping and tube voltage modulation on image quality. METHODS Using a third-generation dual-source CT, eight cadaveric specimens were scanned with varying tube voltage settings with and without tin filter application (Sn 150, Sn 100, 120, 100, and 80 kVp) at three dose levels (3 mGy: standard; 1 mGy: low; 0.5 mGy: ultralow). Image quality was assessed quantitatively by calculation of signal-to-noise ratios (SNR) for various tissues (spleen, kidney, trabecular bone, fat) and subjectively by three independent radiologists based on a seven-point rating scale (7 = excellent; 1 = very poor). RESULTS Irrespective of dose level, Sn 100 kVp resulted in the highest SNR of all tube voltage settings. In direct comparison to Sn 150 kVp, superior SNR was ascertained for spleen (p ≤ 0.004) and kidney tissue (p ≤ 0.009). In ultralow-dose scans, subjective image quality of Sn 100 kVp (median score 3; interquartile range 3-3) was higher compared with conventional imaging at 120 kVp (2; 2-2), 100 kVp (1; 1-2), and 80 kVp (1; 1-1) (all p < 0.001). Indicated by an intraclass correlation coefficient of 0.945 (95% confidence interval: 0.927-0.960), interrater reliability was excellent. CONCLUSIONS In abdominal CT with maximised dose reduction, tin prefiltration at 100 kVp allows for superior image quality over Sn 150 kVp and conventional imaging without spectral shaping.
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Affiliation(s)
- Philipp Feldle
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Jan-Peter Grunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Andreas Steven Kunz
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Pauline Pannenbecker
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Theresa Sophie Patzer
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Svenja Pichlmeier
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Stephanie Tina Sauer
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Robin Hendel
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Süleyman Ergün
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstraße 6, 97070, Würzburg, Germany
| | - Thorsten Alexander Bley
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany
| | - Henner Huflage
- Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080, Würzburg, Germany.
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Inoue A, Uemura R, Takaki K, Sonoda A, Ota S, Nitta N, Batsaikhan B, Takahashi H, Watanabe Y. Clinical impact of low tube voltage computed tomography during hepatic arteriography with low iodine to detect hepatocellular carcinoma before transarterial chemoembolization. Eur J Radiol 2022; 154:110420. [DOI: 10.1016/j.ejrad.2022.110420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 05/31/2022] [Accepted: 06/20/2022] [Indexed: 11/17/2022]
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Assessment of Imaging Protocol and Patients Radiation Exposure in Computed Tomography Colonography. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11114761] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In the screening and identifying of colon and rectum malignancy, computed tomography colonography (CTC) is a highly effective imaging technique, albeit patients receiving a significant effective dose. Accordingly, patient dose evaluation is an important need, seeking to ensure benefits outweigh the projected cancer risk. Objective: For CTC procedures carried out in the Radiology Department, Medical Imaging Operation Services, King Fahad Medical City (KFMC), evaluation is done using the current American College of Radiology (ACR) imaging protocol and concomitant patient-effective doses. Study is carried out on a sample size of 55 CTC procedures, involving 25 males (45%) and 30 females (55%). The patients were classified as follows: two groups based on CT machine; four groups based on the applied protocol; and three groups based on the procedure results. All procedures were carried out using two machines, the products of two different vendors (a GE Healthcare DISCOVERY CT 750 HD 64 slices dual-energy scanner and a Philips Brilliance CT 64 slices scanner). The overall mean, standard deviation (SD), median, and range of the effective dose (in mSv) were 11.57 ± 7.75, 9.25 (2.17–31.93). Automatic tube current modulation (ATCM) shows a significant increase in CTDIvol up to 69% and effective dose (mSv) up to 95% than the manual tube current (mA) compared to the standard protocol. The CT protocol variation results in a three-fold variation in patient-effective dose. The technologist role is crucial in selecting a noise reference based on patient weight and adjusting tube current per slice to avoid overexposure during ATCM protocol.
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Liu JJ, Xue HD, Liu W, Yan J, Pan WD, Li B, Xu K, Wang Y, Li P, Xiao Y, Jin ZY. CT colonography with spectral filtration and advanced modeled iterative reconstruction in the third-generation dual-source CT: image quality, radiation dose and performance in clinical utility. Acad Radiol 2021; 28:e127-e136. [PMID: 32434689 DOI: 10.1016/j.acra.2020.03.040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 03/17/2020] [Accepted: 03/18/2020] [Indexed: 12/23/2022]
Abstract
RATIONALE AND OBJECTIVES To evaluate image quality, radiation dose and its diagnostic performance in clinical utility of CT colonography (CTC) applying spectral filtration and advanced modeled iterative reconstruction (ADMIRE) techniques in third-generation dual-source CT. MATERIALS AND METHODS A total of 125 patients for screening or diagnostic purposes underwent CTC at 120kVp standard dose (120kVp-STD) with filtered-back projection reconstruction (FBP) in supine position, then at a tin-filtered 150 kVp low dose (Sn150kVp-LD) and a tin-filtered 100 kVp ultra-low dose (Sn100kVp-ULD) with ADMIRE reconstruction in prone position. Radiation metrics were recorded. Objective and subjective image qualities were compared, and the diagnostic performance was assessed for both colonic and extracolonic findings using CTC reporting and data system (C-RADS). RESULTS The effective dose was significantly lower for Sn150kVp-LD and Sn100kVp-ULD than 120kVp-STD protocol, resulting in 22.5% and 87.5% reductions (1.55±0.30 and 0.25±0.07 mSv vs. 2.00±0.52 mSv; both p<0.01), respectively. Image noise and signal-to-noise ratio were improved significantly for Sn150kVp-LD with ADMIRE compared with 120kVp-STD, both of which had similar excellent 2D and 3D subjective image quality with equivalent diagnostic performance. Sn100kVp-ULD with ADMIRE had decreased subjective image quality and significant different C-RADS extracolonic-score (E-score) compared with 120kVp-STD, however, C-RADS colonic-score (C-score) of that showed no significantly difference. CONCLUSION Sn150kVp and Sn100kVp with ADMIRE reconstruction provide an alternative low dose CTC strategy and could be feasible in clinical screening or diagnostic scenarios.
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Affiliation(s)
- Jing-Juan Liu
- Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No. 1, Dongcheng District, 100730, Beijing, China
| | - Hua-Dan Xue
- Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No. 1, Dongcheng District, 100730, Beijing, China
| | - Wei Liu
- Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No. 1, Dongcheng District, 100730, Beijing, China.
