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Low-dose multi-detector computed tomography for periradicular infiltrations at the cervical and lumbar spine. Sci Rep 2022; 12:4324. [PMID: 35279689 PMCID: PMC8918321 DOI: 10.1038/s41598-022-08162-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 02/25/2022] [Indexed: 12/22/2022] Open
Abstract
Periradicular infiltrations are frequently performed in daily neuroradiological routine and are often guided by multi-detector computed tomography (MDCT), thus leading to radiation exposure. The purpose of this study was to evaluate MDCT with low dose (LD) and model-based iterative reconstruction for image-guided periradicular infiltrations at the cervical and lumbosacral spine. We retrospectively analyzed 204 MDCT scans acquired for the purpose of cervical or lumbosacral periradicular interventions, which were either derived from scanning with standard dose (SD; 40 mA and 120 kVp) or LD (20–30 mA and 120 kVp) using a 128-slice MDCT scanner. The SD cases were matched to the LD cases considering sex, age, level of infiltration, presence of spinal instrumentation, and body diameter. All images were reconstructed using model-based iterative image reconstruction and were evaluated by two readers (R1 and R2) using 5- or 3-point Likert scales (score of 1 reflects the best value per category). Furthermore, noise in imaging data was quantitatively measured by the standard deviation (StDev) of muscle tissue. The dose length product (DLP) was statistically significantly lower for LD scans (6.75 ± 6.43 mGy*cm vs. 10.16 ± 7.70 mGy*cm; p < 0.01; reduction of 33.5%). Image noise was comparable between LD and SD scans (13.13 ± 3.66 HU vs. 13.37 ± 4.08 HU; p = 0.85). Overall image quality was scored as good to very good with only minimal artifacts according to both readers, and determination of the nerve root was possible in almost all patients (LD vs. SD: p > 0.05 for all items). This resulted in high confidence for intervention planning as well as periprocedural intervention guidance for both SD and LD scans. The inter-reader agreement was at least substantial (weighted Cohen’s κ ≥ 0.62), except for confidence in intervention planning for LD scans (κ = 0.49). In conclusion, considerable dose reduction for planning and performing periradicular infiltrations with MDCT using model-based iterative image reconstruction is feasible and can be performed without clinically relevant drawbacks regarding image quality or confidence for planning.
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Morawitz J, Martin O, Boos J, Sawicki LM, Wingendorf K, Sedlmair M, Mamlins E, Antke C, Antoch G, Schaarschmidt BM. Impact of Different Metal Artifact Reduction Techniques on Attenuation Correction of Normal Organs in 18F-FDG-PET/CT. Diagnostics (Basel) 2022; 12:diagnostics12020375. [PMID: 35204466 PMCID: PMC8870731 DOI: 10.3390/diagnostics12020375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/20/2022] [Accepted: 01/28/2022] [Indexed: 02/04/2023] Open
Abstract
Purpose: To evaluate the impact of different metal artifact reduction algorithms on Hounsfield units (HU) and the standardized uptake value (SUV) in normal organs in patients with different metal implants. Methods: This study prospectively included 66 patients (mean age of 66.02 ± 13.1 years) with 87 different metal implants. CT image reconstructions were performed using weighted filtered back projection (WFBP) as the standard method, metal artifact reduction in image space (MARIS), and an iterative metal artifacts reduction (iMAR) algorithm for large implants. These datasets were used for PET attenuation correction. HU and SUV measurements were performed in nine predefined anatomical locations: liver, lower lung lobes, descending aorta, thoracic vertebral body, autochthonous back muscles, pectoral muscles, and internal jugular vein. Differences between HU and SUV measurements were compared using paired t-tests. The significance level was determined as p = 0.017 using Bonferroni correction. Results: No significant differences were observed between reconstructed images using iMAR and WFBP concerning HU and SUV measurements in liver (HU: p = 0.055; SUVmax: p = 0.586), lung (HU: p = 0.276; SUVmax: p = 1.0 for the right side and HU: p = 0.630; SUVmax: p = 0.109 for the left side), descending aorta (HU: p = 0.333; SUVmax: p = 0.083), thoracic vertebral body (HU: p = 0.725; SUVmax: p = 0.392), autochthonous back muscles (HU: p = 0.281; SUVmax: p = 0.839), pectoral muscles (HU: p = 0.481; SUVmax: p = 0.277 for the right side and HU: p = 0.313; SUVmax: p = 0.859 for the left side), or the internal jugular vein (HU: p = 0.343; SUVmax: p = 0.194). Conclusion: Metal artifact reduction algorithms such as iMAR do not alter the data information of normal organs not affected by artifacts.
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Affiliation(s)
- Janna Morawitz
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (O.M.); (J.B.); (L.M.S.); (K.W.); (G.A.)
