Purpose:
To investigate the development of the common stem
of calcarine sulcus and parietooccipital fissure in the axial plane as a potential early marker of cortical development in fetal MRI
 
Methods and Materials:
From September 2013 to 2016 out of the 658 fetal MRI’s performed in our tertiary care referral hospital 321 fetuses were performed before 20 weeks GA. Sixty-seven fetuses with normal fetal brain MRI and normal outcomes as measured by normal Ages and Stages Questionnaires obtained at least one-year post- delivery were included in the study. Three fetuses with GA of 16, 4 with GA of 17, 18 fetuses with GA of 18, and 42 fetuses with GA of 19 weeks were included in the study. Early midline sulci including the calcarine (cal) and parietooccipital (POF) fissures as well as their common stem were assessed in all fetuses by two radiologists in consensus. The visible sulci based on the method presented by Van der Knaap et al. (0-6).
 
Results:
The mean scores for the common POF-Cal sulcus stem in axial images were 1 and 0.5 and 0.44 and
1.36. The mean scores for Cal in the standard coronal plane was 0 and 0 and 0.16 and 0.10 in fetuses with
GA’s of 16, 17, 18 and 19 weeks respectively, while the mean scores for the proximal Cal in axial images was 0.66 and 0.25 and 0.44 and 1.33.
 
Conclusion:
The common POF-calcarine sulcus stem seems to become visible in MRI earlier than the age mentioned in previous fetal MRI studies. This sulcus is among the first sulci to develop in fetal pathology studies and can be potentially used as an early indicator of early fetal development.