Fast Protocols for Obstruction (Diuretic Renography) and for Renovascular Hypertension (ACE Inhibition)

Renal scintigraphy (SCINT) has proved to be a useful imaging modality for many renal diseases, congenital or acquired, and for the evaluation of complications of renal transplant. However, the modality has limited resolution for small morphologic changes (such as tumors) of the parenchyma and the collecting system, shows neither stones nor calcifications, and usually misses other abdominal pathology. Due to these deficiencies, SCINT never developed into a universal test and today intravenous urography (IVU) remains a useful modality for imaging many acquired renal diseases. However, IVU is currently used less frequently, especially for congenital disorders, because of the introduction of noninvasive ultrasonography (SON) and X-ray computed tomography (CT). The new imaging modalities provided more accurate and practical approaches for studying drainage system and parenchymal morphology, renal space-occupying lesions (SOL), and trauma. The role of magnetic resonance imaging (MRI) is still under evaluation. Despite the availability of CT, SON, and MRI, and due to its unique sensitivity in detecting regional and global functional changes of the kidneys, renal SCINT (with renography) has been accepted as the test of choice for the evaluation (diagnosis, quantitation, and follow-up) of such congenital and acquired diseases of the urinary tract, which induce focal or generalized alterations in renal function or drainage. Indeed, the most common indications for radioisotope renal studies are: obstruction of the drainage system; urinary tract infection (UTI); evaluation of renal function (including split renal function), in general and in particular, in unilateral disease, and in renal insufficiency or failure; renovascular disorders; and complications of renal transplants.