- Correspondence: ; Tel.: +49-2118117552; Fax: +49-2118116145
| | - Ole Martin
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (O.M.); (J.B.); (L.M.S.); (K.W.); (G.A.)
| | - Johannes Boos
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (O.M.); (J.B.); (L.M.S.); (K.W.); (G.A.)
| | - Lino M. Sawicki
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (O.M.); (J.B.); (L.M.S.); (K.W.); (G.A.)
| | - Katrin Wingendorf
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (O.M.); (J.B.); (L.M.S.); (K.W.); (G.A.)
| | - Martin Sedlmair
- Department of Computed Tomography, Siemens Healthineers GmbH, D-91301 Forchheim, Germany;
| | - Eduards Mamlins
- Department of Nuclear Medicine, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (E.M.); (C.A.)
| | - Christina Antke
- Department of Nuclear Medicine, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (E.M.); (C.A.)
| | - Gerald Antoch
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (O.M.); (J.B.); (L.M.S.); (K.W.); (G.A.)
| | - Benedikt M. Schaarschmidt
- Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, D-45147 Essen, Germany;
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OUP accepted manuscript. Eur Heart J Cardiovasc Imaging 2022; 23:e279-e289. [DOI: 10.1093/ehjci/jeac048] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 03/02/2022] [Indexed: 11/14/2022] Open
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Smith-Bindman R, Wang Y, Chu P, Chung R, Einstein AJ, Balcombe J, Cocker M, Das M, Delman BN, Flynn M, Gould R, Lee RK, Nelson T, Schindera S, Seibert A, Starkey J, Suntharalingam S, Wetter A, Wildberger JE, Miglioretti DL. International variation in radiation dose for computed tomography examinations: prospective cohort study. BMJ 2019; 364:k4931. [PMID: 30602590 PMCID: PMC6314083 DOI: 10.1136/bmj.k4931] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
OBJECTIVE To determine patient, institution, and machine characteristics that contribute to variation in radiation doses used for computed tomography (CT). DESIGN Prospective cohort study. SETTING Data were assembled and analyzed from the University of California San Francisco CT International Dose Registry. PARTICIPANTS Standardized data from over 2.0 million CT examinations of adults who underwent CT between November 2015 and August 2017 from 151 institutions, across seven countries (Switzerland, Netherlands, Germany, United Kingdom, United States, Israel, and Japan). MAIN OUTCOME MEASURES Mean effective doses and proportions of high dose examinations for abdomen, chest, combined chest and abdomen, and head CT were determined by patient characteristics (sex, age, and size), type of institution (trauma center, care provision 24 hours per day and seven days per week, academic, private), institutional practice volume, machine factors (manufacturer, model), country, and how scanners were used, before and after adjustment for patient characteristics, using hierarchical linear and logistic regression. High dose examinations were defined as CT scans with doses above the 75th percentile defined during a baseline period. RESULTS The mean effective dose and proportion of high dose examinations varied substantially across institutions. The doses varied modestly (10-30%) by type of institution and machine characteristics after adjusting for patient characteristics. By contrast, even after adjusting for patient characteristics, wide variations in radiation doses across countries persisted, with a fourfold range in mean effective dose for abdomen CT examinations (7.0-25.7 mSv) and a 17-fold range in proportion of high dose examinations (4-69%). Similar variation across countries was observed for chest (mean effective dose 1.7-6.4 mSv, proportion of high dose examinations 1-26%) and combined chest and abdomen CT (10.0-37.9 mSv, 2-78%). Doses for head CT varied less (1.4-1.9 mSv, 8-27%). In multivariable models, the dose variation across countries was primarily attributable to institutional decisions regarding technical parameters (that is, how the scanners were used). CONCLUSIONS CT protocols and radiation doses vary greatly across countries and are primarily attributable to local choices regarding technical parameters, rather than patient, institution, or machine characteristics. These findings suggest that the optimization of doses to a consistent standard should be possible. STUDY REGISTRATION Clinicaltrials.gov NCT03000751.
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Affiliation(s)
- Rebecca Smith-Bindman
- Department of Radiology and Biomedical Imaging Epidemiology and Biostatistics, Obstetrics Gynecology and Reproductive Sciences, Philip R Lee Institute for Health Policy Studies, University of California San Francisco, San Francisco, CA, USA
| | - Yifei Wang
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Philip Chu
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Robert Chung
- Department of Demography, University of California Berkeley, Berkeley, CA, USA
| | - Andrew J Einstein
- Department of Medicine, Division of Cardiology and Department of Radiology, Columbia University Medical Center, New York, NY, USA
| | | | - Mary Cocker
- Department of Medical Physics, Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Marcos Das
- Department of Diagnostic and Interventional Radiology, Helios Kliniken Duisburg, Duisburg, Germany
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, Netherlands
| | - Bradley N Delman
- Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Michael Flynn
- Henry Ford Health System, Radiology and Public Health Sciences, Detroit, MI, USA
| | - Robert Gould
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Ryan K Lee
- Department of Radiology, Einstein Healthcare Network, New York, NY, USA
| | - Thomas Nelson
- University of California San Diego, San Diego, CA, USA
| | | | - Anthony Seibert
- Department of Radiology, University California Davis Medical Center, Sacramento, CA, USA
| | - Jay Starkey
- St Luke's International Hospital, Tokyo, Japan
| | | | - Axel Wetter
- Institute of Diagnostic and Interventional Radiology and Neuroradiology, Essen University, Essen, Germany
| | - Joachim E Wildberger
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, Netherlands
| | - Diana L Miglioretti
