Fig. 17

Bladder outlet obstruction due to posterior urethral valves in a foetus at 21 weeks gestation. The post-mortem imaging was obtained three days after termination of pregnancy. Sagittal post-mortem ultrasound images of the bladder (a) and posterior urethra (b) demonstrate a partially distended urinary bladder (asterisk) with thickened bladder wall, a dilated posterior urethra (solid arrow) and an abrupt urethral narrowing (dotted arrow) at site of obstruction. The corresponding sagittal post-mortem T2 weighted MRI study (c) also demonstrates the large urinary bladder (asterisk) with dilated posterior urethra (solid arrow), although the site of obstruction (dotted arrow) is less well depicted than on the ultrasound