Table 1 Inclusion and exclusion criteria of patients

Inclusion criteria

• Primary nasopharyngeal carcinoma diagnosed by pathology and treated in hospital.

• No distant metastases at the time of initial diagnosis

• Pre-treatment MRI images were available, which included axial T1-enhanced sequences

• Regular review was performed

• Telephone follow-up was available

Exclusion criteria

• nasopharyngeal carcinoma that recurred after treatment

• Pre-treatment MRI was not available, or the images were corrupted, or ther have not axial T1-enhanced sequences

• There has been distant metastasis at the time of diagnosis

• Regular review was not performed