this review article might be useful reading:
Magnetic resonance imaging findings in bilateral basal ganglia lesionshttp://www.researchgate.net/publication ... 491389.pdf
also interesting, just searching on "hyperintensity mri basal ganglia"
T1-weighted hyperintensity in basal ganglia at brain magnetic resonance imaging: are different pathologies sharing a common mechanism?http://www.ncbi.nlm.nih.gov/pubmed/12520756
Basal ganglia hyperintensity on T1-weighted MRI in Rendu-Osler-Weber disease.http://www.ncbi.nlm.nih.gov/pubmed/
Radiological Reasoning: Hyperintensity of the Basal Ganglia and Cortex on FLAIR and Diffusion-Weighted Imaginghttp://www.ajronline.org/doi/full/10.2214/AJR.07.7089
"Abnormalities on imaging of the basal ganglia are often nonspecific. Therefore, a focused approach to limit the differential diagnosis is based on whether the patient presents with acute or chronic symptoms. The most sensitive sequence in the acute setting to detect abnormalities within the basal ganglia is diffusion-weighted imaging (DWI). The differential diagnostic considerations in the acute setting should include hypoglycemia, cerebral hypoxic encephalopathy, carbon monoxide poisoning, encephalitis, osmotic myelinolysis, toxin exposure, vascular causes, and illicit drug use."