Figure 1. Validated and expanded breast MR imaging interpretation model uses the total data set of 454 patients, including the original 192 patients. Individual nodes of the tree-shaped model detail the architectural features that define the node, the number of patients with cancer, the number of patients with benign abnormalities, the NPV, and the PPV. Benign terminal nodes are shaded. Figure 1 represents the model as we currently think it should be used. In the no lesion node, an NPV of 98% (90 of 92) and a PPV of 2% (two of 92) are thought to be more reflective of this feature because two of the cancers were studied by using a two-dimensional enhancement technique and were not located in the region of the breast chosen for dynamic enhancement. The other two cancers were small foci of predominately DCIS.