Risk-adapted imaging of gastric neuroendocrine neoplasms: an entity-, type-, and grade-informed framework for staging and management.

PURPOSE: To develop an evidence-informed imaging framework for gastric neuroendocrine neoplasms (gastric NENs) that separates pathological entity, gastric NET type, and grade and links imaging selection to management-relevant questions. METHODS: This structured narrative review used PubMed/MEDLINE and the Web of Science Core Collection through December 31, 2025, with a reproducibility rerun on August 31, 2026. Evidence was appraised at the recommendation/reporting-item level and tagged as direct gastric or gastroduodenal evidence (G-NEN), formal guidance (GL), broader gastroenteropancreatic NEN evidence (GEP-NEN), or author synthesis (AS). RESULTS: The review yielded a hierarchical two-axis imaging framework, a modality-specific reporting checklist, and an evidence-uncertainty table. Type I-III classification is restricted to well-differentiated gastric NETs, with grade and adverse features treated as modifiers. Somatostatin receptor (SSTR) PET/CT and fluorodeoxyglucose (FDG) PET/CT are selected independently for defined questions, and localized NEC considered for curative-intent surgery is distinguished from unequivocally metastatic NEC. CONCLUSIONS: The framework aligns imaging with pathological entity, gastric NET type, grade, disease extent, and management intent. It is an evidence-informed conceptual framework for imaging selection, reporting, and multidisciplinary decision-making rather than a prospectively validated clinical pathway.