Fig. 10.

Routine post-contrast MRI surveillance (a) for a patient with metastatic melanoma demonstrates a durally-based mass related to the right side of the tentorium cerebelli, best seen in the coronal plane (short arrow). The appearances are suggestive of a meningioma, but the lesion was much smaller on a CT performed only 8 months earlier (b), raising concern for a metastasis. Further characterisation with GaTate-PET (c) demonstrates high uptake, confirming the diagnosis of a meningioma rather than a metastasis