Imaging Practices and Implications in Young Infants With Urinary Tract Infection

Abstract

OBJECTIVES: Management of infants aged ≤60 days with urinary tract infections (UTI) is challenging. We examined renal imaging in infants aged ≤60 days with UTI at a tertiary care children’s hospital to identify the impact of standardizing renal ultrasound (RUS) interpretation. METHODS: We retrospectively studied infants aged ≤60 days hospitalized for UTI or fever with urine culture and renal imaging obtained and final diagnosis of UTI. RUS initially had noncriterion-based (NCB) interpretation by experienced pediatric radiologists. For this study, a single pediatric radiologist used a criterion-based (CB) hydronephrosis grading system to reinterpret films initially classified as “abnormal” on the NCB reading. We compared final renal imaging results between NCB and CB groups. RESULTS: Of 193 infants, 180 (93%) had inpatient RUS with 114 (63%) abnormal NCB interpretation. Of those with initially abnormal NCB interpretation, 85 OF 114 (75%) had minor and 29 OF 114 (25%) had significant abnormality by CB reinterpretation. In follow-up, the CB “minor abnormality” group showed 25% abnormal renal imaging, whereas the “significant abnormality” group showed 77% abnormal renal imaging with 54% having high-grade reflux on a voiding cystourethrogram (VCUG). Patients with CB inpatient RUS minor abnormality showed 3% abnormal RUS at follow-up, but 13% showed high-grade reflux on VCUG. CONCLUSIONS: Standardized RUS interpretation in young infants with UTI improved the accuracy of identification of abnormalities on follow-up renal imaging. In patients with CB minor abnormality on inpatient RUS, our results suggest limited utility of follow-up RUS; however, follow-up VCUG remained useful to identify high-grade reflux.

Kidney Ultrasonography After First Febrile Urinary Tract Infection in Children

“…This likely was an important source of heterogeneity as the use of a standard reporting criteria by radiologists has been associated with improved accuracy of identifying and classifying abnormalities. 58 Studies may have underreported minor abnormalities, thus, the pooled prevalence of abnormalities from this meta-analysis of 22.1% may be an underestimation. Subgroup analyses investigating heterogeneity found that an important study quality item related to the appropriate recruitment of study participants.…”

“…Ultrasonography reporting of abnormalities across studies was not uniform, as no universally accepted standard exists. This likely was an important source of heterogeneity as the use of a standard reporting criteria by radiologists has been associated with improved accuracy of identifying and classifying abnormalities . Studies may have underreported minor abnormalities, thus, the pooled prevalence of abnormalities from this meta-analysis of 22.1% may be an underestimation.…”