| | - Jing Yan
- Siemens Medical System, 201318, Shanghai, China
| | - Wei-Dong Pan
- Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No. 1, Dongcheng District, 100730, Beijing, China
| | - Bin Li
- Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No. 1, Dongcheng District, 100730, Beijing, China
| | - Kai Xu
- Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No. 1, Dongcheng District, 100730, Beijing, China
| | - Yun Wang
- Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No. 1, Dongcheng District, 100730, Beijing, China
| | - Ping Li
- Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No. 1, Dongcheng District, 100730, Beijing, China
| | - Yi Xiao
- Department of General Surgery, Peking Union Medical College Hospital, Shuaifuyuan No. 1, Dongcheng District, 100730, Beijing, China
| | - Zheng-Yu Jin
- Department of Radiology, Peking Union Medical College Hospital, Shuaifuyuan No. 1, Dongcheng District, 100730, Beijing, China
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Iball GR, Tolan D, Avery GR, Cope LH, Hoare T, Lambie H, Lowe A, de Noronha RJ, Roberts CL, Wilkinson ME, Woolfall P. Improving practice in radiology: a quality-improvement project examining CT colonography patient dose and scanning technique. Clin Radiol 2021; 76:626.e13-626.e21. [PMID: 33714540 DOI: 10.1016/j.crad.2021.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 02/05/2021] [Indexed: 11/26/2022]
Abstract
AIM To audit scanning technique and patient doses for computed tomography (CT) colonography (CTC) examinations in a large UK region and to identify opportunities for quality improvement. MATERIALS AND METHODS Scanning technique and patient dose data were gathered for both contrast-enhanced and unenhanced CTC examinations from 33 imaging protocols across 27 scanners. Measurements of patient weight and effective diameter were also obtained. Imaging protocols were compared to identify technique differences between similar scanners. Scanner average doses were calculated and combined to generate regional diagnostic reference limits (DRLs) for both examinations. RESULTS The regional DRLs for contrast-enhanced examinations were volume CT dose index (CTDIvol) of 11 and 5 mGy for the two scan phases (contrast-enhanced and either delayed phase or non-contrast enhanced respectively), and dose-length product (DLP) of 740 mGy·cm. For unenhanced examinations, these were 5 mGy and 450 mGy·cm. These are notably lower than the national DRLs of 11 mGy and 950 mGy·cm. Substantial differences in scan technique and doses on similar scanners were identified as areas for quality-improvement action. CONCLUSION A regional CTC dose audit has demonstrated compliance with national DRLs but marked variation in practice between sites for the dose delivered to patients, notably when scanners of the same type were compared for the same indication. This study demonstrates that the national DRL is too high for current scanner technology and should be revised.
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Affiliation(s)
- G R Iball
- Department of Medical Physics, Old Medical School, Leeds General Infirmary, Leeds, LS1 3EX, UK.
| | - D Tolan
- Radiology Department, St James' University Hospital, Beckett Street, Leeds, LS9 7TF, UK
| | - G R Avery
- Department of Radiology, Hull and East Yorkshire Hospitals NHS Trust Castle Hill Hospital, Cottingham, Hull, HU16 5JQ, UK
| | - L H Cope
- Radiology Department, South Tyneside NHS FT, Harton Lane South Shields, Tyne and Wear, NE34 0PL, UK
| | - T Hoare
- Radiology Department, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Trust, Queen Victoria Road, Newcastle upon Tyne, NE1 4LP, UK
| | - H Lambie
- Radiology Department, St James' University Hospital, Beckett Street, Leeds, LS9 7TF, UK
| | - A Lowe
- Radiology Department, Bradford Royal Infirmary, Duckworth Lane, Bradford, BD9 6RJ, UK
| | - R J de Noronha
- Radiology Department, Sheffield Teaching Hospital Trust, Herries Road, Sheffield, S5 7AU, UK
| | - C L Roberts
- Radiology, Calderdale and Huddersfield NHS Trust, Huddersfield, West Yorkshire, HD3 3EA, UK
| | - M E Wilkinson
- Northumbria Healthcare NHS Foundation Trust, Wansbeck General Hospital, Woodhorn Lane, Ashington, Norhumberland, NE 63 9JJ, UK
| | - P Woolfall
- Radiology Department, University Hospital of North Tees, Stockton on Tees, TS19 8PE, UK
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Dose Reduction in Dental CT: A Phantom Study With Special Focus on Tin Filter Technique. AJR Am J Roentgenol 2020; 215:945-953. [PMID: 32783561 DOI: 10.2214/ajr.19.22461] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE. The purpose of this study was to determine in a phantom the dose exposure of different dental 3D sectional imaging methods (CT and cone-beam CT [CBCT]) and different CT protocols. The aim was to establish optimal protocols with the lowest possible dose and diagnostically high image quality with special consideration given to tin prefiltration. MATERIALS AND METHODS. Dose was determined with thermoluminescence detectors at 20 different measuring points on an anthropomorphic phantom. Eight different CT protocols with and without tin filtering were compared with iterative reconstruction methods and a standard CBCT protocol. Objective and subjective image evaluations and a figure-of-merit analysis of the image data were performed by radiologists and maxillofacial surgeons. RESULTS. The determined dose-length products of the nine examinations were 5.0-111.9 mGy · cm with a calculated effective whole body dose of 20.7-505.9 μSv. Cone-beam CT was in the upper midfield with an effective dose of 229.3 μSv. On the basis of dose, objective image quality, and clinical evaluation results, tin filter protocols performed best. Protocols with higher doses were significantly less useful in the figure of merit comparison but because of their detailed bony representation are particularly necessary to answer certain questions about trauma and tumors. CONCLUSION. The use of tin filtering can reduce dose in dental CT examinations, compared with standard low-dose examinations, while maintaining good image quality. The dose performance is significantly inferior even to that of a cone-beam CT examination. High-dose protocols are necessary only for certain questions.
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Ricci ZJ, Kobi M, Flusberg M, Yee J. CT Colonography in Review With Tips and Tricks to Improve Performance. Semin Roentgenol 2020; 56:140-151. [PMID: 33858640 DOI: 10.1053/j.ro.2020.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Zina J Ricci
- Montefiore Medical Center/Albert Einstein College of Medicine, Bronx, NY.
| | - Mariya Kobi
- Montefiore Medical Center/Albert Einstein College of Medicine, Bronx, NY
| | - Milana Flusberg
- Westchester Medical Center/New York Medical College, Valhalla, NY
| | - Judy Yee
- Montefiore Medical Center/Albert Einstein College of Medicine, Bronx, NY
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Cianci R, Delli Pizzi A, Esposito G, Timpani M, Tavoletta A, Pulsone P, Basilico R, Cotroneo AR, Filippone A. Ultra-low dose CT colonography with automatic tube current modulation and sinogram-affirmed iterative reconstruction: Effects on radiation exposure and image quality. J Appl Clin Med Phys 2018; 20:321-330. [PMID: 30586479 PMCID: PMC6333183 DOI: 10.1002/acm2.12510] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 11/03/2018] [Accepted: 11/20/2018] [Indexed: 12/14/2022] Open
Abstract
Objective To assess the radiation dose and image quality of ultra‐low dose (ULD)‐CT colonography (CTC) obtained with the combined use of automatic tube current (mAs) modulation with a quality reference mAs of 25 and sinogram‐affirmed iterative reconstruction (SAFIRE), compared to low‐dose (LD) CTC acquired with a quality reference mAs of 55 and reconstructed with filtered back projection (FBP). Methods Eighty‐two patients underwent ULD‐CTC acquisition in prone position and LD‐CTC acquisition in supine position. Both ULD‐CTC and LD‐CTC protocols were compared in terms of radiation dose [weighted volume computed tomography dose index (CTDIvol) and effective dose], image noise, image quality, and polyp detection. Results The mean effective dose of ULD‐CTC was significantly lower than that of LD‐CTC (0.98 and 2.69 mSv respectively, P < 0.0001) with an overall dose reduction of 63.2%. Image noise was comparable between ULD‐CTC and LD‐CTC (28.6 and 29.8 respectively, P = 0.09). There was no relevant difference when comparing image quality scores and polyp detection for both 2D and 3D images. Conclusion ULD‐CTC allows to significantly reduce the radiation dose without meaningful image quality degradation compared to LD‐CTC.
