Plain radiography, excretion radiography, and contrast radiography

Radiology is an integral component in the evaluation of the urinary tract. Plain radiography is both a primary abdominal examination technique and an initial component of subsequent excretion and contrast radiographic studies. Excretion radiography is performed by means of antegrade opacification of the renal collecting systems, ureters, and bladder following IV contrast administration. Contrast radiography is obtained following direct injection of contrast media into the urinary tracts in an antegrade or retrograde fashion. Although ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) are increasingly used to compensate for the limitations of excretion radiography, conventional urographic examinations remain important in the diagnosis of some urinary tract conditions.