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Halligan S, Dadswell E, Wooldrage K, Wardle J, von Wagner C, Lilford R, Yao GL, Zhu S, Atkin W. Computed tomographic colonography compared with colonoscopy or barium enema for diagnosis of colorectal cancer in older symptomatic patients: two multicentre randomised trials with economic evaluation (the SIGGAR trials). Health Technol Assess 2015; 19:1-134. [PMID: 26198205 PMCID: PMC4781284 DOI: 10.3310/hta19540] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Computed tomographic colonography (CTC) is a relatively new diagnostic test that may be superior to existing alternatives to investigate the large bowel. OBJECTIVES To compare the diagnostic efficacy, acceptability, safety and cost-effectiveness of CTC with barium enema (BE) or colonoscopy. DESIGN Parallel randomised trials: BE compared with CTC and colonoscopy compared with CTC (randomisation 2 : 1, respectively). SETTING A total of 21 NHS hospitals. PARTICIPANTS Patients aged ≥ 55 years with symptoms suggestive of colorectal cancer (CRC). INTERVENTIONS CTC, BE and colonoscopy. MAIN OUTCOME MEASURES For the trial of CTC compared with BE, the primary outcome was the detection rate of CRC and large polyps (≥ 10 mm), with the proportion of patients referred for additional colonic investigation as a secondary outcome. For the trial of CTC compared with colonoscopy, the primary outcome was the proportion of patients referred for additional colonic investigation, with the detection rate of CRC and large polyps as a secondary outcome. Secondary outcomes for both trials were miss rates for cancer (via registry data), all-cause mortality, serious adverse events, patient acceptability, extracolonic pathology and cost-effectiveness. RESULTS A total of 8484 patients were registered and 5384 were randomised and analysed (BE trial: 2527 BE, 1277 CTC; colonoscopy trial: 1047 colonoscopy, 533 CTC). Detection rates in the BE trial were 7.3% (93/1277) for CTC, compared with 5.6% (141/2527) for BE (p = 0.0390). The difference was due to better detection of large polyps by CTC (3.6% vs. 2.2%; p = 0.0098), with no significant difference for cancer (3.7% vs. 3.4%; p = 0.66). Significantly more patients having CTC underwent additional investigation (23.5% vs. 18.3%; p = 0.0003). At the 3-year follow-up, the miss rate for CRC was 6.7% for CTC (three missed cancers) and 14.1% for BE (12 missed cancers). Significantly more patients randomised to CTC than to colonoscopy underwent additional investigation (30% vs. 8.2%; p < 0.0001). There was no significant difference in detection rates for cancer or large polyps (10.7% for CTC vs. 11.4% for colonoscopy; p = 0.69), with no difference when cancers (p = 0.94) and large polyps (p = 0.53) were analysed separately. At the 3-year follow-up, the miss rate for cancer was nil for colonoscopy and 3.4% for CTC (one missed cancer). Adverse events were uncommon for all procedures. In 1042 of 1748 (59.6%) CTC examinations, at least one extracolonic finding was reported, and this proportion increased with age (p < 0.0001). A total of 149 patients (8.5%) were subsequently investigated, and extracolonic neoplasia was diagnosed in 79 patients (4.5%) and malignancy in 29 (1.7%). In the short term, CTC was significantly more acceptable to patients than BE or colonoscopy. Total costs for CTC and colonoscopy were finely balanced, but CTC was associated with higher health-care costs than BE. The cost per large polyp or cancer detected was £4235 (95% confidence interval £395 to £9656). CONCLUSIONS CTC is superior to BE for detection of cancers and large polyps in symptomatic patients. CTC and colonoscopy detect a similar proportion of large polyps and cancers and their costs are also similar. CTC precipitates significantly more additional investigations than either BE or colonoscopy, and evidence-based referral criteria are needed. Further work is recommended to clarify the extent to which patients initially referred for colonoscopy or BE undergo subsequent abdominopelvic imaging, for example by computed tomography, which will have a significant impact on health economic estimates. TRIAL REGISTRATION Current Controlled Trials ISRCTN95152621.
