Urinary bladder wall thickness: what is the number to remember?
It is not uncommon to see a thickened urinary bladder wall in cases of chronic bladder outlet obstruction. Have you ever wondered how thick is thick? In a study, a bladder wall thickness of 5 mm appeared to be the best cutoff point to diagnose bladder outlet obstruction. Note that we should not comment on the wall thickness or other characteristics when the bladder is empty. In this study for example, the bladder was filled to 150 ml before performing the scan & prior to that, uroflowmetry and pressure-flow studies were performed.
Here are decompressed bladders from two different patients (Note Foley balloon) who presented with hydronephrosis. Though we said the cut off value is not generally not applicable to empty bladder because the wall is thicker at baseline, these walls are too thick (>2 cm) and we can safely assume chronic bladder outlet obstruction.