The balloon and catheter tip can be positioned initially in the descending duodenum because infusion of enteral contrast is done under fluoroscopic control. A 13 Fr diagnostic enteroclysis catheter, or a 13.5 decompression/en-teroclysis catheter are used (MEC or MDEC, Cook, Inc., Bloomington, IN) because of the viscosity of the contrast material. After the balloon is inflated with 30-40 ml of air, a syringe of air is injected into the infusion lumen. Air is added to the balloon if backflow occurs. If, at the start of infusion with slower infusion rates, the balloon is pushed back or contrast refluxes proximal to the balloon, the infusion is stopped and the catheter tip is advanced to the distal duodenum or proximal jejunum and the balloon is inflated. In asthenic patients the catheter tip and balloon should be immediately advanced to the distal duodenum or, when using the long decompression/enteroclysis catheter, to the proximal jejunum. Table 2 shows our CTE protocol with positive enteral contrast.
The amount infused at CT should be increased to 1.5 liters before CT acquisition if the patient eliminates contrast while waiting for a CT table. Otherwise, the amount infused at CT will depend on the amount seen at fluoroscopy, in order to reach the pelvic segments of small bowel or when an abnormality (mass or gradient) is seen fluoroscopically. Determination of optimal infu-
Table 2. CTE with positive enteral contrast
a. Balloon catheter tip in descending or distal duodenum b. 12% water soluble contrast: 2l plus infusion rate at 55-150 ml/min (adjusted for optimal enteral volume challenge)
c. Limited fluoro and radiography to cecum Transfer patient to CT
d. Infuse 500 ml to 1 l on CT table with infusion continued during scanning. Infusion rate increased by 10 ml/min from fluo-roscopically determined infusion rate. Amount determined at fluoroscopy e. Withdraw enteroclysis catheter to stomach (black marker) - suction refluxed contrast then withdraw catheter sion rates during the fluoroscopic phase is important when using positive enteral contrast, as this is the main factor that keeps the small intestine distended during CT acquisition (Fig. 2). Newer digital fluoroscopic units allow improved post processing of fluoroscopic images obtained during optimum distention and result in diagnostic single-contrast examinations when using a 12% solution of sodium diatrizoate. In some instances, subtle gradients of low-grade partial obstruction may be observed during the fluoroscopic phase and not on the CT images. The etiology of obstruction may not be seen flu-oroscopically. When combined with the CT images, flu-oroscopic observations recorded on the spot radiographs add confidence to the diagnosis.
Fig. 2. Positive contrast CTE in 29-year-old male with Crohn's disease with allergy to iv contrast. a Coronal reformat showed low-grade small bowel obstruction with sharp transition point (black arrowhead). The cause of the obstruction was a long segment of fibrostenosis (arrows). b Sagittal reformat showed enteric fistula (white arrowheads). In view of fi-brostenosis, patient was not treated with inflix-imab (inhibitor of tumor necrosis factor-alpha)
Was this article helpful?
Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.