Table 1.

Magnetic resonance imaging scoring system for fetuses with corpus callosal agenesis

Parameter	Score (points)
	0	1	2
Gyration	Normal	Mildly delayed (≤ 2 weeks)	Delayed (> 2 weeks)
Opercularization	Normal	Delayed	—
Temporal lobe asymmetry*	Asymmetrical (R > L)	Symmetrical (R = L) or inverted (L > R)	—
Hippocampi	Normal	Malrotation (mild to moderate and/or unilateral)	Verticalization (bilateral), reduced volume
Lamination	Normal	—	Abnormal
Basal ganglia	Normal	Abnormal	—
Ventricular size†	Normal (< 10 mm)	10–14.9 mm	≥ 15 mm

^*Temporal lobe asymmetry described according to Kasprian et al.²⁴; if not assessable (i.e. at later gestational ages (> 32 weeks)), a score of 0 should be given.

^†Measured at level of atrium; if ventricular size is asymmetrical, larger ventricle should be assessed. L, left; R, right.