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Smith ACJ, Tse JJ, Waungana TH, Bott KN, Kuczynski MT, Michalski AS, Boyd SK, Manske SL. Internal calibration for opportunistic computed tomography muscle density analysis. PLoS One 2022; 17:e0273203. [PMID: 36251648 PMCID: PMC9576101 DOI: 10.1371/journal.pone.0273203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 10/02/2022] [Indexed: 11/05/2022] Open
Abstract
INTRODUCTION Muscle weakness can lead to reduced physical function and quality of life. Computed tomography (CT) can be used to assess muscle health through measures of muscle cross-sectional area and density loss associated with fat infiltration. However, there are limited opportunities to measure muscle density in clinically acquired CT scans because a density calibration phantom, allowing for the conversion of CT Hounsfield units into density, is typically not included within the field-of-view. For bone density analysis, internal density calibration methods use regions of interest within the scan field-of-view to derive the relationship between Hounsfield units and bone density, but these methods have yet to be adapted for muscle density analysis. The objective of this study was to design and validate a CT internal calibration method for muscle density analysis. METHODOLOGY We CT scanned 10 bovine muscle samples using two scan protocols and five scan positions within the scanner bore. The scans were calibrated using internal calibration and a reference phantom. We tested combinations of internal calibration regions of interest (e.g., air, blood, bone, muscle, adipose). RESULTS We found that the internal calibration method using two regions of interest, air and adipose or blood, yielded accurate muscle density values (< 1% error) when compared with the reference phantom. The muscle density values derived from the internal and reference phantom calibration methods were highly correlated (R2 > 0.99). The coefficient of variation for muscle density across two scan protocols and five scan positions was significantly lower for internal calibration (mean = 0.33%) than for Hounsfield units (mean = 6.52%). There was no difference between coefficient of variation for the internal calibration and reference phantom methods. CONCLUSIONS We have developed an internal calibration method to produce accurate and reliable muscle density measures from opportunistic computed tomography images without the need for calibration phantoms.
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Affiliation(s)
- Ainsley C. J. Smith
- Biomedical Engineering Graduate Program, University of Calgary, Alberta, Canada
- Department of Radiology, Cumming School of Medicine, University of Calgary, Alberta, Canada
- McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada
| | - Justin J. Tse
- Department of Radiology, Cumming School of Medicine, University of Calgary, Alberta, Canada
- McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada
| | - Tadiwa H. Waungana
- Biomedical Engineering Graduate Program, University of Calgary, Alberta, Canada
- Department of Radiology, Cumming School of Medicine, University of Calgary, Alberta, Canada
- McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada
| | - Kirsten N. Bott
- Department of Radiology, Cumming School of Medicine, University of Calgary, Alberta, Canada
- McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada
| | - Michael T. Kuczynski
- Biomedical Engineering Graduate Program, University of Calgary, Alberta, Canada
- Department of Radiology, Cumming School of Medicine, University of Calgary, Alberta, Canada
- McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada
| | - Andrew S. Michalski
- Biomedical Engineering Graduate Program, University of Calgary, Alberta, Canada
- Department of Radiology, Cumming School of Medicine, University of Calgary, Alberta, Canada
- McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada
| | - Steven K. Boyd
- Biomedical Engineering Graduate Program, University of Calgary, Alberta, Canada
- Department of Radiology, Cumming School of Medicine, University of Calgary, Alberta, Canada
- McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada
| | - Sarah L. Manske
- Biomedical Engineering Graduate Program, University of Calgary, Alberta, Canada
- Department of Radiology, Cumming School of Medicine, University of Calgary, Alberta, Canada
- McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada
- * E-mail:
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Practice Management Strategies for Imaging Facilities Facing an Acute Iodinated Contrast Media Shortage. AJR Am J Roentgenol 2022; 219:666-670. [PMID: 35549445 DOI: 10.2214/ajr.22.27969] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
An unanticipated but severe shortage in iodinated contrast media (ICM) is currently affecting imaging practices across the globe and is expected to persist through at least the end of June 2022. This supply shock may lead to healthcare systems experiencing an acute imaging crisis, as many affected facilities have contrast agent supplies that are anticipated to last only a week or two under normal operating conditions. To maximize the opportunity to continue to provide optimal care for patients with emergent or life-threatening imaging indications and thereby minimize the overall impact on patient care, practice leaders will need to quickly assess their contrast material inventories, prioritize examination indications, and reduce their expected short-term usage of ICM. This Clinical Perspective reviews ICM conservation techniques that we have deployed, or are considering deploying, depending on the severity and length of the supply shortage.
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Nguyen ET, Hague C, Manos D, Memauri B, Souza C, Taylor J, Dennie C. Canadian Society of Thoracic Radiology/Canadian Association of Radiologists Best Practice Guidance for Investigation of Acute Pulmonary Embolism, Part 1: Acquisition and Safety Considerations. Can Assoc Radiol J 2021; 73:203-213. [PMID: 33781098 DOI: 10.1177/08465371211000737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Acute pulmonary embolism (APE) is a well-recognized cause of circulatory system compromise and even demise which can frequently present a diagnostic challenge for the physician. The diagnostic challenge is primarily due to the frequency of indeterminate presentations as well as several other conditions which can have a similar clinical presentation. This often obliges the physician to establish a firm diagnosis due to the potentially serious outcomes related to this disease. Computed tomography pulmonary angiography (CTPA) has increasingly cemented its role as the primary investigation tool in this clinical context and is widely accepted as the standard of care due to several desired attributes which include great accuracy, accessibility, rapid turn-around time and the ability to suggest an alternate diagnosis when APE is not the culprit. In Part 1 of this guidance document, a series of up-to-date recommendations are provided to the reader pertaining to CTPA protocol optimization (including scan range, radiation and intravenous contrast dose), safety measures including the departure from breast and gonadal shielding, population-specific scenarios (pregnancy and early post-partum) and consideration of alternate diagnostic techniques when clinically deemed appropriate.