- Department of Public Health Sciences, University of California Davis School of Medicine, Sacramento, CA, USA
- Kaiser Permanente Washington Health Research Institute, Kaiser Permanente Washington, Seattle, WA, USA
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Greffier J, Pereira FR, Viala P, Macri F, Beregi JP, Larbi A. Interventional spine procedures under CT guidance: How to reduce patient radiation dose without compromising the successful outcome of the procedure? Phys Med 2017; 35:88-96. [DOI: 10.1016/j.ejmp.2017.02.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 02/15/2017] [Accepted: 02/16/2017] [Indexed: 11/26/2022] Open
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Page L, Wei W, Kundra V, Rong XJ. Dose reduction in CT urography and vasculature phantom studies using model-based iterative reconstruction. J Appl Clin Med Phys 2016; 17:334-342. [PMID: 27929506 PMCID: PMC5690497 DOI: 10.1120/jacmp.v17i6.6184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 06/22/2016] [Accepted: 06/21/2016] [Indexed: 11/23/2022] Open
Abstract
To evaluate the feasibility of radiation dose reduction using model-based iterative reconstruction (MBIR) for evaluating the ureters and vasculature in a phantom, a tissue-equivalent CT dose phantom was scanned using a 64-channel CT scan-ner. Tubes of varying diameters filled with different dilutions of a contrast agent, simulating ureters or vessels, were inserted into the center of the phantom. Each combination was scanned using an existing renal protocol at 140 kVp or 120 kVp, yielding a display volumetric CT dose index (CTDIvol) of 24 mGy. The scans were repeated using reduced scan techniques to achieve lower radiation doses down to 0.8 mGy. The images were reconstructed using filtered back-projection (FBP) and model-based iterative reconstruction (MBIR). The noise and contrast-to-noise ratio (CNR) was measured for each contrast object. Comparisons between the two reconstruction methods at different dose levels were evaluated using a factorial design. At each CTDIvol the measured image noise was lower using MBIR compared to FBP (p < 0.0001). At low doses, the percent change in measured image noise between FBP and MBIR was larger. For the 12 mm object simulating a ureter or large vessel with an HU of 600, the measured CNR using MBIR at a CTDIvol of 1.7 mGy was greater than the CNR of FBP at a CTIDvol of 24 mGy (p < 0.0001). For the 5 mm object simulating a medium-sized vessel with a HU of 250, the mea-sured CNR using MBIR at a CTDIvol of 1.7 mGy was equivalent to that of FBP at a CTDIvol of 24 mGy. For the 2 mm, 100 HU object simulating a small vessel, the measured CNR using MBIR at a CTDIvol of 1.7 mGy was equivalent to that of FBP at a CTDIvol of 24 mGy. Low-dose (3.6 mGy) CT imaging of vasculature and ureter phantoms using MBIR results in similar noise and CNR compared to FBP at approximately one-sixth the dose. This suggests that, using MBIR, a one milliSievert exam of the ureters and vasculature may be clinically possible whilst still maintaining adequate image quality.
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Affiliation(s)
- Leland Page
- The University of Texas MD Anderson Cancer Center.
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Radiation dose optimization for the bolus tracking technique in abdominal computed tomography: usefulness of real-time iterative reconstruction for monitoring scan. Radiol Phys Technol 2016; 10:155-160. [DOI: 10.1007/s12194-016-0378-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 09/14/2016] [Accepted: 09/14/2016] [Indexed: 10/20/2022]
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Urikura A, Hara T, Ichikawa K, Nishimaru E, Hoshino T, Yoshida T, Nakaya Y. Objective assessment of low-contrast computed tomography images with iterative reconstruction. Phys Med 2016; 32:992-8. [DOI: 10.1016/j.ejmp.2016.07.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 06/22/2016] [Accepted: 07/05/2016] [Indexed: 10/21/2022] Open
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Chen YA, MacGregor K, Li I, Concepcion L, Deva DP, Dowdell T, Gray BG. Tracking and Resolving CT Dose Metric Outliers Using Root-Cause Analysis. J Am Coll Radiol 2016; 13:680-7. [PMID: 26953644 DOI: 10.1016/j.jacr.2016.01.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 01/24/2016] [Accepted: 01/28/2016] [Indexed: 10/22/2022]
Abstract
PURPOSE The aim of this study was to examine the frequency and type of outlier dose metrics for three common CT examination types on the basis of a root-cause analysis (RCA) approach. METHODS Institutional review board approval was obtained for this retrospective observational study. The requirement to obtain informed consent was waived. Between January 2010 and December 2013, radiation dose metric data from 34,615 CT examinations, including 26,878 routine noncontrast CT head, 2,992 CT pulmonary angiographic (CTPA), and 4,745 renal colic examinations, were extracted from a radiation dose index monitoring database and manually cleaned. Dose outliers were identified on the basis of the statistical distribution of volumetric CT dose index and dose-length product for each examination type; values higher than the 99th percentile and less than the 1st percentile were flagged for RCA. RESULTS There were 397 noncontrast CT head, 52 CTPA, and 80 renal colic outliers. Root causes for high-outlier examinations included repeat examinations due to patient motion (n = 122 [31%]), modified protocols mislabeled as "routine" (n = 69 [18%]), higher dose examinations for patients with large body habitus (n = 27 [7%]), repeat examinations due to technical artifacts (n = 20 [5%]), and repeat examinations due to suboptimal contrast timing (CTPA examinations) (n = 18 [5%]). Root causes for low-outlier examinations included low-dose protocols (n = 112 [29%]) and aborted examinations (n = 8 [2%]). On the basis of examination frequency over a 3-month period, the 90th and 10th percentile values were set in the radiation dose index monitoring database as thresholds for sending notifications to staff members responsible for outlier investigations. CONCLUSIONS Systematic RCA of dose outliers identifies sources of variation and dose excess and pinpoints specific protocol and technical shortcomings for corrective action.
