UNLABELLED: Technetium-99m-L,L-ethylenedicysteine (99mTc-L,L-EC), a new renal radiopharmaceutical, has been shown to have similar excretion characteristics but a higher plasma clearance than 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) in normal volunteers and patients with obstructive nephropathy. This study evaluated 99mTc-L,L-EC in patients with chronic renal failure. METHODS: The clearance of 99mTc-L,L-EC was compared with that of 125l-hippuran in 26 patients with varying degrees of chronic renal impairment (serum creatine 168-1163 mumol/liter). All 26 patients also were imaged with 99mTc-L,L-EC (70-80 MBq). Fifteen patients had further imaging with 99mTc-MAG3 (100 MBq) the following day. RESULTS: A subjective analysis of the 99mTc-L,L-EC images revealed that all were of acceptable quality regardless of creatinine level. In the 15 patients who were imaged with both 99mTc-L,L-EC and 99mTc-MAG3, general image quality and target-to-background ratios were similar. Time-activity curves and mean parenchymal transit times obtained with the two agents were almost identical. Plasma clearance values (mean +/- s.d.) of 99mTc-L,L-EC and 125l-hippuran were 81 +/- 68 ml/min and 114 +/- 104 ml/min, respectively. Mean 99mTc-L,L-EC clearance was 71% of the mean 125l-hippuran value. CONCLUSION: Technetium-99m-L,L-EC provides equally high-quality images to 99mTc-MAG3 in patients with chronic renal failure. Technetium-99m-L,L-EC clearance more closely resembles that of hippuran than does 99mTc-MAG3 clearance. These features together with its ease of preparation make 99mTc-L,L-EC an attractive alternative to 99mTc-MAG3 in patients with chronic renal failure.
UNLABELLED: Technetium-99m-L,L-ethylenedicysteine (99mTc-L,L-EC), a new renal radiopharmaceutical, has been shown to have similar excretion characteristics but a higher plasma clearance than 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) in normal volunteers and patients with obstructive nephropathy. This study evaluated 99mTc-L,L-EC in patients with chronic renal failure. METHODS: The clearance of 99mTc-L,L-EC was compared with that of 125l-hippuran in 26 patients with varying degrees of chronic renal impairment (serum creatine 168-1163 mumol/liter). All 26 patients also were imaged with 99mTc-L,L-EC (70-80 MBq). Fifteen patients had further imaging with 99mTc-MAG3 (100 MBq) the following day. RESULTS: A subjective analysis of the 99mTc-L,L-EC images revealed that all were of acceptable quality regardless of creatinine level. In the 15 patients who were imaged with both 99mTc-L,L-EC and 99mTc-MAG3, general image quality and target-to-background ratios were similar. Time-activity curves and mean parenchymal transit times obtained with the two agents were almost identical. Plasma clearance values (mean +/- s.d.) of 99mTc-L,L-EC and 125l-hippuran were 81 +/- 68 ml/min and 114 +/- 104 ml/min, respectively. Mean 99mTc-L,L-EC clearance was 71% of the mean 125l-hippuran value. CONCLUSION:Technetium-99m-L,L-EC provides equally high-quality images to 99mTc-MAG3 in patients with chronic renal failure. Technetium-99m-L,L-EC clearance more closely resembles that of hippuran than does 99mTc-MAG3 clearance. These features together with its ease of preparation make 99mTc-L,L-EC an attractive alternative to 99mTc-MAG3 in patients with chronic renal failure.