Wiley, Magnetic Resonance in Medicine, 1(43), p. 52-61, 2000
DOI: 10.1002/(sici)1522-2594(200001)43:1<52::aid-mrm7>3.0.co;2-5
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Decreased, renormalized, or increased values of the calculated apparent diffusion coefficient (ADC) are observed in stroke models. A quantitative description of corresponding tissue states using ADC values may be extended to include true relaxation times. A histogram-based segmentation is well suited for characterizing tissues according to specific parameter combinations irrespective of the heterogeneity found for human healthy and ischemic brain tissues. In a new approach, navigated diffusion-weighted images and ADC maps were incorporated into voxel-based parameter sets of relaxation times (T1, T2), and T1- or T2-weighted images, followed by a supervised histogram-based analysis. Healthy tissues were segmented by incorporating T1 relaxation into the data set, ischemic regions by combining T2- or diffusion-weighted images with ADC maps. Mean values of healthy and pathologic tissues were determined, spatial distributions of the parameter vectors were visualized using color-encoded overlays. One to six days after stroke, ischemic regions exhibited reduced relative mean ADC values.