Chen Yunbin MD, Abstract Co-Author: Nothing to Disclose

Yiqi Yao MS, Presenter: Nothing to Disclose

Jinsheng Hong, Abstract Co-Author: Nothing to Disclose

Jianji Pan, Abstract Co-Author: Nothing to Disclose

Jing Zhong, Abstract Co-Author: Nothing to Disclose

Xiongwei Zheng MD, Abstract Co-Author: Nothing to Disclose

To analyze the differences of dynamic change in apparent diffusion coefficient(ADC) values on human nasopharyngeal carcinoma xenografts with different radiosensitivity after irradiation and the correlation between ADC values and tumor cellularity, necrosis percentage and KI67 scores.

BALB/c-nu nude mice (n = 70) were divided into 2 groups that were subcutaneously injected with CNE1 or CNE2 cell lines. Each group was further divided into control group(Group C,n=5) and therapy group (Group T, n = 30). According to different time points(1 day,2 days,3 days,5 days and 7 days after irradiation), group T then divided into 5 groups, 6 nude mice in each group. All cases received DW-MRI scans prior to irradiation and group T received DW-MRI scans at the time points mensioned above. ADC values of the xenografts were measured on ADC maps. ADC0, ADC1,ADC2,ADC3,ADC5 ,ADC7 were used to respectively symbolize the ADC values prior to as well as 1 day, 2 days, 3 days and 7 days after irradiation. Change in ADC values before and after irradiation was defined as ΔADC%. ΔADC1%, ΔADC2%, ΔADC3%, ΔADC5% and ΔADC7% were used to symbolize ΔADC% of each time point(ΔADC1%=(ADC1-ADC0)/ ADC0*100% and others so on). Speimens of all tumors were stained with HE and KI67.Image J software was adopted to calculate the tumor cellularity, necrosis percentage and KI67 scores.

The ADC0 of CNE1 and CNE2 groups were 1.4883±0.28448*10-3mm2/s and 1.2729±0.25906 *10-3mm2/s, respectively (t=-3.312，P=0.001). The differences of ΔADC1% and ΔADC7% between two groups were statistically significant (ΔADC1%：t=-3.701,P=0.004；ΔADC7%：t’=3.720,P=0.008). With the Pearson correlation analysis, ADC values correlated significantly with tumor cellularity(r=-0.613, P= 0.000), necrosis percentage(r=0.554, P=0.000) and KI67 scores(r=-0.488,P =0.000); and ΔADC% also correlated significantly with tumor cellularity(r=-0.623, P= 0.000), necrosis percentage(r=0.567, P=0.000) and KI67 scores(r=-0.270,P =0.037).

There exist marked differences in initial ADC values and dynamic change of ADC values after irradiation on human nasopharyngeal carcinoma xenografts with different radiosensitivity. The change of ADC values may help to reflect the variation in microstructure of tumor after irradiation.

DWI might become a promising technique for predicting radiosensitivity of nasopharyngeal carcinoma.

Yunbin, C, Yao, Y, Hong, J, Pan, J, Zhong, J, Zheng, X, The Analysis of Dynamic Change in Apparent Diffusion Coefficient Values on Human Nasopharyngeal Carcinoma Xenografts After Irradiation and Its Correlation with Histologic Features.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12029355.html