An automatic method for detecting and delineating Gd- enhanced lesions on T1-weighted magnetic resonance images in multiple sclerosis (MS) brains are described. In order to detect and limit the enhancements to the region defined by the brain mask, a combination of thresholding and mathematical morphological operations was implemented. Three-dimensional connected component labeling algorithm is used for producing both the brain mask and labeling the enhanced lesions. False positives that arise from the enhancing vasculature and structures that do not exhibit blood-brain-barrier (BBB) were automatically detected and eliminated by spatially registering the T1-weighted and the dual echo affirmative images. Lesion enhancements were delineated using fuzzy connectedness. This technique is evaluated on MS patients with excellent results.