Female, 62 years old, with GBM on Avastin and temozolomide. Findings are redemonstrated compatible with prior right craniotomy and tumor resection from the posterior right frontal lobe. The region of the resection cavity contains T2 heterogeneous thickened tissue which, on comparison with multiple prior examinations, shows a slow interval increase in size. On postcontrast images, most this tissue does not enhance. However, there is patchy, discontiguous thin and/or nodular enhancement particularly along the anterior and inferior margins of this tissue which is stable to minimally increased from the prior exams. On rCBV mapping, most of this tissue demonstrates very low blood volume. Areas of elevated volume around the margins could simply represent sulcal vascularity. Elevated blood volume along the inferior margin, however, is more convincing.T2 hyperintensity extending through the white matter of the surrounding parenchyma has progressed from the prior examination, with local mass effect in the form of sulcal effacement. It also appears that the degree of susceptibility indicating microscopic blood product within and around the lesional tissue has increased from prior exams though this could partly be due to imaging at higher field strength.No discontiguous or contralateral lesions are suspected. Scattered foci of T2 hyperintensity elsewhere in the brain are unchanged and nonspecific. The ventricular system is stable in size and morphology.
Heterogeneous tissue within the right posterior frontal resection bed shows a slow but steady increase in size over multiple prior examinations. The lesional tissue shows a pattern of patchy, discontiguous enhancement which may reflect partial suppression by antiangiogenic therapy. A majority of the lesional tissue shows low rCBV, but some elevated blood volume is noted along the inferior margin of the lesion correlating with an area of enhancement.Overall, the findings are concerning for residual and slowly progressive tumor, some features of which are likely masked by antiangiogenic therapy. A mixed process with both tumor and treatment effect would also be likely.