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CT Colonography: Defining Performance and Interventions to Improve Interpretation

By David Burling


CT colonography is now widely regarded as the optimal radiological technique for colonic examination. However, performance characteristics, particularly relating to interpretation accuracy, interpretation times and polyp measurement have been derived primarily from academic centres in the USA. For successful implementation of CT colonography, such performance characteristics must be generalisable to non-academic centres, different patient populations in different geographical locations, and different clinical environments. This thesis aims to investigate current UK implementation and to determine the interpretative performance of observers across the UK and Europe, focussing on those interventions influencing reader accuracy and polyp measurement.\ud The first chapter reviews the technique, diagnostic performance and clinical role of CT colonography. It is followed by two surveys revealing CT colonography is widely available across the UK NHS, and that hitherto unsuspected complications do occur, although CT colonography appears relatively safe in routine clinical practice when compared to alternatives.\ud The effect of directed training on reader performance is investigated in a multi-centre European study and shows that experienced radiologists are significantly more accurate and time-efficient when reporting CT colonography compared to specifically trained but less experienced radiologists and radiographers. A subsequent study also shows they are more accurate than radiologists offering CT colonography in UK clinical practice routinely. Trained radiographers can perform as well as their radiologist counterparts.\ud The accuracy of polyp measurement is investigated and the effect of different visualisation displays determined. Results suggest that an optimised 2D display utilising a 'colon CT window' should be recommended. Finally, we show that an automatic measurement software tool improves inter and intra-observer agreement for polyp measurement 'in vitro' although the benefit for in-vivo measurement is less clear

Publisher: University of Leicester
Year: 2006
OAI identifier: oai:lra.le.ac.uk:2381/9380

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  3. (2000). A comparison of colonoscopy and double-contrast barium enema for surveillance after polypectomy.
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  5. (1999). A comparison of virtual and conventional colonoscopy for the detection of colorectal polyps.
  6. (2004). A prospective study of colonoscopy practice in the UK today: are we adequately prepared for national colorectal cancer screening tomorrow? Gut
  7. (2003). Acceptance by patients of multidetector CT colonography compared with barium enema examinations, flexible sigmoidoscopy, and colonoscopy.
  8. (2004). Actual colonic perforation in virtual colonoscopy: report of a case. Dis Colon Rectum
  9. (2000). Adenoma size and number are predictive of adenoma recurrence: implications for surveillance colonoscopy. Gastrointest Endosc
  10. (2006). Altman DG et at. CT Colonography reporting times: effect of reader experience, fatigue, and scan findings in a multi-centre setting. European Radiology
  11. (2004). American Cancer Society Position Statement on CT Colonography. In:
  12. (1999). An initial experience with screening for colon polyps using spiral CT with and without CT colography (virtual colonoscopy). Gastrointest Endosc
  13. (2005). Analysis of air contrast barium enema, computed tomographic colonography, and colonoscopy: prospective comparison. Lancet
  14. (2006). and Intra-observer reliability in measurements of polyp size in CT colonography: Implications for technique, training and decision analysis. Radiological Society of North America scientific assembly and annual meeting program.
  15. Approximately how many CTC studies are performed in your department as a rough and ready estimate?
  16. Approximately how many CTC studies has your department performed over the last 5 years?
  17. (1993). Are endoscopic measurements of colonic polyps reliable?
  18. (2005). Assessment of the risk of perforation at CT colongraphy.
  19. Assessment of the risk of perforation at CT colongraphy. In Radiological Society of North America scientific assembly and annual meeting program (abstr). Oak Brook, III : Radiological Society of North America 2004,280.2004. Ref Type: Abstract
  20. (2006). Automated insufflation of carbon dioxide for MDCT colonography: distension and patient experience compared with manual insufflation.
  21. (1979). BS 5497, L. Precision of test methods, part 1: guide for the determination of repeatability and reproducibility for a standard test method.
  22. (2005). Building a CT colonography program: necessary ingredients for reimbursement and clinical success. Radiology
  23. (2003). Cardiovascular effects at multidetector row CT colonography compared with those at conventional endoscopy of the colon. Radiology
  24. (2004). Colonic polyp segmentation in CT colonography-based on fuzzy clustering and deformable models.
