Journal Club: October 2010

Br J Radiol. 2010 Oct 19. [Epub ahead of print]

Non-laxative CT colonography with barium-based faecal tagging: is additional phosphate enema beneficial and well tolerated?

Davis W, Nisbet P, Hare C, Cooke D P, Taylor S.


The purpose of this study was to investigate the efficacy and tolerance of an additional phosphate enema prior to non-laxative CT colonography (CTC). A total of 71 patients (mean age 80 years, 28 male) underwent non-laxative CTC following 4 oral doses of diluted 2% w/w barium sulphate. Patients were invited to self-administer a phosphate enema 2 h before CTC. An experienced observer graded the volume of retained stool (1 (nil) to 4 (>75% bowel circumference coated)), retained fluid )1 (nil) to 4 (>50% circumference obscured)), retained stool tagging quality (1 (untagged) to 5 (≥75% to 100%) tagged) and confidence a polyp ≥6 mm could be excluded (yes/no) for each of six colonic segments. Tolerance of the enema was assessed via questionnaire. Data were analysed between those using and not using the enema by Mann-Whitney and Fisher's exact test. In total 18/71 patients declined the enema. There was no reduction in residual stool volume with enema use compared with non-use either overall (mean score 2.6 vs 2.7, p  =  0.76) or in the left colon (mean 2.3 vs 2.4, p  =  0.47). Overall tagging quality was also no different (means score 4.4 vs 4, 3, p  =  0.43). However, there was significantly more retained left colonic fluid post enema (mean score 1.9 vs 1.1, p < 0.0001), and diagnostic confidence in excluding polyps was significantly reduced (exclusion not possible in 35% segments vs 21% without enema, p  =  0.006). Out of 53 patients, 30 (56%) found the enema straightforward to use, but 4 (8%) found it unpleasant. In conclusion, phosphate enema use prior to non-laxative CTC leads to greater retained fluid reducing diagnostic confidence and is not recommended.