Fig. 1
Examples of MRI and FBY PET images in diffuse tumors. A right frontal recurrent WHO grade III oligodendroglioma (IDH mutant, chromosomal 1p/19q codeletion) displayed significant contrast enhancement (A) and FBY activity (B), with increased FBY uptake seen beyond contrast enhancement in the lateral and posterior regions (C). Semiautomated segmentation based on MRI (D) and FBY PET (E) was performed, and nonconcentric expansion of the FBY-based segment compared with the MRI-based segment was noted (F). Similarly, a left temporal recurrent WHO grade IV glioblastoma (IDH-wild type) exhibited contrast enhancement (G) and FBY radioactivity (H), with the increased FBY uptake extended anteriorly and medially (I). The semiautomated segmentations (J, K) also verified the extension of the ROIFBY to the potential invaded regions (with an abnormal T2-weighted signal). This characteristic may result from the infiltrative nature of diffuse gliomas and indicates that FBY can be absorbed in both contrast-enhanced regions and infiltrative noncontrast-enhanced tumors