Radiographic Evaluation of Children with Febrile Urinary Tract Infection: Bottom-Up, Top-Down, or None of the Above?

Table 1

Advantages and Disadvantages of Bottom-Up versus Top-Down Methodology.

	Advantages	Disadvantages	Comments
Bottom-Up; VCUG	Widely available with reproducible techniques and interpretation; Identifies lower urinary tract correctable anomalies	Requires catheterization; Does not identify all vulnerable kidneys; Exposure to focused ionizing radiation; May overtreat cases that are not clinically significant	VUR will predispose kidneys to pyelonephritis and scarring but the relationship is not 1 : 1; Many cases of VUR spontaneously resolve
RUS	Noninvasive; No ionizing radiation; Widely available	Fails to alter management as many abnormalities are now detected in utero; Not a functional study	Gross anatomic assessment to complement VCUG
Top-Down; DMSA	Identifies kidneys vulnerable to injury; Avoids VCUG (and catheterization) in a subset of patients; Acute phase scans have high sensitivity and specificity for clinically significant VUR and recurrent UTI	Heterogeneity in availability, quality, and interpretation; Requires intravenous access and long appointment times; Requires sedation in young children; Misses cases of VUR; If only a late-phase scan is performed, it may miss patients at risk for recurrent FUTI; Exposure to diffuse ionizing radiation	Early scans may show parenchymal inflammation but only 40% may progress to scarring; If only late phase scans are performed, cases of repeat FUTI will be missed