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Affiliation(s)
- Roberta Cianci
- Department of Neuroscience Imaging and Clinical Sciences, University "G. d'Annunzio", SS. Annunziata Hospital, Chieti, Italy
| | - Andrea Delli Pizzi
- Department of Neuroscience Imaging and Clinical Sciences, University "G. d'Annunzio", SS. Annunziata Hospital, Chieti, Italy
| | - Gianluigi Esposito
- Department of Neuroscience Imaging and Clinical Sciences, University "G. d'Annunzio", SS. Annunziata Hospital, Chieti, Italy
| | - Mauro Timpani
- Department of Neuroscience Imaging and Clinical Sciences, University "G. d'Annunzio", SS. Annunziata Hospital, Chieti, Italy
| | - Alessandra Tavoletta
- Department of Neuroscience Imaging and Clinical Sciences, University "G. d'Annunzio", SS. Annunziata Hospital, Chieti, Italy
| | - Pierluigi Pulsone
- Department of Neuroscience Imaging and Clinical Sciences, University "G. d'Annunzio", SS. Annunziata Hospital, Chieti, Italy
| | - Raffaella Basilico
- Department of Neuroscience Imaging and Clinical Sciences, University "G. d'Annunzio", SS. Annunziata Hospital, Chieti, Italy
| | - Antonio Raffaele Cotroneo
- Department of Neuroscience Imaging and Clinical Sciences, University "G. d'Annunzio", SS. Annunziata Hospital, Chieti, Italy
| | - Antonella Filippone
- Department of Neuroscience Imaging and Clinical Sciences, University "G. d'Annunzio", SS. Annunziata Hospital, Chieti, Italy
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Abstract
Significant anxiety has been expressed by some over the radiation risks associated with computed tomography (CT), particularly when it applies to a screening examination such as CT colonography. These theoretic risks are far outweighed by the significant benefits colorectal cancer screening offers. Regardless of how significant the theoretic risk of CT radiation is in the older population, the ALARA principle maintains that radiation dose should be reduced to As Low As Reasonably Achievable. This article will discuss various strategies that may be utilized to reduce radiation dose and mitigate any increase in image noise that may occur.
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Affiliation(s)
- Kevin J Chang
- Department of Radiology, Newton-Wellesley Hospital, Brown University Alpert Medical School, 2014 Washington Street, Newton, MA 02462, USA.
| | - Judy Yee
- Department of Radiology, Montefiore Medical Center, Albert Einstein College of Medicine, 111 East 210th Street, Bronx, NY 10467, USA
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Virtual Computed Tomography Colonography: Evaluation of 2D and Virtual 3D Image Quality of Sub-mSv Examinations Enabled by Third-generation Dual Source Scanner Featuring Tin Filtering. Acad Radiol 2018; 25:1046-1051. [PMID: 29371121 DOI: 10.1016/j.acra.2017.12.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 12/04/2017] [Accepted: 12/17/2017] [Indexed: 12/12/2022]
Abstract
RATIONALE AND OBJECTIVES To evaluate two- and three-dimensional (2D and 3D) image quality of sub-milliSievert (mSv) computed tomography (CT) colonography utilizing a third-generation dual source CT scanner featuring a tin filter. METHODS We retrospectively evaluated 26 consecutive patients who underwent third-generation dual source CT colonography, nine with the standard-dose clinical-scan protocol (SDP) and 17 with a low-dose protocol (LDP) featuring a tin filter. Radiation dose was evaluated by volume computed tomography dose index (CTDIvol), dose length product (DLP), effective dose (E), and size-specific dose estimate. Objective image quality was evaluated utilizing signal-to-noise ratio (SNR) derived from standardized placed regions of interest on the transverse 2D images and the ratio of SNR/CTDIvol (normalized SNR). Two radiologists in consensus assessed subjective image quality of the virtual 3D images. RESULTS There were no significant differences in subjective image quality (P = .661). All examinations were rated "excellent" or "good" for diagnostic confidence. The mean total for DLP/E was 143.4 ± 29.8 mGy/3.00 ± 0.40 mSv in the SDP and therefore significantly higher than in the LDP with 36.9 ± 8.7 mGy/0.75 ± 0.16 mSv (P < .001). The SNR was 8.9 ± 2.1 in the SDP and 4.9 ± 0.8 in the LDP. CONCLUSIONS Third-generation dual source CT featuring a tin filter enables consistent sub-mSv colonography without substantially impairing image quality.
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Abstract
CT colonography (CTC) has demonstrated equivalent accuracy to optical colonoscopy in the detection of clinically relevant polyps and tumors but this is only possible when technique is optimized. The two most important features of a high-quality CTC are a well-prepared colon and a distended colon. This article will discuss the dietary, bowel preparation, and fecal/fluid tagging options to best prepare the colon. Strategies to optimally distend the colon will also be discussed. CT scan techniques including patient positioning and radiation dose optimization will be reviewed. With proper technique which includes sufficient bowel preparation, fecal/fluid tagging, bowel distension, and optimized scan technique, high-quality CTC examinations should become more feasible, easier to interpret, and more consistently reproducible leading to increased utilization and increased referrals.
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Yee J, McFarland E. Extracolonic findings and radiation at CT colonography: what the referring provider needs to know. Abdom Radiol (NY) 2018; 43:554-565. [PMID: 29450613 DOI: 10.1007/s00261-018-1461-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A better understanding of the risks and benefits of extracolonic findings and radiation dose will aid in the safe and proper implementation of CT colonography in clinical practice. The majority of extracolonic findings in screening patients are benign and can be ignored by referring physicians. Radiologists also need to be responsible in reporting extracolonic findings. Referring providers must be knowledgeable about the theoretic risks and controversies regarding the use of ionizing radiation. Screening CT colonography imparts a low-level of radiation to patients that is equivalent or less than annual background dose.
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Affiliation(s)
- Judy Yee
- Department of Radiology, Albert Einstein College of Medicine, Montefiore Medical Center, 111 East 210th St, Bronx, NY, 10467, USA.
| | - Elizabeth McFarland
- SSM St. Joseph Health Center, 300 Capitol Drive, St. Charles, MO, 63301, USA
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Futamata Y, Koide T, Ihara R. Effect of Reduced Tube Voltage on Diagnostic Accuracy of CT Colonography. Nihon Hoshasen Gijutsu Gakkai Zasshi 2017; 73:548-555. [PMID: 28724866 DOI: 10.6009/jjrt.2017_jsrt_73.7.548] [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: 11/11/2022]
Abstract
The normal tube voltage in computed tomography colonography (CTC) is 120 kV. Some reports indicate that the use of a low tube voltage (lower than 120 kV) technique plays a significant role in reduction of radiation dose. However, to determine whether a lower tube voltage can reduce radiation dose without compromising diagnostic accuracy, an evaluation of images that are obtained while maintaining the volume CT dose index (CTDIvol) is required. This study investigated the effect of reduced tube voltage in CTC, without modifying radiation dose (i.e. constant CTDIvol), on image quality. Evaluation of image quality involved the shape of the noise power spectrum, surface profiling with volume rendering (VR), and receiver operating characteristic (ROC) analysis. The shape of the noise power spectrum obtained with a tube voltage of 80 kV and 100 kV was not similar to the one produced with a tube voltage of 120 kV. Moreover, a higher standard deviation was observed on volume-rendered images that were generated using the reduced tube voltages. In addition, ROC analysis revealed a statistically significant drop in diagnostic accuracy with reduced tube voltage, revealing that the modification of tube voltage affects volume-rendered images. The results of this study suggest that reduction of tube voltage in CTC, so as to reduce radiation dose, affects image quality and diagnostic accuracy.