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Affiliation(s)
- Steve Halligan
- Centre for Medical Imaging, University College London, London, UK
| | - Edward Dadswell
- Cancer Screening and Prevention Research Group, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Kate Wooldrage
- Cancer Screening and Prevention Research Group, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Jane Wardle
- Health Behaviour Research Centre, Department of Epidemiology and Public Health, University College London, London, UK
| | - Christian von Wagner
- Health Behaviour Research Centre, Department of Epidemiology and Public Health, University College London, London, UK
| | - Richard Lilford
- School of Health and Population Sciences, University of Birmingham, Birmingham, UK
- Population Evidence and Technologies, University of Warwick, Warwick, UK
| | - Guiqing L Yao
- School of Health and Population Sciences, University of Birmingham, Birmingham, UK
- Primary Care and Population Sciences, University of Southampton, Southampton, UK
| | - Shihua Zhu
- School of Health and Population Sciences, University of Birmingham, Birmingham, UK
| | - Wendy Atkin
- Cancer Screening and Prevention Research Group, Department of Surgery and Cancer, Imperial College London, London, UK
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Halligan S. CT colonography for investigation of patients with symptoms potentially suggestive of colorectal cancer: a review of the UK SIGGAR trials. Br J Radiol 2013; 86:20130137. [PMID: 23568360 DOI: 10.1259/bjr.20130137] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
This paper argues for the use of CT colonography (CTC) to investigate patients with symptoms potentially suggestive of colorectal cancer. It describes the rationale for the UK Special Interest Group in Gastrointestinal and Abdominal Radiology (SIGGAR) randomised controlled trials that compared CTC with barium enema (BE) or colonoscopy for diagnosis of colorectal cancer or large polyps in symptomatic patients. Diagnostic outcomes from the trials are detailed for both intra- and extracolonic disease, along with psychological reactions of patients to the tests, and cost-effectiveness of the different diagnostic strategies. The author concludes that BE should be replaced by CTC immediately and that CTC is a sensitive, acceptable and equally cost-effective alternative to colonoscopy in patients in whom colonoscopy is contraindicated or undesirable.
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Affiliation(s)
- S Halligan
- Centre for Medical Imaging, University College London, London, UK.
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Shariff MK, Sheikh K, Carroll NR, Whitley S, Greenberg D, Parkes M, Cameron EAB. Colorectal cancer detection: time to abandon barium enema? Frontline Gastroenterol 2011; 2:105-109. [PMID: 28839591 PMCID: PMC5517211 DOI: 10.1136/fg.2010.003616] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/10/2010] [Indexed: 02/04/2023] Open
Abstract
OBJECTIVES To assess the sensitivity of double contrast barium enema (DCBE) for diagnosing colorectal cancer (CRC). DESIGN Retrospective evaluation of DCBE performed in the 2 years prior to diagnosis of CRC. SETTING Teaching hospital in Cambridge, UK. PATIENTS 1310 consecutive cases of CRC identified from cancer registry data. INTERVENTIONS DCBE and colonoscopy. MAIN OUTCOME MEASURES Sensitivity of DCBE for diagnosing CRC. RESULTS 215 patients had undergone a DCBE within the 2 years prior to diagnosis with CRC. After excluding those reported as inadequate, 37 of these were reported as normal, giving a sensitivity of 83% (81-85%). CONCLUSIONS The performance of DCBE is inadequate for the exclusion of CRC. Expansion of colonoscopy and CT colonography capacity is urgently required nationally so that DCBE can finally be abandoned as a firstline test in patients at risk of CRC.
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Affiliation(s)
- M K Shariff
- Department of Gastroenterology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - K Sheikh
- Department of Gastroenterology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - N R Carroll
- Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - S Whitley
- Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - D Greenberg
- Eastern Cancer Registration and Information Centre, Unit C, Hinton Way, Cambridge, UK
| | - M Parkes
- Department of Gastroenterology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - E A B Cameron
- Department of Gastroenterology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
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Hafeez R, Greenhalgh R, Rajan J, Bloom S, McCartney S, Halligan S, Taylor SA. Use of small bowel imaging for the diagnosis and staging of Crohn's disease--a survey of current UK practice. Br J Radiol 2010; 84:508-17. [PMID: 21081570 DOI: 10.1259/bjr/65972479] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVES This study used a postal survey to assess the current use of small bowel imaging investigations for Crohn's disease within National Health Service (NHS) radiological practice and to gauge gastroenterological referral patterns. METHODS Similar questionnaires were posted to departments of radiology (n = 240) and gastroenterology (n = 254) identified, by the databases of the Royal College of Radiologists and British Society of Gastroenterologists. Questionnaires enquired about the use of small bowel imaging in the assessment of Crohn's disease. In particular, questionnaires described clinical scenarios including first diagnosis, disease staging and assessment of suspected extraluminal complications, obstruction and disease flare. The data were stratified according to patient age. RESULTS 63 (27%) departments of radiology (20 in teaching hospitals and 43 in district general hospitals (DGHs)) and 73 (29%) departments of gastroenterology replied. These departments were in 119 institutions. Of the 63 departments of radiology, 55 (90%) routinely performed barium follow-though (BaFT), 50 (80%) CT, 29 (46%) small bowel ultrasound (SbUS) and 24 (38%) small bowel MRI. BaFT was the most commonly used investigation across all age groups and indications. SbUS was used mostly for patients younger than 40 years of age with low index of clinical suspicion for Crohn's disease (in 44% of radiology departments (28/63)). MRI was most frequently used in patients under 20 years of age for staging new disease (in 27% of radiology departments (17/63)) or in whom obstruction was suspected (in 29% of radiology departments (18/63)). CT was preferred for suspected extraluminal complications or obstruction (in 73% (46/63) and 46% (29/63) of radiology departments, respectively). Gastroenterological referrals largely concurred with the imaging modalities chosen by radiologists, although gastroenterologists were less likely to request SbUS and MRI. CONCLUSION BaFT remains the mainstay investigation for luminal small bowel Crohn's disease, with CT dominating for suspected extraluminal complications. There has been only moderate dissemination of the use of MRI and SbUS.
