Multislice Enterography With Isoosmotic Mannitol As Oral Contrast

Purpose: To observe the value of isoosmotic mannitol as oral contrast to distend small bowel and establish the best way to perform multislice enterography(MSCTE) .Materials and methods: Forty volunteers were randomly divided into four groups, group A and B given water and isoosmotic mannitol respectively while group C and D given water and isoosmotic mannitol combined with intravenous 20 mg of Raceanisodamine hydrochloride repectivly. CT scanning on a Siemens Sensation 16 scanner( Siemens ,Erlanger, Germany) with CARE DOSE 4D software and the following parameters: 120 KVP, 130 effective mAs, 0.5 s rotation time,7.0 mm thicknees , Kernel B 20f smooth. After plain scan, arterial phase and venous phase were scanned 20-30 s and 50-70 s after the start of the i.v. injection of l00mL Omnipaque (300 mgl/mL) at a rate of 3.5 mL/s. Raw data were retrospectively reconstructed with a thickness of 0.75 mm and a gap of 0.7 mm, which was post-processed into MPR, thin MIP and VRT at a WIZARD workstation,using Inspace when necessary. Small bowel was divided into three segments: duodenum, jejunum and ileum. Adequacy of luminal distention was assessed with a four-point scale in each segment. A distention score 0 ,1,2,3 represents less than 30%, 30-50%, 50-80% and more than 80% respectively of the evaluated segment was adequately distended. The maximun outer diameters of duodenum, jejunum and ileum were measured and the CT values of bowelwall in different phase were measured with a ROI of 2 mm2 .RESULTS: All volunteers and patients considered the taste of isosmotic mannitol as good or acceptable, and no discomfort and complication were found. The total luminal distension were 8.30+0.82 in group D, 6.80 + 0.63 in group B, 7.80 +1.81 in group C, 4.80 +1.69 in group A The normal outer diameter and wall thickness of small bowel were less than 30 mm and 3 mm in all volunteers. Conclusion: Luminal distention is MOST satisfactory and adequately especially in group D. MSCTE with isoosmotic mannitol is an effective method in demonstrating normal bowel.