Magnetic resonance imaging (MRI) was used for the first time in the preoperative 
planning for separation of conjoined twins. In these omphalopagus infants, MRI 
showed normal biliary and cardiovascular structures and demonstrated, in detail, 
a relatively avascular plane through the liver bridge, which enabled safe 
separation with minimal blood loss at 3 1/2 months of age. A single MRI study 
supplied information superior to that obtained with multiple previously 
available imaging studies. MRI should be an essential part of the preoperative 
workup of all types of conjoined twins.