Brain MRI of a patient with biopsy-confirmed infantile Alexander disease

A and B: At the age of 1.5 months, the frontal white matter has a slightly higher signal intensity on T2-weighted images and slightly lower signal intensity on unenhanced T1-weighted images than does the remainder of the cerebral white matter, which has normal signal intensity for unmyelinated white matter. There is a periventricular rim of low signal intensity on T2-weighted images (arrows, A) and high signal intensity on T1-weighted images (arrows, B), with some extensions into the frontal white matter (arrowheads, A and B). The caudate nucleus and putamen have high signal intensity on T2-weighted images and are mildly swollen.
C and D: At the age of 3 months, a major increase in ventricular size is seen with extreme thinning of the posterior cerebral mantle. The frontal white matter has a more abnormal signal intensity than the occipital white matter, appears markedly swollen, and shows early cystic degeneration (arrows, D). There is a thin periventricular rim of low signal intensity on T2-weighted images (arrows, C). The basal ganglia are now markedly atrophic. After contrast administration, enhancement occurs in the ventricular lining, caudate nucleus, putamen, frontal white matter, and parts of the frontal cortex (D).