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Affiliation(s)
- Elsie T Nguyen
- Department of Radiology, Joint Department of Medical Imaging, Toronto General Hospital, University of Toronto, Ontario, Canada
| | - Cameron Hague
- Department of Radiology, University of British Columbia, Ontario, Canada
| | - Daria Manos
- Department of Diagnostic Radiology, Dalhousie University, Ontario, Canada
| | - Brett Memauri
- Department of Radiology, University of Manitoba, Cardiothoracic Sciences Division, St. Boniface General Hospital, Ontario, Canada
| | - Carolina Souza
- Department of Medical Imaging, The Ottawa Hospital, University of Ottawa, Ontario, Canada
| | - Jana Taylor
- Department of Radiology, McGill University Health Centre, Ontario, Canada
| | - Carole Dennie
- Department of Medical Imaging, The Ottawa Hospital, University of Ottawa, Ontario, Canada.,Department of Radiology, University of Ottawa, Ottawa Hospital Research Institute, Ontario, Canada
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Valtchinov VI, Siegelman J, Zhai BK, Khorasani R, Sodickson A. One size does not fit all: Factors associated with increased frequency of radiation overexposure alerts based on fixed-alert thresholds. Phys Med 2021; 82:79-86. [PMID: 33601164 DOI: 10.1016/j.ejmp.2021.02.003] [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: 09/30/2020] [Revised: 01/22/2021] [Accepted: 02/06/2021] [Indexed: 10/22/2022] Open
Abstract
OBJECTIVES Quantify the expected rate of CT radiation dose alerts for three body regions using accepted radiation dose benchmarks and assess key determinants of alert frequency. METHODS This IRB-approved retrospective cohort study evaluated consecutive CT examinations performed between July and December 2013 within an academic medical system. CTDIvol x-ray tube output metrics were compared to the body-region-specific benchmark levels, Achievable Doses (AD), Diagnostic Reference Levels (DRL), and Dose Notification Values (DNV). A logistic regression model for the simulated alerts was fit as a function of the independent predictors: scanner, body region, gender, weight, and age. RESULTS For 17,000 exams, the proportion of events triggering alerts increased with patient weight. Significant covariates were scanner, body region, patient weight and patient age (all p < 0.0001). Odds of alert generation for the AD, DRL, and DNV benchmarks increased by 7.6%, 6.6% and 2.9% per kilogram, respectively, and by 0.8%, 1.1% and -2.7% per year of age (all p < 0.0001). Compared to the most highly optimized scanner, odds of alert generation varied by a factor of 595 for AD, 1126 for DRL, and 13 for DNV. CONCLUSION Alert frequency was significantly correlated with weight, age, body region and scanner. Controllable factors include scanner functionality and associated protocol optimization. Patient factors driving alert frequency are predominantly weight, and to a lesser degree, age. Size-agnostic fixed dose thresholds can frequently produce false positive alerts in appropriately performed exams of large patients, while missing opportunities to identify outlier scans of higher-than-expected dose in small patients.
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Affiliation(s)
- Vladimir I Valtchinov
- Center for Evidence-Based Imaging (CEBI), Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA
| | - Jenifer Siegelman
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Takeda Pharmaceuticals, Boston, MA, USA
| | - Bingxue K Zhai
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ramin Khorasani
- Center for Evidence-Based Imaging (CEBI), Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Aaron Sodickson
- Center for Evidence-Based Imaging (CEBI), Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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Singh R, Wu W, Wang G, Kalra MK. Artificial intelligence in image reconstruction: The change is here. Phys Med 2020; 79:113-125. [DOI: 10.1016/j.ejmp.2020.11.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 11/06/2020] [Accepted: 11/07/2020] [Indexed: 12/19/2022] Open
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Aldosari S, Sun Z. A Systematic Review of Double Low-dose CT Pulmonary Angiography in Pulmonary Embolism. Curr Med Imaging 2020; 15:453-460. [PMID: 32008552 DOI: 10.2174/1573405614666180813120619] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 07/20/2018] [Accepted: 07/31/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND The aim of this study is to perform a systematic review of the feasibility and clinical application of double low-dose CT pulmonary angiography (CTPA) in the diagnosis of patients with suspected pulmonary embolism. DISCUSSION A total of 13 studies were found to meet selection criteria reporting both low radiation dose (70 or 80 kVp versus 100 or 120 kVp) and low contrast medium dose CTPA protocols. Lowdose CTPA resulted in radiation dose reduction from 29.6% to 87.5% in 12 studies (range: 0.4 to 23.5 mSv), while in one study, radiation dose was increased in the dual-energy CT group when compared to the standard 120 kVp group. CTPA with use of low contrast medium volume (range: 20 to 75 ml) was compared to standard CTPA (range: 50 to 101 ml) in 12 studies with reduction between 25 and 67%, while in the remaining study, low iodine concentration was used with 23% dose reduction achieved. Quantitative assessment of image quality (in terms of signal-to-noise ratio and contrast-to-noise ratio) showed that low-dose CTPA was associated with higher, lower and no change in image quality in 3, 3 and 6 studies, respectively when compared to the standard CTPA protocol. The subjective assessment indicated similar image quality in 11 studies between low-dose and standard CTPA groups, and improved image quality in 1 study with low-dose CTPA. CONCLUSION This review shows that double low-dose CTPA is feasible in the diagnosis of pulmonary embolism with significant reductions in both radiation and contrast medium doses, without compromising diagnostic image quality.
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Affiliation(s)
- Sultan Aldosari
- Discipline of Medical Radiation Sciences, School of Molecular and Life Sciences, Curtin University, Perth, Australia
| | - Zhonghua Sun
- Discipline of Medical Radiation Sciences, School of Molecular and Life Sciences, Curtin University, Perth, Australia
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Hou KY, Tsujioka K, Yang CC. Optimization of HU threshold for coronary artery calcium scans reconstructed at 0.5-mm slice thickness using iterative reconstruction. J Appl Clin Med Phys 2020; 21:111-120. [PMID: 31889419 PMCID: PMC7021007 DOI: 10.1002/acm2.12806] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/30/2019] [Accepted: 12/13/2019] [Indexed: 12/22/2022] Open
Abstract
PURPOSE This work investigated the simultaneous influence of tube voltage, tube current, body size, and HU threshold on calcium scoring reconstructed at 0.5-mm slice thickness using iterative reconstruction (IR) through multivariate analysis. Regression results were used to optimize the HU threshold to calibrate the resulting Agatston scores to be consistent with those obtained from the conventional protocol. METHODS A thorax phantom set simulating three different body sizes was used in this study. A total of 14 coronary artery calcium (CAC) protocols were studied, including 1 conventional protocol reconstructed at 3-mm slice thickness, 1 FBP protocol, and 12 statistical IR protocols (3 kVp values*4 SD values) reconstructed at 0.5-mm slice thickness. Three HU thresholds were applied for calcium identification, including 130, 150, and 170 HU. A multiple linear regression method was used to analyze the impact of kVp, SD, body size, and HU threshold on the Agatston scores of three calcification densities for IR-reconstructed CAC scans acquired with 0.5-mm slice thickness. RESULTS Each regression relationship has R2 larger than 0.80, indicating a good fit to the data. Based on the regression models, the HU thresholds as a function of SD estimated to ensure the quantification accuracy of calcium scores for 120-, 100-, and 80-kVp CAC scans reconstructed at 0.5-mm slice thickness using IR for three different body sizes were proposed. Our results indicate that the HU threshold should be adjusted according to the imaging condition, whereas a 130-HU threshold is appropriate for 120-kVp CAC scans acquired with SD = 55 for body size of 24.5 cm. CONCLUSION The optimized HU thresholds were proposed for CAC scans reconstructed at 0.5-mm slice thickness using IR. Our study results may provide a potential strategy to improve the reliability of calcium scoring by reducing partial volume effect while keeping radiation dose as low as reasonably achievable.