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Affiliation(s)
- Yoshihiro Futamata
- Division of Radiologic Technology, Department of Medical Technology, Abashiri-Kosei General Hospital
| | - Tomoaki Koide
- Division of Radiologic Technology, Department of Medical Technology, Abashiri-Kosei General Hospital
| | - Riku Ihara
- Division of Radiologic Technology, Department of Medical Technology, Abashiri-Kosei General Hospital
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Optimizing CT technique to reduce radiation dose: effect of changes in kVp, iterative reconstruction, and noise index on dose and noise in a human cadaver. Radiol Phys Technol 2016; 10:180-188. [DOI: 10.1007/s12194-016-0382-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 09/21/2016] [Accepted: 09/25/2016] [Indexed: 10/20/2022]
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Maggialetti N, Capasso R, Pinto D, Carbone M, Laporta A, Schipani S, Piccolo CL, Zappia M, Reginelli A, D'Innocenzo M, Brunese L. Diagnostic value of computed tomography colonography (CTC) after incomplete optical colonoscopy. Int J Surg 2016; 33 Suppl 1:S36-44. [PMID: 27255132 DOI: 10.1016/j.ijsu.2016.05.053] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION This study evaluated the role of computed tomography colonography (CTC) in patients who previously underwent incomplete optical colonoscopy (OC). We analyzed the impact of colonic lesions in intestinal segments not studied by OC and extracolonic findings in these patients. METHODS Between January 2014 and May 2015, 61 patients with a history of abdominal pain and incomplete OC examination were studied by CTC. CTCs were performed by 320-row CT scan in both the supine and the prone position, without intravenous administration of contrast medium. In all patients both colonic findings and extracolonic findings were evaluated. RESULTS Among the study group, 24 CTC examinations were negative for both colonic and extracolonic findings while 6 examinations revealed the presence of both colonic and extracolonic findings. In 24 patients CTC depicted colonic anomalies without extracolonic ones, while in 7 patients it showed extracolonic findings without colonic ones. DISCUSSION CTC is a noninvasive imaging technique with the advantages of high diagnostic performance, rapid data acquisition, minimal patient discomfort, lack of need for sedation, and virtually no recovery time. CTC accurately allows the evaluation of the nonvisualized part of the colon after incomplete OC and has the distinct advantage to detect clinically important extracolonic findings in patients with incomplete OC potentially explaining the patient's symptoms and conditioning their therapeutic management. CONCLUSION CTC accurately allows the assessment of both colonic and extracolonic pathologies representing a useful diagnostic tool in patients for whom complete OC is not achievable.
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Affiliation(s)
- N Maggialetti
- Department of Medicine and Health Science, University of Molise, Campobasso, Italy.
| | - R Capasso
- Department of Internal and Experimental Medicine, Magrassi-Lanzara, Second University of Naples, Piazza Miraglia 2, 80138 Naples, Italy.
| | - D Pinto
- Radiological Research, Molfetta, BA, Italy.
| | - M Carbone
- Department of Radiology, A.O.U. San Giovanni di Dio e Ruggi d'Aragona, Salerno, Italy.
| | - A Laporta
- Department of Radiology, A.O. Solofra, Italy.
| | - S Schipani
- Department of Medicine and Health Science, University of Molise, Campobasso, Italy.
| | - C L Piccolo
- Department of Medicine and Health Science, University of Molise, Campobasso, Italy.
| | - M Zappia
- Department of Medicine and Health Science, University of Molise, Campobasso, Italy.
| | - A Reginelli
- Department of Internal and Experimental Medicine, Magrassi-Lanzara, Second University of Naples, Piazza Miraglia 2, 80138 Naples, Italy.
| | | | - L Brunese
- Department of Medicine and Health Science, University of Molise, Campobasso, Italy.
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Lamba R, Corwin MT, Fananapazir G. Practical dose reduction tips for abdominal interventional procedures using CT-guidance. Abdom Radiol (NY) 2016; 41:743-53. [PMID: 26920005 DOI: 10.1007/s00261-016-0670-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Reducing the radiation dose should be an endeavor not only for diagnostic CT exams but also for interventional procedures using CT-guidance. Given that interventional procedures vary in scope and complexity, there is greater variability in radiation doses delivered during CT procedures. The goal in an interventional procedure is simply to advance the interventional instruments into the target lesions, and as such diagnostic level doses are not required and only narrow scan range scans need to be acquired. Adherence to the principles outlined in this article will allow such procedures to be performed with reduced radiation doses.
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Affiliation(s)
- Ramit Lamba
- Department of Radiology, University of California Davis Medical Center, 4860 Y Street, Sacramento, CA, 95817, USA.
| | - Michael T Corwin
- Department of Radiology, University of California Davis Medical Center, 4860 Y Street, Sacramento, CA, 95817, USA
| | - Ghaneh Fananapazir
- Department of Radiology, University of California Davis Medical Center, 4860 Y Street, Sacramento, CA, 95817, USA
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Reducing the radiation dose for computed tomography colonography using model-based iterative reconstruction. ACTA ACUST UNITED AC 2016; 40:1183-9. [PMID: 25331565 DOI: 10.1007/s00261-014-0271-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
PURPOSE To determine whether radiation doses during computed tomography (CT) colonography (CTC) can be further reduced while maintaining image quality using model-based iterative reconstruction (MBIR). METHODS Twenty patients underwent CTC at a standard dose in supine and prone positions and at a reduced dose in the supine position. All other scan parameters (except noise index) were held constant. Acquisitions were reconstructed using 3 algorithms: filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR), and MBIR. Noise was assessed quantitatively by comparing the SD in Hounsfield units at 5 standard locations. Qualitative assessment was made by 2 experienced radiologists blinded to technique who subjectively scored image quality, noise, and sharpness (from 0 to 4). RESULTS The standard-dose and reduced-dose CT dose index/dose-length product were 6.7/328 and 2.7 mGy/129 mGy-cm, respectively (60% reduction). Measured mean noise level increased from the standard to the reduced dose (FBP, from 58.6 to 97.2; ASIR from 35.8 to 60.6; and MBIR from 16.6 to 21.9). MBIR had significantly less noise than ASIR on 2-dimensional images at both standard and reduced doses (P < .01). CONCLUSIONS Radiation dose in CTC using MBIR can be reduced by 60% while maintaining image quality and reducing image noise.
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Yamamura S, Oda S, Imuta M, Utsunomiya D, Yoshida M, Namimoto T, Yuki H, Kidoh M, Funama Y, Baba H, Yamashita Y. Reducing the Radiation Dose for CT Colonography: Effect of Low Tube Voltage and Iterative Reconstruction. Acad Radiol 2016; 23:155-62. [PMID: 25872861 DOI: 10.1016/j.acra.2015.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 02/27/2015] [Accepted: 03/08/2015] [Indexed: 12/17/2022]
Abstract
RATIONALE AND OBJECTIVES The purpose of this study was to assess the effect of a low-tube-voltage technique and iterative reconstruction (IR) on the radiation dose and image quality of computed tomography colonography (CTC). MATERIALS AND METHODS We studied 30 patients (14 women and 16 men; mean age, 64.5 ± 13.1 years; range, 39-90 years) with colorectal cancer referred for surgical treatment. All underwent CTC with fecal tagging under a standard 120-kVp protocol in the supine position and a 100-kVp protocol in the prone position. The 120-kVp images were reconstructed with filtered back projection (FBP). The 100-kVp images were postprocessed using FBP and a hybrid type of IR (adaptive iterative dose reduction 3D). The effective radiation dose (ED), image noise, and contrast-to-noise ratio (CNR) were compared among the three protocols. The visual image quality was scored on a four-point scale. RESULTS The mean ED was significantly lower under the 100-kVp protocol than the 120-kVp protocol, resulting in a 27% radiation dose decrease (3.5 ± 2.0 vs 2.5 ± 1.5 mSv; P < .01). Image noise decreased by 48%, and the mean attenuation of tagged fluid increased from 452 to 558 HU on images acquired at 100 kVp with IR compared to that in the 120-kVp protocol; these differences were significant. The mean CNR was significantly higher under the 100 kVp with IR than the other two protocols. We found no significant differences in the visual scores for diagnostic utility between the 100 kVp with IR and the 120 kVp with FBP protocol (P = .10). CONCLUSIONS Low-tube-voltage CTC reduced the radiation dose by approximately 27% while maintaining the image quality.