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Affiliation(s)
- Yingming Amy Chen
- Department of Medical Imaging, St Michael's Hospital, Toronto, Ontario, Canada; Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
| | - Kate MacGregor
- Department of Medical Imaging, St Michael's Hospital, Toronto, Ontario, Canada
| | - Iris Li
- Department of Medical Imaging, St Michael's Hospital, Toronto, Ontario, Canada; University of Toronto, Scarborough, Ontario, Canada
| | - Lianne Concepcion
- Department of Medical Imaging, St Michael's Hospital, Toronto, Ontario, Canada
| | - Djeven Parameshvara Deva
- Department of Medical Imaging, St Michael's Hospital, Toronto, Ontario, Canada; Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Timothy Dowdell
- Department of Medical Imaging, St Michael's Hospital, Toronto, Ontario, Canada; Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Keenan Research Centre, Li Ka Shing Knowledge Institute, Toronto, Ontario, Canada
| | - Bruce Garstang Gray
- Department of Medical Imaging, St Michael's Hospital, Toronto, Ontario, Canada; Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Keenan Research Centre, Li Ka Shing Knowledge Institute, Toronto, Ontario, Canada
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Automated Tube Potential Selection as a Method of Dose Reduction for CT of the Neck: First Clinical Results. AJR Am J Roentgenol 2015; 204:1049-54. [PMID: 25905940 DOI: 10.2214/ajr.14.12975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The objective of our study was to investigate whether the use of a software-based automated tube potential selection (ATPS) CT neck protocol can result in radiation dose reduction as compared with a set 120-kV protocol without a statistically significant reduction in image quality. MATERIALS AND METHODS Three hundred sixty-four patients (median age, 52 years) underwent CT of the neck. Group 1 (n = 320) underwent CT with ATPS with 80, 100, or 120 kV. Group 2 (n = 44) was examined with the standard CT protocol at 120 kV. Attenuation, image background noise, signal-to-noise ratio (SNR), dose-length product (DLP), volume CT dose index (CTDIvol), body mass index (BMI [weight in kilograms divided by the square of height in meters]), and subjective image quality (5-point Likert scale, two readers in consensus) were analyzed. RESULTS A tube potential of 100 kV was selected in 279 patients, 120 kV in 40 patients, and 80 kV in one patient of the ATPS group. A significant correlation was found for selected tube potential and BMI (80 kV, BMI = 20.4; 100 kV, mean BMI = 24.2; 120 kV, BMI = 28.6; r = 0.28, p < 0.01). The average radiation dose was significantly lower with ATPS activated than with the standard protocol (mean DLP, 259 vs 350 mGy × cm, respectively). Background noise did not differ between groups 1 and 2 at the levels of the mandibular angle and the upper mediastinum; however, attenuation and SNR increased significantly with lower tube potential settings. Subjective image quality did not suffer (mean image quality score: ATPS protocol vs standard protocol, 4.56 vs 4.61, respectively; p > 0.05) with good interobserver agreement (κ > 0.56). CONCLUSION ATPS allows significant dose savings for CT of the neck compared with a standard protocol that uses a fixed 120-kV setting without a statistically significant reduction in image quality.
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Dindyal S, Rahman S, Kyriakides C. Review of the Use of Ionizing Radiation in Endovascular Aneurysm Repair. Angiology 2014; 66:607-12. [PMID: 25225195 DOI: 10.1177/0003319714548564] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Endovascular repair for aortic aneurysm (EVAR) is rapidly increasing in popularity. The nature of this intervention requires significant exposure to ionizing radiation both during the procedure and for postoperative surveillance, generally in the form of computed tomography. Here the authors review the literature for radiation exposure during EVAR, both for the patient and the physician.