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Affiliation(s)
- Kuei-Yuan Hou
- Department of Radiology, Cathay General Hospital, Taipei, Taiwan
| | - Katsumi Tsujioka
- Faculty of Radiological Technology, Fujita Health University, Aichi, Japan
| | - Ching-Ching Yang
- Department of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan
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Cohen SL, Wang J, Mankerian M, Feizullayeva C, McCandlish JA, Barnaby D, Sanelli P, McGinn T. Evaluation of CTPA interpreted as limited in pregnant patients suspected for pulmonary embolism. Emerg Radiol 2019; 27:165-171. [PMID: 31813073 DOI: 10.1007/s10140-019-01728-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 09/06/2019] [Indexed: 10/25/2022]
Abstract
PURPOSE The purpose of this study is to determine the rates of CT pulmonary angiography (CTPA) interpreted as limited and severely limited in pregnant patients suspected for pulmonary embolism (PE), and to evaluate factors that influence these rates. METHODS This is a retrospective study with CTPA for evaluation of PE in pregnancy across a large health system from 2006 to 2017. CTPA was classified as limited from the radiology report with a subset of those studies classified as severely limited. Bivariate and multivariate analysis was performed for limited and severely limited rates with maternal age and patient size as a continuous variable and race, trimester, patient location study priority status, and result of chest radiograph before CTPA as categorical variables. RESULTS 874 patients with 33% of studies limited and 4% of studies severely limited. Multivariate logistic regression of CTPA studies revealed decreasing patient age (OR 0.967, p = 0.0129) and increasing patient size (OR 1.013, p < 0.0001). Studies performed in the second trimester (OR 1.869, p = 0.0242) and third trimester (OR 2.314, p = 0.0021) were more likely to be reported as limited (each p < 0.05). Increasing patient size (OR 1.017, p = 0.0046) was the only significant predictor of severely limited versus non-severely limited studies. CONCLUSION CTPA interpreted as limited in pregnancy are common and may be associated with younger age, larger patient size, and second and third trimesters. However, severely limited interpretations are much less common, with patient size the only significant predictor.
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Affiliation(s)
- S L Cohen
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA. .,Northwell Health Imaging, 600 Community Drive, Manhasset, NY, 11030, USA. .,Imaging Clinical Effectiveness & Outcomes Research Program at Northwell Health, 600 Community Drive, Manhasset, NY, 11030, USA. .,Feinstein Institute for Medical Research at Northwell Health, 600 Community Drive, Manhasset, NY, 11030, USA.
| | - J Wang
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA.,Imaging Clinical Effectiveness & Outcomes Research Program at Northwell Health, 600 Community Drive, Manhasset, NY, 11030, USA.,Feinstein Institute for Medical Research at Northwell Health, 600 Community Drive, Manhasset, NY, 11030, USA
| | - M Mankerian
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA
| | - C Feizullayeva
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA.,Northwell Health Imaging, 600 Community Drive, Manhasset, NY, 11030, USA.,Imaging Clinical Effectiveness & Outcomes Research Program at Northwell Health, 600 Community Drive, Manhasset, NY, 11030, USA.,Feinstein Institute for Medical Research at Northwell Health, 600 Community Drive, Manhasset, NY, 11030, USA
| | | | - D Barnaby
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA.,Feinstein Institute for Medical Research at Northwell Health, 600 Community Drive, Manhasset, NY, 11030, USA.,Northwell Health Emergency Medicine, Manhasset, NY, USA
| | - P Sanelli
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA.,Northwell Health Imaging, 600 Community Drive, Manhasset, NY, 11030, USA.,Imaging Clinical Effectiveness & Outcomes Research Program at Northwell Health, 600 Community Drive, Manhasset, NY, 11030, USA.,Feinstein Institute for Medical Research at Northwell Health, 600 Community Drive, Manhasset, NY, 11030, USA
| | - T McGinn
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA.,Feinstein Institute for Medical Research at Northwell Health, 600 Community Drive, Manhasset, NY, 11030, USA.,Northwell Health Internal Medicine, Manhasset, NY, USA
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Chen R, Paschalidis IC, Hatabu H, Valtchinov VI, Siegelman J. Detection of unwarranted CT radiation exposure from patient and imaging protocol meta-data using regularized regression. Eur J Radiol Open 2019; 6:206-211. [PMID: 31194104 PMCID: PMC6551377 DOI: 10.1016/j.ejro.2019.04.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 04/26/2019] [Accepted: 04/27/2019] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Variability in radiation exposure from CT scans can be appropriate and driven by patient features such as body habitus. Quantitative analysis may be performed to discover instances of unwarranted radiation exposure and to reduce the probability of such occurrences in future patient visits. No universal process to perform identification of outliers is widely available, and access to expertise and resources is variable. OBJECTIVE The goal of this study is to develop an automated outlier detection procedure to identify all scans with an unanticipated high radiation exposure, given the characteristics of the patient and the type of the exam. MATERIALS AND METHODS This Institutional Review Board-approved retrospective cohort study was conducted from June 30, 2012 - December 31, 2013 in a quaternary academic medical center. The de-identified dataset contained 28 fields for 189,959 CT exams. We applied the variable selection method Least Absolute Shrinkage and Selection Operator (LASSO) to select important variables for predicting CT radiation dose. We then employed a regression approach that is robust to outliers, to learn from data a predictive model of CT radiation doses given important variables identified by LASSO. Patient visits whose predicted radiation dose was statistically different from the radiation dose actually received were identified as outliers. RESULTS Our methodology identified 1% of CT exams as outliers. The top-5 predictors discovered by LASSO and strongly correlated with radiation dose were Tube Current, kVp, Weight, Width of collimator, and Reference milliampere-seconds. A human expert validation of the outlier detection algorithm has yielded specificity of 0.85 [95% CI 0.78-0.92] and sensitivity of 0.91 [95% CI 0.85-0.97] (PPV = 0.84, NPV = 0.92). These values substantially outperform alternative methods we tested (F1 score 0.88 for our method against 0.51 for the alternatives). CONCLUSION The study developed and tested a novel, automated method for processing CT scanner meta-data to identify CT exams where patients received an unwarranted amount of radiation. Radiation safety and protocol review committees may use this technique to uncover systemic issues and reduce future incidents.
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Affiliation(s)
- Ruidi Chen
- Department of Biomedical Engineering, Boston University, United States
- Department of Electrical and Computer Engineering, Boston University, 8 St. Mary’s Street, Boston, MA 02215, USA
| | - Ioannis Ch. Paschalidis
- Department of Biomedical Engineering, Boston University, United States
- Department of Electrical and Computer Engineering, Boston University, 8 St. Mary’s Street, Boston, MA 02215, USA
| | - Hiroto Hatabu
- Center for Evidence-Based Imaging (CEBI), Brigham and Women’s Hospital, United States
- Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, United States
| | - Vladimir I. Valtchinov
- Center for Evidence-Based Imaging (CEBI), Brigham and Women’s Hospital, United States
- Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, United States
- Department of Biomedical Informatics, Harvard Medical School, United States
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Bunch PM, Fulwadhva UP, Wortman JR, Primak AN, Madan R, Steigner ML, Sodickson AD. Motion Artifact Reduction From High-Pitch Dual-Source Computed Tomography Pulmonary Angiography. J Comput Assist Tomogr 2018; 42:623-629. [PMID: 29613990 DOI: 10.1097/rct.0000000000000736] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE The purpose of this study was to compare quantitative and qualitative measures of aortic, cardiac, and respiratory motion artifact between high-pitch dual-source (DS) and single-source (SS) computed tomography pulmonary angiography (CTPA) protocols. METHODS This institutional review board-approved, Health Insurance Portability and Accountability Act-compliant study retrospectively reviewed 80 non-electrocardiogram-gated CTPA examinations acquired with a second-generation DS system at 100 kVp following 50 mL iodinated contrast injection - 40 consecutive SS and 40 consecutive DS studies. Quantitative measures of aortic, left ventricular, and diaphragmatic motion were recorded as the maximal excursion of a structure's "double image," and 3 independent readers performed qualitative motion assessments. Pulmonary arterial contrast enhancement, image noise, and radiation dose metrics were recorded. Statistical analyses were performed with 1-way analysis of variance and Fisher exact test. RESULTS Dual source outperformed SS technique in both quantitative and qualitative measures of motion. Mean distances between motion-artifact double images were reduced with DS protocol at each location (all P ≤ 0.004), and DS examinations were more likely to receive an assessment of no motion in all locations (all P < 0.0001). The DS protocol demonstrated increases in contrast enhancement, although increased image noise resulted in lower enhancement to noise ratio. Mean radiation dose was 60% lower using the DS protocol. CONCLUSION High-pitch DS CTPA significantly reduces artifacts resulting from ascending aortic, cardiac, and diaphragmatic motion.