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Affiliation(s)
- R Hafeez
- Department of Surgery, University College London, 74 Huntley Street, London, UK
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McFarland EG, Fletcher JG, Pickhardt P, Dachman A, Yee J, McCollough CH, Macari M, Knechtges P, Zalis M, Barish M, Kim DH, Keysor KJ, Johnson CD. ACR Colon Cancer Committee white paper: status of CT colonography 2009. J Am Coll Radiol 2010; 6:756-772.e4. [PMID: 19878883 DOI: 10.1016/j.jacr.2009.09.007] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Accepted: 09/02/2009] [Indexed: 12/21/2022]
Abstract
PURPOSE To review the current status and rationale of the updated ACR practice guidelines for CT colonography (CTC). METHODS Clinical validation trials in both the United States and Europe are reviewed. Key technical aspects of the CTC examination are emphasized, including low-dose protocols, proper insufflation, and bowel preparation. Important issues of implementation are discussed, including training and certification, definition of the target lesion, reporting of colonic and extracolonic findings, quality metrics, reimbursement, and cost-effectiveness. RESULTS Successful validation trials in screening cohorts both in the United States with ACRIN and in Germany demonstrated sensitivity > or = 90% for patients with polyps >10 mm. Proper technique is critical, including low-dose techniques in screening cohorts, with an upper limit of the CT dose index by volume of 12.5 mGy per examination. Training new readers includes the requirement of interactive workstation training with 2-D and 3-D image display techniques. The target lesion is defined as a polyp > or = 6 mm, consistent with the American Cancer Society joint guidelines. Five quality metrics have been defined for CTC, with pilot data entered. Although the CMS national noncoverage decision in May 2009 was a disappointment, multiple third-party payers are reimbursing for screening CTC. Cost-effective modeling has shown CTC to be a dominant strategy, including in a Medicare cohort. CONCLUSION Supported by third-party payer reimbursement for screening, CTC will continue to further transition into community practice and can provide an important adjunctive examination for colorectal screening.
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Thomas S, Atchley J, Higginson A. Audit of the introduction of CT colonography for detection of colorectal carcinoma in a non-academic environment and its implications for the national bowel cancer screening programme. Clin Radiol 2009; 64:142-7. [DOI: 10.1016/j.crad.2008.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Revised: 10/01/2008] [Accepted: 10/14/2008] [Indexed: 11/27/2022]
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Abstract
Double contrast barium enema (DCBE) continues its decline. One area where DCBE and CT colonography surpass colonoscopy is in documentation. Colonoscopy could improve documentation by systematic videorecording of examinations (or at least of the withdrawal portions). Investigation of the impact of systematic videorecording of colonoscopy on quality, cost, and medical-legal risk is warranted.
