The importance of DMSA scan in comparison with ultrasound in the early detection of renal parenchymal involvement in children with first-time febrile UTI

The high risk of pyelonephritis in the presence of a febrile Urinary tract infection (UTI) and possible complications including renal scarring, hypertension (HTN) and chronic kidney disease (CKD), warrants accurate and timely diagnosis, evaluation and therapy. In ۲۰۱۱ and ۲۰۲۱ imaging studies in selected international guidelines for the diagnosis and management of the initial UTI in febrile infants and children ۲ to ۲۴ months were revised. Some of suggestions revision were as follows: ۱- Except ultrasound (US), there is no need to use other imaging modalities. ۲- If the US is normal, there is no need to do cystography. ۳- Renal cortical scintigraphy should be avoided in the acute phase of the first febrile UTI. ۴-The follow-up of the patients was conditional on the recurrence of febrile UTI. Significant controversy surrounded this recommendation, and many Authors disagreed with the American Academy of Pediatrics guidelines. According to the research conducted and for the following reasons, US can not be an appropriate and comprehensive imaging modality in evaluating a child with the first episode of febrile UTI. At the time of presentation, slides of ۱۶ children whose abnormalities were missed due to treatment based on the mentioned guidelines will be shown. Many of these recommendations are based on expert opinion alone because there are few studies, and in their suggestions, not even a prospective study was mentioned as cited evidence. In the majority of prospective studies expressed in high sensitivity of Dimercaptosuccinic Acid (DMSA) scans (۹۱%) compared to low sensitivity of ultrasound (۱۱% - ۴۰%) in the identification of renal parenchymal involvement. These guidelines are presented while the findings of renal cortical scintigraphy in at least ۱۹ prospective studies conducted in the world from ۱۹۹۱ to ۲۰۱۹ (۴ studies in Iran, one of which has not yet been published) show that renal parenchymal involvement in children with the first episode of febrile UTI is ۴۴.۱% to ۸۸% with an average of ۶۷.۹%. According to Coulthard et al. results, potentially important abnormalities (۸% of pts) will be missed if the newer guidelines are followed. They concluded that the NICE guidance should be reconsidered. Take home message For the early detection of renal parenchymal involvement in children with the first episode of febrile UTI, we have no choice but to use renal cortical scintigraphy to prevent or reduce the process of not identifying renal parenchymal involvement (missing) until the results of prospective research are ready.