Figure 5.

Contrast-enhanced MRI and FET PET of a 31-years-old female patient (patient #29) with an astrocytoma (IDH-mutant, WHO CNS grade 3, MGMT promoter methylated) treated with lomustine-based chemotherapy. After two cycles, the contrast-enhancing lesion progressed slightly. In contrast, the follow-up FET PET showed, relative to the baseline scan, a considerably decreased metabolic activity of 21% as assessed by a relative reduction of maximum tumor-to-brain ratios (baseline, 4.3; follow-up, 3.4) and indicated metabolic response. Without clinical deterioration or treatment change, the patient had a favorable PFS and OS (both not reached; 71.8 months at the time of data evaluation).