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Affiliation(s)
- S Dindyal
- Academic department of circulatory sciences, Vascular and Endovascular Surgery, Barts and The London NHS Trust, The Royal London Hospital, Whitechappel, London, United Kingdom
| | - S Rahman
- Academic department of circulatory sciences, Vascular and Endovascular Surgery, Barts and The London NHS Trust, The Royal London Hospital, Whitechappel, London, United Kingdom
| | - C Kyriakides
- Academic department of circulatory sciences, Vascular and Endovascular Surgery, Barts and The London NHS Trust, The Royal London Hospital, Whitechappel, London, United Kingdom
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Radiation risk and protection of patients in clinical SPECT/CT. Eur J Nucl Med Mol Imaging 2013; 41 Suppl 1:S125-36. [PMID: 24052089 DOI: 10.1007/s00259-013-2543-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 08/08/2013] [Indexed: 10/26/2022]
Abstract
Clinical studies have demonstrated that hybrid single photon emission computed tomography (SPECT)/CT for various diagnostic issues has an added value as compared to SPECT alone. However, the combined acquisition of functional and anatomical images can substantially increase radiation exposure to patients, in particular when using a hybrid system with diagnostic CT capabilities. It is, therefore, essential to carefully balance the diagnostic needs and radiation protection requirements. To this end, the evidence on health effects induced by ionizing radiation is outlined. In addition, the essential concepts for estimating radiation doses and lifetime attributable cancer risks associated with SPECT/CT examinations are presented taking into account both the new recommendations of the International Commission on Radiological Protection (ICRP) as well as the most recent radiation risk models. Representative values of effective dose and lifetime attributable risk are reported for ten frequently used SPECT radiopharmaceuticals and five fully diagnostic partial-body CT examinations. A diagnostic CT scan acquired as part of a combined SPECT/CT examination contributes considerably to, and for some applications even dominates, the total patient exposure. For the common SPECT and CT examinations considered in this study, the lifetime attributable risk of developing a radiation-related cancer is less than 0.27 %/0.37 % for men/women older than 16 years, respectively, and decreases markedly with increasing age at exposure. Since there is no clinical indication for a SPECT/CT examination unless an emission scan has been indicated, the issue on justification comes down to the question of whether it is necessary to additionally acquire a low-dose CT for attenuation correction and anatomical localization of tracer uptake or even a fully diagnostic CT. In any case, SPECT/CT studies have to be optimized, e.g. by adapting dose reduction measures from state-of-the-art CT practice, and exposure levels should not exceed the national diagnostic reference levels for standard situations.
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Bodelle B, Bauer RW, Holthaus L, Schulz B, Al-Butmeh F, Wichmann JL, Beeres M, Vogl TJ, Kerl JM. Dose and image quality of high-pitch dual source computed tomography for the evaluation of cervical lymph node status - comparison to regular 128-slice single source computed tomography. Eur J Radiol 2013; 82:e281-5. [PMID: 23414716 DOI: 10.1016/j.ejrad.2013.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Revised: 12/31/2012] [Accepted: 01/09/2013] [Indexed: 02/06/2023]
Abstract
PURPOSE A high-pitch dual-source CT (DSCT) was compared to a standard single-source CT protocol in terms of dose and image quality for malignant lymphoma staging. MATERIALS AND METHODS Data from 43 patients who underwent DSCT (group 1) of the neck for staging of malignant lymphoma and 40 patients who underwent regular single source CT (group 2) were investigated retrospectively. Volume CT dose index (CTDIvol), dose length product (DLP), background noise (BN), attenuation values, signal-to-noise-ratio (SNR), scan time, effective tube current-time product (eff. mAs), subjective diagnostic image quality and artifact burden were compared. RESULTS CTDIvol (5.5 ± 0.8 mGy vs. 12.4 ± 1.4 mGy), DLP (172 ± 27 mGycm vs. 344 ± 60 mGycm, p<0.0001), eff. mAs (98 ± 15 mAs vs. 183 ± 20 mAs, p<0.0001) and scan time (0.64 ± 0.05 s vs. 8.21 ± 0.72 s) were lower for group 1. BN was higher (p<0.001) for group 1 with a mean difference of 2.6 HU. SNR for sternocleidomastoid and pectoral muscle was lower (6.6-12.3 vs. 7.8-19.1) for group 1. Subjective image quality (1.55 ± 0.6 vs. 1.42 ± 0.5) and artifact burden (1.62 ± 1.0 vs. 1.57 ± 0.9) were not rated significantly different (p=0.47 and p=0.80) with a good inter-observer agreement (κ=0.59-0.90). CONCLUSION High-pitch DSCT allows reduction of patient dose for cervical lymphoma staging while diagnostic image quality is preserved.
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Affiliation(s)
- Boris Bodelle
- Goethe University of Frankfurt, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
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Sosna J, Mahgerefteh S, Goshen L, Kafri G, Aviram G, Blachar A. Virtual nonenhanced abdominal dual-energy MDCT: Analysis of image characteristics. World J Radiol 2012; 4:167-73. [PMID: 22590671 PMCID: PMC3351685 DOI: 10.4329/wjr.v4.i4.167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 02/20/2012] [Accepted: 02/27/2012] [Indexed: 02/06/2023] Open
Abstract
AIM: To evaluate abdominal and pelvic image characteristics and artifacts on virtual nonenhanced (VNE) images generated from contrast-enhanced dual-energy multidetector computed tomography (MDCT) studies.
METHODS: Hadassah-Hebrew University Medical Institutional Review Board approval was obtained; 22 patients underwent clinically-indicated abdominal and pelvic single-source dual-energy MDCT (Philips Healthcare, Cleveland, OH, USA), pre- and post-IV administration of Omnipaque 300 contrast (100 cc). Various solid and vascular structures were evaluated. VNE images were generated from the portal contrast-enhanced phase using probabilistic separation. Contrast-enhanced-, regular nonenhanced (RNE)-, and VNE images were evaluated with a total of 1494 density measurements. The ratio of iodine contrast deletion was calculated. Visualization of calcifications, urinary tract stones, and image artifacts in VNE images were assessed.