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One-mSv CT colonography: Effect of different iterative reconstruction algorithms on radiologists' performance. Eur J Radiol 2016; 85:641-8. [PMID: 26860679 DOI: 10.1016/j.ejrad.2015.12.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 12/22/2015] [Accepted: 12/29/2015] [Indexed: 12/24/2022]
Abstract
PURPOSE To analyze the effect of different reconstruction algorithms on image noise and radiologists' performance at ultra-low dose CT colonography (CTC) in human subjects. MATERIALS AND METHODS This retrospective study had institutional review board approval, with waiver of the need to obtain informed consent. CTC and subsequent colonoscopy were performed at the same day in 28 patients. CTC was scanned at the supine/prone positions using 120/100kVp and fixed 10mAs, and reconstructed using filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR), and model-based IR (Veo) algorithms. Size-specific dose estimates (SSDE) and effective radiation doses were recorded. Image noise was compared among the three datasets using repeated measures analysis of variance (ANOVA). Per-polyp sensitivity and figure-of-merits were compared among the datasets using the McNemar test and jackknife alternative free-response receiver operating characteristic (JAFROC) analysis, respectively, by one novice and one expert reviewer in CTC. RESULTS Mean SSDE and effective radiation dose of CTC were 1.732mGy and 1.002mSv, respectively. Mean image noise at supine/prone position datasets was significantly lowest with Veo (17.2/13.3), followed by ASIR (52.4/38.9) and FBP (69.9/50.8) (P<0.0001). Forty-two polyps in 25 patients were reference polyps. For both readers, per-polyp sensitivity of all 42 polyps was highest with Veo reconstruction (81.0%, 64.3%), followed by ASIR (73.8%, 54.8%) and FBP (57.1%, 50.0%) with statistical significance between Veo and FBP for reader 1 (P=0.002). JAFROC analysis revealed that the figure-of-merit for the detection of polyps was highest with Veo (0.917, 0.786), followed by ASIR (0.881, 0.750) and FBP (0.750, 0.746) with statistical significances between Veo or ASIR and FBP for reader 1 (P<0.05). CONCLUSION One-mSv CTC was not feasible using the standard FBP algorithm. However, diagnostic performance expressed as per-polyp sensitivity and figures-of-merit can be improved with the application of IR algorithms, particularly Veo.
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Seyal AR, Arslanoglu A, Abboud SF, Sahin A, Horowitz JM, Yaghmai V. CT of the Abdomen with Reduced Tube Voltage in Adults: A Practical Approach. Radiographics 2015; 35:1922-39. [PMID: 26473536 DOI: 10.1148/rg.2015150048] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Recent innovations in computed tomographic (CT) hardware and software have allowed implementation of low tube voltage imaging into everyday CT scanning protocols in adults. CT at a low tube voltage setting has many benefits, including (a) radiation dose reduction, which is crucial in young patients and those with chronic medical conditions undergoing serial CT examinations for disease management; and (b) higher contrast enhancement. For the latter, increased attenuation of iodinated contrast material improves the evaluation of hypervascular lesions, vascular structures, intestinal mucosa in patients with bowel disease, and CT urographic images. Additionally, the higher contrast enhancement may provide diagnostic images in patients with renal dysfunction receiving a reduced contrast material load and in patients with suboptimal peripheral intravenous access who require a lower contrast material injection rate. One limitation is that noisier images affect image quality at a low tube voltage setting. The development of denoising algorithms such as iterative reconstruction has made it possible to perform CT at a low tube voltage setting without compromising diagnostic confidence. Other potential pitfalls of low tube voltage CT include (a) photon starvation artifact in larger patients, (b) accentuation of streak artifacts, and (c) alteration of the CT attenuation value, which may affect evaluation of lesions on the basis of conventional enhancement thresholds. CT of the abdomen with a low tube voltage setting is an excellent radiation reduction technique when properly applied to imaging of select patients in the appropriate clinical setting.
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Affiliation(s)
- Adeel R Seyal
- From the Department of Radiology, Northwestern University-Feinberg School of Medicine, 676 N Saint Clair St, Suite 800, Chicago, IL 60611
| | - Atilla Arslanoglu
- From the Department of Radiology, Northwestern University-Feinberg School of Medicine, 676 N Saint Clair St, Suite 800, Chicago, IL 60611
| | - Samir F Abboud
- From the Department of Radiology, Northwestern University-Feinberg School of Medicine, 676 N Saint Clair St, Suite 800, Chicago, IL 60611
| | - Azize Sahin
- From the Department of Radiology, Northwestern University-Feinberg School of Medicine, 676 N Saint Clair St, Suite 800, Chicago, IL 60611
| | - Jeanne M Horowitz
- From the Department of Radiology, Northwestern University-Feinberg School of Medicine, 676 N Saint Clair St, Suite 800, Chicago, IL 60611
| | - Vahid Yaghmai
- From the Department of Radiology, Northwestern University-Feinberg School of Medicine, 676 N Saint Clair St, Suite 800, Chicago, IL 60611
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Chang K, Heisler M, Mahesh M, Baird G, Mayo-Smith W. CT colonography at low tube potential: using iterative reconstruction to decrease noise. Clin Radiol 2015; 70:981-8. [DOI: 10.1016/j.crad.2015.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 03/24/2015] [Accepted: 05/12/2015] [Indexed: 01/15/2023]
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Clinical indications for computed tomographic colonography: European Society of Gastrointestinal Endoscopy (ESGE) and European Society of Gastrointestinal and Abdominal Radiology (ESGAR) Guideline. Eur Radiol 2015; 25:331-45. [PMID: 25278245 PMCID: PMC4291518 DOI: 10.1007/s00330-014-3435-z] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Lambert L, Danes J, Jahoda J, Masek M, Lisy J, Ourednicek P. Submilisievert ultralow-dose CT colonography using iterative reconstruction technique: a feasibility study. Acta Radiol 2015; 56:517-25. [PMID: 24855290 DOI: 10.1177/0284185114533683] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 04/08/2014] [Indexed: 12/24/2022]
Abstract
BACKGROUND Computed tomography (CT) colonography is a well established modality for the examination of symptomatic patients as well as in screening. Recent technical advances in improving image quality by iterative reconstruction contribute to the reduction of the radiation dose which is a major concern in CT imaging. PURPOSE To evaluate image quality of ultralow-dose submilisievert CT colonography using hybrid iterative reconstruction technique. MATERIAL AND METHODS Sixteen patients underwent contrast-enhanced CT colonography with standard protocol in supine position and ultralow-dose protocol in prone position. Ultralow-dose datasets were reconstructed with filtered back projection and an advanced hybrid iterative reconstruction technique. Two radiologists independently evaluated 96 colonic segments for image quality in the endoluminal view and axial thin sections. Colonic distension, smoothness of colonic wall and distortion of folds in the endoluminal view, sharpness of colonic wall delineation, perceived image noise, and presence of photon starvation artifact were rated on a five-point scale. Intraluminal noise expressed as standard deviation of Hounsfield density was measured in all segments. RESULTS The mean radiation dose was 0.42 mSv and 5.48 mSv in prone and supine scans, respectively. All distended segments were rated evaluable in standard dose and ultralow-dose series reconstructed with the iterative reconstruction technique, whereas in 61% segments image quality was rated poor or unacceptable in ultralow-dose series where filtered back projection was used with worst ratings in the rectum and the sigmoid colon. CONCLUSION This pilot study shows that iterative reconstruction technique is a feasible method to decrease the radiation dose from CT colonography for both positions below 1mSv. Further investigations of larger scale need to be done to clarify, whether such a low radiation dose would influence the detection of polyps.
