Correlation Between Magnetic Reasonance Diffusion Weighted Imaging And Radiotherapy Effect In Nasopharyngeal Carcinoma

Objective: To evaluate alleosis regularity and correlation between the apprent diffusion coefficients in magnetic reasonance diffusion weighted imaging with echo-planar technique and volume value in nasopharyngeal carcinoma (NPC)after radiotherapy.Method: Thirteen nasopharyngeal poorly differentiated squamous carcinoma initial treatment patient,including 10 male and 3 female with age from 29-52 years (mean 38.8years), proved by pathology ,clinical stage T2N0-3M0(refer to International Union against Cancer),of them,5 had stageⅡ,8 had stageⅢ. All patients were examined by MRI before radiotherapy,each week after radiotherapy in 3 weeks and when radiothery is over(interval time is approxiate seven days).ADC value of NPC was determined on magnetic reasonance diffusion weighted images. Volume value of NPC was analyzed using Picture Archiving Communication System.Result: The ADC value(in units of 10-4mm2/s) of NPC before radiotherapy,the first,the second,the third and the fourth week after radiotherapy and radiotherapy termination was 8.38±0.89×10-4mm2/s,11.66±0.43×10-4mm2/s,12.82±0.40×10-4 mm2/s,13.90±0.74×10-4mm2/s,11.53±0.82×10-4mm2/s,9.05±0.62×10-4mm2/s,the each increased percentage of ADC value in the first three weeks after radiotherapy was 39.14%,9.95%及8.42%,the difference of ADC value of each week had statistics significance (t1=15.461 p<0.01,t2=9.066, p<0.05, t3=6.104, p<0.05),the ADC value(in units of 10-4mm2/s) of NPC began to decrease in the fourth week ,the percentage of decreased ADC value was 17%。The volume value (in units of mm3 )of NPC before radiotherapy,the first,the second,the third week and the fourth week after radiotherapy and radiotherapy termination was 10.72±3.22mm3,9.91±3.22mm3,7.38±3.03mm3,4.50±1.82mm3 ,3.56±0.81,1.43±0.51mm3,the each decreased percentage volume value of NPC in the first three weeks after radiotherapy was 7.56%,25.53%,39.02%,the difference of volume value between each week had statistics significance,(t1=3.256, p<0.05; t2=4.472, p<0.05; t3=6.888, p<0.05).The ADC value before radiotherapy had lineal negative correlation with the decreased volume percentage when radiotherapy is over(r=-0.694,F=10.208,p<0.05),the increased ADC value in the first week had lineal positive correlation with the decreased volume percentage when radiotherapy is over(r=0.728,F=12.372,p<0.05),However,the increased ADC value in the second week or the third week had not correlation with the decreased volume percentage when radiotherapy is over.Conclusion: The ADC value(in units of 10-4mm2/s) of NPC gradually increased in the 3 weeks after radiotherapy,especially in the first week,however,the obvious regression of tumor volume occurred in the third week.The ADC value before radiotherapy or the increased ADC value in the first week had correlation with volume regression,so as an image biomaker,magnetic reasonance diffusion weighted imaging can predict tumor therapeutic efficacy in early period.