CT and MR imaging of neuroaxonal leukodystrophy presenting as early-onset frontal dementia

Abstract

CT and MR imaging showed diffuse changes of the frontal white matter and genu of the corpus callosum with minimal atrophy and no contrast enhancement in a 41-year-old woman with progressive dementia. Brain biopsy disclosed axonal spheroids and gliosis in the white matter without macrophage or inflammatory infiltration or vessel abnormalities consistent with neuroaxonal leukodystrophy. This disease can be suspected on CT and MR imaging findings but requires neuropathologic examination to be diagnosed.

Fig 1.

Axial contrast-enhanced CT scan (A); unenhanced axial T1-weighted (B) MR image (repetition time, 460 milliseconds; echo time, 20 milliseconds; number of excitations, 4 [TR/TE/NEX]), and T2-weighted (C) MR image (2000/100/2) show low attenuation and signal intensity changes confined to the frontal white matter and the genu of the corpus callosum. No contrast enhancement or overt atrophy is present.

Fig 2.

A, Tolouidine blue staining (60×) of the stereotactic biopsy of the right frontal subcortical white matter shows numerous astrocytes and myelinated fibers and an axonal dilation spheroid (arrow). B, Paraffin section of the affected white matter (15×) stained with antibodies to neurofilaments (DAKO) demonstrates intense staining within a spheroid. C, Ultrastructural examination (8000×) of the affected white matter shows a swollen axon whose cytoplasm is filled in the central area with altered mithocondria and attenuated bodies, whereas neurofilaments and neurotubules tend to occupy the periphery.