Pantothenate kinase-associated neurodegeneration: MR imaging, proton MR spectroscopy, and diffusion MR imaging findings

Abstract

We herein report the case of a 15-year-old male patient with pantothenate kinase-associated neurodegeneration. The classic "eye-of-the-tiger" appearance was initially present on the globus pallidi on T2-weighted MR images and had disappeared by the time of the 10-month follow-up examination. Fluid-attenuated inversion recovery images revealed marked hypointensity in the globus pallidi and dentate nuclei and high signal intensity changes in the deep cerebral white matter. Proton MR spectroscopy revealed markedly decreased N-acetylaspartate in the globus pallidi, associated with decreased N-acetylaspartate and increased myoinositol in the deep cerebral white matter. Diffusion MR images (b=1000 s/mm(2)) were negative (normal appearing) for deep cerebral white matter lesions, whereas apparent diffusion coefficient values were slightly increased (1.08-1.12 x 10(-3) mm(2)/s), compared with the apparent diffusion coefficient values from the normal white matter regions. Apparent diffusion coefficient values in the globus pallidi were lower than those in the unaffected thalamus.

Fig 1.

T2-weighted and fluid-attenuated inversion recovery images from the initial examination. A, T2-weighted image reveals marked hypointensity in the globus pallidi with high signal intensity foci (eye-of-the-tiger appearance). B, Fluid-attenuated inversion recovery image reveals marked hypointensity of the globus pallidi. Note that the eye-of-the-tiger appearance cannot be detected. C, Fluid-attenuated inversion recovery image reveals high signal intensity lesions in the deep cerebral white matter and dentate nuclei.

Fig 2.

Spectra from the initial examination. A, Proton MR spectroscopy (1500/40) reveals markedly decreased NAA in the globus pallidi. B, Spectrum from deep cerebral white matter reveals decreased NAA and increased myoinositol peaks. C, Spectrum from a normal region in the cerebral parenchyma.

Fig 3.

Images obtained at the 10-month follow-up examination. A, T2-weighted image reveals further hypointense appearance of the globus pallidi. Note loss of the eye-of-the-tiger appearance. B, b=1000 s/mm² image from trace diffusion MR imaging sequence (5700/139) reveals low signal intensity in the globus pallidi. C, Corresponding ADC map (same section as that shown in B) reveals low ADC values (0.45–0.54 × 10⁻³ mm²/s) in the globus pallidi, compared with the unaffected thalamus (0.77 to 0.83 × 10⁻³ mm²/s). D, b=1000 s/mm² image is negative (normal appearing) for the deep cerebral white matter lesions. E, Corresponding ADC map (same section as that shown in D) reveals slightly increased ADC values (1.08–1.12 × 10⁻³ mm²/s) compared with the ADC values from the normal white matter regions (0.78–0.87 × 10⁻³ mm²/s).