Fetal magnetic resonance imaging in prenatal diagnosis of central nervous system abnormalities: 3-year experience.
OBJECTIVE
To evaluate the comparative merits of ultrasound and fetal magnetic resonance imaging (MRI) in the correct antenatal diagnosis of suspected central nervous system abnormalities.


METHODS
A retrospective review of 27 consecutive pregnancies referred for fetal MRI for suspected central nervous system abnormalities between July 1998 and July 2001. Women were referred for the MRI examination when further anatomical and/or pathological clarification of the ultrasound scan findings was needed. Antenatal ultrasound scan and MRI were reviewed in relation to the findings on postpartum investigations.


RESULTS
Data were complete for 26 pregnancies. The median gestational age at the time of the ultrasound examination was 26 weeks (95% CI 24 weeks 2 days to 28 weeks 1 day). The median gestational age at the time of magnetic resonance imaging was 27 weeks' gestation (95% Cl 26 weeks 1 day to 29 weeks 2 days). Eight fetuses had associated skeletal, renal and/or cardiac abnormalities previously noted on ultrasound examination. MRI confirmed the ultrasound diagnosis in 15/26 cases (58%). It changed the diagnosis to the correct one in 7/26 (27%) and misdiagnosed four cases (15%). Three of the four cases that were misdiagnosed on MRI occurred in the first 18 months of our 36-month experience.


CONCLUSIONS
Ultrasound remains the primary imaging modality for prenatal diagnosis. Fetal MRI appears to be a useful adjunct to ultrasound to confirm or exclude certain abnormalities; this will consequently help in the counselling of parents and assist in planning further management. However, like any imaging technique, the sensitivity and specificity of the test are likely to improve with experience.
Ismail
K M K
KM
Academic Department of Obstetrics and Gynaecology, North Staffordshire Hospital/Keele University, Stoke-on-Trent, UK.
Ashworth
J R
JR
Martin
W L
WL
Chapman
S
S
McHugo
J
J
Whittle
M J
MJ
Kilby
M D
MD
D000328:Adult; D001921:Brain / Q000002:abnormalities*; D004200:Diseases in Twins; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis*; D005865:Gestational Age; D006801:Humans; D008279:Magnetic Resonance Imaging; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013116:Spinal Cord / Q000002:abnormalities*; D016216:Ultrasonography, Prenatal