  25. (2002). Colonic polyps: complementary role of computer-aided detection
  26. (2004). Colonography Study Group Investigators. CT Colonography: Effect of Directed Training on Reader Performance. European Radiology
  27. (2003). Colorectal cancer screening and surveillance: clinical guidelines and rationale-Update based on new evidence. Gastroenterology
  28. (2003). Colorectal cancer screening with CT colonography, colonoscopy, and double-contrast barium enema examination: prospective assessment of patient perceptions and preferences. Radiology
  29. (2002). Colorectal cancer: role of CT colonography in preoperative evaluation after incomplete colonoscopy. Radiology
  30. (2004). Colorectal neoplasia screening with CT colonography in average-risk asymptomatic subjects: communitybased study. Radiology
  31. (2001). Colorectal neoplasia: performance characteristics of CT colonography for detection in 300 patients. Radiology
  32. Comparison of colonic distention using electronic C02 insufflation and manual atmospheric insufflation on CT colonography.
  33. (2003). Comparison of supine and prone scanning separately and in combination at CT colonography. Radiology
  34. (2000). Comparison of timeefficient CT colonography with two- and three-dimensional colonic evaluation for detecting colorectal polyps.
  35. (2004). Complications from radiographer-performed double contrast barium enemas. Clin Radiol
  36. (1992). Complications of barium enema examinations: a survey of UK Consultant Radiologists
  37. (2004). Computed tomographic colonography (virtual colonoscopy): a multicenter comparison with standard colonoscopy for detection of colorectal neoplasia.
  38. (2001). Computed tomographic colonography and conventional colonoscopy for colon diseases: a prospective, blinded study.
  39. (2004). Computer-aided diagnosis for CT colonography.
  40. (2002). Computer-aided diagnosis scheme for detection of polyps at CT colonography. Radiographics
  41. (2006). Computer-assisted reader software versus expert reviewers for polyp detection on CT colonography.
  42. (2002). Computeraided detection of polyps in a colon phantom: effect of scan orientation, polyp size, collimation, and dose.
  43. (2003). Computerized tomographic colonography: performance evaluation in a retrospective multicenter setting. Gastroenterology
  44. (2004). Computerized tomography colonography Expert rev Anticancer Ther.
  45. (2005). Consensus on current clinical practice of virtual colonoscopy.
  46. (2003). controlled trial of carbon dioxide insufflation during colonoscopy. Dis Colon Rectum
  47. (2002). Cost-effectiveness of barium enemas performed by radiographers. Clin Radiol
  48. (2003). CT attenuation of colorectal polypoid lesions: evaluation of contrast enhancement
  49. (2002). CT colonography at different radiation dose levels: feasibility of dose reduction. Radiology
  50. (2005). CT colonography in the detection of colorectal polyps and cancer: systematic review, meta-analysis, and proposed minimum data set for study level reporting. Radiology
  51. (2003). CT colonography of colorectal polyps: a metaanalysis.
  52. (2003). CT colonography practice in the United Kingdom: a national survey. 4th Virtual colonoscopy symposium handbook,
  53. (2004). CT colonography practice in the United Kingdom: a national survey. Clinical Radiology
  54. (2005). CT colonography reporting and data system: a consensus proposal. Radiology
  55. (1998). CT colonography with threedimensional problem solving for detection of colonic polyps.
  56. (2005). CT colonography: Automated diameter and volume measurement of colonic polyps compared with a manual technique - in vitro study.
  57. (2006). CT colonography: Automatic measurement of polyp diameter compared with manual assessment in-vivo. European Radiology
  58. (2007). CT colonography: Automatic measurement of polyp diameter compared with manual assessment: An in-vivo study. Clinical Radiology
  59. (2002). CT colonography: colonic distention improved by dual positioning but not intravenous glucagon. Eur Radiol
  60. (2005). CT colonography: contrast enhancement of benign and malignant colorectal lesions versus fecal residuals. Abdom Imaging
  61. (2004). CT colonography: effect of experience and training on reader performance. Eur Radiol
  62. (2007). CT colonography: Interpretative performance in a non-academic environment. Clinical Radiology
  63. (2005). CT colonography: Interpretative performance outside of a research environment In: Radiological Society of North America scientific assembly and annual meeting program. Oak Brook, III : Radiological Society of North America,
  64. (2005). CT colonography: Interpretative performance outside of a research environment. European Radiology
  65. (2002). CT colonography: multiobserver diagnostic performance. Radiology
  66. (2005). CT colonography: Only for experts? Gastrointestinal Nursing
  67. (2002). CT colonography: pitfalls and interpretation. Abdom Imaging
  68. (1999). CT colonography: potential pitfalls and problem-solving techniques.
