Table 2.

Principal abnormalities reported on CT and MRI brain scans in the 225 undiagnosed cases

Principal abnormality	CT brain scans	MRI brain scans
Normal	28	45
Cerebral atrophy	20	33
Cerebellar atrophy	1	9
Generalised atrophy	3	32
White matter abnormalities	–	25
Basal ganglia changes	5	8
Intracranial calcification	5	–
Periventricular low intensity	1	–
Mixed (atrophy plus white matter abnormalities)	–	24
Other*	–	7
No result	2	1
Total	65	184

Forty-nine children had both CT and MRI scans, so there was overlap in the findings on the scans.

Brainstem abnormalities reported on MRI scans: small/atrophic 6, signal abnormalities 2. None of these findings were reported as the principal abnormality on the relevant scan so these cases are included in the numbers shown in the table.

*Partial callosal agenesis, microcephaly, ventriculomegaly, hypoplastic optic chiasm, right hemiatrophy, multiple small infarcts, arteriovenous malformation.