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Affiliation(s)
- Lukas Lambert
- Department of Radiology, First Faculty of Medicine of Charles University, Prague, Czech Republic
| | - Jan Danes
- Department of Radiology, First Faculty of Medicine of Charles University, Prague, Czech Republic
| | - Jiri Jahoda
- Department of Radiology, First Faculty of Medicine of Charles University, Prague, Czech Republic
| | - Martin Masek
- Department of Radiology, First Faculty of Medicine of Charles University, Prague, Czech Republic
| | - Jiri Lisy
- Department of Radiology, 2nd Faculty of Medicine of Charles University and Motol University Hospital, Prague, Czech Republic
| | - Petr Ourednicek
- Department of Imaging Methods, St. Anne’s University Hospital, Brno, Czech Republic
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Vardhanabhuti V, James J, Nensey R, Hyde C, Roobottom C. Model-based iterative reconstruction in low-dose CT colonography-feasibility study in 65 patients for symptomatic investigation. Acad Radiol 2015; 22:563-71. [PMID: 25683499 DOI: 10.1016/j.acra.2014.12.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 12/17/2014] [Accepted: 12/18/2014] [Indexed: 12/29/2022]
Abstract
RATIONALE AND OBJECTIVES To compare image quality on computed tomographic colonography (CTC) acquired at standard dose (STD) and low dose (LD) using filtered-back projection, adaptive statistical iterative reconstruction, and model-based iterative reconstruction (MBIR) techniques. MATERIALS AND METHODS A total of 65 symptomatic patients were prospectively enrolled for the study and underwent STD and LD CTC with filtered-back projection, adaptive statistical iterative reconstruction, and MBIR to allow direct per-patient comparison. Objective image noise, subjective image analyses, and polyp detection were assessed. RESULTS Objective image noise analysis demonstrates significant noise reduction using MBIR technique (P < .05) despite being acquired at lower doses. Subjective image analyses were superior for LD MBIR in all parameters except visibility of extracolonic lesions (two-dimensional) and visibility of colonic wall (three-dimensional) where there were no significant differences. There was no significant difference in polyp detection rates (P > .05). Doses: LD (dose-length product, 257.7), STD (dose-length product, 483.6). CONCLUSIONS LD MBIR CTC objectively shows improved image noise using parameters in our study. Subjectively, image quality is maintained. Polyp detection shows no significant difference but because of small numbers needs further validation. Average dose reduction of 47% can be achieved. This study confirms feasibility of using MBIR in this context of CTC in symptomatic population.
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Lubner MG, Pooler BD, Kitchin DR, Tang J, Li K, Kim DH, Munoz del Rio A, Chen GH, Pickhardt PJ. Sub-milliSievert (sub-mSv) CT colonography: a prospective comparison of image quality and polyp conspicuity at reduced-dose versus standard-dose imaging. Eur Radiol 2015; 25:2089-102. [PMID: 25903700 DOI: 10.1007/s00330-015-3603-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 01/09/2015] [Accepted: 01/15/2015] [Indexed: 01/30/2023]
Abstract
OBJECTIVE To prospectively compare reduced-dose (RD) CT colonography (CTC) with standard-dose (SD) imaging using several reconstruction algorithms. METHODS Following SD supine CTC, 40 patients (mean age, 57.3 years; 17 M/23 F; mean BMI, 27.2) underwent an additional RD supine examination (targeted dose reduction, 70-90%). DLP, CTDI(vol), effective dose, and SSDE were compared. Several reconstruction algorithms were applied to RD series. SD-FBP served as reference standard. Objective image noise, subjective image quality and polyp conspicuity were assessed. RESULTS Mean CTDI(vol) and effective dose for RD series was 0.89 mGy (median 0.65) and 0.6 mSv (median 0.44), compared with 3.8 mGy (median 3.1) and 2.8 mSv (median 2.3) for SD series, respectively. Mean dose reduction was 78%. Mean image noise was significantly reduced on RD-PICCS (24.3 ± 19HU) and RD-MBIR (19 ± 18HU) compared with RD-FBP (90 ± 33), RD-ASIR (72 ± 27) and SD-FBP (47 ± 14 HU). 2D image quality score was higher with RD-PICCS, RD-MBIR, and SD-FBP (2.7 ± 0.4/2.8 ± 0.4/2.9 ± 0.6) compared with RD-FBP (1.5 ± 0.4) and RD-ASIR (1.8 ± 0.44). A similar trend was seen with 3D image quality scores. Polyp conspicuity scores were similar between SD-FBP/RD-PICCS/RD-MBIR (3.5 ± 0.6/3.2 ± 0.8/3.3 ± 0.6). CONCLUSION Sub-milliSievert CTC performed with iterative reconstruction techniques demonstrate decreased image quality compared to SD, but improved image quality compared to RD images reconstructed with FBP. KEY POINTS • CT colonography dose can be substantially lowered using advanced iterative reconstruction techniques. • Iterative reconstruction techniques (MBIR/PICCS) reduce image noise and improve image quality. • The PICCS/MBIR-reconstructed, reduced-dose series shows decreased 2D/3D image quality compared to the standard-dose series. • Polyp conspicuity was similar on standard-dose images compared to reduced-dose images reconstructed with MBIR/PICCS.
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Affiliation(s)
- Meghan G Lubner
- Departments of Radiology, University of Wisconsin School of Medicine and Public Health, E3/311 Clinical Sciences Center, 600 Highland Ave, Madison, WI, 53792-3252, USA,
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Lee ES, Kim SH, Im JP, Kim SG, Shin CI, Han JK, Choi BI. Effect of different reconstruction algorithms on computer-aided diagnosis (CAD) performance in ultra-low dose CT colonography. Eur J Radiol 2015; 84:547-54. [DOI: 10.1016/j.ejrad.2014.11.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Revised: 11/18/2014] [Accepted: 11/22/2014] [Indexed: 10/24/2022]
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de Haan MC, Pickhardt PJ, Stoker J. CT colonography: accuracy, acceptance, safety and position in organised population screening. Gut 2015; 64:342-50. [PMID: 25468258 DOI: 10.1136/gutjnl-2014-308696] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Colorectal cancer (CRC) is the second most common cancer and second most common cause of cancer-related deaths in Europe. The introduction of CRC screening programmes using stool tests and flexible sigmoidoscopy, have been shown to reduce CRC-related mortality substantially. In several European countries, population-based CRC screening programmes are ongoing or being rolled out. Stool tests like faecal occult blood testing are non-invasive and simple to perform, but are primarily designed to detect early invasive cancer. More invasive tests like colonoscopy and CT colonography (CTC) aim at accurately detecting both CRC and cancer precursors, thus providing for cancer prevention. This review focuses on the accuracy, acceptance and safety of CTC as a CRC screening technique and on the current position of CTC in organised population screening. Based on the detection characteristics and acceptability of CTC screening, it might be a viable screening test. The potential disadvantage of radiation exposure is probably overemphasised, especially with newer technology. At this time-point, it is not entirely clear whether the detection of extracolonic findings at CTC is of net benefit and is cost effective, but with responsible handling, this may be the case. Future efforts will seek to further improve the technique, refine appropriate diagnostic algorithms and study cost-effectiveness.