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Barclay RL, Vicari JJ, Greenlaw RL. Effect of a time-dependent colonoscopic withdrawal protocol on adenoma detection during screening colonoscopy. Clin Gastroenterol Hepatol 2008; 6:1091-8. [PMID: 18639495 DOI: 10.1016/j.cgh.2008.04.018] [Citation(s) in RCA: 205] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Revised: 04/16/2008] [Accepted: 04/18/2008] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Screening colonoscopy can prevent cancer by removal of adenomatous polyps. Recent evidence suggests that insufficient time for inspection during overly rapid colonoscope withdrawal may compromise adenoma detection. We conducted a study of the effect of a minimum prespecified time for instrument withdrawal and careful inspection on adenoma detection rates during screening colonoscopy. METHODS Baseline data consisted of neoplasia detection rates during 2053 screening colonoscopies performed without a specified withdrawal protocol. During a subsequent 13-month period we performed 2325 screening colonoscopies using dedicated inspection techniques and a minimum 8-minute withdrawal time. With colonoscopists comprising the study population, we compared overall and individual rates of neoplasia detection in postintervention procedures with those in baseline examinations. RESULTS As compared with baseline subjects, postintervention subjects had higher rates of any neoplasia (34.7% vs 23.5%, P < .0001) and of advanced neoplastic lesions per patient screened (0.080 +/- 0.358 vs 0.055 +/- 0.241, P < .01). Twenty-five percent of advanced neoplastic lesions detected in postintervention examinations were 9 mm or less in diameter, versus 10% in baseline examinations (P < .001). Endoscopists with mean withdrawal times of 8 minutes or longer had higher rates of detection of any neoplasia (37.8% vs 23.3%, P < .0001) and of advanced neoplasia (6.6% vs 4.5%, P = .13) compared with those with mean withdrawal times of less than 8 minutes. CONCLUSIONS After implementing a protocol of careful inspection during a minimum of 8 minutes to withdraw the colonoscope, we observed significantly greater rates of overall and advanced neoplasia detection during screening colonoscopy.
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Affiliation(s)
- Robert L Barclay
- Rockford Gastroenterology Associates, Rockford, Illinois 61107-5078, USA.
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Halligan S. Screening for colorectal cancer. Colorectal Cancer 2007. [DOI: 10.1017/cbo9780511902468.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Halligan S, Lilford RJ, Wardle J, Morton D, Rogers P, Wooldrage K, Edwards R, Kanani R, Shah U, Atkin W. Design of a multicentre randomized trial to evaluate CT colonography versus colonoscopy or barium enema for diagnosis of colonic cancer in older symptomatic patients: the SIGGAR study. Trials 2007; 8:32. [PMID: 17963520 PMCID: PMC2174515 DOI: 10.1186/1745-6215-8-32] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2007] [Accepted: 10/27/2007] [Indexed: 01/11/2023] Open
Abstract
Background and Aims The standard whole-colon tests used to investigate patients with symptoms of colorectal cancer are barium enema and colonoscopy. Colonoscopy is the reference test but is technically difficult, resource intensive, and associated with adverse events, especially in the elderly. Barium enema is safer but has reduced sensitivity for cancer. CT colonography ("virtual colonoscopy") is a newer alternative that may combine high sensitivity for cancer with safety and patient acceptability. The SIGGAR trial aims to determine the diagnostic efficacy, acceptability, and economic costs associated with this new technology. Methods The SIGGAR trial is a multi-centre randomised comparison of CT colonography versus standard investigation (barium enema or colonoscopy), the latter determined by individual clinician preference. Diagnostic efficacy for colorectal cancer and colonic polyps measuring 1 cm or larger will be determined, as will the physical and psychological morbidity associated with each diagnostic test, the latter via questionnaires developed from qualitative interviews. The economic costs of making or excluding a diagnosis will be determined for each diagnostic test and information from the trial and other data from the literature will be used to populate models framed to summarise the health effects and costs of alternative approaches to detection of significant colonic neoplasia in patients of different ages, prior risks and preferences. This analysis will focus particularly on the frequency, clinical relevance, costs, and psychological and physical morbidity associated with detection of extracolonic lesions by CT colonography. Results Recruitment commenced in March 2004 and at the time of writing (July 2007) 5025 patients have been randomised. A lower than expected prevalence of end-points in the barium enema sub-trial has caused an increase in sample size. In addition to the study protocol, we describe our approach to recruitment, notably the benefits of extensive piloting, the use of a sham-randomisation procedure, which was employed to determine whether centres interested in participating were likely to be effective in practice, and the provision of funding for dedicated sessions for a research nurse at each centre to devote specifically to this trial. Trial registration Current Controlled Trials ISRCTN95152621
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Affiliation(s)
- Steve Halligan
- Department of Specialist Radiology, University College Hospital London, London, UK.
