- Paulsen, Huprich, Fletcher, et al., Mayo Clinic, Rochester, MN.

Purpose
In a retrospective analysis of 756 patients who underwent CTE at the Mayo Clinic, the authors described their preferred methods for performing CTE, including the use of a 0.1% barium sulfate suspension, VoLumen, as a preferred oral contrast agent. The article covers various considerations in achieving small bowel distension, and the authors discuss and illustrate CT enterographic findings in the most common diseases encountered in their series, including: Crohn's, ulcerative colitis, SB tumors, celiac disease and incidental findings.

Conclusion

"Compared with traditional small bowel follow-through examination, CT enterography has several advantages: (a) it displays the entire thickness of the bowel wall, (b) it allows examination of deep ileal loops in the pelvis without superimposition, and (c) it permits evaluation of the surrounding mesentery and perienteric fat. CT enterography also allows assessment of solid organs and provides a global overview of the abdomen." (p. 642)

- Megibow, et al., New York University School of Medicine

Purpose
To prospectively evaluate the performance of an orally administered 0.1% barium suspension, VoLumen, as a bowel-marking agent for multi-detector row computed tomography (CT).

Method
A total of 60 patients (33 women, 27 men; average age 58.2 years) who were referred for multi-detector row CT of the pancreas were randomized into two groups.

An additional 60 consecutive outpatients (34 women, 26 men; average age 64.0 years) who received Readi-Cat® 2% were also included in the study.

Results
There was significantly better distention in the stomach (P = 0.013), duodenum (P = 0.006), jejunum (P = 0.029) and ileum (P = 0.014) in the VoLumen group (Group 1) compared to the water/methylcellulose group (Group 2).

Significant distention was also evident by comparing the products of the widest cross-sectional diameters in the duodenum (P = 0.014), jejunum (P <0.001), and ileum (P <0.001).

VoLumen group (Group 1) also demonstrated significantly better visualization of mural features in the duodenum (P = 0.003), jejunum (P = 0.024), and ileum (P = 0.01) and a trend toward better visualization of mural features in the stomach (P = 0.092).

Conclusion
Oral administration of VoLumen provided excellent distention and excellent visualization of mural features in the gastrointestinal tract.

The more rapid cycle time could improve patient throughput without compromising diagnosis.

The ability of this contrast agent (VoLumen) to produce neutral contrast enhancement provides considerable advantages for emerging volume imaging with multi-detector row CT.

Exam Details
Fourteen exams were performed with a 4-detector row CT scanner and the remaining 46 were performed with a 16-detector row CT scanner. All exams included IV contrast that was administered by means of an EmpowerCT® injector at rates of between 2 and 4 mL/sec.

Dual acquisition protocol

Phase 1 (pancreatic phase): images obtained 40 sec after initiation of bolus from the xiphoid to the top of the sacroiliac joints using a 4 x 1-mm detector configuration, creating 3-mm sections.

Phase 2 (portal phase): images obtained beginning at 75 sec after initiation of bolus from xiphoid to symphysis pubis using a 4 x 2.5-mm detector configuration, creating 4-mm sections.

16-detector row scanner
Phase 1: images obtained at 50 sec with a 16 x 0.75-mm detector configuration, creating
3-mm sections.

Phase 2: images obtained at 90 sec using a 16 x 1.5-mm detector configuration, creating
4-mm sections.

Two attending radiologists (Megibow & Hecht), one with more than 25 years experience and one with 2 years experience in dedicated body imaging, independently reviewed images from each exam as transverse 3- or 4-mm sections on a PACS workstation. Both were blinded to the type of oral contrast used. Images were rated on a continuous five-point scale (0 = worst, 4 = best) for the ability of the readers to visualize selected segments of the GI tract, and for the qualitative assessment of distention in each segment.

Results of Qualitative Analysis in Small Intestine for Each Group

* For Group 1, 1200 mL of VoLumen was administered, and for Group 2, 1200 mL of water with methylcellulose was administered.

A quantitative analysis of the degree of distention was also performed.

Results of Quantitative Analysis in Small Intestine for Each Contrast Agent

Note: For quantitative analysis, a mixed-model least-squares regression that was adjusted for age and sex was used to calculate volume assessments (i.e., the product of the cross-sectional diameters, as measured in square centimeters) that were associated with each of the three contrast agents in each of the three segments of the small intestine. Numbers are presented as the mean ± standard error of the mean.