Diagnostic Criteria for Skull-Base Invasion in Nasopharyngeal Carcinoma

Based on the relevant literature 15 (link), 16 (link), the inclusion criteria for SBI of NPC were as follows: (1) a pathological diagnosis of NPC; and (2) an imaging diagnosis of SBI based on a low signal intensity defect of the bone cortex on MRI, high signal intensity bone marrow replaced by low signal intensity tissue on MRI, skull-base muscle signal changes, and an unclear demarcation between skull-base muscle and the primary tumor. The images had to show the invasion of 1 or more of the following sites: the pterygopalatine fossa, infratemporal fossa, sinus sphenoidalis, sellar floor, clivus, pars petrosa of the temporal bone, foramen ovale, foramen rupture, cavernous sinus, or jugular regions. Patients were excluded from the study if they met any of the following exclusion criteria: (1) had claustrophobia, a pacemaker, or severe liver and kidney insufficiency, or were in a coma, or had other symptoms; (2) had images of a quality that could not be assessed; (3) had other primary malignant tumors; and/or (4) did not have SBI according to the above SBI criteria.