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Taylor PM. A review of research into the development of radiologic expertise: implications for computer-based training. Acad Radiol 2007; 14:1252-63. [PMID: 17889342 DOI: 10.1016/j.acra.2007.06.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Revised: 06/08/2007] [Accepted: 06/08/2007] [Indexed: 11/25/2022]
Abstract
RATIONALE AND OBJECTIVES Studies of radiologic error reveal high levels of variation between radiologists. Although it is known that experts outperform novices, we have only limited knowledge about radiologic expertise and how it is acquired. MATERIALS AND METHODS This review identifies three areas of research: studies of the impact of experience and related factors on the accuracy of decision-making; studies of the organization of expert knowledge; and studies of radiologists' perceptual processes. RESULTS AND CONCLUSION Interpreting evidence from these three paradigms in the light of recent research into perceptual learning and studies of the visual pathway has a number of conclusions for the training of radiologists, particularly for the design of computer-based learning programs that are able to illustrate the similarities and differences between diagnoses, to give access to large numbers of cases and to help identify weaknesses in the way trainees build up a global representation from fixated regions.
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Affiliation(s)
- Paul M Taylor
- University College London, Archway Campus, Highgate Hill, London N19 5LW, United Kingdom.
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Burling D, Moore A, Taylor S, La Porte S, Marshall M. Virtual colonoscopy training and accreditation: a national survey of radiologist experience and attitudes in the UK. Clin Radiol 2007; 62:651-9. [PMID: 17556034 DOI: 10.1016/j.crad.2007.02.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2006] [Revised: 01/29/2007] [Accepted: 02/14/2007] [Indexed: 01/22/2023]
Abstract
AIM Expert consensus recommends directed training and possibly in the future, formal accreditation before independent virtual colonoscopy (VC) reporting. We surveyed radiologists' experience of VC training, compared with barium enema, and assessed attitudes towards accreditation. MATERIALS AND METHODS A questionnaire was sent to 78 consultant radiologists from 72 centres (65 National Health Service hospitals; seven independent primary screening centres) offering a VC service. RESULTS Fifty-four (69%) eligible radiologists responded. They had interpreted 18,152 examinations (range 3-1500) in total versus 232,350 (13 times more) barium enemas. Twenty-two (41%) deemed their VC training as inadequate [including five (45%) of screening centre radiologists], and only 14 (26%) had attended a training workshop due to lack of availability (54%) or financial/study leave constraints (24%). Eleven (20%) radiologists routinely double-reported VC examinations versus 37 (69%) barium enemas, yet 21 (39%) considered requirements for VC training were greater than barium enema. Thirty-eight (70%) favoured accreditation beyond internal audit for VC versus 15(28%) for barium enema. Of these 38, seven (18%) favoured "one-off," and 18 (47%) periodic testing, with 16 (42%) favouring external audit alone or in combination with testing. Overall, 42 (78%) considered specific accreditation for reporting screening examinations appropriate and 45 (83%) respondents preferred a national radiological organization to regulate such a scheme. CONCLUSION There is wide variability in reporting experience and recommendations for VC training have not been widely adopted, in part due to limited access to dedicated workshops. UK radiologists are generally in favour of VC accreditation, governed by a national radiology organization.
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Affiliation(s)
- D Burling
- St Mark's Hospital, Harrow, Middlesex, UK.
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European Society of Gastrointestinal and Abdominal Radiology CT Colonography Group Investigators. Effect of directed training on reader performance for CT colonography: multicenter study. Radiology 2007; 242:152-61. [PMID: 17185666 DOI: 10.1148/radiol.2421051000] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
PURPOSE To define the interpretative performance of radiologists experienced in computed tomographic (CT) colonography and to compare it with that of novice observers who had undergone directed training, with colonoscopy as the reference standard. MATERIALS AND METHODS Physicians at each participating center received ethical committee approval and followed the committees' requests regarding informed consent. Nine experienced radiologists, nine trained radiologists, and 10 trained technologists from nine centers read 40 CT colonographic studies selected from a data set of 51 studies and modeled to simulate a population with positive fecal occult blood test results: Studies were obtained in eight patients with cancer, 12 patients with large polyp, four patients with medium polyp, and 27 patients without colonic lesions. Findings were verified with colonoscopy. An experienced radiologist used 50 endoscopically validated studies to train novice observers before they were allowed to participate. Observers used one software platform to read studies over 2 days. Responses were collated and compared with the known diagnostic category for each subject. The number of correctly classified subjects was determined for each observer, and differences between groups were examined with bootstrap analysis. RESULTS Overall, 28 observers read 1084 studies and detected 121 cancers, 134 large polyps, and 33 medium polyps; 448 healthy subjects were categorized correctly. Experienced radiologists detected 116 lesions; trained radiologists and technologists detected 85 and 87 lesions, respectively. Overall accuracy of experienced observers (74.2%) was significantly better than that of trained radiologists (66.6%) and technologists (63.2%). There was no significant difference (P=.33) between overall accuracy of trained radiologists and that of technologists; however, some trainees reached the mean performance achieved by experienced observers. CONCLUSION Experienced observers interpreted CT colonographic images significantly better than did novices trained with 50 studies. On average, no difference between trained radiologists and trained technologists was found; however, individual performance was variable and some trainees outperformed some experienced observers.
