Correlation Between Ultrasonographic Bladder Measurements and Urodynamic Findings in Children with Recurrent Urinary Tract Infection

Objective: To evaluate the role of bladder variables measured by ultrasonography (US) in assessing bladder dysfunction in children with urinary tract infections (UTIs).

Patients And Methods: Children presenting with recurrent UTI (with or with no vesico-ureteric reflux) were prospectively recruited. At entry, each patient had US and both natural- filling (NFC) and conventional-filling (CFC) cystometry. Bladder volume and wall thickness index (BVWI) was calculated, and based on US studies and the bladder pattern on US, were classified as thick (BVWI <70), normal (70-130) and thin (>130) as previously reported. The criteria for diagnosing urodynamic patterns included normal, overactive and hypocontractile, as reported previously. The correlation between the US measured variables and urodynamic findings were then evaluated. Sixty-one children (38 boys and 23 girls; mean age 4.82 years, range 1-11) were selected for further evaluation.

Results: Of the 61 children, 16 had a normal BVWI, 36 a 'thick' value and nine 'thin'. When the BVWI was correlated with the urodynamic findings, 14 of 16 with a normal BVWI had a normal bladder pattern, whereas 92% of the patients with a BVWI of <70 had overactive bladder (P < 0.001). Among children with a BVWI of >130, six of nine had a hypocontractile pattern. The mean (sd) bladder capacity (on CFC) compared to that expected for age was significantly lower, at 56.7 (32.3)% in 'thick' bladders, vs children with normal and thin bladders, at 91.3 (23.8)% and 98.7 (31.8)%, respectively (P < 0.001). A high voiding detrusor pressure was significantly associated with children who had a thick bladder rather than normal or thin bladder (P < 0.001).

Conclusions: This study further confirmed that the BVWI is a sensitive tool for diagnosing bladder dysfunction in children, and it can be used as a reliable guide for the appropriate choice of further invasive urodynamic studies.