Published in:
01-02-2011 | Gastrointestinal
Ascending colon rotation following patient positional change during CT colonography: a potential pitfall in interpretation
Published in: European Radiology | Issue 2/2011
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Objective
To investigate the degree and pattern of ascending colonic rotation as patients moved from supine to prone positions during CTC.
Methods
A search of our CTC and colonoscopy database found 37 patients (43 eligible lesions) who fulfilled the following criteria: colonoscopy-proven sessile polyps ≥6 mm in the straight mid-ascending colon, lesion visualisation in both supine and prone CTC, and optimal colonic distension. A coordinate system was developed to designate the polyp radial location (°) along the luminal circumference, unaffected by rotation of the torso. The degree/direction of polyp radial location change (i.e. ascending colonic rotation) between supine and prone positions correlated with anthropometric measurements.
Results
Movement from supine to prone positions resulted in a change in the radial polyp location of between −23° and 79° (median, 21°), demonstrating external rotation of the ascending colon in almost all cases (2° to 79° in 36/37 patients and 42/43 lesions). The degree/direction of rotation mildly correlated with the degree of abdominal compression in the anterior-posterior direction in prone position (r = 0.427 [P = 0.004] and r = 0.404 [P = 0.007]).
Conclusion
The ascending colon was usually found to rotate externally as patients moved from supine to prone positions, partly dependent on the degree of abdominal compression.