Postmortem examination of human fetal hearts at or below 20 weeks' gestation: a comparison of high-field MRI at 9.4 T with lower-field MRI magnets and stereomicroscopic autopsy.

OBJECTIVES: To compare the diagnostic usefulness of high-field with low-field
magnetic resonance imaging (MRI) and stereomicroscopic autopsy for examination of
the heart in fetuses at or under 20 weeks' gestation.
METHODS: Prior to invasive stereomicroscopic autopsy, MRI scans at 9.4, 3.0 and
1.5 T were performed on 24 fetuses between 11 and 20 weeks' gestation, including
10 fetuses with cardiac abnormalities. The ability to visualize different heart
structures was evaluated according to the different field strength MRI magnets
used and gestational age at examination.
RESULTS: On 1.5- and 3.0-T MRI, only the heart situs and four-chamber view could
be visualized consistently (in 75% or more of cases) when the fetus was beyond 16
weeks' gestation, but other heart structures could not be visualized for fetuses
at any gestational age. In contrast, using high-field MRI at 9.4 T, the heart
situs, four-chamber view and the outflow tracts could be visualized in all
fetuses irrespective of gestational age. Using high-field MRI, the sensitivity
for detecting an abnormality of the four-chamber view was 66.7% (95% CI,
30.1-92.1%) with a specificity of 80.0% (95% CI, 51.9-95.4%). For abnormalities
of the outflow tracts, sensitivity was 75.0% (95% CI, 20.3-95.9%) and specificity
100.0% (95% CI, 83.3-100.0%). Eight fetuses out of 10 with congenital heart
disease (CHD) were classified as having major CHD. High-field MRI at 9.4 T was
able to identify seven out of the eight cases of major CHD.
CONCLUSION: High-field MRI at 9.4 T seems to be an acceptable alternative
approach to invasive stereomicroscopic autopsy for fetuses with CHD at or below
20 weeks' gestation.

Jaar van publicatie:2012

Trefwoorden:MRI, high field, low field, fetuses