Table 4.

Differentials for idiopathic epilepsy that may require high resolution imaging to identify

Condition	Imaging features	References
Congenital and developmental causes
Nodular heteroptopia/ focal cortical dysplasia	Abnormal location or thickness of deep grey matter, commonly periventricular or interspersed amongst white matter.	[69]
L2-hydroxyglutaric aciduria	Poor distinction between grey and white matter throughout cerebral hemispheres and deep grey matter. Bilateral grey matter hyperintensity, especially the thalamus and cerebellum	[70]
Infectious and inflammatory causes
Distemper encephalitis	Patchy, asymmetric T2-weighted hyperintensities with mild or no contrast enhancement on T1W scans. Lesions are usually asymmetric, large, round to ovoid in shape throughout different parts of the forebrain, especially in grey matter of the temporal lobe, as well as the brainstem, cerebellum and subcortical white matter.	[71]
Rabies encephalitis	Very mild lesions - bilaterally symmetrical T2W hyperintensities in temporal lobes, hippocampus, hypothalamus, midbrain and pons with little or no contrast enhancement.	[72]
Metabolic, endocrine and nutritional causes
Hepatic encephalopathy	Bilaterally symmetrical T1W hyperintensities in caudate nuclei, thalamus, not associated with contrast enhancement	[73]
Thiamine deficiency	Bilateral, symmetric T2W hyperintensities in caudate nuclei, lateral geniculate nuclei, red nucleus, caudal colliculi, facial and vestibular nuclei	[74]