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Abstract
BACKGROUND Colonoscopy is commonly used to screen for neoplasia. To assess the performance of screening colonoscopy in everyday practice, we conducted a study of the rates of detection of adenomas and the amount of time taken to withdraw the colonoscope among endoscopists in a large community-based practice. METHODS During a 15-month period, 12 experienced gastroenterologists performed 7882 colonoscopies, of which 2053 were screening examinations in subjects who had not previously undergone colonoscopy. We recorded the numbers, sizes, and histologic features of the neoplastic lesions detected during screening, as well as the duration of insertion and of withdrawal of the colonoscope during the procedure. We compared rates of detection of neoplastic lesions among gastroenterologists who had mean colonoscopic withdrawal times of less than 6 minutes with the rates of those who had mean withdrawal times of 6 minutes or more. According to experts, 6 minutes is the minimum length of time to allow adequate inspection during instrument withdrawal. RESULTS Neoplastic lesions (mostly adenomatous polyps) were detected in 23.5% of screened subjects. There were large differences among gastroenterologists in the rates of detection of adenomas (range of the mean number of lesions per subject screened, 0.10 to 1.05; range of the percentage of subjects with adenomas, 9.4 to 32.7%) and in their times of withdrawal of the colonoscope from the cecum to the anus (range, 3.1 to 16.8 minutes for procedures during which no polyps were removed). As compared with colonoscopists with mean withdrawal times of less than 6 minutes, those with mean withdrawal times of 6 minutes or more had higher rates of detection of any neoplasia (28.3% vs. 11.8%, P<0.001) and of advanced neoplasia (6.4% vs. 2.6%, P=0.005). CONCLUSIONS In this large community-based gastroenterology practice, we observed greater rates of detection of adenomas among endoscopists who had longer mean times for withdrawal of the colonoscope. The effect of variation in withdrawal times on lesion detection and the prevention of colorectal cancer in the context of widespread colonoscopic screening is not known. Ours was a preliminary study, so the generalizability and implications for clinical practice need to be determined by future studies.
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SLATER A. Alteration in bowel habit. Imaging 2006. [DOI: 10.1259/imaging/15701929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Koo BC, Ng CS, U-King-Im J, Prevost AT, Freeman AH. Minimal preparation CT for the diagnosis of suspected colorectal cancer in the frail and elderly patient. Clin Radiol 2006; 61:127-39. [PMID: 16439217 DOI: 10.1016/j.crad.2005.07.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2005] [Revised: 06/29/2005] [Accepted: 07/07/2005] [Indexed: 12/30/2022]
Abstract
Colorectal cancer is a common malignancy with an increased incidence in the elderly population. Traditional methods of evaluating this disease have included double contrast barium enema and colonoscopy. Unfortunately, in the frail and elderly patient, these investigations can be difficult to perform and are often not tolerated. Minimal preparation computed tomography (MPCT) of the colon has been suggested as an alternative in this patient population. In this technique, no bowel preparation is used apart from the administration of oral contrast medium. The patient is imaged only in the supine position, without per rectal insufflation of gas or barium. This article reviews the experience to date of MPCT in detecting colonic tumours, and compares its efficacy to the traditional methods. A meta-analysis of the studies allowed estimation of the pooled sensitivity of MPCT to be 83% (95% confidence interval: 76-89%), and pooled specificity to be 90% (95% CI: 85-94%). An added advantage of MPCT is the ability to identify extra-colonic pathology, and this aspect is also reviewed. In addition, the common radiological features and pitfalls in identifying colonic tumours by MPCT are discussed.
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Affiliation(s)
- B C Koo
- Department of Radiology, Addenbrooke's NHS Trust, Cambridge, UK.