RESULTS: VNE images were successfully generated in all patients. Significant portal-phase iodine contrast deletion was seen in the kidney (61.7%), adrenal gland (55.3%), iliac artery (55.0%), aorta (51.6%), and spleen (34.5%). Contrast deletion was also significant in the right atrium (RA) (51.5%) and portal vein (39.3%), but insignificant in the iliac vein and inferior vena cava (IVC). Average post contrast-to-VNE HU differences were significant (P < 0.05) in the: RA -135.3 (SD 121.8), aorta -114.1 (SD 48.5), iliac artery -104.6 (SD 53.7), kidney -30.3 (SD 34.9), spleen -9.2 (SD 8.8), and portal vein -7.7 (SD 13.2). Average VNE-to-RNE HU differences were significant in all organs but the prostate and subcutaneous fat: aorta 38.0 (SD 9.3), RA 37.8 (SD 16.1), portal vein 21.8 (SD 12.0), IVC 12.2 (SD 11.6), muscle 3.3 (SD 4.9), liver 5.7 (SD 6.4), spleen 22.3 (SD 9.8), kidney 40.5 (SD 6.8), and adrenal 20.7 (SD 13.5). On VNE images, 196/213 calcifications (92%) and 5/6 renal stones (84%) were visualized. Lytic-like artifacts in the vertebral bodies were seen in all studies.
CONCLUSION: Iodine deletion in VNE images is most significant in arteries, and less significant in solid organs and veins. Most vascular and intra-abdominal organ calcifications are preserved.
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Amacker NA, Mader C, Alkadhi H, Leschka S, Frauenfelder T. Routine chest and abdominal high-pitch CT: An alternative low dose protocol with preserved image quality. Eur J Radiol 2012; 81:e392-7. [DOI: 10.1016/j.ejrad.2011.12.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 12/01/2011] [Accepted: 12/03/2011] [Indexed: 11/15/2022]
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Shepherd TM, Hess CP, Chin CT, Gould R, Dillon WP. Reducing patient radiation dose during CT-guided procedures: demonstration in spinal injections for pain. AJNR Am J Neuroradiol 2011; 32:1776-82. [PMID: 21920858 DOI: 10.3174/ajnr.a2634] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND AND PURPOSE CT guidance may improve precision for diagnostic and therapeutic spinal injections, but it can increase patient radiation dose. This study examined the impact of reducing tube current on patient radiation exposure and the technical success for these procedures, by using axial acquisitions for short scan lengths and eliminating nonessential imaging. MATERIALS AND METHODS Our institutional review board approved retrospective analysis of records from 100 consecutive outpatients undergoing spinal injections for pain before and after the CT protocol modification to reduce radiation dose. Data collected included patient age and sex, response to injection, number of sites and spinal levels treated, injection type, performing physician, CT acquisition method, number of imaging series, tube current, scan length, and DLP. RESULTS Image contrast was reduced with the low-dose protocol, but this did not affect technical success or immediate pain relief. Mean DLP for all procedures decreased from 1458 ± 1022 to 199 ± 101 mGy · cm (P < .001). The range of radiologist-dependent DLP per procedure also was reduced significantly with the modified protocol. Selective nerve root blocks, lumbar injections, multiple injection sites, and the lack of prior imaging were each associated with a slightly higher DLP (<50 mGy · cm). CONCLUSIONS Radiation to patients undergoing CT-guided spinal injections can be decreased significantly without affecting outcome by reducing tube current, using axial acquisitions for short scan lengths, and eliminating nonessential imaging guidance. These measures also decrease variability in radiation doses between different practitioners and should be useful for other CT-guided procedures in radiology.
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Affiliation(s)
- T M Shepherd
- Neuroradiology Division, Department of Radiology and Biomedical Imaging, University of California, San Francisco, 94143-0628, USA
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Dougeni E, Faulkner K, Panayiotakis G. A review of patient dose and optimisation methods in adult and paediatric CT scanning. Eur J Radiol 2011; 81:e665-83. [PMID: 21684099 DOI: 10.1016/j.ejrad.2011.05.025] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2010] [Revised: 05/18/2011] [Accepted: 05/19/2011] [Indexed: 12/14/2022]
Abstract
An increasing number of publications and international reports on computed tomography (CT) have addressed important issues on optimised imaging practice and patient dose. This is partially due to recent technological developments as well as to the striking rise in the number of CT scans being requested. CT imaging has extended its role to newer applications, such as cardiac CT, CT colonography, angiography and urology. The proportion of paediatric patients undergoing CT scans has also increased. The published scientific literature was reviewed to collect information regarding effective dose levels during the most common CT examinations in adults and paediatrics. Large dose variations were observed (up to 32-fold) with some individual sites exceeding the recommended dose reference levels, indicating a large potential to reduce dose. Current estimates on radiation-related cancer risks are alarming. CT doses account for about 70% of collective dose in the UK and are amongst the highest in diagnostic radiology, however the majority of physicians underestimate the risk, demonstrating a decreased level of awareness. Exposure parameters are not always adjusted appropriately to the clinical question or to patient size, especially for children. Dose reduction techniques, such as tube-current modulation, low-tube voltage protocols, prospective echocardiography-triggered coronary angiography and iterative reconstruction algorithms can substantially decrease doses. An overview of optimisation studies is provided. The justification principle is discussed along with tools that assist clinicians in the decision-making process. There is the potential to eliminate clinically non-indicated CT scans by replacing them with alternative examinations especially for children or patients receiving multiple CT scans.
