Van der Knaap syndrome: MR imaging findings including FLAIR, diffusion imaging, and proton MR spectroscopy

A patient is reported with diffuse leukoen-cephalopathy associated with cystic degeneration of the white matter of the brain (van der Knaap syndrome). The changes were studied by fluid attenuated inversion recovery (FLAIR) and diffusion-weighted MR imaging. The FLAIR sequence revealed suppressed signal of the cysts, and widespread high-signal white matter changes associated with thinned cortices. On diffusion-weighted MR imaging, apparent diffusion coefficient (ADC) values ranged from 3.0 x 10-3 to 2.7 x 10-3 mm2/s in the temporal cysts, similar to that of CSF. The ADC values within the parenchyma ranged between 2 x 10-3 and 2.1 x 10-3 mm2/s, a value falling between normal parenchyma and cerebrospinal fluid, compared with a control group of three healthy subjects. The changes were also evaluated by proton MR spectroscopy, and were compared with a control group of 12 cases. Magnetic resonance spectroscopy revealed apparently increased NAA/Cr ratios in most parts of the brain. The NAA/Cho ratios were either high or low, and the Cho/Cr ratios were increased or normal in different regions.