Purpose or Case Report: A spatio-temporal delay in maturation and reorganization of transient fetal compartements, such as subplate zone, Von Monakow segments of white matter, crossroad areas and migrating cell bands, seems to be linked to abnormal brain growth and radial vulnerability(Kostovic et al. 2014) in preterm born infants (PT). The aim of our study was to test the MRI visibility of these transient fetal structures and eventually to compare their appearance patterns in two group of infants: term borns and PT at term equivalent age.
Methods & Materials: Two readers retrospectively reviewed 3D T2 weighted MRI images of 13 term born neonates (mean age=40.1±0.7 GW) and 14 PT (mean age=28.1±2.2 GW) that were acquired on a 3T Siemens system at term equivalent age. The following was assessed: MRI characteristics of subplate (0=not detectable, 1=”patchy” appearance, 2= hyperintense and narrow), von Monakow segments of white matter (0=not discernable, 1= hyperintense, 2=hypointense), presence of crossroads (1=not visible, 2=visible) and presence of migrating glial cells bands (1=visible, 2=not visible). Agreement and reproducibility between readers and visibility difference in the 2 groups were assessed for each structure by a Cohen Kappa statistic system. Appropriate statistical test (Fischer or Mann–Whitney U test) were used.
Results: Inter-observer reliability was high (K = 0.8) for detection of subplate, von Monakow segments of white matter and crossroads aspect and perfect (K = 1) for presence of migrating glial cells bands. Term born neonates display more mature pattern of subplate zone (Figure 1:red arrows) in frontal and occipital regions (seen as T2 hyperintense narrow band) while in PT this zone had a « patchy » appearance (Table1). Compared to term borns, PT showed immature (T2 hyperintense) von Monakow segments II and III in frontal, central and occipital regions (Table1; Figure 1:II-III). C1, C4 and C6 crossroads were visible in majority of term borns, while only C2 and C5 were visible in PT (Figure 2:white arrows). Migrating glial cells bands were equally visible in the two groups.
Conclusions: Fetal transient cerebral structures can be visualized in MRI studies in term and PT babies . Our results suggest that reorganisation of transient fetal compartments is altered in PT (Figure1,2). Therefore, these parameters could be in the future included in a new scoring system and further studies are needed to understand if they can be reliable marker for prediciton of cognitive and motor development of PT.