Head and neck cancer (HNC) is considered the seventh most common malignancy worldwide. Recurrence of HNC poses a significant challenge to long-term survival, with a loco-regional recurrence rate of 30-50% within the first two years of management. Detecting recurrence in HNC through imaging techniques is challenging due to the complexities caused by surgery, radiation, and chemotherapy.
To address these challenges, NI-RADS was developed as a standardized reporting template with management recommendations. NI-RADS categorizes imaging findings and provides management recommendations to differentiate between post-management changes and residual or recurrent tumour. Initially, NI-RADS was applied to CECT and PET-CT and could be used similarly to CE-MRI. Subsequently, in 2021 an independent addition was made for MRI NI-RADS with inclusion of T2 signal intensity (T2SI) at the primary tumour site.
T2SI in MRI can help differentiate fibrotic tissue from edema and granulation tissue, providing varying levels of suspicion. DWI, a functional MRI sequence, detects microscopic changes by measuring the diffusion of water molecules in tissues and assessing tissue cellularity.