PURPOSE: To test whether Renal scintigraphy with Tc99m-MAG3 scan with Low dose SPECT CT (LSCT) is non-inferior to NCCT in the setting of acute stone event (ASE) and to evaluate if the scintigraphic data add valuable physiologic information
METHODS: NCCT was routinely performed in all patients at admission and findings were blinded to the radio nucleic team. Within 24h a MAG 3 renal scan conjugated with low dose SPECT CT was performed and findings were blinded to the urologists.
RESULTS: From January to august 2017, 30 consecutive ASE patients who were admitted with single stone were enrolled. NCCT versus LSC: in 26 (87%) the stone was also recognized by low dose SPECT CT. In two patients the stone expulsed in the time elapsed between NCCT and LSC. Remaining two cases had Scintigraphic data: In 19/30 (64%) Renal scintigraphy demonstrated severe obstruction (T 1/2 >20 min.). In 23/30(77%) elevated serum creatinine was noted. In 6/30 (20%) serum creatinine was elevated but Renal scintigraphy did not demonstrate obstruction. 2/9 cases(23%) were decompressed by ureteral stent due to colic with no obstruction and 11/30(37%) were not decompressed despite proven obstruction and severe functional decline( relative split function delta > 15%)
CONCLUSIONS: Renal scintigraphy with LSCT as a primary diagnostic modality provides adequate stone recognition with significant radiation reduction and enables the clinician to recognize severe obstructed kidney otherwise not diagnosed by NCCT nor creatinine measures
