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Fluid Tagging for CT Colonography: Effectiveness of a 2-Hour Iodinated Oral Preparation After Incomplete Optical Colonoscopy

Chang, Kevin J. MD*; Rekhi, Satinder S. Jr BS; Anderson, Stephan W. MD; Soto, Jorge A. MD

Journal of Computer Assisted Tomography: January-February 2011 - Volume 35 - Issue 1 - p 91-95
doi: 10.1097/RCT.0b013e3181f5a610
Original Articles

Objective: To evaluate the distal extent and attenuation of bowel opacification achieved after administration of a single low volume dose of oral contrast 2 hours before computed tomographic colonography (CTC) after incomplete optical colonoscopy.

Methods: This retrospective study included 144 patients undergoing CTC after incomplete colonoscopy from April 2006 to July 2008 at 2 separate medical centers. Each patient received 20 to 30 mL of diatrizoate meglumine and diatrizoate sodium solution 2 hours before being scanned.

Results: The distalmost extent of opacification was: stomach/small bowel, n = 13; cecum, n = 2; ascending colon, n = 7; transverse colon, n = 19; descending colon, n = 14; sigmoid colon, n = 24; rectum, n = 65. The mean attenuation of each opacified segment was: cecum, 449 Hounsfield units (HU); ascending colon, 474 HU; transverse colon, 468 HU; descending colon, 421 HU; sigmoid colon, 391 HU; and rectum, 382 HU. In 103 (71.5%) patients, oral contrast reached the distal colon (descending colon, sigmoid colon, or rectum). The oral contrast did not reach the colon in only 13 (9.0%) patients.

Conclusions: Oral administration of a small volume hyperosmolar oral contrast agent 2 hours before CTC results in satisfactory colonic opacification in the majority of patients. Adding same-day fluid tagging in incomplete colonoscopy patients presenting for completion CTC should result in adequate fluid opacification for most of the colon, especially proximal segments not visualized at the time of incomplete colonoscopy.

From the *Department of Diagnostic Imaging, Rhode Island Hospital and Brown University Alpert Medical School, Providence, RI; and †Department of Radiology, Boston Medical Center, Boston MA.

Received for publication April 22, 2010; accepted July 23, 2010.

Reprints: Kevin J. Chang, MD, Department of Diagnostic Imaging, Rhode Island Hospital and Brown University Alpert Medical School, 593 Eddy St, Providence, RI 02903 (e-mail:

The authors have no relevant financial disclosures.

© 2011 Lippincott Williams & Wilkins, Inc.