<prompt> Male child with hyper intensities on T2 weighted MRI in bilateral frontal lobe. Most probable diagnosis is:Canavan diseaseKrabbe diseaseX-linked adrenoleukodystrophyAlexander disease  <response>: d. Alexander diseaseRef: Nelsons 20e p 713-714;Radiopaedia.org; Caffeys 12ep337Name of diseaseMRI Brain findingAlexander diseaseT2 hyperintensities in frontal white matter; shows contrast enhancement;Canavan diseaseMacrocephaly; bilateral symmetric T2 white matter hyperintensity diffusely throughout cerebral white matter; does not enhance at CT MRI; Large N acetyl aspartate NAA peak on MRSAdrenoleukodystrophySymmetrical cerebral white matter signal change involving posterior occipitoparietal periventricular white matterKrabbes diseaseCT: Hyperdense areas symmetrically involving thalami, caudate nuclei basal ganglia, cerebellum, posterior limbs of internal capsule and brainstem.MRI: 2 patterns; i A patchy hyperintense periventricular signal with thalamic involvement onT2-weighted images, consistent with hypomyelination, ii patchy low signal on T2-weighted images in a similar distribution to the hyperdense regions seen on CT, which is suspected to represent a paramagnetic effect from calcium deposition in the region. 