Figure 1
CT colonography and conventional colonoscopy
Clinical History
First degree relative of a patient who died of colorectal cancer. No complaint. CT colonography for screening purposes.
Imaging Findings
The patient, with no complaint, was a first degree relative of a patient who died of colorectal cancer. 10 years ago, she underwent a conventional colonoscopy which lacked examining the right colon because of intolerance of the patient.
She now presented to our department for a low dose CT colonography. CT colonography was performed after colon cleansing with polyethylenglycol (PEG); and before insufflation of room air, for obtaining pneumocolon, Buscopan was administered intravenously. A low dose study, in supine and prone acquisition, was obtained by using 120 Kvp and 50 mAs.
At CT colonography a sessile polyp, with a 9 mm large implant base, was found in the descending colon, seen on axial view (fig.1a) as well as on the 3D endoluminal view on virtual colonoscopy (fig.1b). On the same day, she underwent a conventional colonoscopy, which confirmed the presence of the polyp (fig.1c) and allowed its removal.
She now presented to our department for a low dose CT colonography. CT colonography was performed after colon cleansing with polyethylenglycol (PEG); and before insufflation of room air, for obtaining pneumocolon, Buscopan was administered intravenously. A low dose study, in supine and prone acquisition, was obtained by using 120 Kvp and 50 mAs.
At CT colonography a sessile polyp, with a 9 mm large implant base, was found in the descending colon, seen on axial view (fig.1a) as well as on the 3D endoluminal view on virtual colonoscopy (fig.1b). On the same day, she underwent a conventional colonoscopy, which confirmed the presence of the polyp (fig.1c) and allowed its removal.
Discussion
CT colonography is progressively gaining an important role especially in the study of patients who refuse or have contraindications to conventional colonoscopy, or when the latter is incomplete.
The technique is promising in detecting polyps and colorectal cancers with a very high sensitivity, comparable to that of conventional colonoscopy. With respect to this latter, CT colonography is better tolerated by patients with a minimal discomfort during the exam; the preparation is the same as for conventional colonoscopy, and remains the 'unpleasant' part of the exam.
The technique is promising in detecting polyps and colorectal cancers with a very high sensitivity, comparable to that of conventional colonoscopy. With respect to this latter, CT colonography is better tolerated by patients with a minimal discomfort during the exam; the preparation is the same as for conventional colonoscopy, and remains the 'unpleasant' part of the exam.
Differential Diagnosis List
Sessile polyp of the descending colon
Final Diagnosis
Sessile polyp of the descending colon
References
[1]
Macari M, Bini EJ, Jacobs SL, Naik S, Lui YW, Milano A, Rajapaksa R, Megibow AJ, Babb J.
Colorectal Polyps and Cancers in Asymptomatic Average-Risk Patients: Evaluation with CT Colonography.
Radiology 2004 Jan 22. (PMID: 14739311)
[2]
Morrin MM, LaMont JT.
Screening virtual colonoscopy--ready for prime time ?
N Engl J Med. 2003 Dec 4;349(23):2261-4. (PMID: 14657435)
[3]
Pickhardt PJ, Choi JR, Hwang I, Butler JA, Puckett ML, Hildebrandt HA, Wong RK, Nugent PA, Mysliwiec PA, Schindler WR.
Computed tomographic virtual colonoscopy to screen for colorectal neoplasia in asymptomatic adults.
N Engl J Med. 2003 Dec 4;349(23):2191-200. (PMID: 14657426)
[4]
Ginnerup Pedersen B, Christiansen TE, Bjerregaard NC, Ljungmann K, Laurberg S.
Colonoscopy and multidetector-array computed-tomographic colonography: detection rates and feasibility.
Endoscopy 2003 Sep;35(9):736-42. (PMID: 12929020)
[5]
Iannaccone R, Laghi A, Catalano C, Brink JA, Mangiapane F, Trenna S, Piacentini F, Passariello R.
Detection of colorectal lesions: lower-dose multi-detector row helical CT colonography compared with conventional colonoscopy.
Radiology 2003 Dec;229(3):775-81. (PMID: 14657315)
Case information
| URL: | https://www.eurorad.org/case/2972 |
| DOI: | 10.1594/EURORAD/CASE.2972 |
| ISSN: | 1563-4086 |
