The Application Value Study Of Diffusion-Weighted Magnetic Resonance Imaging(DWI) In Evaluation Of Therapeutic Effect And Prognosis For Lung Carcinoma

Objective: To investigate efficacy evaluation for lung cancer before and after radiotherapy with the magnetic resonance diffusion-weighted imaging(DWI) and apparent diffusion coefficient(ADC) values. The conclusion could be used to guide the clinical treatment.Methods: Forty-three lung cancer patients from December 2010 to October 2013 were included in this study. Besides, the thirty patients were biopsy-proven( squamous cell carcinoma in 12 cases,adenocarcinoma in 9 cases,small cell carcinoma in 9 cases, 3 cases couldn’t been further defined histologically).10 cases of them were clinically diagnosed for lung cancer though imaging, all of them accepted the three-dimensional conformal or intensity-modulated radiation therapy. Prescription dose : 46-66 Gy(The median dose 60Gy), signal dose 2.0~2.2 Gy, 1 time/day,5 times/week. Among them,there were 14 patients accepted 1 or 2 cycles of chemotherapy in the same period, program for TP(taxol 135mg/m2,d1,cisplatin 25mg/m2,d2-4), EP(Etoposide 100mg/m2,d1-5,Cisplatin 30mg/ m2,d1-4), 28 days for one cycle, the medicament were provided in 1th and 5th week. CT scan and routine MRI scans(T1WI,T2 WI)and diffusion-weighted imaging(DWI) were done 1 week before and 1 week after the radiotherapy. The change between ADC values and the size of the tumor were compared before and after radiotherapy.Responsing evaluation criteria in solid tumors,RECIST 1.0, the short-term curative effect was evaluated. The curative effect include four grades: complete response,CR; partial response,PR; stable disease,SD; progressive disease,PD. Observing the change of DWI hyperintensity expression and ADC values of tumor before and after radiotherapy, the clinical value of diffusion-weighted imaging( DWI) in assessing the therapeutic effect of chemoradiotherapy could be investigated. Statistical analysis was performed using an SPSS statistical package(Version 13.0)Results:(1)The follow-up toward the 43 patients above-mentioned lasted to January 24,2014, the rate of follow-up reached 100%, the duration of follow-up was 16-49 months, and the median follow-up time was 41 months, 2 years in 34 cases, 30 cases over 3 years.(2) CT scan and routine MRI scans were done after the radiotherapy to assess the therapeutic effect of chemoradiotherapy, statistic results shown:8 cases in CR, accounting for 8%; 30 cases in PR, accounting for 69.8%;5 cases in NR, accounting for 11.6%(4 cases in SD,1case in PD),the total therapeutic effect rate of the patients above-mentioned was 88.4%. The survival rate of whole group in 1th、2th、3th year was 51.2%、9.3%、4.6% in turn. The survival rate of CR group、PR group and NR group had no statistical significance,P=0.000. Beside,the survival situation of CR and PR group had statistical difference,P=0.01.(3)DWI image of all group shown high signal before radiotherapy, 14 cases occurred high signal disappeared, 29 cases retained(25 cases appeared slightly high signal,4 cases appeared significant high signal). The term efficacy efficiency of high signal disappearing group and high signal retaining group had no statistical significance,P=0.100. The survival rate of high signal disappearing group in 1th、2th、3th year was 71.4%、24.5%、12.4% in turn,as the same,the survival rate of high signal retaining group was 41.4%、7.8%、3.9%, the survival situation of these groups had statistical difference,P=0.04. Further, the survival situation of slightly high signal group and significant high signal group had no statistical difference,P=0.85.(4) The ADC values of squamous cell carcinoma group 、adenocarcinoma group and small cell carcinoma group had had no statistical difference,P=0.99. The ADC values of NR group(1.15 ± 0.17) × 10-3mm2/s) was topmost compared to the CR group((1.07 ± 0.15) × 10-3mm2/s) and PR group((1.02 ± 0.15) ×10-3mm2/s),but the ADC values of these group had no statistical difference,P=0.25. The survival situation of ADC values high group(≥1.02×10-3mm2/s,22/43) and ADC values low group(<1.02×10-3mm2/s,21/43) had no statistical difference,P=0.43.(5)The ADC values of PR group((1.42±0.18)×10-3mm2/s) was higher than NR group(( 1.33 ± 0.11)×10-3mm2/s) after radiotherapy, and they had no statistical difference,P=0.12. The survival situation of ADC values high group(≥1.41×10-3mm2/s) and ADC values low group(<1.41×10-3mm2/s) had no statistical difference after radiotherapy,P=0.43.(6)The ADC values increased Significantly after radiotherapy((1.04 ± 0.16) × 10-3mm2/s vs(1.41 ± 0.17) × 10-3mm2/s,P=0.000).(7)The mean of △ADC was(0.37±0.19)×10-3mm2/s befor and after radiotherapy in turn. △ADC of PR group was significiant higher than NR group(( 0.40 ± 0.19)× 10-3mm2/s VS(0.18 ± 0.16) × 10-3mm2/s,P=0.007). The correlation between △ADC and △tumor regression rate was moderate(r=0.46,P=0.006). The survival situation of △ADC values high group(≥0.33×10-3mm2/s) and △ADC values low group(<0.33×10-3mm2/s) had no statistical difference,P=0.43.Conclusion:(1) The diffusion-weighted imaging( DWI) has certain clinical value in assessing the therapeutic effect of chemoradiotherapy.(2)The prognosis of patients whose hyperintensity existent is worse than those cases whose hyperintensity disappeared.(3)The direction and rangeability of ADC values(△ADC) is helpful to monitor the short-term efficacy of lung cancer.