Global and region-specific analyses of apparent diffusion coefficient in dentatorubral-pallidoluysian atrophy.

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Dentatorubral-pallidoluysian atrophy (DRPLA ) is an autosomal dominant spinocerebellar ataxia . Techniques for the quantitative assessment of neurodegenerative lesions remain to be established in this disease . We attempted to quantify global and region-specific neurodegeneration in DRPLA using analysis of apparent diffusion coefficient (ADC ) maps .Diffusion-weighted images (b = 1000 s /mm (2 )) by echo -planar sequences were obtained with the use of a 1 .5 T clinical scanner . Whole-brain histogram and region of interest (ROI ) analyses of ADC values as well as conventional MR imaging studies were performed in 6 patients with genetically confirmed DRPLA .Histograms demonstrated significantly higher mean ADC values in the patients than in age- and sex-matched control subjects (P < .01 ). ROI analysis revealed that the patients had significantly higher ADC values in the cerebellum and globus pallidus , preferentially affected regions (P < .05 ), but not in the thalamus , the region relatively spared in this disease . ADC values in the white matter were higher only in patients with adult-onset disease . Histogram analyses could more sensitively identify abnormalities than ROI analyses , because the former avoided errors associated with setting ROIs and thus had smaller P values on statistical analysis than the latter .Histogram ADC analyses were more sensitive for the detection of neurodegeneration in DRPLA than ROI analyses , whereas ROI analyses revealed regional alterations reflecting the distribution of pathologic changes . Thus , histogram and ROI analyses complement each other and may permit the sensitive , quantitative evaluation of neurodegeneration in DRPLA , especially that involving the globus pallidus showing normal T 2 signals .