Computed tomography, magnetic resonance imaging, positron emission tomography and evoked potentials at early stage of adrenoleukodystrophy.

An 8 year-old-boy with adrenoleukodystrophy (ALD) was subject to an x-ray computed tomography (CT) scan, magnetic resonance imaging (MRI), positron emission tomography (PET) using 18F-fluorodeoxy glucose and evoked potential studies, about 3 months after the onset of neurologic symptoms. A CT showed decreased radiodensity over the white matter of both occipital lobes, and high density areas on the periventricular space. No contrast enhancement was observed around the low dense white matter, while occipital grey matter seemed to be almost normal. MRI demonstrated a larger and more obvious lesion of prolonged T2 relaxation time which was 170-250 msec than that detected by CT scan. The PET demonstrated wide and severe hypometabolism for glucose over the grey and the white matter of bilateral occipital lobes. The visual evoked potential (VEP) was scarcely elicitable, while the auditory brainstem response (ABR) and short latency somatosensory evoked potential (SSEP) was normal. These imaging studies suggest that extensive and profound demyelination exists in the occipital white matter. For detection of demyelinizing process, MRI may be more effective than CT in this disorder. The PET study revealed that there may have been an abnormality of the grey matter as well as the white matter in the occipital lobe. The VEP disappeared in the relatively early stage. The brainstem may not be involved at such early stage in light of normal ABR and SSEP.