Excretory urography is a time-lapse radiographic study of an injectable contrast medium circulating in the venous bloodstream, renal arteries, veins and tissues up 'until it is filtered and collected in the kidneys (Lavin, 240). It helps measure and evaluate the kidneys and provides morphological information regarding the renal pelvis and ureters (Vaden, 270). Additionally, intravenous urography is the only procedure that provides primary information on ureteral morphology and function (Vaden, 270). It should be noted, however, that although the urogram is a useful tool for the qualitative assessment of renal function, it does not provide quantitative diagnostic confirmation and should not replace other renal function tests (Kirk, 527 , Thrall, 556). It is useful for detecting renal mass lesions such as neoplasia, renal cysts, traumatic renal and ureteral injuries, as well as pyelonephritis, hydroureter, hydronephrosis, renal agenesis, hypoplasia, obstructions pelvic and ureteral caused by urinary stones and blood clots, kidney parasites, ectopics. ureter and duplication of collecting system (Kirk, 527, Thrall, 562). There are two phases of a urogram: the nephrogram and the pyelogram (Lavin, 240). The first phase of the urogram, the nephrogram, is characterized on radiographs by the opacification of the renal tissues (Lavin, 240). Performed immediately after injection of the contrast medium as it begins to distribute into the renal vasculature, this study allows assessment of vascular and renal perfusion, demonstrating the viability and health of renal tissues (Lavin, 240) . A nephrogram of the healthy renal vasculature should become largely radiopaque within 10 to 30 seconds after injection and perfusion should...... middle of paper...... of the renal system (Kirk, 527, Thrall, 556). Works Cited Kirk, Robert W., BS, DVM, Stephen I. Bistner, BS, DVM, and Richard B. Ford, DVM, MS. “Excretory urography.” Manual of veterinary procedures and emergency treatments. 5th ed. Philadelphia: WB Saunders, 1990. 527. Print. Lavin, Lisa M., MBA, CVT. "Chapter 18: Special Procedures." Radiography in veterinary technology. 4th ed. St. Louis, MO: Saunders/Elsevier, 2007. 240-243. Print.Thrall, Donald E., DVM, PhD. "Chapter 42: The kidneys and the ureters." Manual of veterinary diagnostic radiology. 4th ed. St. Louis, MO: Saunders Elsevier, 2002. 556-62. Print.Vaden, Shelly L., Joyce S. Knoll, Francis WK Smith, and Larry P. Tilley. “Excretory urography.” Blackwell's Five-Minute Veterinary Consultation: Diagnostic Procedures and Lab Tests: Canine and Feline. 1st ed. Oxford: Wiley-Blackwell, 2009. 270-72. Print.