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Iezzi R, Larici AR, Franchi P, Marano R, Magarelli N, Posa A, Merlino B, Manfredi R, Colosimo C. Tailoring protocols for chest CT applications: when and how? Diagn Interv Radiol 2018; 23:420-427. [PMID: 29097345 DOI: 10.5152/dir.2017.16615] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In the medical era of early detection of diseases and tailored therapies, an accurate characterization and staging of the disease is pivotal for treatment planning. The widespread use of computed tomography (CT)-often with the use of contrast material (CM)-probably represents the most important advance in diagnostic radiology. The result is a marked increase in radiation exposure of the population for medical purposes, with its intrinsic carcinogenic potential, and CM affecting kidney function. The radiologists should aim to minimize patient's risk by reducing radiation exposure and CM amount, while maintaining the highest image quality. To achieve this goal, it is necessary to perform "patient-centric imaging". The purpose of this review is to provide radiologists with "tips and tricks" to control radiation dose at CT, summarizing technical artifices in order to reduce image noise and increase image contrast. Also chest CT tailored protocols are supplied, with particular attention to three most common thoracic CT protocols: aortic/cardiac CT angiography (CTA), pulmonary CTA, and routine chest CT.
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Affiliation(s)
- Roberto Iezzi
- Institute of Radiology, Department of Radiological Sciences, Università Cattolica del Sacro Cuore, Rome, Italy.
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Implementation of Size-Dependent Local Diagnostic Reference Levels for CT Angiography. AJR Am J Roentgenol 2018; 210:W226-W233. [DOI: 10.2214/ajr.17.18566] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Fu W, Marin D, Ramirez-Giraldo JC, Choudhury KR, Solomon J, Schabel C, Patel BN, Samei E. Optimizing window settings for improved presentation of virtual monoenergetic images in dual-energy computed tomography. Med Phys 2017; 44:5686-5696. [PMID: 28777467 DOI: 10.1002/mp.12501] [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: 12/06/2016] [Revised: 06/06/2017] [Accepted: 07/20/2017] [Indexed: 12/21/2022] Open
Abstract
PURPOSE Dual-energy computed tomography virtual monoenergetic imaging (VMI) at 40 keV exhibits superior contrast-to-noise ratio (CNR), although practicing radiologists do not consistently prefer it over VMI at 70 keV due to high perceivable noise. We hypothesize that the presentation of 40 keV VMI may be compromised using window settings (i.e., window-and-level values [W-L values]) designed for conventional single-energy CT. This study aimed to devise optimum window settings that reduce the apparent noise and utilize the high CNR of 40 keV VMI, in order to improve the conspicuity of hypervascular liver lesions. MATERIALS AND METHODS Three W-L value adjustment methods were investigated to alter the presentation of 40 keV VMI. To harness the high CNR of 40 keV VMI, the methods were designed to achieve (a) liver histogram distribution, (b) lesion-to-liver contrast, or (c) liver background noise comparable to those perceived in 70 keV VMI. This IRB-approved study included 18 patient abdominal datasets reconstructed at 40 and 70 keV. For each patient, the W-L values were determined using the three methods. For each of the images with default or adjusted W-L values, the noise, contrast, and CNR were calculated in terms of both display space and native CT number (referred to as HU) space. An observer study was performed to compare the 40 keV images with the three adjusted W-L values, and 40 and 70 keV images with default W-L values in terms of noise, contrast, and diagnostic preference. A comparison was also made in terms of the applicability of using patient-specific or patient-averaged W-L values. RESULTS Using the default W-L values, 40 keV VMI exhibited higher HU CNR than 70 keV VMI by 24.6 ± 14.9% (P < 0.001) but lower display CNR by 38.0 ± 16.4% (P < 0.001). Using adjusted W-L values, 40 keV images showed increased display CNR as compared to 70 keV images, by 21.2 ± 13.1%, 17.4 ± 13.6%, and 24.2 ± 15.9% (P < 0.001) for histogram-, noise-, and contrast equalization methods, respectively. The 40 keV images with all three W-L value adjustment methods showed improved perceived conspicuity (CNR) of liver presentation by 103-120% (P < 0.001), as compared to default W-L values. The qualitative observer study revealed that 40 keV images with noise- and histogram-equalized W-L values were the most preferred, followed by 40 keV images with contrast-equalized W-L values and 70 keV images with default W-L values. The 40 keV images with default W-L values were the least preferred. Patient-specific W-L values offered similar results to those of patient-averaged W-L values. CONCLUSION The adjusted W-L values can significantly improve the perception of VMI dataset image quality by improving the actual display CNR.