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Affiliation(s)
- E Dougeni
- Imaging Physics and Radiation Safety Section, Regional Medical Physics Department, Freeman Hospital, Freeman Road, Newcastle Upon Tyne NE7 7DN, UK.
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Lau LS, Pérez MR, Applegate KE, Rehani MM, Ringertz HG, George R. Global Quality Imaging: Improvement Actions. J Am Coll Radiol 2011; 8:330-4. [DOI: 10.1016/j.jacr.2011.01.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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64-Slice CT urography: optimisation of radiation dose. Radiol Med 2011; 116:417-31. [DOI: 10.1007/s11547-011-0623-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Accepted: 05/06/2010] [Indexed: 01/21/2023]
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Sinnott B, Ron E, Schneider AB. Exposing the thyroid to radiation: a review of its current extent, risks, and implications. Endocr Rev 2010; 31:756-73. [PMID: 20650861 PMCID: PMC3365850 DOI: 10.1210/er.2010-0003] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Accepted: 06/04/2010] [Indexed: 12/26/2022]
Abstract
Radiation exposure of the thyroid at a young age is a recognized risk factor for the development of differentiated thyroid cancer lasting for four decades and probably for a lifetime after exposure. Medical radiation exposure, however, occurs frequently, including among the pediatric population, which is especially sensitive to the effects of radiation. In the past, the treatment of benign medical conditions with external radiation represented the most significant thyroid radiation exposures. Today, diagnostic medical radiation represents the largest source of man-made radiation exposure. Radiation exposure related to the use of computerized tomography is rising exponentially, particularly in the pediatric population. There is direct epidemiological evidence of a small but significant increased risk of cancer at radiation doses equivalent to computerized tomography doses used today. Paralleling the increasing use of medical radiation is an increase in the incidence of papillary thyroid cancer. At present, it is unclear how much of this increase is related to increased detection of subclinical disease from the increased utilization of ultrasonography and fine-needle aspiration, how much is due to a true increase in thyroid cancer, and how much, if any, can be ascribed to medical radiation exposure. Fortunately, the amount of radiation exposure from medical sources can be reduced. In this article we review the sources of thyroid radiation exposure, radiation risks to the thyroid gland, strategies for reducing radiation exposure to the thyroid, and ways that endocrinologists can participate in this effort. Finally, we provide some suggestions for future research directions.
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Affiliation(s)
- Bridget Sinnott
- Section of Endocrinology, Diabetes, and Metabolism, College of Medicine, University of Illinois at Chicago, 1819 West Polk Street (MC 640), Chicago, Illinois 60612, USA
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Mahgerefteh S, Blachar A, Fraifeld S, Sosna J. Dual-Energy Derived Virtual Nonenhanced Computed Tomography Imaging: Current Status and Applications. Semin Ultrasound CT MR 2010; 31:321-7. [DOI: 10.1053/j.sult.2010.06.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Affiliation(s)
- Rebecca Smith-Bindman
- Department of Radiology and Biomedical Imaging, University of California at San Francisco, San Francisco, USA
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Carrascosa PM, Capuñay C, Vallejos J, Martín López EB, Baronio M, Carrascosa JM. Virtual Hysterosalpingography: A New Multidetector CT Technique for Evaluating the Female Reproductive System. Radiographics 2010; 30:643-61. [DOI: 10.1148/rg.303095732] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Rogalla P, Blobel J, Kandel S, Meyer H, Mews J, Kloeters C, Kashani H, Lembcke A, Paul N. Radiation dose optimisation in dynamic volume CT of the heart: tube current adaptation based on anterior-posterior chest diameter. Int J Cardiovasc Imaging 2010; 26:933-40. [PMID: 20422293 DOI: 10.1007/s10554-010-9630-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 04/05/2010] [Indexed: 11/26/2022]
Abstract
To compare tube current adaptation based on 3 body mass index (BMI) categories versus anterior-posterior chest diameter (APD) for radiation dose optimisation in patients undergoing dynamic volume cardiac CT. Two cardiac imaging centres participated in the study. 20 patients underwent a prospectively triggered 320-slice single beat cardiac CT using the X-ray tube current [mA] manually adjusted to the patient's BMI (group I). In 20 subsequent patients, the tube current was adapted according to the patient's APD (group II). All other parameters were kept constant. Image noise was defined as the standard deviation of attenuation values and measured using a ROI in the descending aorta. Variation in image noise was statistically compared between both patient groups. Average and standard deviation of pixel noise were 29.1 HU and 14.8 HU in group I and 28.0 HU and 4.2 HU in group II. Inter-individual variation of pixel noise was significantly lower in group II compared to group I (p < 0.0001). Tube current adaptation based on APD is superior to stepwise adaptation based on BMI for optimising radiation dose in dynamic volume cardiac CT and therefore limits unnecessary radiation dose while ensuring diagnostic image quality in patients with diverse body habitus.
