Application of nuclear medicine methods for diagnosis of urolithiasis and its complications

The most common complications of urolithiasis are obstructive nephropathy and pyelonephritis, which often lead to irreversible consequences for the affected kidney. For the diagnosis is not sufficient just to visualize the stone, but also to evaluate the extent of functional changes in renal parenchyma, which will determine the type of therapeutic approach. The most common diagnostic algorithm of imaging methods in the diagnosis of urolithiasis includes ultrasound, X-ray overview and intravenous urography. Less commonly are performed CT, renal scintigraphy and retrograde urography and others. Problems in application of that algorithm are mainly related to incorrect localization of stones and difficulties to assess its effects on renal function. Dynamic renal scintigraphy (DRS) and its variety the diuretic scintigraphy is an established method for assessing the functional status of parenhima and drainage disorders of the kidney in renal colic and long standing hydronephrosis. Advantages of the method is rapid, accurate and noninvasive determination of the renal parenchyma and function, urodynamics of upper urinary tract, and the ability to present the relative percentage contribution of each kidney in total renal function. DRS is characterized by precise quantitative results, lack of bias and low radiation dose. However, recently in the literature we found some contradictory views on the application protocol and the importance of diuretic renal scintigraphy in the evaluation of renal obstruction. Moreover, there are some different viewpoints about the exact location of DRS in the diagnostic algorithm of patients with urolithiasis. In could be summarized that there are various imaging methods which provide extensive diagnostic capabilities in diagnoses of urolithiasis and its complications. Nevertheless, an express and complex method that combine functional and morphological data and provides comprehensive and reliable information hasn't been described yet. (authors)