TECHNETIUM-99M-MAG3 IN EARLY IDENTIFICATION OF PYELONEPHRITIS IN CHILDREN

The purpose of this study was to determine whether Tc-99m-mercaptotria cetylglycine (MAG3) can substitute for Tc-99m-glucoheptonate (GH) in t he detection of pyelonephritis, Methods: One hundred thirty renal scin tigraphies were evaluated retrospectively in 38 children (21% boys, 79 % girls; age range 1 mo-21 yr; mean age 7.2 yr) referred for evaluatio n during an acute clinical urinary tract infection and for follow-up s tudies. Twelve topographical regions were designated on each kidney. E ach area was graded for severity of decreased radionuclide localizatio n: mild (Grade 1), moderate (Grade 2) or marked (Grade 3). Early poste rior views of MAG3 studies were compared to delayed posterior GH image s. In all patients, both studies were performed on the same day, Resul ts: Eighty-two studies were performed during an acute clinical infecti on and 48 were performed as follow-up. Seventy-seven percent of the st udies had focal cortical lesions. Of all the cortical lesions identifi ed by GH, MAG3 detected 74% (match lesions). A comparable percentage o f lesions was identified in each region by both studies, GH scintigrap hy detected 261 lesions(63 Grade 1, 149 Grade 2 and 49 Grade 3), and M AG3 detected 201 lesions (37 Grade 1, 117 Grade 2 and 47 Grade 3). MAG 3 was unable to recognize 60 lesions identified by GH studies in 11 pa tients (mismatch lesions). Of these, 41% (26 of 63) were Grade 1, 21% (32 of 1 49) were Grade 2 and 4% (2 of 49) were Grade 3. In three case s, MAG3 identified lesions not seen by GH (reverse mismatch); all had acute symptomatic infection, Conclusion: These data document that MAG3 in the early phase of the study (1-2 min) can detect Grade 2 to Grade 3 cortical lesions in patients with pyelonephritis, but it is less ef fective in detecting Grade 1 lesions.