What contrast do you put in the bladder (type and volume)?

We drip in up to 530 cc of contrast (500 cc bag of saline mixed with 30cc of Omnipaque-350). The contrast is dripped in under gravity and when the patient has pain or the contrast runs out we will stop and then start the study.

Do we ever place contrast in the bladder similar to a cystogram and if so why?

In cases of suspected bladder perforation, be it due to trauma (MVA and commonly associated with pelvic fractures) or surgical complication, the most accurate technique to detect contrast extravasation is a CT Cystogram. The presence of perforation, its site and its cause can all be defined on this study. The key to a successful exam is distension by contrast of the bladder under gravity (contrast dripped in) and typically not by hand injection of the contrast. Bladder rupture can be classified as intra and extraperitoneal. The intraperitoneal cases typically require surgery.

What is virtual colonoscopy and what is the patient prep for the study?

Virtual colonoscopy is a new exam that is used for screening the colon for polyps. It is usually done in asymptomatic patients as part of the American Cancer Society's screening program but is also used in patients with failed classic fiberoptic colonoscopy.

Do we ever use rectal contrast and if so when and why?

We do use rectal contrast for select applications. The basic principle would be for cases where opacification of the rectum and sigmoid colon is needed for defining the presence and/or absence of specific pathology. Some of the specific applications include:

Are there any contrast volume limitations for the use of IV contrast?

Indeed there is and here are some rules for Omnipaque and Visipaque courtesy of Rich Vitti MD from GE Healthcare.

Have you ever seen a patient develop diffuse erythema distal to the IV injection site in the absence of extravasation?

Here is the answer courtesy of Richard A. Vitti MD from Medical Affairs at GE Healthcare. Rare, isolated cases of localized redness at the injection site have been reported to us at GE Healthcare over the years since the introduction of our non-ionic Omnipaque and Visipaque products.

Is it ok for patients to have both an MR and a CT with contrast on the same day?

This question was addressed on the RSNA site and there is no issue doing both MRI and CT the same day with Gadolinium and Iodinated Contrast.