Helical CT of the urinary tract.

The advent of helical CT has changed the practice of uroradiology and has significantly benefited patients. Painful, obstructing ureteral stones can be diagnosed with certainty in less than 1 min without contrast medium. Radiologists can now thoroughly evaluate and characterize small renal masses without fear of skip areas caused by respiratory misregistration. Radiologic evaluation of living potential renal donors, formerly a two- or three-stage procedure, can now be performed in a single visit. Finally, three-dimensional reconstructions allow use of the same data both to diagnose tumors and to plan their resection. Axial or three-dimensional images generated using helical CT will likely be increasingly important in detecting and staging cancer, determining stone composition and appropriate therapy, and evaluating renal artery stenosis.