Hand-crafted features extracted from dynamic contrast-enhanced magnetic resonance images (DCE-MRIs) have shown strong predictive abilities in characterization of breast lesions. However, heterogeneity across medical image datasets hinders the generalizability of these features. One of the sources of the heterogeneity is the variation of MR scanner magnet strength, which has a strong influence on image quality, leading to variations in the extracted image features. Thus, statistical decision algorithms need to account for such data heterogeneity. Despite the variations, we hypothesize that there exist underlying relationships between the features extracted from the datasets acquired with different magnet strength MR scanners. We compared the use of a multi-task learning (MTL) method that incorporates those relationships during the classifier training to support vector machines run on a merged dataset that includes cases with various MRI strength images. As a result, higher predictive power is achieved with the MTL method.