Diagnostic difficulties in the differentiation of urine retention and developmental anomalies in the pelvicalyceal system in the ultrasound examination of children.

Ultrasound examination of the abdominal cavity is part of the baseline diagnostics of urinary tract diseases. Dilatation of the pelvicalyceal system is one of the most frequent findings. In ultrasonography of the urinary tract there are, however, some images of anatomical anomalies of the pelvicalyceal system which should not be consider as abnormal. In the study we analysed 920 ultrasound examinations of the urinary tract. Of all the ultrasound images only those with isolated dilatation of the renal pelvises and calices were selected (130 cases). Ampulla-shaped and/or external pelvises, isolated calices or both abnormalities were disclosed in 104, 46 and 20 cases, respectively. In about one-third of patients additional examinations (voiding cystography, intravenous urography, renal scyntygraphy) were performed which revealed normal anatomy of the urinary tract and disorders of urine flow in 80% and 20% of patients, respectively. In conclusion, the study implies that not all dilatation of the pelvicalyceal system structures signifies urine retention, although in the event of further doubt, there is a need for additional diagnostics.