Characterization of genitourinary lesions with diffusion-weighted imaging.

Diffusion-weighted imaging has been widely accepted as a powerful imaging technique in neuroradiology. Until recently, the inclusion of diffusion-weighted sequences in body imaging protocols has been hindered by technical limitations. However, with advances in magnetic resonance (MR) imaging technology and technique, these limitations are being overcome. The addition of diffusion-weighted sequences to routine abdominopelvic MR imaging protocols has been found to yield diagnostically useful information with only a minimal increase in imaging time. More specifically, the use of diffusion-weighted imaging in the genitourinary system can facilitate the detection and characterization of genitourinary tract lesions that demonstrate equivocal signal intensity characteristics with routine MR imaging sequences. Diffusion-weighted imaging is not only helpful in differentiating benign from malignant processes, but it can also be used to assess meta-static lesions, possible tumor recurrence, and treatment response. Because it does not require injection of a gadolinium-based contrast agent, diffusion-weighted imaging can be used in patients with renal insufficiency or contrast material allergy. Most of the body diffusion-weighted imaging studies reported in the literature to date have been conducted with 1.5-T magnets. However, the feasibility of body diffusion-weighted imaging at 3.0 T is currently under investigation in an effort to determine the efficacy of the routine inclusion of diffusion-weighted imaging sequences in 3.0-T body MR imaging protocols. (c) RSNA, 2009.