Contribution of MRI to ultrasound in the diagnosis of fetal anomalies.

PURPOSE

To evaluate the contribution of MRI to ultrasound (US) in the diagnosis of fetal anomalies.

MATERIALS AND METHODS

After informed consent and institutional review board approval, concomitant US and MR imaging were performed for 184 fetuses with suspected anomalies in university hospital. Postnatal final diagnoses were obtained for 183 anomalies in 151 fetuses either by radiological examination, surgery, autopsy, or inspection. The prenatal US and MR diagnoses were compared with respect to postnatal diagnoses. Sign test was used to determine the statistical significance.

RESULTS

Both ultrasound and MR imaging correctly diagnosed 93 (50%) cases and failed in 12 (7%) cases. Ultrasound was superior in 7 (4%) cases. MR imaging was superior in 71 (39%) cases (P < 0.001). MR contributed to the prenatal diagnosis by the confirmation of the suspected US diagnosis in 13%, by demonstration of additional findings in 31% and by changing the diagnosis in 56% of the cases. The contribution rates were 55% for the central nervous system (CNS) (P < 0.001), 44% for thorax (P = 0.016), 38% for gastrointestinal system (GIS) (P = 0.031) and 29% for genitourinary system (GUS) (P = 0.003) anomalies. In facial, cardiac and extremity-skeletal system anomalies, there was not a significant contribution of MR imaging over US.

CONCLUSION

MR imaging can be used as an adjunct to US in the prenatal diagnosis of fetal anomalies of not only the CNS but also the non-CNS origin especially those involving the GIS, GUS and thorax.