Comparison of Tc-99m MAG, and Tc-99m DTPA Renal Scans in Patients with Upper Urinary Tract Obstruction

Park, Youngwoong; Song, Hocheun; Ryu, Soobang

Abstract

Tc-99m mercaptoacetyltriglycine (MAG3) is a new Tc-99m renal agent that is excreted by tubular function. To evaluate the efficacy of Tc-99m MAG3, renal scans with Tc-99m MAG3 and Tc-99m diethylenetriamine penta-acetic acid(DTPA) were performed in patients with upper urinary tract obstruction within the time interval of 3 days. Of the 36 patients 17 had ureteropelvic junction (UPJ) strictures, 5 had renal stones, 10 had ureteral stones, and 4 had ureterovesical junction (UVJ) strictures. The patient ages were ranged from 1 to 72 years and the numbers of male and female were 22 and 14, respectively. Split renal function ratio(%), time parameters and image quality using target to background ratio of the Tc-99m MAG, renal scan were compared with those of Tc-99m DTPA, in terms of age group (less than 16, 16 or more), obstruction site (UPJ or proximal to UPJ, distal to UPJ) and treatment pre-treatment, post-treatment state). The split rena1 function ratio(%) of Tc-99m MAG, was well correlated with that of Tc-99m DTPA (r=0.92). There was no statistically significant difference between time parameters of Tc-99m MAG, and Tc-99m DTPA. The image quality of Tc-99m MAG, was superior to that of Tc-99m DTPA (p<0.05). In conclusion, Tc-99m MAG, renal scan had a superior image quality to that of Tc-99m DTPA and correlated well with other Tc-99m DTPA parameters. Thus, Tc-99m MAG, renal scan may be considered to replace Tc-99m DTPA in the evaluation of patients with upper urinary tract obstruction.