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Affiliation(s)
- Wanyi Fu
- Department of Electrical and Computer Engineering, and Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University, Durham, NC, 27705, USA
| | - Daniele Marin
- Department of Radiology, Duke University Medical Center, Durham, NC, 27705, USA
| | | | - Kingshuk Roy Choudhury
- Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University, Durham, NC, 27705, USA
| | - Justin Solomon
- Carl E. Ravin Advanced Imaging Laboratories, Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, NC, 27705, USA
| | - Christoph Schabel
- Department of Radiology, Duke University Medical Center, Durham, NC, 27705, USA
| | - Bhavik N Patel
- Department of Radiology, Duke University Medical Center, Durham, NC, 27705, USA
| | - Ehsan Samei
- Carl E. Ravin Advanced Imaging Laboratories, Medical Physics Graduate Program, Department of Radiology, and Departments of Physics, Biomedical Engineering, and Electrical and Computer Engineering, Duke University, Durham, NC, 27705, USA
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15
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Armstrong L, Gleeson F, Mackillop L, Mutch S, Beale A. Survey of UK imaging practice for the investigation of pulmonary embolism in pregnancy. Clin Radiol 2017; 72:696-701. [DOI: 10.1016/j.crad.2017.03.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 03/13/2017] [Accepted: 03/30/2017] [Indexed: 01/26/2023]
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16
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Niiniviita H, Kulmala J, Pölönen T, Määttänen H, Järvinen H, Salminen E. Excess of Radiation Burden for Young Testicular Cancer Patients using Automatic Exposure Control and Contrast Agent on Whole-body Computed Tomography Imaging. Radiol Oncol 2017; 51:235-240. [PMID: 28740460 PMCID: PMC5514665 DOI: 10.1515/raon-2017-0012] [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: 07/28/2016] [Accepted: 02/03/2017] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND The aim of the study was to assess patient dose from whole-body computed tomography (CT) in association with patient size, automatic exposure control (AEC) and intravenous (IV) contrast agent. PATIENTS AND METHODS Sixty-five testicular cancer patients (mean age 28 years) underwent altogether 279 whole-body CT scans from April 2000 to April 2011. The mean number of repeated examinations was 4.3. The GE LightSpeed 16 equipped with AEC and the Siemens Plus 4 CT scanners were used for imaging. Whole-body scans were performed with (216) and without (63) IV contrast. The ImPACT software was used to determine the effective and organ doses. RESULTS Patient doses were independent (p < 0.41) of patient size when the Plus 4 device (mean 7.4 mSv, SD 1.7 mSv) was used, but with the LightSpeed 16 AEC device, the dose (mean 14 mSv, SD 4.6 mSv) increased significantly (p < 0.001) with waist cirfumference. Imaging with the IV contrast agent caused significantly higher (13% Plus 4, 35% LightSpeed 16) exposure than non-contrast imaging (p < 0.001). CONCLUSIONS Great caution on the use of IV contrast agent and careful set-up of the AEC modulation parameters is recommended to avoid excessive radiation exposure on the whole-body CT imaging of young patients.
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Affiliation(s)
- Hannele Niiniviita
- Department of Medical Physics, Turku University Hospital, Turku, Finland
- Department of Diagnostic Radiology, University of Turku, Turku, Finland
| | - Jarmo Kulmala
- Department of Medical Physics, Turku University Hospital, Turku, Finland
- Oncology and Radiotherapy, Turku University Hospital, Turku, Finland
| | - Tuukka Pölönen
- Department of Biostatistics, University of Turku, Turku, Finland
| | - Heli Määttänen
- Department of Medical Physics, Turku University Hospital, Turku, Finland
| | - Hannu Järvinen
- STUK-Radiation and Nuclear Safety Authority, Helsinki, Finland
| | - Eeva Salminen
- Oncology and Radiotherapy, Turku University Hospital, Turku, Finland
- STUK-Radiation and Nuclear Safety Authority, Helsinki, Finland
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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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Chen EL, Ross JA, Grant C, Wilbur A, Mehta N, Hart E, Mar WA. Improved Image Quality of Low-Dose CT Pulmonary Angiograms. J Am Coll Radiol 2017; 14:648-653. [PMID: 28082157 DOI: 10.1016/j.jacr.2016.11.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/04/2016] [Accepted: 11/08/2016] [Indexed: 10/20/2022]
Abstract
OBJECTIVE The use of CT pulmonary angiography (CTPA) to evaluate for pulmonary embolism has been increasing, and carries a significant radiation dose. We evaluate image quality of lower-dose images, taking into account patient size as well as the effects of image postprocessing. METHODS A total of 250 CTPAs were retrospectively reviewed. The following parameters were obtained: kVp, mA, dose length product, Hounsfield units (HU) with standard deviation in the main pulmonary artery, transverse scout measurement, and subjective image quality. RESULTS Radiation dose decreased 55% by reducing kVp from 120 to 100, and 60% from 100 to 80 kVp. Radiation dose decreased 82% from 120 to 80 kVp. Noise increased 38% from 120 kVp to 100 kVp, and increased 23% from 100 kVp to 80 kVp. Adding an overlapped reconstructed image decreased noise by 16% to 21%. Despite the increase in image noise, diagnostic quality was significantly improved at 80 and 100 kVp, compared with 120 kVp, with an average subjective quality rating of 3.8, 4.0, and 3.2, respectively, and an average pulmonary artery density of 536, 423, and 278 HU. Even in larger patients, qualitative image quality was better at 100 kVp compared with 120 kVp, with an average quality rating of 3.6 versus 2.9, respectively. CONCLUSIONS Radiation dose exposure can be easily reduced on CTPA by lowering kVp, which at the same time improves image quality. Studies using a lower kVp were of significantly higher diagnostic quality. This held true even in larger patients.
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Affiliation(s)
- Eric L Chen
- College of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Jeremy A Ross
- College of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | | | - Andrew Wilbur
- University of Illinois at Chicago, Chicago, Illinois
| | | | - Eric Hart
- Northwestern Memorial Hospital, Chicago, Illinois
| | - Winnie A Mar
- Department of Radiology, University of Illinois at Chicago, Chicago, Illinois.
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19
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State-of-the-Art Pulmonary CT Angiography for Acute Pulmonary Embolism. AJR Am J Roentgenol 2016; 208:495-504. [PMID: 27897042 DOI: 10.2214/ajr.16.17202] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Pulmonary CT angiography (CTA) is the imaging modality of choice in suspected acute pulmonary embolism (PE). Current pulmonary CTA techniques involve ever lower doses of contrast medium and radiation along with advanced postprocessing applications to enhance image quality, diagnostic accuracy, and provide added value in patient management. The objective of this article is to summarize these current developments and discuss the appropriate use of state-of-the-art pulmonary CTA. CONCLUSION Pulmonary CTA is well established as a fast and reliable means of excluding or diagnosing PE. Continued developments in CT system hardware and postprocessing techniques will allow incremental reductions in radiation and contrast material requirements while improving image quality. Advances in risk stratification and prognostication from pulmonary CTA examinations should further refine its clinical value while minimizing the potential harm from overutilization and overdiagnosis.
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20
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Strategies to Lessen the Radiation Risk from CT: A Multination Perspective. CURRENT RADIOLOGY REPORTS 2016. [DOI: 10.1007/s40134-016-0186-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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21
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Shen Y, Hu X, Zou X, Zhu D, Li Z, Hu D. Did low tube voltage CT combined with low contrast media burden protocols accomplish the goal of "double low" for patients? An overview of applications in vessels and abdominal parenchymal organs over the past 5 years. Int J Clin Pract 2016; 70 Suppl 9B:B5-B15. [PMID: 27577514 DOI: 10.1111/ijcp.12861] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Accepted: 06/15/2016] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Imaging communities have already reached a consensus that the radiation dose of computed tomography (CT) should be reduced as much as reasonably achievable to lower population risks. Increasing attention is being paid to iodinated contrast media (CM) induced nephrotoxicity (CIN); a decrease in the intake of iodinated CM is required by increasingly more radiologists. Theoretically, the radiation dose varies with the tube current time and square of the tube voltage, with higher iodine contrast at low photon energies (Huda et al. [2000] Radiology, 21 7, 430-435).The use of low tube voltage is a promising strategy to reduce both the radiation dose and CM burden. The term 'double low' has been coined to describe scanning protocols that reduce radiation dose and iodine intake synchronously. These protocols are becoming increasingly popular in the clinical setting. PURPOSE The aim of this review was to describe all original studies using the 'double low' strategy in the last 5 years. METHODS We searched an online electronic database (PubMed) from January 2011 to December 2015 for original studies published on the relationship of low tube voltage with low radiation dose and low iodine contrast media burden in patients undergoing CT scans. Studies that failed to reduce radiation dose or iodine CM burden were excluded in this study. RESULTS Thirty-seven studies aimed at reducing radiation dose using low tube voltage combined with iodine CM reduced protocols were included in this study. Most studies evaluated conditions associated with arteries. Four were cerebral and neck computed tomography angiography (CTA) studies, 15 were pulmonary CTA (pCTA) and coronary CTA (cCTA) studies, one concerned myocardial perfusion, five studies focused on the thoracic and abdominal aorta, and one investigated renal arteries. Three studies consisted of CT venography (CTV) of the pelvis and lower extremities. Six publications examined the liver, and two focused on the kidney. CONCLUSION Overall, this review demonstrates that the low tube voltage CT protocol is a powerful tool to reduce the radiation dose in CTA, especially with pCTA and cCTA.