  69. (2003). CT colonography: Probably the best colon investigation in the world?
  70. (2001). CT colonography: single- versus multi-detector row imaging. Radiology
  71. (1999). CT colonography: value of scanning in both the supine and prone positions.
  72. (1997). CT colonoscopy of colorectal neoplasms: two-dimensional and three-dimensional virtual-reality techniques with colonoscopic correlation.
  73. (2002). Detection of colorectal lesions with virtual computed tomographic colonography.
  74. (1996). Detection of colorectal polyps by computed tomographic colography: feasibility of a novel technique. Gastroenterology
  75. (1997). Detection of colorectal polyps with CT colography: initial assessment of sensitivity and specificity. Radiology
  76. (2002). Detection of flat lesions in the colon with CT colonography. Abdom Imaging
  77. Does your department have a CT scanner? IiI b. Is it a multislice scanner? l ý_I c.
  78. Does your department offer a CTC Yes No service in day-to-day clinical practice? II If you answered 'yes' to 2 please go to question 4. If `no' then answer question 3.
  79. (2005). Dose reduction and image quality assessment in MDCT virtual colonography by online Z-axis tube current modulation. Eur Radiol.
  80. (2002). Double contrast barium enema sensitivity: a comparison of studies by radiographers and radiologists. Clin Radiol
  81. (2002). Effect of investigator experience
  82. (2006). Effective radiation doses in CT colonography: results of an inventory among research institutions. Eur Radiol
  83. (2003). Efficacy of IV Buscopan as a muscle relaxant in CT colonography. Eur Radiol
  84. EJ. The Cochrane Electronic Library: self training guide and notes R&D directorate, NHS Executive Anglia and Oxford 1997.1997. Ref Type: Report
  85. (1999). Endoluminal CT colonography after an incomplete endoscopic colonoscopy.
  86. (1995). Endoscopic estimation of size: improved accuracy by directed teaching. Gastrointest Endosc
  87. (1997). Endoscopists, polyp size, and post-polypectomy surveillance: making a mountain out of a molehill? Gastrointest Endosc
  88. (2003). et at. Computed tomographic virtual colonoscopy to screen for colorectal neoplasia in asymptomatic adults.
  89. (1997). et at. Is in vivo measurement of size of polyps during colonoscopy accurate? Gastrointest Endosc
  90. (2006). European society of gastrointestinal and abdominal radiology (ESGAR): Consensus statement on CT colonography. Eur Radiol
  91. (2002). Evaluation of CT in identifying colorectal carcinoma in the frail and disabled patient. Eur Radiol
  92. (2005). External Validation of Computer-assisted Reading for CT Colonography. In Radiological Society of North America scientific assembly and annual meeting program (abstr). Oak Brook, III : Radiological Society of North America
  93. (2005). Extracolonic abnormalities discovered incidentally at CT colonography in a male population. Radiology
  94. (2003). Extracolonic findings at CT colonography: evaluation of prevalence and cost in a screening population. Gastroenterology
  95. (2004). Fast reading of CT Colonography.
  96. (2003). Feasibility of ultra-low-dose multislice CT colonography for the detection of colorectal lesions: preliminary experience. Eur Radiol
  97. Filling defects at CT colonography: pseudo- and diminutive lesions (the good), polyps (the bad), flat
  98. (2000). Flat and depressed colonic neoplasms: a prospective study of 1000 colonoscopies in the UK. Lancet
  99. (2002). Flat and depressed colorectal tumours in a southern Swedish population: a prospective chromoendoscopic and histopathological study. Gut
  100. (1986). Heron CW. A preliminary study of the possible benefits of using carbon dioxide insufflation during double-contrast barium enema.
  101. (2005). How to Get the Colon Distended? In: Lefere
  102. (1997). Importance of adenomas 5 mm or less in diameter that are detected by sigmoidoscopy.
  103. (2005). Incidental lesions found on CT colonography: their nature and frequency.
