Scintigraphy and sonography in reflux nephropathy: a comparison

Comparison of screening of vesicoureteral reflux with renal ultrasound and voiding cystourethrography

PURPOSE

To suggest a different method for diagnosing vesicoureteral reflux (VUR) in lieu of voiding cystourethrography (VCU), in order to prevent radiation exposure.

MATERIALS AND METHODS

Fifty-two ureterorenal units of 26 patients were evaluated ultrasonographically for visualizing the renal collecting systems, both before and after filling up the bladder with saline infusion. Every patient also underwent evaluation with VCU.

RESULTS

All patients with Grade 2 or higher degrees of VUR on VCU can be identified by ultrasound (USG). Overall sensitivity and specificity of this technique were 66.7% and 93.48%, respectively, in our patient group.

CONCLUSION

After being diagnosed with VCU initially a VUR patient can be effectively followed up by USG in order to prevent radiation exposure. Considering the clinical management of a patient with Grade 1 VUR which could not be detected with USG, it is concluded that failure to detect Grade 1 VUR will not be a handicap.

99mTc-2GAM: a tracer for renal imaging

We propose a renal imaging agent, the 99mTc complex of the bidentate-N,S chelate N-(mercaptoacetyl)glycine (99mTc-2GAM), with the imaging characteristics of 99mTc-DMSA but a faster kidney uptake; chemical evidence supports the formulation of 99mTc-2GAM as [Tc(v)(O)(GAM)2]-. After biodistribution and toxicity studies in animals, 99mTc-2GAM was evaluated in five normal volunteers. 99mTc-2GAM is rapidly cleared from the blood (t1/2 = 9 min) and 50% of the ID is excreted in the urine in the first 2 h. Dynamic data show a rapid renal uptake that increases up to 1 h with no significant wash-out between 1 and 8 h. The uptake in each kidney ranges from 11.3% to 20.7% ID. Low, stable liver uptake is observed. No significant activity is detected in other organs. We showed no differences between 99mTc-2GAM and 99mTc-DMSA compared in three patients with unilateral kidney disease. We conclude that 99mTc-2GAM has good practical and dosimetric features for renal imaging.