In this issue, Karlberg and colleagues present "18F-FACBC PET/MRI in Diagnostic Assessment and Neurosurgery of Gliomas."
This pilot study evaluated the amino acid tracer 18F-FACBC with simultaneous PET/MRI in 11 patients with suspected primary or recurrent low- or high-grade gliomas prior to surgery. PET and MRI were used for diagnostic assessment and for guiding tumor resection with histopathological tissue sampling. PET uptake, tumor-to-background ratios (TBRs), time-activity curves and PET and MRI tumor volumes were measured.
The overall lesion detection sensitivity was 54.5% (95% CI, 23.4–83.3) for PET, 45.5% (95% CI, 16.7–76.6) for contrast-enhanced MRI (MRICE), and 100% (95% CI, 71.5–100.0) for combined 18F-FACBC PET/MRI, with a significant difference between MRICE and combined PET/MRI (P = 0.031). TBRs increased with tumor grade (P = 0.004) and were stable from 10 minutes post injection. PET tumor volumes corresponded more than 98% of the MRICE volumes and were 1.5–2.8 times larger. Based on image-localized biopsies, combined PET/MRI demonstrated higher concurrence with malignant findings at histopathology (89.5%) than MRICE (26.3%).
The authors concluded that low- versus high-grade glioma differentiation may be possible with 18F-FACBC using TBR. 18F-FACBC PET/MRI outperformed MRICE in glioma tissue localization.
Perhaps 18F-FACBC will assume a new role in brain tumor PET…