Study On Threshold Of Multi-slice CT Perfusion Parameters In Nasopharyngeal Carcinoma And Its Diagnostic Value

Objective To study the threshold of multi-slice CT(MSCT)prefusion (CTP)parameters in pre-treatment nasopharyngeal carcinoma(NPC),and its diagnostic value for differentiating post-radiotherapy local recurrence tumor from fibrosis.Patiensts and Methods A total 77 patients including 46 patients with pre-treatment NPC,14 patiens with post-radiotherapy local recurrence tumor and 17 patients with local fibrosis were performed perfusion CT(GE/lightspeed Ultra 8)between June 2004 and June 2007.Images obtained by CTP were inputed GE AW4.2 workstation.Perfusion3 software package was used to postprocess.External carotid artery and retromandibular vein is as inputing artery and outputting vein.The measurement of perfusion parameters were analysed and perfusion parameters threshold was calculated the statistical difference perfusion parameters including blood flow(BF),blood volume(BV), permeability surface(PS)and mean transition time(MTT)were compared by statistics software spss 13.0 respectively.If there was no statistical difference between the perfusion parameter values of pre-treatment NPC and local recurrence tumor,and the perfusion parameter values in pre-treatment NPC and local recurrence tumor were significantly different with those in post-radiotherapy fibrosis,then the sensitivity and specificity were used to evaluate the diagnostic value of perfusion parameters threshold in the local recurrence tumor of NPC.Results The means of perfusion parameter values including BF,BV,MTT and PS were(795.81+242.65)ml/min/100g,(48.51+29.99)ml/100g,(2.98+2.21)s, (49.35+35.15)ml/min/g,(837.10+227.01)ml/min/100g,(48.37+33.83)ml/100g, (2.50+0.99)s,(40.87+37.86)ml/min/g and(111.82+78.51)ml/min/100g, (5.24+2.26)mi/100g,(8.59+6.12)s,(17.33+11.91)ml/min/g,respectively.The perfusion parameters threshold of BF,BV,MTT and PS in the pre-treatment NPC were 210ml/min/100g,8.21ml/100g,8.92s,14 ml/min/g,respectively. There was no statistical difference between the perfusion parameter values of pre-treatment NPC and the recurrence tumor(P＞0.05).The perfusion parameter values including BF,BV,PS in pre-treatment NPC and local recurrence tumor were were higher and MTT values were lower than those in post-radiotherapy fibrosis(P＜0.05).The Sensitivity and the Specificity of diagnosis in local recurrence tumor were 100%,100%,100%,71.34%and 94.12%,88.24%, 35.29%,58.82%respectively.Conclusion①There was no statistical difference between the perfusion parameter values(BF,BV,MTT and PS)of pre-treatment NPC and the recurrence tumor(P＞0.05),and the perfusion parameter values in pre-treatment NPC and local recurrence tumor were significantly different with those in radiofibrosis.②The perfusion parameters threshold of BF,BV,MTT and PS in the pre-treatment NPC can substitute for those of local recurrence tumor and those were helpful for the differential diagnosis of post-radiotherapy local recurrence tumor and local radiofibrosis.