OP06.04: Comparison between two‐dimensional and three‐dimensional assessment of the corpus callosum: reproducibility of measurements and acquisition time

Abstract

Objectives:The sonographic diagnosis of short and partial CC agenesis (PACC) is conventionally based on measurement of a short for gestational age anterior-posterior length of the corpus callosum, typically associated with abnormal CC morphology. We suggest a new method for evaluation of PACC without referring to biometry tables. Methods: We measured the CC length and the internal cranial occipitofrontal dimension (ICOFD) in mid-sagittal plane in 245 normal pregnancies between 21 to 34 week and in 24 pregnancies with a diagnosis of PACC (range 24 to 35+6 weeks). The mean ratio between ICOFD and CC length and standard deviation was calculated throughout the pregnancy. We compared this ratio between normal pregnancies and pregnancies with partial agenesis of the CC. Results: The ICOFD/CC length for normal pregnancies was 2.39 ± 0.14 (range 2.25-2.41). This ratio was constant throw-out the pregnancy. The sagittal to CC length ratio of pregnancies with CC partial agenesis was significantly higher 3.32±0.92 (range 1.92-5.75) (P<0.0001). Conclusions:The ratio between the fetal internal cranial occipitofrontal dimension and the CC length was constant throughout the pregnancy. This ratio is significantly higher in pregnancies with partial agenesis of the CC. Measurement of this ratio during fetal anatomical scan may enable the diagnosis of this pathology instantly without the need to refer to biometry tables. It should be emphasised that our results concerns PACC without microcephaly. OP06.03 Fluid-attenuated inversion recovery sequences in the diagnosis of lissencephaly on fetal MRI