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Affiliation(s)
- Patrik Rogalla
- Department of Medical Imaging, University Health Network, University of Toronto, Toronto, ON, Canada
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Reiner BI. Quantifying Radiation Safety and Quality in Medical Imaging, Part 2: The Radiation Scorecard. J Am Coll Radiol 2009; 6:615-9. [DOI: 10.1016/j.jacr.2009.05.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Accepted: 05/05/2009] [Indexed: 11/29/2022]
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Matsubara K, Koshida K, Suzuki M, Shimono T, Yamamoto T, Matsui O. Effective dose evaluation of multidetector CT examinations: influence of the ICRP recommendation in 2007. Eur Radiol 2009; 19:2855-61. [DOI: 10.1007/s00330-009-1497-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Revised: 05/28/2009] [Accepted: 06/04/2009] [Indexed: 11/24/2022]
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Shintaku WH, Venturin JS, Azevedo B, Noujeim M. Applications of cone-beam computed tomography in fractures of the maxillofacial complex. Dent Traumatol 2009; 25:358-66. [PMID: 19515071 DOI: 10.1111/j.1600-9657.2009.00795.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Imaging plays an essential role in the evaluation of maxillofacial fractures both pre- and postoperatively. Several studies support the use of conventional two-dimensional imaging for traumas involving mainly the mandible, but for more complex situations advanced imaging modalities such as computed tomography (CT) and magnetic resonance imaging have higher indication. Nowadays, besides CT, cone-beam computed tomography (CBCT) has appeared as a reasonable and reliable alternative considering radiation dosage, image quality and comfort for the patient. The purpose of this study was to review the fracture patterns involving the maxillofacial complex, provide a technical and practical comparison between CT and CBCT, and finally present the potential applications of CBCT illustrated with clinical examples.
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Affiliation(s)
- Werner H Shintaku
- The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA.
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New response evaluation criteria in solid tumours: revised RECIST guideline (version 1.1). Eur J Cancer 2009; 45:228-47. [PMID: 19097774 DOI: 10.1016/j.ejca.2008.10.026] [Citation(s) in RCA: 19594] [Impact Index Per Article: 1306.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Accepted: 10/29/2008] [Indexed: 11/23/2022]
Abstract
BACKGROUND Assessment of the change in tumour burden is an important feature of the clinical evaluation of cancer therapeutics: both tumour shrinkage (objective response) and disease progression are useful endpoints in clinical trials. Since RECIST was published in 2000, many investigators, cooperative groups, industry and government authorities have adopted these criteria in the assessment of treatment outcomes. However, a number of questions and issues have arisen which have led to the development of a revised RECIST guideline (version 1.1). Evidence for changes, summarised in separate papers in this special issue, has come from assessment of a large data warehouse (>6500 patients), simulation studies and literature reviews. HIGHLIGHTS OF REVISED RECIST 1.1: Major changes include: Number of lesions to be assessed: based on evidence from numerous trial databases merged into a data warehouse for analysis purposes, the number of lesions required to assess tumour burden for response determination has been reduced from a maximum of 10 to a maximum of five total (and from five to two per organ, maximum). Assessment of pathological lymph nodes is now incorporated: nodes with a short axis of 15 mm are considered measurable and assessable as target lesions. The short axis measurement should be included in the sum of lesions in calculation of tumour response. Nodes that shrink to <10mm short axis are considered normal. Confirmation of response is required for trials with response primary endpoint but is no longer required in randomised studies since the control arm serves as appropriate means of interpretation of data. Disease progression is clarified in several aspects: in addition to the previous definition of progression in target disease of 20% increase in sum, a 5mm absolute increase is now required as well to guard against over calling PD when the total sum is very small. Furthermore, there is guidance offered on what constitutes 'unequivocal progression' of non-measurable/non-target disease, a source of confusion in the original RECIST guideline. Finally, a section on detection of new lesions, including the interpretation of FDG-PET scan assessment is included. Imaging guidance: the revised RECIST includes a new imaging appendix with updated recommendations on the optimal anatomical assessment of lesions. FUTURE WORK A key question considered by the RECIST Working Group in developing RECIST 1.1 was whether it was appropriate to move from anatomic unidimensional assessment of tumour burden to either volumetric anatomical assessment or to functional assessment with PET or MRI. It was concluded that, at present, there is not sufficient standardisation or evidence to abandon anatomical assessment of tumour burden. The only exception to this is in the use of FDG-PET imaging as an adjunct to determination of progression. As is detailed in the final paper in this special issue, the use of these promising newer approaches requires appropriate clinical validation studies.
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Current Awareness in Contrast Media and Molecular Imaging. CONTRAST MEDIA & MOLECULAR IMAGING 2007. [DOI: 10.1002/cmmi.152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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