To evaluate the effectiveness of transabdominal ultrasonography for bladder volume and detrusor muscle thickness and to research the relationship of these measurements with age, height, and body mass index.

We reviewed the records of 244 healthy, school-aged children from February to May 2003. After a complete urologic examination, the weight and height of all children were measured, and their body mass index was determined. Transabdominal ultrasonography with a high-frequency probe was performed to obtain the anterior, posterior, and lateral bladder wall thicknesses.

The mean age of the children was 10.7 ± 3.6 years (range 7 to 15), and the mean bladder volume was 256 cm³ (range 78 to 790). The relationship between bladder volume and age was significant (P = 0.0001, r = 0.568). The mean anterior, posterior, and lateral detrusor thickness was 1.42 mm (range 0.8 to 2.8), 1.57 mm (range 0.7 to 3.1), and 1.49 mm (range 0.6 to 2.6), respectively. The relationships between increasing age and the anterior and posterior wall thicknesses were significant (P <0.05), but the relationship between age and the lateral wall thickness was not (P >0.05). The relationship between bladder volume and body mass index was significant (P = 0.0001, r = 0.2959). A strong positive and significant correlation was found between the anterior (P = 0.0001) and posterior (P = 0.001) wall thicknesses and body mass index, but the correlation between the lateral wall thickness and body mass index was not significant (P = 0.079, r = 0.113).

Strong, positive correlations were found between the anterior and posterior wall detrusor thicknesses and increased age and body mass index, but the same correlations for lateral wall detrusor thickness were not found.