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Vehmas T. Factors influencing the detection of abnormalities in barium enemas performed by junior radiologists. Clin Radiol 2006; 61:270-5. [PMID: 16488209 DOI: 10.1016/j.crad.2005.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Revised: 10/21/2005] [Accepted: 10/29/2005] [Indexed: 11/20/2022]
Abstract
AIM To study the effects of patient variability, technical examination and radiologist-related factors on the radiological diagnosis of barium enema studies. MATERIALS AND METHODS Twenty-one residents (12 women and nine men, age 26-39 years) performed 523 double contrast barium enemas in a university hospital. Diagnoses were classified as normal (n = 203), diverticulosis (n = 224), polyps (n = 25), tumours (n = 20) and other (n = 46); five were missing diagnoses. Binary and multinomial logistic regressions were used to study the relations between the independent variables and the radiological diagnoses. RESULTS Patients' advanced age (p < 0.001) and obesity (p = 0.041) were significant positive predictors for the detection of any abnormalities, as was good or moderate study quality (p = 0.023). However, patients' obesity was negatively associated with the detection of polyps (p = 0.037). Pathological findings were associated with higher dose-area products (p = 0.047) than normal cases. Residents' advanced age (p = 0.029) and experience (a high number of previously performed barium enemas; p = 0.009) were negative predictors for the detection of pathological findings. CONCLUSION Patients' obesity hampers polyp detection, possibly due to decreased image quality or coexisting diverticula. The most experienced and oldest residents missed positive findings, possibly due to insufficient consultation of supervising radiologists, emphasizing the need for their optimal cooperation.
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Affiliation(s)
- T Vehmas
- Department of Occupational Medicine, Finnish Institute of Occupational Health, Helsinki, Finland.
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Donovan T, Manning D. Successful reporting by non-medical practitioners such as radiographers, will always be task-specific and limited in scope. Radiography (Lond) 2006. [DOI: 10.1016/j.radi.2005.01.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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20
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Booth AM, Mannion RA. Radiographer and radiologist perception error in reporting double contrast barium enemas: A pilot study. Radiography (Lond) 2005; 11:249-54. [DOI: 10.1016/j.radi.2005.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
Virtual colonoscopy (CT colonography) is a technique whereby CT images of the cleansed and distended colon are acquired, ostensibly for detecting colonic neoplasia, although also providing additional diagnostic information from extracolonic organs. This article examines the current status of virtual colonoscopy, reviewing the technical parameters, performance characteristics, and issues surrounding implementation in routine clinical practice. Future directions for virtual colonoscopy are explored, including advances toward prepless examinations and automated interpretation.
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Affiliation(s)
- David Burling
- Intestinal Imaging Centre, St. Mark's Hospital, London, UK
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Abstract
Colorectal cancer is the third leading type of cancer, and the second leading cause of cancer-related death in the United States. Prevention of colorectal cancer should be achievable by screening programs that detect adenomas in asymptomatic patients and lead to their removal. In this manuscript, we review the major screening modalities, the advantages and disadvantages of each approach, the data supporting their use, and various issues affecting the implementation of each test. Screening guidelines will be reviewed, and future techniques for colorectal cancer screening examined.
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Glancy DG, Card M, Sylvester PA, Thomas MG, Durdey P, Callaway M, Virjee J. Fast-track barium enema: meeting the two-week wait rule for patients with suspected colorectal cancer. Colorectal Dis 2005; 7:241-4. [PMID: 15859961 DOI: 10.1111/j.1463-1318.2005.00761.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
OBJECTIVES To meet the introduction of the two-week wait (TWW) rule for patients with suspected colorectal cancer, a fast-track barium enema (FTBE) service was set up. This study was conducted to evaluate the success of this approach in preparation for meeting the forthcoming targets on waiting times to treatment from referral and diagnosis. METHODS All patients were offered a double-contrast barium enema within two-weeks, except those with a palpable rectal mass. FTBE were double-reported by specialist gastrointestinal radiologists. Patients with a suspected malignancy were booked for an urgent staging CT and outpatient appointment, whilst the remaining patients were referred back to their general practitioner with a report. Prospective data were collected and two 16-month periods analysed. RESULTS Three hundred and nine patients had a FTBE over the first 16-month period and 277 (89.6%) were seen within two-weeks. Mean times from initial referral to staging CT and first outpatient appointment were 30.7 and 36.0 days, respectively. Cancer was confirmed histologically in 32 (10.4%) patients. Of 267 patients without a malignancy, 46 (17.2%) were referred back to the colorectal outpatient or endoscopy service within 6-months. The number of referrals increased with time from a mean of 19.3 per month in the first period to 27.8 in the second, but the percentage with a suspected malignancy remained similar at 13.6% and 10.1%, respectively. CONCLUSION FTBE diagnosed malignancy accurately and facilitated rapid staging. The TWW target was met in almost 90% of patients, whilst the impact on the colorectal outpatient and endoscopy service was minimized.
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Affiliation(s)
- D G Glancy
- Department of Coloproctology, Bristol Royal Infirmary, Bristol, UK.
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Affiliation(s)
- Steve Halligan
- Department of Intestinal Imaging and Cancer Research UK Colorectal Cancer Unit, St Mark's Hospital, Northwick Park, Middlesex HA1 3UJ, UK.