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Affiliation(s)
- Yaqi Shen
- Departments of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Xuemei Hu
- Departments of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Xianlun Zou
- Departments of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Di Zhu
- Departments of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Zhen Li
- Departments of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Daoyu Hu
- Departments of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
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Kalra MK, Sodickson AD, Mayo-Smith WW. CT Radiation: Key Concepts for Gentle and Wise Use. Radiographics 2016; 35:1706-21. [PMID: 26466180 DOI: 10.1148/rg.2015150118] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Use of computed tomography (CT) in medicine comes with the responsibility of its appropriate (wise) and safe (gentle) application to obtain required diagnostic information with the lowest possible dose of radiation. CT provides useful information that may not be available with other imaging modalities in many clinical situations in children and adults. Inappropriate or excessive use of CT should be avoided, especially if required information can be obtained in an accurate and time-efficient manner with other modalities that require a lower radiation dose, or non-radiation-based imaging modalities such as ultrasonography and magnetic resonance imaging. In addition to appropriate use of CT, the radiology community also must monitor scanning practices and protocols. When appropriate, high-contrast regions and lesions should be scanned with reduced dose, but overly zealous dose reduction should be avoided for assessment of low-contrast lesions. Patients' cross-sectional body size should be taken into account to deliver lower radiation dose to smaller patients and children. Wise use of CT scanning with gentle application of radiation dose can help maximize the diagnostic value of CT, as well as address concerns about potential risks of radiation. In this article, key concepts in CT radiation dose are reviewed, including CT dose descriptors; radiation doses from CT procedures; and factors and technologies that affect radiation dose and image quality, including their use in creating dose-saving protocols. Also discussed are the contributions of radiation awareness campaigns such as the Image Gently and Image Wisely campaigns and the American College of Radiology Dose Index Registry initiatives.
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Affiliation(s)
- Mannudeep K Kalra
- From the Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Mass (M.K.K.); and Department of Radiology, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115 and Harvard Medical School, Boston, Mass (A.D.S., W.W.M.S.)
| | - Aaron D Sodickson
- From the Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Mass (M.K.K.); and Department of Radiology, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115 and Harvard Medical School, Boston, Mass (A.D.S., W.W.M.S.)
| | - William W Mayo-Smith
- From the Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Mass (M.K.K.); and Department of Radiology, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115 and Harvard Medical School, Boston, Mass (A.D.S., W.W.M.S.)
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23
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Synergistic Radiation Dose Reduction by Combining Automatic Tube Voltage Selection and Iterative Reconstruction. J Thorac Imaging 2016; 31:111-8. [DOI: 10.1097/rti.0000000000000196] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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24
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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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25
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Abstract
Acute pulmonary embolism is recognized as a difficult diagnosis to make. It is potentially fatal if undiagnosed, yet increasing referral rates for imaging and falling diagnostic yields are topics which have attracted much attention. For patients in the emergency department with suspected pulmonary embolism, computed tomography pulmonary angiography (CTPA) is the test of choice for most physicians, and hence radiology has a key role to play in the patient pathway. This review will outline key aspects of the recent literature regarding the following issues: patient selection for imaging, the optimization of CTPA image quality and dose, preferred pathways for pregnant patients and other subgroups, and the role of CTPA beyond diagnosis. The role of newer techniques such as dual-energy CT and single-photon emission-CT will also be discussed.
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26
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Shyu JY, Sodickson AD. Communicating radiation risk to patients and referring physicians in the emergency department setting. Br J Radiol 2016; 89:20150868. [PMID: 26647958 DOI: 10.1259/bjr.20150868] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Heightened awareness about the radiation risks associated with CT imaging has increased patients' wishes to be informed of these risks, and has motivated efforts to reduce radiation dose and eliminate unnecessary imaging. However, many ordering providers, including emergency physicians, are ill prepared to have an informed discussion with patients about the cancer risks related to medical imaging. Radiologists, who generally have greater training in radiation biology and the risks of radiation, often do not have a face-to-face relationship with the patients who are being imaged. A collaborative approach between emergency physicians and radiologists is suggested to help explain these risks to patients who may have concerns about getting medical imaging.
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Affiliation(s)
- Jeffrey Y Shyu
- Department of Radiology, Brigham and Women's Hospital/Harvard Medical School, Boston, MA, USA
| | - Aaron D Sodickson
- Department of Radiology, Brigham and Women's Hospital/Harvard Medical School, Boston, MA, USA
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Sabbatini AK, Merck LH, Froemming AT, Vaughan W, Brown MD, Hess EP, Applegate KE, Comfere NI. Optimizing Patient-centered Communication and Multidisciplinary Care Coordination in Emergency Diagnostic Imaging: A Research Agenda. Acad Emerg Med 2015; 22:1427-34. [PMID: 26575785 DOI: 10.1111/acem.12826] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 07/06/2015] [Indexed: 12/17/2022]
Abstract
Patient-centered emergency diagnostic imaging relies on efficient communication and multispecialty care coordination to ensure optimal imaging utilization. The construct of the emergency diagnostic imaging care coordination cycle with three main phases (pretest, test, and posttest) provides a useful framework to evaluate care coordination in patient-centered emergency diagnostic imaging. This article summarizes findings reached during the patient-centered outcomes session of the 2015 Academic Emergency Medicine consensus conference "Diagnostic Imaging in the Emergency Department: A Research Agenda to Optimize Utilization." The primary objective was to develop a research agenda focused on 1) defining component parts of the emergency diagnostic imaging care coordination process, 2) identifying gaps in communication that affect emergency diagnostic imaging, and 3) defining optimal methods of communication and multidisciplinary care coordination that ensure patient-centered emergency diagnostic imaging. Prioritized research questions provided the framework to define a research agenda for multidisciplinary care coordination in emergency diagnostic imaging.
