FIG 2. Case 5: 37-year-old man with a GBM who had previously undergone surgical resection, irradiation, and chemotherapy for a GBM of the right frontal lobe. Recently, a recurrent tumor was found on follow-up CT studies. A transaxial section of a contrast-enhanced T1-weighted spin-echo MR image (333/10/3) is shown on the left, a corresponding V_T1U map is in the middle, and the V_T1C map is on the right. The recurrent GBM shows dense contrast enhancement in the right frontal lobe, extending to the corpus callosum. Small, enhanced foci are also depicted in the left frontal lobe. Note that the lesion in the corpus callosum is depicted as an area of hypervascular blood volume on the V_T1C map (arrow), and the blood volume of this lesion is similar to that of gray matter on the V_T1U map, indicating the tumor blood volume is underestimated on the V_T1U map. The qualitative analysis was rated as 1 in this case. The V_T1U/V_T1C ratio is 0.64