NI-RADS risk stratification guidelinesa
| Description | Category | Imaging Findings | Management |
|---|---|---|---|
| Incomplete | 0 | New baseline study or unavailable previous imaging | Previous imaging |
| No evidence of recurrence | 1 | Posttreatment changes without mass or abnormal FDG uptake | Routine surveillance |
| Low suspicion (superficial) | 2a | Enhancement without FDG uptake or mild/moderate FDG uptake without a mass | Direct visual inspection |
| Low suspicion (deep) | 2b | Enhancement without FDG uptake or mild/moderate FDG uptake without a mass | Short imaging follow-up |
| High suspicion | 3 | New or enlarged mass or lymph node, enhancement, and intense FDG uptake | Biopsy |
| Definitive recurrence | 4 | Pathologically proved or definite progression | Clinical management |
↵a The NI-RADS risk stratification guidelines grade head and neck tumor treatment response; adapted from Ref. 26.