  104. (2000). Influence of image acquisition parameters on CT artifacts and polyp depiction in spiral CT colonography: in vitro evaluation. Radiology
  105. Invited commentary to Observer variation in the detection of colorectal neoplasia on double-contrast barium enema: implications for colorectal cancer screening and training.
  106. (1998). Is colonoscopy indicated for small adenomas found by screening flexible sigmoidoscopy? Ann Intern Med
  107. (1997). Is in vivo measurement of size of polyps during colonoscopy accurate? Gastrointest Endosc
  108. (1998). Is minimal preparation computed tomography comparable with barium enema in elderly patients with colonic symptoms? Clin Radiol
  109. (2005). Linear polyp measurement at CT colonography: in vitro and in vivo comparison of two-dimensional and three-dimensional displays. Radiology
  110. (2005). Mass screening with CT colonography: should the radiation exposure be of concern? Gastroenterology
  111. (2001). Megibow AJ. Pitfalls of using three-dimensional CT colonography with two-dimensional imaging correlation.
  112. (1999). Megibow AJ. Usefulness of CT colonography in patients with incomplete colonoscopy.
  113. (2005). Meta-analysis: computed tomographic colonography. Ann Intern Med
  114. (2000). Mucosal detail at CT virtual reality: surface versus volume rendering. Radiology
  115. (2005). National audit of the sensitivity of double-contrast barium enema for colorectal carcinoma, using control charts For the Royal College of Radiologists Clinical Radiology Audit Sub-Committee. Clin Radiol
  116. (1994). Noninvasive colonoscopy using helical CT scanning, 3D reconstruction, and virtual reality. Presented at Society of Gastrointestinal Radiologists,
  117. (2005). Nonradiologists as second readers for intraluminal findings at CT colonography. Acad Radiol
  118. (2003). Observer variation in the detection of colorectal neoplasia on double-contrast barium enema: implications for colorectal cancer screening and training. Clin Radio[
  119. (2007). of Gastrointestinal and Abdominal Radiology (ESGAR) CT colonography study group investigators. Effect of Directed Training on Reader Performance for CT Colonography: Multi-Centre Study. Radiology
  120. (2004). on behalf ESGAR CT colonography study GROUP investigators Effect of directed training on reader performance for CT colonography: European multi-centre study.
  121. (2005). on behalf ESGAR CT colonography study GROUP investigators. CT colonography reporting times: effect of reader experience, fatigue, and scan findings in a pan-European multi-centre setting. European Radiology
  122. (2004). on behalf ESGAR CT colonography study GROUP investigators. Polyp Measurement and size categorization by CT colonography: Agreement with colonoscopy and effect of observer experience.
  123. (2005). on behalf ESGAR CT colonography study GROUP investigators. Polyp Measurement and size categorization by CT colonography: Agreement with colonoscopy and effect of observer experience. European Radiology
  124. (2000). Optimization of CT colonography technique: prospective trial in 180 patients. Radiology
  125. (2003). Optimizing colonic distention for multidetector row CT colonography: effect of hyoscine butyibromide and rectal balloon catheter. Radiology
  126. (2002). Patient acceptance of CT colonography and conventional colonoscopy: prospective comparative study in patients with or suspected of having colorectal disease. Radiology
  127. (2004). Perforated colon secondary to virtual colonoscopy: report of a case. Dis Colon Rectum
  128. (2002). Performance parameters for screening and diagnostic mammography: specialist and general radiologists. Radiology
  129. (1995). Physical activity, obesity, and risk for colon cancer and adenoma in men. Ann Intern Med
  130. (1998). Planning for a possible national colorectal cancer screening programme.
  131. (2006). Polyp Measurement and size categorisation by CT colonography: Effect of observer experience in a multi-centre setting. European Radiology
  132. (2006). Polyp measurement by CT colonography: Agreement with colonoscopy, and effect of viewing conditions on inter- and intra-observer agreement.
  133. (2004). Polyp size measurement by CT colonography: Effect of viewing conditions on inter- and intra-observer agreement, and agreement with colonoscopy.
