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

A patient is reported with diffuse leukoencephalopathy associated with cyst ic degeneration of the white matter of the brain (van der Knaap syndrome)Th e changes were studied by fluid attenuated inversion recovery (FLAIR), and diffusion-weighted MR imaging. The FLAIR sequence revealed suppressed signa l 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) mm(2)/s in the temporal cysts, Similar to that of CSF. The ADC values within the pa renchyma ranged between 2 x 10(-3) and 2.1 x 10(-3) mm(2)/s, a value fallin g between normal parenchyma and cerebrospinal fluid, compared with a contro l group of three healthy subjects. The changes were also evaluated by proto n MR spectroscopy, and were compared with a control group of 12 cases. Magn etic resonance spectroscopy revealed apparently increased NAA/Cr ratios in most parts of the brain. The NAA/Cho ratios were either high or low, and th e Cho/Cr ratios were increased or normal in different regions.