The major classes of contrast agents currently used for magnetic resonance (MR) imaging of the liver include extracellular agents (eg, low-molecular-weight gadolinium chelates), reticuloendothelial agents (eg, ferumoxides), hepatobiliary agents (eg, mangafodipir), blood pool agents, and combined agents. Mechanisms of action, dosage, elimination, toxic effects, indications for use, and MR imaging technical considerations vary according to class. Gadolinium chelates are the most widely used. Ferumoxides are a useful adjunct for detection of hepatocellular carcinoma, particularly when used in combination with gadolinium to achieve improved lesion-to-liver contrast over that achievable with gadolinium alone. Mangafodipir is a prototype hepatobiliary agent that is taken up by lesions with functioning hepatocytes. It may be used for MR cholangiography as well as liver imaging. Although mangafodipir is no longer commercially available in the United States, it is currently marketed and used in Europe. Blood pool agents have not yet been approved for human use in the United States. However, a new combined MR contrast agent, gadobenate dimeglumine, recently was approved, and other agents are in various stages of development.
Introduction: Pelvic radiation is often used as radical treatment or additional therapy in patients with gynecologic malignancies. Irradiation damages deoxyribonucleic acid (DNA) of tumor cells by an inflammatory process with several inciting factors. The inflammatory process continues well after the treatment has been given and its effects can present decades after initial treatment. Complications of radiation are related to tissue damage due to parenchymal and vascular endothelial cell death as well as fibrosis resulting from innate immune response. Fibrosis is a late complication of radiation therapy and can present as stenosis or fistulas. Fistulas have an annual incidence rate of up to 5% and can develop anywhere in the irradiated field.Case Report: This case describes a patient with vesicovaginal fistula secondary to stage IV cervical cancer treated with pelvic radiation. The patient had ureteral stent placement for radiation-induced ureteral stricture which exited the body through the anus through the vesicovaginal fistula and a colovesical fistula which developed over the course of 10 years after initial treatment with radiation therapy.
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