Fig. 1
From: Diagnostic accuracy of 18F–FDG PET/CT and MR imaging in patients with adenoid cystic carcinoma
ACC recurrence: PET/CT imaging was true-positive, indistinctive finding on MRI. Patient after resection of an adenoid cystic carcinoma in the left parotid gland and after combined neutron/proton therapy. Recurrence is seen on the fused PET/CT (a) and PET image (b) with a focally increased FDG-uptake (arrow), but not on the contrast-enhanced T1-weighted MR image (c). In MRI, the finding was evaluated as radiation necrosis