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Affiliation(s)
| | - Lisa H. Merck
- Department of Emergency Medicine; Brown University; Providence RI
- Department of Diagnostic Imaging; Brown University; Providence RI
| | | | | | - Michael D. Brown
- Department of Emergency Medicine; Michigan State University; Grand Rapids MI
| | - Erik P. Hess
- Department of Emergency Medicine; Mayo Clinic; Rochester MN
- Knowledge and Evaluation Research Unit; Division of Healthcare Policy Research; Department of Health Services Research; Robert D. and Patricia E. Kern Center for the Science of Healthcare Delivery; Mayo Clinic; Rochester MN
| | - Kimberly E. Applegate
- Department of Radiology and Imaging Sciences; Emory University School of Medicine; Atlanta GA
| | - Nneka I. Comfere
- Department of Dermatology; Laboratory Medicine & Pathology; Mayo Clinic; Rochester MN
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28
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Qi L, Zhao Y, Zhou CS, Spearman JV, Renker M, Schoepf UJ, Zhang LJ, Lu GM. Image quality and radiation dose of lower extremity CT angiography at 70 kVp on an integrated circuit detector dual-source computed tomography. Acta Radiol 2015; 56:659-65. [PMID: 24919466 DOI: 10.1177/0284185114535391] [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: 01/06/2014] [Accepted: 04/21/2014] [Indexed: 11/15/2022]
Abstract
BACKGROUND Despite the well-established requirement for radiation dose reduction there are few studies examining the potential for lower extremity CT angiography (CTA) at 70 kVp. PURPOSE To compare the image quality and radiation dose of lower extremity CTA at 70 kVp using a dual-source CT system with an integrated circuit detector to similar studies at 120 kVp. MATERIAL AND METHODS A total of 62 patients underwent lower extremity CTA. Thirty-one patients were examined at 70 kVp using a second generation dual-source CT with an integrated circuit detector (70 kVp group) and 31 patients were evaluated at 120 kVp using a first generation dual-source CT (120 kVp group). The attenuation and image noise were measured and signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Two radiologists assessed image quality. Radiation dose was compared. RESULTS The mean attenuation of the 70 kVp group was higher than the 120 kVp group (575 ± 149 Hounsfield units [HU] vs. 258 ± 38 HU, respectively, P < 0.001) as was SNR (44.0 ± 22.0 vs 32.7 ± 13.3, respectively, P = 0.017), CNR (39.7 ± 20.6 vs 26.6 ± 11.7, respectively, P = 0.003) and the mean image quality score (3.7 ± 0.1 vs. 3.2 ± 0.3, respectively, P < 0.001). The inter-observer agreement was good for the 70 kVp group and moderate for the 120 kVp group. The dose-length product was lower in the 70 kVp group (264.5 ± 63.1 mGy × cm vs. 412.4 ± 81.5 mGy × cm, P < 0.001). CONCLUSION Lower extremity CTA at 70 kVp allows for lower radiation dose with higher SNR, CNR, and image quality when compared with standard 120 kVp.
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Affiliation(s)
- Li Qi
- Department of Medical Imaging, Jinling Hospital, Clinical School of South Medical University, Nanjing, Jiangsu Province, PR China
- Department of Medical Imaging, Jinling Hospital, Clinical School of Nanjing University, Nanjing, Jiangsu Province, PR China
| | - Yan’E Zhao
- Department of Medical Imaging, Jinling Hospital, Clinical School of South Medical University, Nanjing, Jiangsu Province, PR China
- Department of Medical Imaging, Jinling Hospital, Clinical School of Nanjing University, Nanjing, Jiangsu Province, PR China
| | - Chang Sheng Zhou
- Department of Medical Imaging, Jinling Hospital, Clinical School of South Medical University, Nanjing, Jiangsu Province, PR China
- Department of Medical Imaging, Jinling Hospital, Clinical School of Nanjing University, Nanjing, Jiangsu Province, PR China
| | - James V Spearman
- Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA
| | - Matthias Renker
- Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA
- Department of Cardiology, Kerckhoff Heart and Thorax Center, Bad Nauheim, Germany
| | - U Joseph Schoepf
- Department of Medical Imaging, Jinling Hospital, Clinical School of South Medical University, Nanjing, Jiangsu Province, PR China
- Department of Medical Imaging, Jinling Hospital, Clinical School of Nanjing University, Nanjing, Jiangsu Province, PR China
- Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA
| | - Long Jiang Zhang
- Department of Medical Imaging, Jinling Hospital, Clinical School of South Medical University, Nanjing, Jiangsu Province, PR China
- Department of Medical Imaging, Jinling Hospital, Clinical School of Nanjing University, Nanjing, Jiangsu Province, PR China
| | - Guang Ming Lu
- Department of Medical Imaging, Jinling Hospital, Clinical School of South Medical University, Nanjing, Jiangsu Province, PR China
- Department of Medical Imaging, Jinling Hospital, Clinical School of Nanjing University, Nanjing, Jiangsu Province, PR China
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Zhang LJ, Lu GM, Meinel FG, McQuiston AD, Ravenel JG, Schoepf UJ. Computed tomography of acute pulmonary embolism: state-of-the-art. Eur Radiol 2015; 25:2547-57. [DOI: 10.1007/s00330-015-3679-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 02/17/2015] [Indexed: 12/13/2022]
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Clarke R, Lewis EF. Feasibility of Using Iterative Reconstruction to Reduce Radiation Dose for Computed Tomography Pulmonary Angiograms. J Med Imaging Radiat Sci 2015; 46:50-56. [DOI: 10.1016/j.jmir.2014.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 10/27/2014] [Accepted: 10/29/2014] [Indexed: 10/24/2022]
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Application of low tube voltage coronary CT angiography with low-dose iodine contrast agent in patients with a BMI of 26–30 kg/m2. Clin Radiol 2015; 70:138-45. [PMID: 25468636 DOI: 10.1016/j.crad.2014.10.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Revised: 09/26/2014] [Accepted: 10/08/2014] [Indexed: 10/24/2022]
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Assessment of an Advanced Image-Based Technique to Calculate Virtual Monoenergetic Computed Tomographic Images From a Dual-Energy Examination to Improve Contrast-To-Noise Ratio in Examinations Using Iodinated Contrast Media. Invest Radiol 2014; 49:586-92. [PMID: 24710203 DOI: 10.1097/rli.0000000000000060] [Citation(s) in RCA: 235] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Lu GM, Luo S, Meinel FG, McQuiston AD, Zhou CS, Kong X, Zhao YE, Zheng L, Schoepf UJ, Zhang LJ. High-pitch computed tomography pulmonary angiography with iterative reconstruction at 80 kVp and 20 mL contrast agent volume. Eur Radiol 2014; 24:3260-8. [PMID: 25100336 DOI: 10.1007/s00330-014-3365-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Revised: 05/12/2014] [Accepted: 07/21/2014] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To evaluate the image quality, radiation dose and diagnostic accuracy of 80kVp, high-pitch CT pulmonary angiography (CTPA) with iterative reconstruction using 20 ml of contrast agent. METHODS One hundred patients with suspected pulmonary embolism (PE) were randomly divided into two groups (n = 50 each; group A, 100 kVp, 1.2 pitch, 60 ml of contrast medium and filtered back projection algorithm; group B, 80 kVp, 2.2 pitch, 20 ml of contrast medium and sinogram affirmed iterative reconstruction). Image quality, diagnostic accuracy and radiation dose were evaluated and compared. RESULTS Mean CT numbers of pulmonary arteries in group B were higher than those in group A (all P < 0.001). Contrast-to-noise ratio and signal-to-noise ratio of group B were higher than those of group A (both P < 0.001). There was no significant difference in subjective image quality scores between two groups (P = 0.807). The interobserver agreement was excellent (k = 0.836). There was no significant difference in diagnostic accuracy between the two groups (P > 0.05). Compared with group A, radiation dose of group B was reduced by 50.3% (P < 0.001). CONCLUSIONS High-pitch CTPA at 80 kVp can obtain sufficient image quality in normal-weight individuals with 20 ml of contrast agent and half the radiation dose of a conventional CTPA protocol. KEY POINTS CTPA is feasible at 80 kVp using only 20 ml of contrast agent. High-pitch CTPA at 80 kVp has an effective dose under 1 mSv. This CTPA protocol can obtain sufficient image quality in normal-weight individuals.