  134. (2006). Potentially serious adverse events associated with CT colonography performed in symptomatic patients: A national survey of the UK. Radiology
  135. (1991). Practical statistics for medical research Chapman and Hall,
  136. (2004). Preoperative T and N staging of colorectal cancer: accuracy of contrastenhanced multi-detector row CT colonography--initial experience. Radiology
  137. Prevalence and characteristics of flat and depressed colorectal neoplasms in a Western population: A prospective study by a Japanese-trained endoscopist. id no. 102879 DDW 2004.2004. Ref Type: Abstract
  138. (2002). Procedural success and complications of large-scale screening colonoscopy. Gastrointest Endosc
  139. (2003). Prospective blinded evaluation of computed tomographic colonography for screen detection of colorectal polyps. Gastroenterology
  140. (1996). Randomised controlled trial of faecal-occult-blood screening for colorectal cancer. Lancet
  141. (1996). Randomised study of screening for colorectal cancer with faecal-occult-blood test. Lancet
  142. (2005). Reader training in CT colonography: how much is enough? Radiology
  143. (1993). Reducing mortality from colorectal cancer by screening for fecal occult blood.
  144. (1997). Retention balloon catheters and barium enemas: attitudes, current practice and relative safety in the UK. Clin Radiol
  145. (2002). Risk factors for advanced colorectal adenomas: a pooled analysis. Cancer Epidemiol Biomarkers Prev
  146. (2001). Royal College of Radiologists newsletter issue 67 (Autumn
  147. Spasmolysis with Butyl Scopolamine versus Glucagon in CT Colonography. In Radiological Society of North America scientific assembly and annual meeting program Oak Brook, III : Radiological Society of North America 2004: 433.2004. Ref Type: Abstract
  148. (1986). Statistical methods for assessing agreement between two methods of clinical measurement. Lancet
  149. (2002). Subspecialist radiology. Clin Radiol
  150. (1990). Subspecialization in radiology [.
  151. (2004). Supine/left decubitus scanning: a valuable alternative to supine/prone scanning
  152. (2002). Surveillance guidelines after removal of colorectal adenomatous polyps. Gut
  153. (1996). Technical report: spiral CT pneumocolon for suspected colonic neoplasms. Clin Radiol
  154. (1996). The difference in colon polyp size before and after removal. Gastrointest Endosc
  155. (1993). The effect on apparent size of simulated pulmonary nodules of using three standard CT window settings. Clin Radiol
  156. (2005). The Efficacy of Computer Aided Detection of colorectal polyps When Applied to Initial Inexperienced Radiologist Interpretations of CT Colonography: A Pilot Study.
  157. (1975). The evolution of cancer of the colon and rectum. Cancer
  158. (1990). The National Polyp Study. Patient and polyp characteristics associated with high-grade dysplasia in colorectal adenomas. Gastroenterology
  159. (1997). The pathologic measurement of polyp size is preferable to the endoscopic estimate. Gastrointest Endosc
  160. (1979). The Practice of social research . 4th ed
  161. (2002). The use of minimal preparation computed tomography for the primary investigation of colon cancer in frail or elderly patients. Clin Radiol
  162. (1999). The usefulness of glucagon hydrochloride for colonic distention in CT colonography.
  163. (2003). Three-dimensional endoluminal CT colonography (virtual colonoscopy): comparison of three commercially available systems.
  164. Two dimensional (2D) versus Threedimensional (3D) Reading. In Radiological Society of North America scientific assembly and annual meeting program (abstr). Oak Brook, III : Radiological Society of North America 2004: 479.2004. Ref Type: Abstract
  165. (2005). Unbiased studies are needed before virtual colonoscopy can be dismissed. Lancet
  166. (2004). Understanding interpretive errors in radiologists learning computed tomography colonography. Acad Radiol
  167. (2003). Use of multidetector-row computed tomographic colonography before flexible sigmoidoscopy in the investigation of rectal bleeding.
  168. (2003). Use of multidetector-row CT colonography for detection of colorectal neoplasia in patients referred via the Department of Health "2-Week-wait" initiative. Clin Radiol
  169. (2000). Utility of intravenously administered contrast material at CT colonography. Radiology
  170. (2005). Virtual colonoscopy: issues in implementation. Australas Radiol
  171. (2005). Virtual colonoscopy: State of the Art and Future Directions
  172. Virtual Colonoscopy.
  173. (2004). Virtual colonoscopy. JAMA
  174. (1996). Wessex regional radiology audit: barium enema in colo-rectal carcinoma. Clin Radiol
  175. Why does your department currently not offer CTC? Please tick any applicable response. Financial restrictions (hardware or software) I-I Scanner capacity limited by other clinical demands.

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