Twin-twin transfusion syndrome - fetal MRI
Updates to Study Attributes
At 20 weeks gestation, the interhemispheric and Sylvian fissures are always present. Note the shallow, rounded appearance of the Sylvian fissure at this stage. Over the next few weeks, it will become deeper, more squared and then angular as the temporal lobe folds over to cover the operculum. Other fissures have not yet appeared.
Also at this stage, we begin to see the normal 5 layered laminar appearance, which will persist until approximately 30 weeks gestation. From inner to outer, the layers are: 1.Ventricular zone (arrowhead); 2. periventricular fibre-rich zone (dotted arrow); 3. intermediate zone (curved arrow); 4. sub-plate (long thin arrow); 5. cortex (short thick arrow).
Note on the right side, localised disruption of the normal laminar pattern near the site of previous antenatal haemorrhage in this fetus (marked #).
The ganglionic eminences are low signal, highly cellular areas present within the subventricular zone, and still prominent at this stage; they will become less so as cells migrate from the ganglionic eminences to the neocortex, grey matter nuclei, thallami and hippocampi.
Image Annotated image (Sulcation) ( update )
Image Annotated image (Lamination) ( update )
Image 2 Annotated image (Lamination) ( update )
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