Medical Community: Abstracts




RSNA, Radiological Society of North America:
Mark R. Wax, MD, Ingmar Bitter, Stuart May, MD, Donald Wade, MD, Charlie Mazzarese

Purpose: To evaluate different types of bowel preparation to aid in residual fluid tagging necessary for virtual colonoscopy (VC) electronic cleansing.

Method and Materials: 58 patients scheduled for virtual colonoscopy underwent a daylong preprocedure bowel preparation program of a low residue diet, low-density barium sulfate suspension for stool tagging, laxatives of magnesium citrate, bisacodyl tablets and suppository. To evaluate residual fluid tagging, these patients were divided into 3 groups. 16 patients in group (1) used 3 doses of 40 cc of gastroview with meals the day prior to VC. In groups (2) and (3), contrast was given in two doses, at bedtime and in the morning, at least 1 ½ - 2 hours prior to VC using barium sulfate suspension (2 % w/v, 250cc) for 18 patients and diatrizoate meglumine and diatrizoate sodium solution (gastroview, 60cc) for 24 patients.

All patients underwent VC (120 kvp, 100mA/s, 5mm collimation, pitch 1.6-2.0, 1mm reconstruction intervals), which included automatic electronic cleansing which removes tagged residual fluid. Data recorded from the axial images included Houndsfield values (HU) of residual fluid in eight segments within the colon. The average density and standard deviation were calculated. The presence of remaining fluid at each segment following electronic cleansing was determined. Electronic cleansing was considered effective only if there was no remaining fluid in all eight segments.

Results: The average fluid density for group (1) was 97 HU (Std dev: 145); (2): 221 HU (Std dev: 182); (3): 599 HU (Std dev: 246). Group (3) differs statistically significant from (1) and (2) with p-values of 0.0000000013 and 0.0000011. Prior to electronic cleansing, the total number of segments with remaining fluid was (1): 91; (2): 79; (3): 159. The number of segments cleansed was 5, 13, and 148 respectively. Effective electronic cleansing occurred in 11%, 13% and 87% of each group.

Conclusion: Only the use of bowel preparations with gastroview given the evening before and morning of virtual colonoscopy results in sufficient enhancement of residual fluid, leading to effective automatic electronic colonic cleansing.

Virtual Endosocopy, Volume Rendering, Interactive
Navigation, Complete Surface Coverage

Back to Abstracts