Grey-scale ultrasound imaging: assessment of acute hydronephrosis.

Rapid changes in the renal anatomy during the development and resolution of an acute hydronephrosis may require multiple imaging procedures. The ionising radiation hazard limits the extent to which this may be achieved by intravenous pyelography. Grey-scale ultrasound offers a safe, non-intrusive technique for visualising the renal pelvis which may be repeated daily. The value of such an ultrasound facility is illustrated by 3 case histories.