Combining functional and structural brain magnetic resonance imaging in Huntington disease.

OBJECTIVE: To concurrently investigate with magnetic resonance (MR) the brain activation and regional brain atrophy in patients with Huntington disease (HD). METHODS: Nine symptomatic HD patients and 11 healthy subjects underwent an MR study including functional MR acquisition during finger tapping of the right hand and high-resolution T1-weighted images. Functional and structural data were analyzed using Statistical Parametric Mapping 2 software. RESULTS: As compared with control subjects, HD patients showed decreased activation in the left caudate nucleus and medial frontal and anterior cingulate gyri and increased activation in the right supplementary motor area and supramarginal gyrus and left intraparietal sulcus. The pattern of atrophy included thinning of the gray matter (GM) in the insula, inferior frontal gyrus, caudate, lentiform nucleus, and thalamus, bilaterally, in the left middle frontal, middle occipital, and middle temporal gyri, and of periventricular, subinsular, right temporal lobe, and left internal capsule white matter. Only the decreased activation in the caudate nucleus correlated topographically with the caudate GM loss. CONCLUSION: The cortical areas of functional changes do not correspond to those of GM atrophy in patients with HD and are likely to reflect decreased output of the motor basal ganglia-thalamo-cortical circuit and compensatory recruitment of accessory motor pathways.

Huntington disease: volumetric, diffusion-weighted, and magnetization transfer MR imaging of brain.

PURPOSE: To investigate whether diffusion-weighted and magnetization transfer (MT) magnetic resonance (MR) imaging depict regional and/or global brain abnormalities in patients with Huntington disease (HD). MATERIALS AND METHODS: Twenty-one carriers of the HD mutation (mean age, 58 years +/- 11 [SD]) and 21 healthy control subjects (mean age, 54 years +/- 13) underwent conventional, diffusion-weighted, and MT MR imaging. Volumes, mean apparent diffusion coefficients (ADCs), and MT ratios (MTRs) for left and right caudate nucleus, putamen, and cerebral periventricular white matter-as well as an index of normalized brain volume and whole-brain ADC and MT histograms-were computed. Asymmetry in volume, ADC, and MTR measurements in caudate nucleus, putamen, and periventricular white matter in control subjects and HD carriers were evaluated with Wilcoxon testing for paired samples. Differences in MR imaging variables between HD carriers and control subjects were evaluated with Mann-Whitney U testing; correlations between stages of clinical severity and MR imaging data were investigated with Spearman rank correlation testing. RESULTS: No significant asymmetry was observed for any of the MR imaging variables. Caudate nucleus, putamen, and whole-brain volumes were smaller (P <.001 for all) in HD carriers than in control subjects. HD carriers also had increased ADC in the caudate nucleus (P =.002), putamen (P <. 001), cerebral periventricular white matter (P <.001), and whole brain (P <.001). MTR was not significantly different between HD carriers and control subjects. Correlation was observed between stages of increasing clinical disease severity and both decrease in volume of caudate nucleus (Spearman rho = -0.63), putamen (rho = -0.64), and whole brain (rho = -0.46) and increase in ADC in caudate nucleus (rho = 0.52), periventricular white matter (rho = 0.45), and whole brain (rho = 0.44). CONCLUSION: Regional and global volume loss in HD is accompanied by an increase in ADC; this correlates with disease severity.