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Affiliation(s)
- Guang Ming Lu
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210002, China,
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Kumamaru KK, Rybicki FJ, Madan R, Gill R, Wake N, Hunsaker AR. Incidental findings detection using low tube potential for CT pulmonary angiography. Int J Cardiovasc Imaging 2014; 30:1579-88. [DOI: 10.1007/s10554-014-0484-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 06/30/2014] [Indexed: 10/25/2022]
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McLaughlin PD, Liang T, Homiedan M, Louis LJ, O'Connell TW, Krzymyk K, Nicolaou S, Mayo JR. High pitch, low voltage dual source CT pulmonary angiography: assessment of image quality and diagnostic acceptability with hybrid iterative reconstruction. Emerg Radiol 2014; 22:117-23. [PMID: 24993583 DOI: 10.1007/s10140-014-1230-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 04/23/2014] [Indexed: 12/20/2022]
Abstract
Increased use of CT Pulmonary angiography in suspected pulmonary embolism (PE) has driven research to minimize radiation dose while maintaining image quality and diagnostic accuracy. Following institutional review board approval, we performed a retrospective comparison study in patients with suspected PE. Patients were scanned using an ultra high pitch dual source technique (pitch = 2.6) using 120 kV (SVCTPA) (n = 54) or 100 kV (RV-CTPA) (n = 52). SV-CTPA images were reconstructed using filtered back projection (SV-wFBP) and RV-CTPA images were reconstructed using both FBP (RV-wFBP) and Iterative Reconstruction (RV-IR). Comparison of radiation dose, diagnostic ability, subjective image noise, quality, and sharpness, diagnostic agreement, signal to noise (SNR) and contrast to noise ratios (CNR) were performed. Mean effective dose was 2.56 ± 0.19 mSv for the RV protocol compared to 5.36 ± 0.60 mSv for the SV. The RV-CTPA protocol resulted in a mean DLP reduction of 52 % and mean CTDI reduction of 51 %. Pulmonary artery SNR and CNR were significantly higher on RV-IR images than SV-wFBP (p = 0.007, p = 0.003). Mean subjective image noise, quality and sharpness scores did not differ significantly between the SV-wFBP and RVIR images (p > 0.05). Subjective quality scores were significantly better for the RV-IR group compared to the RV-wFBP group (p < 0.001). Agreement between readers for presence or absence of pulmonary emboli on RV-IR images was almost perfect (κ = 0.891, p < 0.001). Iterative reconstruction complements ultra high pitch dual source CTPA examinations acquired using a reduced voltage resulting in higher mean pulmonary artery SNR and CNR when compared to both RV-wFBP and SV-CTPA.
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Affiliation(s)
- Patrick D McLaughlin
- Department of Radiology, Vancouver General Hospital, Vancouver, BC, Canada, V5Z 1M9,
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Chae IH, Kim Y, Lee SW, Park JE, Shim SS, Lee JH. Standard chest CT using combined automated tube potential selection and iterative reconstruction: image quality and radiation dose reduction. Clin Imaging 2014; 38:641-7. [PMID: 24849196 DOI: 10.1016/j.clinimag.2014.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/03/2014] [Accepted: 04/14/2014] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To evaluate the image quality and radiation dose reduction of chest computed tomography (CT) using combined automated tube potential selection (ATPS) and iterative reconstruction (IR). MATERIALS AND METHODS Image quality and radiation dose were compared between conventional contrast-enhanced chest CT using 120 kVp and filtered back projection (Protocol A) and CT using ATPS and IR (Protocol B) in 43 patients. RESULTS The effective radiation dose was 3.6 ± 0.4 mSv for Protocol A and 2.2 ± 0.6 mSv for Protocol B (mean dose reduction, 39.7%). Protocol B showed diagnostic image quality in all patients. CONCLUSION ATPS and IR allows for radiation dose reduction while maintaining diagnostic image quality.
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Affiliation(s)
- In Hye Chae
- Department of Radiology, School of Medicine, Ewha Womans University, Seoul, South Korea
| | - Yookyung Kim
- Department of Radiology, School of Medicine, Ewha Womans University, Seoul, South Korea.
| | - So Won Lee
- Department of Radiology, School of Medicine, Ewha Womans University, Seoul, South Korea
| | - Ji Eun Park
- Department of Radiology, School of Medicine, Ewha Womans University, Seoul, South Korea
| | - Sung Shine Shim
- Department of Radiology, School of Medicine, Ewha Womans University, Seoul, South Korea
| | - Jin Hwa Lee
- Division of Pulmonology in Department of Internal Medicine, School of Medicine, Ewha Womans University, Seoul, South Korea
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Siegel MJ, Hildebolt C, Bradley D. Effects of Automated Kilovoltage Selection Technology on Contrast-enhanced Pediatric CT and CT Angiography. Radiology 2013; 268:538-47. [PMID: 23564712 DOI: 10.1148/radiol.13122438] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Marilyn J Siegel
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, St Louis, MO 63110, USA.
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Sodickson A. Strategies for Reducing Radiation Exposure from Multidetector Computed Tomography in the Acute Care Setting. Can Assoc Radiol J 2013; 64:119-29. [DOI: 10.1016/j.carj.2013.01.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Accepted: 01/21/2013] [Indexed: 11/28/2022] Open
Abstract
Many tools and strategies exist to enable reduction of radiation exposure from computed tomography (CT). The common CT metrics of x-ray output, the volume CT dose index and the dose-length product, are explained and serve as the basis for monitoring radiation exposure from CT. Many strategies to dose-optimize CT protocols are explored that, in combination with available hardware and software tools, allow robust diagnostic quality CT to be performed with a radiation exposure appropriate for the clinical scenario and the size of the patient. Specific emergency department example protocols are used to demonstrate these techniques.
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Affiliation(s)
- Aaron Sodickson
- Emergency Radiology, Brigham and Women's Hospital, Boston, Massachusetts, USA Harvard Medical School, Boston, Massachusetts, USA
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George E, Hunsaker AR, Rybicki FJ, Kumamaru KK. Effect of Lower Tube Voltage on the Reproducibility of Right-to-Left Ventricular Diameter Ratio Measurements on Computed Tomographic Pulmonary Angiography Images. J Comput Assist Tomogr 2013; 37:737-42. [DOI: 10.1097/rct.0b013e3182994f37] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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