en Pediatric Pediatric Original Research Original Research <p> <strong>Abstract</strong></p><p> <strong>Background:</strong> Screening for patients at risk of renal scarring is a challenge in children with acute pyelonephritis (APN). Diuretic Tc-99m mercaptoacetyltriglycine (MAG3) scintigraphy with zero time injection of furosemide (MAG3-F0) was observed to display focal parenchymal disorders. The advantages of MAG3 include: lower radiation dose and short duration of the test. The aim of this study was to compare the role of Tc-MAG3 (F0) dynamic study and Tc-99m dimercaptosuccinic acid (DMSA) scan in early detection of renal scarring of children with suspected pyelonephritis in comparison to after-6-month Tc-DMSAscan as gold standard.</p><p> <strong>Methods:</strong> 28 patients (56 renal units) with their first urinary tract infection (UTI) episode were evaluated prospectively for renal scarring with radioisotope scan. The patients were divided into 2 groups: Group Aconsisted of patients who underwent MAG3 scintigraphy in acute phase of pyelonephritis and Group B consisted of patients who underwent DMSA scan in this phase for renal cortical assessment. Follow up DMSA scan was performed for all patients in both groups 4-6 months after UTI episode.</p><p> <strong>Results:</strong> The accuracy of MAG3-F0 scintigraphy and DMSA scan in detecting parenchymal changes in acute pyelonephritic phase were 89.3% and 96.4%, respectively. Positive predictive value (PPV) of both MAG3-F0 and DMSA was 100%. Whereas, negative predictive values (NPV) of MAG3-F0 and DMSA scan were 62.5% and 75%, respectively.</p><p> <strong>Conclusion:</strong> Conclusively, if the MAG3 parenchymal image is abnormal, then there is renal damage but if this image is normal, a focal defect has not been excluded. Thus an abnormal MAG3-F0 precludes the need for a Tc-DMSAscan for detection of persistent renal damage in acute phase of pyelonephritis.</p> acute pyelonephritis, scar, dimercaptosuccinic acid (DMSA), mercaptoacetyltriglycine (MAG3) 17 24 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1-146&slc_lang=en&sid=1 Hassan Otukesh 20031947532846002043 20031947532846002043 No Iran University of Medical Sciences and Health Services, Labafi Nejad Hospital, Tehran, Iran. Seyed Mohammad Fereshtehnejad sm_fereshtehnejad@yahoo.com 20031947532846002044 20031947532846002044 Yes Iran University of Medical Sciences Amir Jalali 20031947532846002045 20031947532846002045 No Shahid Beheshti University of Medical Sciences, Labafi-Nejad Hospital,Tehran, Iran R Hoseini 20031947532846002046 20031947532846002046 No Iran University of Medical Sciences, Labafi-Nejad Hospital, Tehran, Iran. A Bordbar 20031947532846002047 20031947532846002047 No Pediatrician, Iran University of Medical Sciences, Labafi-Nejad Hospital, Tehran, Iran. N Najimi 20031947532846002048 20031947532846002048 No Iran University of Medical Sciences and Health Services, Tehran, Iran. A Tabarroki 20031947532846002049 20031947532846002049 No