Fig 2.

Images illustrate step 3: segmentation of enhancing tumor.

A, I_T1, or T1-weighted axial image, demonstrates the postoperative cavity in the left frontoparietal area, with hemorrhage, edema, and possible residual tumor.

B, I_T1e1, or axial image obtained after the administration of gadolinium-based contrast material, shows rim enhancement along the margins of the postoperative cavity, as well as anterior nodular enhancement. Note the overlying postoperative dural enhancement.

C, I′_T1e1 − I_T1, or axial image obtained after subtracting the registered, resection volume in B from the volume in A, shows that only areas in which signal intensity increased on B compared with A have high signal intensity.