CT colonography after fecal tagging with a reduced cathartic cleansing and a reduced volume of barium.

OBJECTIVE: The objective of our study was to assess the efficacy of fecal tagging with a small volume of barium in combination with a reduced cathartic cleansing before CT colonography. MATERIALS AND METHODS: The study consists of a review of 200 patients examined in a clinical setting. Conventional colonoscopy and CT colonography or follow-up were used as the gold standard. All patients prepared for CT colonography the day before the examination with a dedicated low-residue diet. Fecal tagging was performed with 50 mL of barium. The residual feces and fluid were evaluated on a segmental basis. The residual feces was divided in two categories (< 6 mm and > or = 6 mm). The amount of fluid was assessed on the axial slices. The efficacy of tagging was evaluated visually. RESULTS: For the study, 1,200 segments were evaluated. Residual feces was present in 413 segments (34.41%), with feces less than 6 mm in 210 segments (17.5%) and feces 6 mm or greater in 203 segments (16.92%). There was residual fluid in 527 segments (43.91%). Nontagged feces 6 mm or greater was present in 49 segments (4.08%) and nontagged fluid in 178 segments (14.83%). All nontagged feces 6 mm or greater was easy to assess. All fluid redistributed with dual positioning. A total of 65 lesions 6 mm or greater were correctly diagnosed on primary CT colonography. In two patients, two lesions adjacent to each other were misinterpreted as being only one. Another 8-mm lesion was missed. CONCLUSION: In the present study, CT colonography after fecal tagging with 50 mL of barium combined with a reduced cathartic cleansing was feasible.

Supine/left decubitus scanning: a valuable alternative to supine/prone scanning in CT colonography.

The purpose was to evaluate supine/left decubitus as an alternative to supine/prone scanning in computed tomographic colonography (CT colonography). Fifty patients were randomised to supine/prone, another 50 to supine/left decubitus scanning. Patients were scanned using a single-slice CT scanner. The colon was divided into eight segments. Comparisons of distension, breathing artefacts, residus and polyp detection were made between the two groups as well as between the different positions. Adequate distension was found in approximately 85, 97 and 95% of segments in the supine, prone and left decubitus positions, respectively. Combined scanning increased the percentage of adequate distension to 98.5% for prone-supine and 97.7% for left decubitus-supine scanning ( P<0.0005 compared to supine, P=0.001 compared to left decubitus and P=0.046 compared to prone scanning). Absence of residual material was found in approximately 62.7, 69.7 and 64% of segments in the supine, prone and left decubitus positions, respectively. Combined scanning increased this percentage to approximately 99% for both groups. No significant differences towards distension or residual material were found between combined supine-prone or supine-left decubitus scanning. In the supine-prone group, combined scanning additionally revealed four lesions and improved conspicuity in two cases of stalked polyps. In the supine-left decubitus group, combined scanning additionally revealed two lesions and improved conspicuity in one stalked polyp. There were significantly fewer breathing artefacts with left decubitus scanning than prone scanning ( P=0.005). A strong positive correlation was found between breathing artefacts and the age of patients in both patient groups. Colonic distension and preparation is improved by using supine and prone or supine and left decubitus scanning in combination, with a subsequent improved polyp detection. There were no significant differences between the two scanning protocols. Prone scanning, however, is hampered by breathing artefacts, especially in the elderly. Therefore, supine-left decubitus scanning is considered a valuable alternative to supine-prone scanning for the elderly.

Diverticular disease in CT colonography.

The aim of this study was to evaluate findings on CT colonography (CTC) in patients with diverticular disease. In a retrospective analysis of 160 consecutive patients, who underwent CTC and conventional colonoscopy (CC), patients with diverticular disease were retrieved. The CTC images were compared with CC and, if possible, with pathology. Findings on both 2D and 3D images are illustrated with emphasis on diagnostic problems and the possible solutions to overcome these problems. Several aspects of diverticulosis were detected: prediverticulosis (3%); global (55.6%); and focal wall thickening (4%) caused by thickened haustral folds, fibrosis, inflammation and adenocarcinoma; diverticula (52%); pseudopolypoid lesions caused by diverticular fecaliths (39%); inverted diverticula (1.2%); and mucosal prolapse (0.6%). Solutions to overcome pitfalls are described as abdominal windowing, content of the pseudopolypoid lesion, comparison of 2D and 3D images, prone-supine imaging and the aspect of the pericolic fat. In this series there were equivocal findings in case of mucosal prolapse (0.6%) and focal wall thickening (4%). Diverticulosis is a challenge for CTC to avoid false-positive diagnosis of polypoid and tumoral disease. Knowledge of possible false causes of polypoid disease and comparison of 2D and 3D images are necessary to avoid false-positive diagnosis. In case of equivocal findings additional conventional colonoscopy should be advised whenever a clinically significant lesion (> or = 1 cm) is suspected.

Dietary fecal tagging as a cleansing method before CT colonography: initial results polyp detection and patient acceptance.

PURPOSE: To compare reduced colonic cleansing based on dietary fecal tagging (FT) with standard (non-FT) colonic cleansing with regard to patient acceptance, sensitivity, and specificity. MATERIALS AND METHODS: In 50 patients (FT group), FT was performed by means of diet, magnesium citrate, and a barium suspension. In another 50 patients (non-FT group), preparation was based on polyethylene glycol administration. All patients underwent conventional colonoscopy after computed tomographic (CT) colonography. Sensitivity and specificity for polyp detection were calculated by using conventional colonography as the reference standard. At CT colonography, fecal residue was evaluated. Patients were interviewed to determine discomfort, side effects, sleep quality, final opinion on examination comfort, and whether they would be reluctant to undergo the same examination again. RESULTS: FT left more fecal residue but improved differentiation from polyps (FT specificity, 88% [30 of 34 patients]; non-FT, 77% [23 of 30 patients]). Sensitivities were comparable: FT, 88% (14 of 16 patients); non-FT, 85% (17 of 20 patients). FT significantly reduced discomfort, side effects, and sleep disturbance, and resulted in an improved final opinion of how comfortable the examination was (P <.05). Although FT improved patient willingness to repeat the examination, this improvement was not statistically significant (P >.05). CONCLUSION: FT offers the patient a well-tolerated preparation and improves specificity, with improved differentiation of polyps from residual stool.