[Imaging characteristics of CT, MRI of tumors involving skull base in the parapharyngeal space].

OBJECTIVE: To discuss imaging characteristics of CT, MRI of tumors involving skull base in the parapharyngeal space,maximatily limit and improve the diagnosis rate of tumors involving skull base in the parapharyngeal space.

METHOD: Thirty-one patients with tumors involving skull base in the parapharyngeal space treated in our department were collected and reviewed. All the patients have pathological diagnosis and were examined by CT and/or MRI. To explore shape of tumor, its relation with surrounding structures, CT shows density size and the MRI signal directly through retrospective analysis of imaging characteristics of CT, MRI.

RESULT: In all the 31 cases, 19 tumors were schwannoma, 8 tumors were mixed tumor of salivary gland, 2 tumors were carotid body tumor. 2 tumors were nasopharyngeal carcinoma involving skull base. Schwannomas and salivary gland mixed tumor can be expressed as round or oval with periphery smooth, and had intact capsule. The tumors had necrosis, sac variable area. Pleomorphic adenoma are all derived from deep parotid. Schwannoma had clear boundary with deep parotid. The effect of cavum nasopharyngeal and cavum oropharyngeal is relevant to tumor sizes and locations. Imaging characteristics of CT, MRI for carotid body tumor show soft tissue mass with attenuation similar to that of muscle. CT enhancement scan show intense enhancement. MRI show imaging of flowing empty vein. Imaging characteristics of MRI for nasopharyngeal carcinoma involving skull base in the parapharyngeal space show oval mass with low density signal, T1WI enhancement scan show necrosis, sac variable area.

CONCLUSION: CT and MRI could provide the position, size, boundary of the tumor and its relationship with cervical blood vessels well, which were important to operation schemes. CT and MRI before operation are valuable to the treatment of PPS tumors.