Table 2.

Diagnostic clues from MR scanning of the brain

Condition	MR brain scan finding(s)	MRI sequence
‘Diagnostic’
Multiple systems atrophy type C	‘Hot-cross bun’ sign*; pontine atrophy (figure 1)	T2/FLAIR
Fragile X tremor-ataxia syndrome	Middle cerebellar peduncle sign† (figure 2)	T2/FLAIR
Superficial siderosis	Deposition of haemosiderin; cerebellar atrophy (figure 3)	GRE/T2*
Sporadic Creutzfeldt-Jakob disease	High basal ganglia signal; cortical high (and persistent DWI) signal	T2/FLAIR, DWI/ADC
Autosomal recessive spastic ataxia of Charlevoix-Saguenay	Hypointense pontine stripes (figure 4); atrophy of superior cerebellar vermis; thinning of posterior mid-body of corpus callosum	T2/FLAIR
SPG7	High dentate nuclei signal (figure 5)38	T2/FLAIR
‘Suggestive’ (in familial forms)
Friedreich’s ataxia, vitamin E deficiency	Upper cervical cord atrophy; cerebellar atrophy late (figure 6)	T1/T2
Ataxia-telangiectasia, ataxia with oculomotor apraxia, types 1 and 2	Cerebellar atrophy	T1/T2
Autosomal dominant spinocerebellar ataxia	Cerebellar and pontine atrophy	T1/T2

*Also occurs in autosomal dominant spinocerebellar ataxia.

†Can occur in multiple systems atrophy type C.

ADC, apparent diffusion coefficient; DWI, diffusion-weighted imaging; FLAIR, fluid-attenuated inversion recovery; GRE, gradient echo; SPG7, spastic paraplegia 7.