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[Dynamic enhanced spiral CT characteristics of recurrent nasopharyngeal carcinoma and radiofibrosis].

OBJECTIVE
To study the characteristics of dynamic enhanced density-time curves of recurrent nasopharyngeal carcinoma(RNPC) and radiofibrosis(RF) in spiral CT.


METHODS
Fifty cases of RF and 46 cases of RNPC were examined both before and after contrasting in spiral CT. The CT values of the regions of interest (ROI) at various acquisition time (0, 20, 30, 40, 50, 60, 90, 120, 150, 180, 210, 240, 270, and 300 sec after the beginning of the contrast injection) were collected. The difference in CT value of various acquisition time was analysed statisticaly and the dynamic enhanced density-time curves were established.


RESULTS
The typical curve in RF group was a slowly ascending-slowly descending one. Its peak CT value as seen at 210 sec postcontrast and measured 60.1 +/- 2.57 Hu. That of the RNPC was of rapidly ascending-slowly ascending-slowly descending one. Its peak CT valne was seen at 150 sec postcontrst and measured 75.4 +/- 7.2 Hu. The differences of CT values were significant between RNPC and RF from 40 to 300 sec postcontrast (P < 0.001).


CONCLUSION
The different characteristics of the dynamic enhanced desity-time curves and CT values of the ROI may provide important informations for differential diagnosis of RNPC and RF.