Evaluation of the biliary intestinal limb can be challenging. Pseudotumors in the pancreaticojejunal anastomosis region are common and may be difficult to distinguish from true tumor recurrence.3,4,6
In our 2 cases, CT cholangiography clearly contributed to patient management of the biliary intestinal limb of a Roux-en-Y choledochojejunostomy by clarifying the anatomy. In particular, we found value in use of the left lateral decubitus position to promote passive flow of biliary-excreted contrast material into the more proximal segment of jejunum at the pancreatic anastomosis in our patients who both had prior Whipple procedure.
There is a paucity of literature describing bowel opacification with CT cholangiography. Only 1 prior report described the use of CT cholangiography to evaluate the bowel,8
but the results were confounded by the concurrent use of oral contrast material, and patients with suboptimal biliary intestinal limb opacification were not imaged in the left lateral decubitus position.8
Another report described the use of CT cholangiography to evaluate patients where a Roux-en-Y choledochojejunostomy prevented direct biliary evaluation by endoscopic retrograde cholangiography,9
but the value of CT cholangiography to examine the bowel was not assessed in this latter study.
Although the use of intravenous biliary-excreted contrast material to evaluate the jejunum by CT scans has not been extensively studied, it is a relatively noninvasive study, simple to perform, and has many potential advantages. First, the contrast material enters the biliary intestinal limb largely in an antegrade fashion, which allows for opacification of this targeted and often inaccessible segment of bowel. Second, the contrast material is inexpensive. Third, the study does not require sedation. Fourth, the biliary intestinal limb remains under physiological, rather than external mechanical pressure; therefore, artifactual dilatation of the bowel by a bolus effect is unlikely. Fifth, intravenous contrast agents may be better tolerated than oral agents in nauseated patients.
Although use of biliary-excreted contrast material may be useful for opacification of the biliary intestinal limb, it also has several clear limitations. An important consideration is that the excretion of intravenous cholangiographic contrast material is variable and under the influence of poorly understood factors.7,9
The best documented predictor of poor excretion is a serum total bilirubin greater than 2.0 mg/dL.7
However, in patients whose primary concern is disease of the bowel, biliary function is usually normal. Another consideration for the use of iodinated intravenous biliary contrast material is the perceived high risk of contrast reactions.10,11
However, in several recent studies of CT cholangiography, reactions were minor and seen in only 1% to 3% of patients,12–16
a rate similar to that of conventional intravenous contrast-enhanced CT. No major reactions were reported.12–16
Nevertheless, to minimize the risk of adverse reactions, we premedicated our patients with diphenhydramine, diluted the contrast material, and gave it by slow infusion.7,16
These precautions seem logical, but systematic studies confirming their efficacy are unavailable. A third concern is that borderline renal function may be a contraindication because 10% or more of the intravenous cholangiographic contrast material may be excreted through the kidneys (package insert). However, for patients without hepatorenal disease, several radiology groups routinely administer both biliary-excreted and conventional intravenous contrast agents in the same day for CT examination.8,16,17
Other biliary-excreted contrast agents with low complication rates are also available, including oral iodinated agents and intravenous magnetic resonance imaging agents (eg, mangafodipir trisodium, gadobenate dimeglumine), but their usefulness for evaluating the bowel has not yet been described.
Certainly, other imaging options are available for the evaluation of the biliary intestinal limb, including MR imaging and ultrasound, and each have their own advantages, including the absence of exposure to ionizing radiation. Magnetic resonance imaging can assess for the folds of bowel if sufficient fluid is present in the bowel lumen, and similarly, ultrasound can evaluate the Whipple resection bed if an acoustic window is available. The choice of whether additional imaging workup is needed, and which modality to use, depends on the level of suspicion for tumor and local expertise. In our 2 cases, the suspicion for pancreatic adenocarcinoma recurrence was sufficiently high to prompt a CT-guided biopsy. The CT cholangiograms were performed only to help guide the biopsies. Unexpectedly and fortuitously, both cases demonstrated only normal bowel.
Our study has limitations. Although the contrast material completely opacified the proximal biliary intestinal limb when the patients were in the left-lateral decubitus position, complete opacification might not occur if intestinal peristalsis is active or the configuration of the bowel is unfavorable. However, because the distance between the hepatojejunostomy and the important pancreatic anastomosis is generally short, only a small amount of contrast material needs to reflux into that segment for good opacification. In addition, our experience is very limited at this point. Certainly, further study is needed to define the role of CT cholangiography in segments of otherwise inaccessible bowel, and our positive initial experience suggests that such study is warranted.
In summary, CT cholangiography can clarify the anatomy and function of the biliary intestinal limb of a Roux-en-Y choledochojejunostomy at CT when prior conventional imaging studies give ambiguous results. In particular, left lateral decubitus positioning may improve opacification of the peripancreatic segment of the biliary intestinal limb of a Whipple reconstruction.