This chapter describes the imaging techniques for the examination of the kidney using magnetic resonance (MR), from the fundamental morphologic sequences to the advanced applications. The basic MR features of vascular and infectious renal diseases, solid benign and malignant renal tumors, and cystic renal tumors are described. Advanced MR applications are described as a generai introduction to the following chapters describing the different renal pathologies. Cross-sectional imaging plays a criticai role in the detection and workup of renal pathologies. Even if computed tomography (CT) is stili playing the leader, the role of magnetic resonance imaging (MRI) is increasing, thanks to its better tissue contrast resolution and the absence of radiation exposure. Furthermore, MRI can be used as a problem-solving modality when CT findings are nondiagnostic.
While MRI has been shown to be useful in the detection and characterization of renal masses, in the staging of cancers, and in the evaluation of urinary tract anomalies and
obstructive disease, attempts are being made to use it for assessment of renal function, such as perfusion, glomerular filtration rate, and intrarenal oxygen measurement.
Although the nephrogenic systemic fibrosis has been recently recognized, gadolinium contrast agents are still considered safe. They can be used even in atopic patients
and in patients with moderate impairment of renal function (estimateci glomerular filtration rate >30 mL/ min/1.73 m2 ).
