Evaluation on CT and MRI image features for the diagnosis of local recurrences or residues of nasopharyngeai carcinoma after radiotherapy

Objective To explore the feasibility of evaluation on CT and MRI image features for the diagnosis of local recurrences or residues of nasopharyngeal carcinoma (NPC) after radiotherapy.Methods Included in this study were 85 cases of nasopharyngeal carcinoma with abnormal mass image in the nasophary- nx as displayed by CT or MRI images obtained 3 months to 2 years after the radiotherapy.Then,biopsy was given to them for making a pathohistological diagnosis to confirm if there was a focus reoccurred or being resi- due in the nasopharynx.For those with a negative pathohistological finding,CT or MRI image following up was continuously carried out among them,until a certain negative or positive conclusion about the focus making out.At last,a correlative analysis was made to evaluate the feasibility of such a program for the diagnosis of this kind of condition.Results Among this group of cases,41 were diagnosed with local recurrences or resi- dues of the lesion (41/85,48.2%) and 44 were seen with a kind of post-radiotherapeutic changes (44/85, 51.8%) in the nasopharynx by pathohistology,CT and MRI.The sensitivity,specificity and accuracy of CT and MRI image evaluation in the diagnosis of recurrence or residue of NPC after radiotherapy were 61.9%, 84.2% ,76.3% and 69.2% ,83.8 % ,77.8% respectively.Conclusions The accuracy of CT and MRI im- age evaluation in the diagnosis of recurrence or residue of NPC after radiotherapy is relatively lower,with a lit- tle superior diagnostic evaluation for MRI here,while a combination with CT and MRI can reduce the rate of misdiagnosis for such a kind of condition.