Assessing Biological Response to Bevacizumab Using 18F-Fluoromisonidazole PET/MR Imaging in a Patient with Recurrent Anaplastic Astrocytoma

Figure 1

Single modality FMISO PET/MR imaging in a 65-year-old man with recurrent left temporal lobe WHO grade III anaplastic astrocytoma immediately prior to (a) and concurrent with bevacizumab therapy (b). Baseline, simultaneously obtained, axial T2 weighted (left), FMISO PET (middle left), fused FMISO PET and T1 weighted post contrast (middle right), and apparent diffusion coefficient (right) PET/MR imaging demonstrate recurrence of disease evidenced by contrast enhancing focus bordering the posterior margin of an anterior left temporal lobe resection cavity. This region demonstrates increased FMISO uptake with no evidence of associated reduced diffusion. Follow-up PET/MR imaging 10 weeks later (after 4 doses of bevacizumab) demonstrates the development of a nonenhancing T2 hyperintense mass about the posterior margin of the resection cavity that is associated with the development of reduced diffusion and diminished FMISO uptake.

(a)

(b)