Fetal skeletal deformities - the diagnostic accuracy of prenatal ultrasonography and fetal magnetic resonance imaging.

Objective: To evaluate the diagnostic accuracy of prenatal ultrasonography and fetal magnetic resonance imaging (MRI) in fetuses with skeletal deformities (SD).

Methods: Fourteen pregnant women of 21 - 34 weeks of gestation whose fetuses had SD on prenatal ultrasound (seven fetuses with spina bifida, four with complex malformation syndrome, two with scoliosis, and one with chondrodysplasia) were additionally investigated by fetal MRI using a 1.5T superconducting system with T1-and T2-weighted sequences in three section-planes. Main outcome measures were diagnostic accuracy, potential effect on parental counselling and influence on perinatal management of the additional investigation with fetal MRI.

Results: In 10 cases ultrasound had a better diagnostic accuracy than MRI concerning the diagnosis of SD. In four cases with spina bifida MRI provided additional information towards preoperative evaluation for neurosurgery. In five cases parental counselling was improved. There was no influence on perinatal management.

Conclusion: MRI may provide additional information to ultrasound scan in fetuses with spina bifida and consecutive neurosurgery; in fetuses with other skeletal deformities additional information may be expected only in rare cases.