[Evaluation of enhanced CT examination in the differential diagnosis of local recurrence and postradiation fibrosis in nasopharyngeal carcinoma].
OBJECTIVE
To evaluate enhanced CT examination in the differential diagnosis of local tumor recurrence and postradiation fibrosis when a mass appeared is observed after radiation therapy of carcinoma of nasopharynx.


METHODS
159 cases of nasopharyngeal carcinoma were examined by CT, including 37 cases of local recurrence(RT) after radiation therapy and 54 cases of postradiation fibrosis (RF) 68 cases of nasopharyngeal carcinoma (PT) before radiation therapy sened as comparison. Elscint sprint 2000 CT machine was used. The CT number of plain and enhanced examination of the mass appearing after radiation therapy were measured. Variance analysis was used as statistical management for CT number difference of different kinds of mass lesions before and after contrast enhancement.


RESULTS
In the RT cases, the average CT number of the mass lesion for plain scan were 50.40 +/- 8.10 Hu, and for enhanced scan it was 73.74 +/- 7.37 Hu. In the RF cases plain scan 48.62 +/- 10.15 Hu, enhanced scan 56.74 +/- 8.69 Hu, In the control cases (PT), the CT number in the plain scan of lesion was 48.32 +/- 9.20 Hu, and 72.38 +/- 7.75 Hu in the enhanced examination. These measurement showed obvious enhancement of recurrence tumor. The CT number of contrast scan of RT and RF was obviousy different (P < 0.01).


CONCLUSIONS
If a mass lesion appears after radiation therapy in carcinoma of nasopharyx, enhancement of the lesion in CT scan is an important criterion for differential diagnosis.
Sichuan Cancer Hospital, Chengdu.
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Yan
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Wang
D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000532:radiotherapy*; D003937:Diagnosis, Differential; D005260:Female; D005355:Fibrosis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D009364:Neoplasm Recurrence, Local; D011832:Radiation Injuries / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed