Ultrasonic evaluation of the unilateral nonvisualized kidney.

There are several techniques for evaluating the nonvisualized kidney. Nephrotomography may be helpful in those patients who have some remaining renal function. Radionuclide renal flow and imaging studies are more sensitive than nephrotomography in detecting hydronephrosis, the most common cause of unilateral renal nonvisualization, but also require some renal function to be of diagnostic value. Diagnostic ultrasound, since it is independent of renal function, is an even more sinsitive indicator of urinary obstruction, detecting those cases where no functioning renal parenchyma is present. This non-invasive technique can accurately guide percutaneous puncture of the collecting system, permitting antegrade localization of the obstructing lesion. When ultrasonography demonstrates a solid mass in the renal fossa, angiography is recommended for definitive diagnosis. When no kidney is identified renal venography may be useful in differentiating between a small nonfunctioning kidney and renal agenesis.