Methods (2900), apparatuses (3000), and computer program products for segmenting an infarct in a diffusion-weighted imaging (DWI) volume are disclosed. A Region of Interest in at least one slice of the DWI volume is selected (2912). The ROI comprises at least a portion of the slice. A threshold for a minimum size of an infarct region is selected (2916). An energy mask is convolved (2918) with that slice, and the resulting energy image is normalized (2920). The ROI in the convolved energy image is selected (2922). An initial threshold is determined (2924) using a histogram of the ROI of the slice without a background region, and an initial segmentation of the slice is performed (2926). Individual components of the initial segmentation of the slice are labeled (2930). A final threshold is determined (2932) using histograms of labeled components if the initial segmentation, and a final segmentation if the slice is performed (2934) using that threshold.