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Halligan S. Reply to: Observer variation in the detection of colorectal neoplasia on double-contrast barium enema: implications for colorectal cancer screening and training. Clin Radiol 2005. [DOI: 10.1016/j.crad.2004.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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26
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Hassan I. Observer variation in the detection of colorectal neoplasia on double-contrast barium enema: implications for colorectal cancer screening and training. Clin Radiol 2005; 60:133; author reply 133-4. [PMID: 15642307 DOI: 10.1016/j.crad.2004.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Abstract
CT colonography allows reliable, non-invasive, rapid, high resolution imaging of the whole large bowel. Recent advances in technology such as computer-aided detection (CAD), scanning with or without bowel preparation, and low radiation are continually developing to improve the efficacy of this technique. This review will update the reader as to ongoing developments while presenting current thinking from the gastroenterological perspective.
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Abstract
First introduced a decade ago, computerized tomography (CT) colonography (virtual colonoscopy) is emerging as an important radiologic investigation for colorectal neoplasia, with diagnostic performance likely exceeding barium enema and comparable with optical colonoscopy. Employing state-of-the-art multislice technology, CT colonography allows a complete examination of the colon and surrounding organs in less than 30 seconds. This article reviews current techniques, indications, comparison with existing technologies, and diagnostic performance. Although already widely disseminated, important future developments, such as prepless bowel cleansing (laxative free) and computer-aided diagnosis, may establish CT colonography as the preferred first-line, whole-colon investigation.
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Affiliation(s)
- David Burling
- St. Mark's Hospital, Intestinal Imaging Center, Level 4V, Watford Road, Northwick Park, Harrow, Middlesex, HA1 3UJ, UK.
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Halligan S. Re: Observer variation in the detection of colorectal neoplasia on double-contrast barium enema: implications for colorectal cancer screening and training. Clin Radiol 2004. [DOI: 10.1016/j.crad.2004.03.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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D'Costa H. Observer variation in the detection of colorectal neoplasia on double-contrast barium enema: implications for colorectal cancer screening and training. Clin Radiol 2004; 59:761; author reply 762-3. [PMID: 15262553 DOI: 10.1016/j.crad.2004.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Bartram C. Observer variation in the detection of colorectal neoplasia on double-contrast barium enema: implications for colorectal cancer screening and training. Clin Radiol 2004; 59:641-2. [PMID: 15208074 DOI: 10.1016/j.crad.2004.01.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Taylor SA, Halligan S, Burling D, Morley S, Bassett P, Atkin W, Bartram CI. CT colonography: effect of experience and training on reader performance. Eur Radiol 2004; 14:1025-33. [PMID: 14872280 DOI: 10.1007/s00330-004-2262-z] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2003] [Revised: 12/05/2003] [Accepted: 01/06/2004] [Indexed: 10/26/2022]
Abstract
The purpose of this paper was to investigate the effect of radiologist experience and increasing exposure to CT colonography on reader performance. Three radiologists of differing general experience (consultant, research fellow, trainee) independently analysed 100 CT colonographic datasets. Readers had no prior experience of CT colonography and received feedback and training after the first 50 cases from an independent experienced radiologist. Diagnostic performance and reporting times were compared for the first and second 50 datasets and compared with the results of a radiologist experienced in CT colonography. Before training only the consultant reader achieved statistical equivalence with the reference standard for detection of larger polyps. After training, detection rates ranged between 25 and 58% for larger polyps. Only the trainee significantly improved after training ( P=0.007), with performance of other readers unchanged or even worse. Reporting times following training were reduced significantly for the consultant and fellow ( P<0.001 and P=0.03, respectively), but increased for the trainee ( P<0.001). In comparison to the consultant reader, the odds of detection of larger polyps was 0.36 (CI 0.16, 0.82) for the fellow and 0.36 (CI 0.14, 0.91) for the trainee. There is considerable variation in the ability to report CT colonography. Prior experience in gastrointestinal radiology is a distinct advantage. Competence cannot be assumed even after directed training via a database of 50 cases.
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Affiliation(s)
- Stuart A Taylor
- Department of Intestinal Imaging, St. Mark's Hospital, Watford Road, Northwick Park, London HA1 3UJ, UK
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Shorvon P. Commentary on: Observer Variation in the Detection of Colorectal Neoplasia on Double-contrast Barium Enema: Implications for Colorectal Cancer Screening and Training. Clin Radiol 2003; 58:945-7. [DOI: 10.1016/s0009-9260(03)00318-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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