Before imaging, patients are asked to drink approximately 1 L of VoLumen over a 30-45 minute period. They may also be given 10 mg of metoclopramide (to promote gastric emptying) and 0.5 mg of glucagon IV (to reduce peristalsis). Increased water within the bowel means that the intraluminal contents will have long T1 and T2 values. In MR enterography T2-weighted ultrafast breath-hold sequences like HASTE or TrueFISP are are typically used rendering the intestinal contents bright and their walls dark.
GastroMARK® (ferumoxsil) is such a product — an oral suspension of siloxane-coated magnetite nanoparticles. GastroMARK® causes a remarkable drop in signal within the bowel lumen on both T1 and T2-weighted images. The darkening on T1-weighted images allows visualization of mucosal enhancement. Some centers mix VoLumen® and GastroMARK® as a combined agent. Like VoLumen®, GastroMARK® also causes abdominal pain and diarrhea in up to 30% of patients. And, as a bonus, it tastes terrible!
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GastroMARK® is known under the trade name of Lumirem® in nine European countries.
The theoretical benefit of negative contrast agents is that they provide better visualization of bowel wall edema and mucosal enhancement as well as the ability to discriminate between intraluminal and extraluminal fluid. Conversely, positive contrast agents may be better at demonstrating bowel wall thickening.
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Mallinkrodt Inc. GastroMARK® package insert/prescribing information. Accessed 1/1/15.
Papanikolauou N, Karantanas A, Maris T, Gourtsoyiannis N. MR cholangiopancreatography before and after oral blueberry juice administration. J Comput Assist Tomogr 2000; 24:229-234.
Rinck PA, Smevik O, Nilsen G, et al. Oral magnetic particles in MR imaging of the abdomen and pelvis. Radiology 1991;178:775.
Whatever happened to Feridex®? Aren't iron-containing contrast agents useful for liver MRI?