Static renal scintigraphy with 99mTc-DMSA or dynamic renal scintigraphy with 99mTc-EC at the assessment of diseases of the kidneys and the urinary tract in pediatrics

In the field of pediatric nephrourology the nephropathies of children caused by obstruction and reflux of the urinary tract are very important. The pathogenesis of these diseases begins with an outflow impairment of urine because of a congenital ureteropelvic or ureterovesical obstruction, vesicouereteral reflux respectively. Etiologically a malformed ureter, or a neuropathic bladder with voiding disorders due to meningomyelocele are responsible for these problems. This outflow impairment of urine is followed by parenchymal damage of the involved kidneys, on the one hand caused by ascending dysplasia and nephrogenic arrest during the development of the urinary tract, and on the other hand caused by ascending urinary tract infections and water hammer effect with dilatative obstructive damage. Basically there are two ways of treatment for these little patients: first the conservative therapy with watchful waiting for maturation while giving medication and some further possibilities when treating a neuropathic bladder, and second surgery with invasive removal of the outflow impairment. To choose correctly between these possibilities of treatment clarifying convincing diagnostics are necessary (identification and evaluation of the outflow impairment and of the parenchymal damage, and evaluation of the kidney function separately for each side). Since the average age of these patients is very low the strain by diagnostics should also be as low as possible, especially concerning the radiation burden. The static renal scintigraphy with 99mTc-DMSA is considered to be the gold standard for identification and evaluation of parenchymal damage and scaring of kidneys. Now the dynamic renal scintigraphy with 99mTc-EC was found to reveal parenchymal damage as well as the static renal scintigraphy. In addition to this equivalence as far as the evaluation of parenchymal function is concerned, the dynamic renal scintigraphy with 99mTc-EC shows evidence to be superior to the static renal scintigraphy as far as the diagnostic validity is concerned, because of its dynamic character and the possibility to provide information about the outflow of the urine through the whole urinary tract. Compared to techniques of conventional radiology in the routine diagnostics of nephrourology of children with outflow impairment of urine the nuclear medical method (dynamic renal scintigraphy with 99mTc-EC) is very well completed by ultrasound and micturating cystourethrography. The urography on the other hand should be replaced by the dynamic renal scintigraphy in the routine diagnosis of these diseases, because the scintigraphy shows the same diagnostic value as the urography, but the strain for the little patients is lower with the nuclear medical technique (lower radiation burden, no application of contrast medium). The nuclear medicine with the dynamic renal scintigraphy with 99mTc-EC has a high value in the pediatric nephrourology and especially in this field its advantages should be used. (author)