MR Contrast Agents

Despite the excellent soft tissue contrast pro› vided by plain MRI, the use of intravascular contrast agents is often performed in a variety of clinical settings being an instrumental component of many MR studies. Several compounds have been developed for contrast-enhanced MR imaging of the abdomen, with the purpose of increasing tumor detection and differentiation between normal and pathological tissues. MR contrast agents can be divided according to their magnetic properties into paramagnetic and superparamagnetic agents. They are also classified as interstitial, nonspecific, or liver-specific contrast media, with the latter subdivided according to their target-cell population: hepatocyte-selective or Kupffer cell contrast agents. A review of their main characteristics includ› ing physicochemical properties, pharmacokinetics, and safety profile is performed under the scope of this chapter. For each class of contrast media, suggested imaging protocols and current clinical indications are also provided for the typical setting of 1.5T magnets. Main imaging findings and diagnostic information obtained with these agents is provided for comparing accuracy with other imaging techniques or modalities. Pitfalls, limitations, and future directions are also addressed in order to keep the reader fully aware of their current clinical spectrum.