Magnetic resonance imaging of renal masses

The increasing frequency of incidentally detected renal masses supports the need for accurate imaging characterization to avoid unnecessary surgery/interventional procedures. Furthermore, the need for accurate presurgical diagnosis of specific histologic subtypes of renal malignancies is increasingly important as advances in understanding of tumor biology direct targeted courses of therapy. Magnetic resonance imaging is uniquely suited for the evaluation of renal masses because of its ability to provide excellent soft-tissue contrast and demonstration of enhancement, as well as its multiplanar capabilities. Although the spectrum of masses that may occur in the kidneys is broad, specific imaging features may assist in their accurate diagnosis. Examples of the imaging appearance of common and uncommon renal masses are provided along with a protocol for comprehensive magnetic resonance examination of the kidneys.