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Affiliation(s)
- Margriet C de Haan
- Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands Department of Radiology, University Medical Center, Utrecht, The Netherlands
| | - Perry J Pickhardt
- Department of Radiology, University of Wisconsin School of Medicine & Public Health, Madison, Wisconsin, USA
| | - Jaap Stoker
- Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands
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Shen H, Liang D, Luo M, Duan C, Cai W, Zhu S, Qiu J, Li W. Pilot study on image quality and radiation dose of CT colonography with adaptive iterative dose reduction three-dimensional. PLoS One 2015; 10:e0117116. [PMID: 25635839 PMCID: PMC4311968 DOI: 10.1371/journal.pone.0117116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 12/17/2014] [Indexed: 12/19/2022] Open
Abstract
Objective To investigate image quality and radiation dose of CT colonography (CTC) with adaptive iterative dose reduction three-dimensional (AIDR3D). Methods Ten segments of porcine colon phantom were collected, and 30 pedunculate polyps with diameters ranging from 1 to 15 mm were simulated on each segment. Image data were acquired with tube voltage of 120 kVp, and current doses of 10 mAs, 20 mAs, 30 mAs, 40 mAs, 50 mAs, respectively. CTC images were reconstructed using filtered back projection (FBP) and AIDR3D. Two radiologists blindly evaluated image quality. Quantitative evaluation of image quality included image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). Qualitative image quality was evaluated with a five-score scale. Radiation dose was calculated based on dose-length product. Ten volunteers were examined supine 50 mAs with FBP and prone 20 mAs with AIDR3D, and image qualities were assessed. Paired t test was performed for statistical analysis. Results For 20 mAs with AIDR3D and 50 mAs with FBP, image noise, SNRs and CNRs were (16.4 ± 1.6) HU vs. (16.8 ± 2.6) HU, 1.9 ± 0.2 vs. 1.9 ± 0.4, and 62.3 ± 6.8 vs. 62.0 ± 6.2, respectively; qualitative image quality scores were 4.1 and 4.3, respectively; their differences were all not statistically significant. Compared with 50 mAs with FBP, radiation dose (1.62 mSv) of 20 mAs with AIDR3D was decreased by 60.0%. There was no statistically significant difference in image noise, SNRs, CNRs and qualitative image quality scores between prone 20 mAs with AIDR3D and supine 50 mAs with FBP in 10 volunteers, the former reduced radiation dose by 61.1%. Conclusion Image quality of CTC using 20 mAs with AIDR3D could be comparable to standard 50 mAs with FBP, radiation dose of the former reduced by about 60.0% and was only 1.62 mSv.
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Affiliation(s)
- Hesong Shen
- Department of Radiology, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Dan Liang
- Department of Radiology, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Mingyue Luo
- Department of Radiology, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
- * E-mail:
| | - Chaijie Duan
- Research Center of Biomedical Engineering, Graduate School at Shenzhen, Tsinghua University, Shenzhen, Guangdong, China
| | - Wenli Cai
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Shanshan Zhu
- Department of Radiology, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Jianping Qiu
- Department of Radiology, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Wenru Li
- Department of Radiology, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
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Lambert L, Ourednicek P, Jahoda J, Lambertova A, Danes J. Model-based vs hybrid iterative reconstruction technique in ultralow-dose submillisievert CT colonography. Br J Radiol 2015; 88:20140667. [PMID: 25605346 DOI: 10.1259/bjr.20140667] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE To compare image quality of different reconstruction techniques in submillisievert ultralow-dose CT colonography (CTC) and to correlate colonic findings with subsequent optical colonoscopy. METHODS 58 patients underwent ultralow-dose CTC. The images were reconstructed with filtered back projection (FBP), hybrid iterative reconstruction (HIR) or model-based iterative reconstruction (MBIR) techniques. In each segment, endoluminal noise (expressed as standard deviation of endoluminal density) was measured and image quality was rated on a five-point Likert scale by two independent readers. Colonic lesions were evaluated in consensus and correlated with subsequent optical colonoscopy where possible. RESULTS The estimated radiation dose was 0.41 ± 0.05 mSv for the supine and 0.42 ± 0.04 mSv for the prone acquisitions. In the endoluminal view, the image quality was rated better in HIR, whereas better scores were obtained in MBIR in the cross-sectional view, where the endoluminal noise was the lowest (p < 0.0001). Five (26%) polyps were not identified using both computer-aided detection and endoluminal inspection in FBP images vs only one (5%) in MBIR and none in HIR images. CONCLUSION This study showed that in submillisievert ultralow-dose CTC, the image quality for the endoluminal view is better when HIR is used, whereas MBIR yields superior images for the cross-sectional view. The inferior quality of images reconstructed with FBP may result in decreased detection of colonic lesions. ADVANCES IN KNOWLEDGE Radiation dose from CTC can be safely reduced <1 mSv for both positions when iterative reconstruction is used. MBIR provides better image quality in the cross-sectional view and HIR in the endoluminal view.
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Affiliation(s)
- L Lambert
- 1 Department of Radiology, First Faculty of Medicine of Charles University in Prague, Prague, Czech Republic
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Levine MS, Yee J. History, evolution, and current status of radiologic imaging tests for colorectal cancer screening. Radiology 2015; 273:S160-80. [PMID: 25340435 DOI: 10.1148/radiol.14140531] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Colorectal cancer screening is thought to be an effective tool with which to reduce the mortality from colorectal cancer through early detection and removal of colonic adenomas and early colon cancers. In this article, we review the history, evolution, and current status of imaging tests of the colon-including single-contrast barium enema, double-contrast barium enema, computed tomographic (CT) colonography, and magnetic resonance (MR) colonography-for colorectal cancer screening. Despite its documented value in the detection of colonic polyps, the double-contrast barium enema has largely disappeared as a screening test because it is widely perceived as a labor-intensive, time-consuming, and technically demanding procedure. In the past decade, the barium enema has been supplanted by CT colonography as the major imaging test in colorectal cancer screening in the United States, with MR colonography emerging as another viable option in Europe. Although MR colonography does not require ionizing radiation, the radiation dose for CT colonography has decreased substantially, and regular screening with this technique has a high benefit-to-risk ratio. In recent years, CT colonography has been validated as an effective tool for use in colorectal cancer screening that is increasingly being disseminated.
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Affiliation(s)
- Marc S Levine
- From the Department of Radiology, Hospital of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104 (M.S.L.); and Department of Radiology and Biomedical Imaging, University of California-San Francisco, San Francisco Veterans Affairs Medical Center, San Francisco, Calif (J.Y.)
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Mayo-Smith WW, Hara AK, Mahesh M, Sahani DV, Pavlicek W. How I Do It: Managing Radiation Dose in CT. Radiology 2014; 273:657-72. [PMID: 25420167 DOI: 10.1148/radiol.14132328] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- William W Mayo-Smith
- From the Department of Radiology, Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI (W.W.M.); Department of Radiology, Mayo Clinic Arizona, Scottsdale, Ariz (A.K.H., W.P.); Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Md (M.M.); and Department of Abdominal Imaging/Intervention, Massachusetts General Hospital, Boston, Mass (D.V.S.)
