HOW GOOD IS TC-99M MERCAPTOACETYLTRIGLYCINE INDIRECT CYSTOGRAPHY

The aim of the present study was to estimate the sensitivity of indire ct radionuclide cystography (IRC) performed with technetium-99m mercap toacetyltriglycine (MAG3), in comparison with the micturition cystoure thrography (MCUG) and direct radionuclide cystography (DRC), for the d iagnosis of vesicoureteric reflux. Two groups of patients were selecte d: group I comprised 40 children who underwent IRC during the acute ph ase of urinary tract infection and an MCUG 6 weeks later; group II com prised 42 (other) children with known reflux, who underwent IRC and DR C during follow-up. Taking as the reference the total number of reflux ing kidneys detected by means of any cystographic technique, Tc-99m-MA G3 ICR missed two-thirds of the refluxing kidneys. Most of the small r efluxes were missed, but so too were 50% of the major refluxes. Taking as the reference Tc-99m dimercaptosuccinic acid (DMSA) scintigraphy, MCUG detected 91% of the patients with DMSA abnormalities on at least one kidney, DRC detected 95%, and IRC detected 46% and 43% respectivel y, in groups I and II. The use of Tc-99m-MAG3 IRC as the sole techniqu e for the detection of vesicoureteric reflux gives rise to an unaccept able number of false-negative results.