Fig. 4
From: Diagnostic accuracy of 18F–FDG PET/CT and MR imaging in patients with adenoid cystic carcinoma
ACC recurrence: PET/CT imaging was false-negative and MRI true-positive. Patient after multiple resections of the primary and recurrent tumours of an ACC in the right parotid gland area. A false-negative finding is seen on the on the fused PET/CT (a) and PET image (b), but there was a true-positive finding on the contrast-enhanced T1-weighted MR image (c) with a hyperintense tumour recurrence (arrow)