Nasopharyngeal CT and sinus CT examine different parts of the body, nasopharyngeal CT mainly examines the nasopharynx, and sinus CT mainly observes the specific conditions of the sinuses. If you suspect nasopharyngeal cancer, adenoid hypertrophy and other diseases, CT nasopharyngeal examination is able to see the specific extent of tumor invasion and the specific degree of adenoid hypertrophy, and whether the posterior nostrils are blocked. If you consider maxillary sinusitis, sieve sinusitis, frontal sinusitis, pterygoid sinusitis and whether there is a large amount of pus in each group of sinuses, whether there is tumor growth, the CT examination of the sinuses can make clear which sinus is the problem, and provide a scientific basis for the development of future surgical plan, and play a guiding role in the operation. Nasopharyngeal CT and sinus CT in a certain plane of the axial CT slice is the same, are cut horizontally, coronal and sagittal CT slice is not exactly the same.