Prenatal cerebral magnetic resonance imaging.
Ultrasonography (USG) is the preferred screening method for fetal brain examination. It has some technical limitations and a relatively low sensibility and specificity for many central nervous system (CNS) malformations. Fetal cerebral magnetic resonance imaging (MRI) offers better resolution and sensibility, with scarce limitations.


OBJECTIVE
To determine the fetal age according to cortical maturation as seen in MRI, correlating these data with those obtained by means of USG measurements; to correlate USG pathological findings with the MRIs and to determine how the sequence of cortical maturation varies in abnormal brains.


METHODS
50 pregnant women were submitted to USG and fetal brain MRI. Fifteen carried out normal pregnancies. In the remaining 35, the USG, the clinical assessment or both, raised the suspicion of a CNS malformation. Facts studied were: the gestational age calculated by USG, analysis of the cortical gyral development by MRI (cortical age), the presence of CNS abnormalities and the correlation between the cortical maturation and the presence of CNS pathologies. Statistical analysis included the Student's t test for paired samples, the Pearson's correlation coefficient (r) and linear regression curves.


RESULTS
In the control group, fetal age highly correlated with the cortical age estimated by MRI. In the abnormal group, a wide variety of pathologies could be found, with higher sensibility and specificity than USG when applying MRI techniques. Cortical age did not correlate with the gestational age in this group; moreover, its estimation could not be achieved in severely malformed brains.


CONCLUSIONS
MRI allows a detailed study of the CNS before birth. It proved to be more reliable and specific than USG, with fewer technical limitations. Cortical maturation can be accurately assessed by this method in normal or slightly abnormal fetuses. However, USG is better than MRI for diagnosing skull bony defects.
Bendersky
Mariana
M
III Normal Human Anatomy Department, Medical School, Buenos Aires University. Paraguay 2155, Buenos Aires, Argentina. mbendersky@fmed.uba.ar
Tamer
Inés
I
Van Der Velde
Juan
J
Dunaievsky
Armando
A
Schuster
Gustavo
G
Rugilo
Carlos
C
Sica
Roberto E P
RE