Staging and follow-up of high-grade malignant salivary gland tumours: The role of traditional versus functional imaging approaches – A review

•Adenoid cystic carcinoma is the most common high-grade malignant tumour.•Imaging: MRI is the best choice for T-staging a malignant salivary tumour.•Combining traditional MRI with functional MRI improves diagnostic accuracy.•US guided FNAC may confirm nature of primary tumour lymph node metastases.•Follow-up: In high-grade malignant tumours FDG PET/CT is not recommended on a routine basis.