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Gryspeerdt SS, Salazar P, Lefere P. Image quality improvement in submillisievert computed tomographic colonography using a fast 3-dimensional noise reduction method. J Comput Assist Tomogr 2014; 38:705-13. [PMID: 24834893 DOI: 10.1097/rct.0000000000000092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVE The objective of this study was to evaluate the image quality in submillisievert computed tomographic colonography (CTC) images using a structure preserving diffusion denoising method. METHODS Image quality was compared before and after denoising in 31 patients. One hundred twenty-kilovolt, 30-mAs prone CTC scans were used as reference and compared with submillisievert 140-kV, 10-mAs supine scans. Two readers assessed 2-dimensional and endoluminal image quality. The image noise and the signal-to-noise ratio were measured. RESULTS After denoising, image quality scores improved in both supine series and prone series (P < 0.0001), with the submillisievert denoised images being equal to or better than the native prone reference images. In both the supine images and the prone images, the noise was reduced by a factor of 2 and the signal-to-noise ratio was significantly higher (P < 0.001). The signal-to-noise ratio in the denoised submillisievert images was higher than those in the native prone images (P < 0.001). CONCLUSIONS The structure preserving diffusion denoising method preserves the image quality in submillisievert CTC images compared with the native 30-mAs reference images.
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Affiliation(s)
- Stefaan S Gryspeerdt
- From the *Virtual Colonoscopy Teaching Centre, Hooglede; †Department of Radiology, Stedelijk Ziekenhuis Roeselare, Roeselare, Belgium; ‡Vital Images, Inc, Minnetonka, MN
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Shin CI, Kim SH, Lee ES, Lee DH, Hwang EJ, Chung SY, Lee JM, Han JK, Choi BI. Ultra-low peak voltage CT colonography: effect of iterative reconstruction algorithms on performance of radiologists who use anthropomorphic colonic phantoms. Radiology 2014; 273:759-71. [PMID: 25010640 DOI: 10.1148/radiol.14140192] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE To analyze the effect of a decrease in computed tomographic (CT) colonographic voltage, from 100 and 120 kVp to 80 kVp and reconstructed with filtered back projection ( FBP filtered back projection ), on radiation dose, image noise, and diagnostic performance in anthropomorphic phantoms and to assess the effect of iterative reconstruction ( IR iterative reconstruction ) algorithms on radiologists' performance for 80-kVp CT colonography. MATERIALS AND METHODS Seven colon phantoms with 68 simulated polyps (≥6 mm) were scanned at three peak voltage settings (80, 100, 120 kVp) and 10 mAs. Images were reconstructed by using FBP filtered back projection , hybrid statistic-based IR iterative reconstruction , and knowledge-based IR iterative reconstruction algorithms. Effective radiation dose, image noise, and per-polyp sensitivity were recorded and compared by two reviewers with Friedman test, repeated measures analysis of variance, and McNemar test. RESULTS Median size-specific dose estimate and effective radiation dose of 80-kVp CT colonography was 0.231 mGy and 0.167 mSv, respectively, which was lower than with 100- and 120-kVp CT colonography, with significant difference between 80 and 120 kVp (P = .0005). Image noise (202.0 HU) at 80-kVp FBP filtered back projection CT colonography was significantly higher than at 100-kVp FBP filtered back projection (139.1 HU) and 120-kVp FBP filtered back projection (120.4 HU) (P < .0001). Per-polyp sensitivity (reviewer 1, 14.7% [10 of 68]; reviewer 2, 7.4% [five of 68]) at 80-kVp FBP filtered back projection was significantly lower than at 100-kVp FBP filtered back projection (reviewer 1, 57.4% [39 of 68]; reviewer 2, 39.7% [27 of 68]) and 120-kVp FBP filtered back projection (reviewer 1, 85.3% [58 of 68]; reviewer 2, 83.8% [57 of 68]) (P < .0001). With statistic-based IR iterative reconstruction , image noise at 80 kVp decreased significantly (52.8% [106.7 HU of 202.0 HU]) compared with that at 80-kVp FBP filtered back projection (P < .0001), but per-polyp sensitivity (reviewer 1, 79.4% [54 of 68]; reviewer 2, 66.2% [45 of 68]) at 80-kVp statistic-based IR iterative reconstruction remained significantly lower than at 100-kVp statistic-based IR iterative reconstruction (reviewer 1, 95.6% [65 of 68]; reviewer 2, 86.8% [59 of 68]) (P = .001) and 120-kVp statistic-based IR iterative reconstruction (reviewer 1, 98.5% [67 of 68]; reviewer 2, 89.7% [61 of 68]) (P < .001). For knowledge-based IR iterative reconstruction , per-polyp sensitivity at 80 kVp was improved to 98.5% (67 of 68) and 94.1% (64 of 68), not significantly different from that at 100 kVp (reviewer 1, 100% [68 of 68]; reviewer 2, 95.6% [65 of 68]) and 120 kVp (reviewer 1, 100% [68 of 68]; reviewer 2, 95.6% [65 of 68]) (P > .999). CONCLUSION A decrease in tube voltage to 80 kVp caused reduction in radiation dose (0.166 mSv) with deterioration in image noise and per-polyp sensitivity. By using a knowledge-based IR iterative reconstruction algorithm, radiologists' performance of 80-kVp CT colonography was acceptable and on par with that at 100- or 120-kVp CT colonography.
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Affiliation(s)
- Cheong-Il Shin
- From the Department of Radiology (C.I.S., S.H.K., E.S.L., D.H.L., E.J.H., J.M.L., J.K.H., B.I.C.), Institute of Radiation Medicine (S.H.K., J.M.L., J.K.H., B.I.C.), and Healthcare System Gangnam Center (S.Y.C.), Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul 110-744, Korea
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The Challenges of CT Colonography Reimbursement. J Am Coll Radiol 2013; 10:937-42. [DOI: 10.1016/j.jacr.2013.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Accepted: 09/13/2013] [Indexed: 12/21/2022]
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The time has arrived for national reimbursement of screening CT colonography. AJR Am J Roentgenol 2013; 201:73-9. [PMID: 23789660 DOI: 10.2214/ajr.13.10656] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE CT colonography (CTC) has been fully validated as an accurate screening test for colorectal carcinoma and is being disseminated globally. There is an abundance of new literature addressing the prior concerns of the U.S. Preventive Services Task Force and the Centers for Medicare & Medicaid Services. Specific areas related to radiation dose, extracolonic findings, and generalizability of CTC to senior patients are discussed. CONCLUSION The time has arrived for national reimbursement of CTC in the United States.
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Abstract
Patients, referring physicians, the media, and government agencies have all expressed concern over the risks of medical radiation, particularly as it relates to CT. This concern is particularly paramount when associated with a screening examination such as CT colonography. These theoretical risks must be weighed realistically against the substantial benefits of colon cancer screening as well as against the risks inherent in the major alternative screening option, optical colonoscopy. When put into perspective, the risk-benefit ratio is highly in favor of the performance of CT colonography. Nevertheless, in following the ALARA principle, there is an ever increasing armamentarium of options that can be employed in the pursuit of CT radiation dose reduction, all of which can be used in many synergistic combinations allowing for dose reduction while simultaneously preserving image quality and minimizing image noise. After a brief tutorial on estimating radiation dose, various strategies will be discussed including reductions in tube current and tube voltage as well as the use of automatic dose modulation and iterative reconstruction. Other practical considerations will also be reviewed including proper patient isocentering, optimization of colonic insufflation to minimize additional decubitus scans, proper choice of scan volumes to avoid overranging, and variation of slice thickness and window width to minimize perceived image noise. Finally, a strategy for how to incrementally introduce these methods as well as a way to compare dose reduction efforts across institutions throughout the country will be offered.
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