Application Of 3.0T MRI Multi-b-value Diffusion Weighted Imaging In Evaluation The Treatment Effect Of Radiotherapy In Pancreatic Cancer

Objective:Different b values of DWI sequence were used to process the pancreatic radiotherapy of before and after. To investigate the effection of multi-b-value diffusion weighted imaging(DWI) on early radiotherapy and clinical application for pancreatic cancer.Materials and Methods: The investigation elected 23 patients who had been diagnosed pancreatic cancer, including 15 males and 8 females. The age changes from43 to 65 years, and the median age is 51 years. About 11 patients were diagnosed in adenocarcinoma through aspiration biopsy,anther 12 cases were diagnosed by clinical manifestations, various laboratory tests and a variety of imaging studies.There were 18 cases located in the head of the pancreas, 4 cases located in pancreatic body, 1 case located in the tail of the pancreas.The case that we choose meet the following condition:⑴Pancreatic cancer was diagnosed by comprehensive methods;⑵The patients with no other parts of the outer primary malignant tumors in addition to pancreatic cancer; ⑶ The patients did not receive the pancreatic tumor resection, chemotherapy and targeted biological therapy;⑷Patients signed informed consent form.The value of DWI sequences b was set at 0, 600, 800, 1000 s / mm2, the original scan data uploaded to the AW-4.5 workstation in the end.The Functool ADC softwarewas used to detect the image data of DWI in different b-values. And ADC values of these regions need respectively record, such as the original tumor, near area of the tumor, the remote end of tumor. After the patients accepted one month TOMO radiation therapy, MRI scanning performed to record the data again. In order to more clearly showed the anatomical structure of the pancreas and peripancreatic, and position mass region more accurately, the images of DWI and ADC were merged.The ADC values under the condition of different b values and different zones were compared before and after radiotherapy in patients with pancreatic cancer.Pairwise comparison:⑴before radiotherapy:lump zone and adjacent lump zone,lump zone and away from the lump zone; ⑵ before and after radiotherapy:lump zone and itself; ⑶before and after radiotherapy:adjacent lump zone and itself; ⑷ before and after radiotherapy:away from the lump zone and itself.In conclusion, the best b value can be used to evaluate the effect of radiotherapy in pancreatic cancer, according to pairwise comparison results in different b values, the image quality and the relative ADC value(r ADC).Results:Pancreas.b values were set at 600,800,1000s/mm2. The ADC values were compared before radiotherapy:there were no significant difference between lump zone and adjacent lump zone(t=1.934 、 0.376 、 0.661,P > 0.05);there were statistically significant between lump zone and away from the lump zone(t=7.824、5.564、4.806,P<0.01).The ADC values were compared before and after radiotherapy:the differences of lump zone and adjacent lump zone were both statistically significant between before radiotherapy and after radiotherapy(lump zone:t=10.45、8.612、8.429,P<0.01;adjacent lump zone:t=5.785、11.38、14.08,P<0.01).The away from the lump zone are no significant difference between before radiotherapy and after radiotherapy(t=1.232、1.894、1.997,P>0.05).The r ADC values:The r ADC was(32.42 ± 1.97)%,(28.44 ± 2.44)%,(30.27 ±2.03)% when b values was 600, 800, 1000s/mm2, respectively.The differences of r ADC600 and r ADC800,and r ADC600 and r ADC1000 were both no significant difference(t= 1.270、0.760, P> 0.05).We came to the conclusion that the best b value to evaluate the effect of radiotherapy was 600 s/mm2. that based on the analysis of SNR,CNR,r ADC and the image quality.Liver.The differences were no statistically significant between before radiotherapy(the ADC was 1.238±0.213,1.169±0.117,1.063±0.282, when b values was 600, 800, 1000s/mm2, respectively)and after radiotherapy(the ADC was 1.215±0.292,1.201 ± 0.171,1.119 ± 0.234 when b values was 600,800,1000s/mm2,respectively).Conclusion: As a non-invasive, highly sensitive screening method, DWI has been applied in a variety of tumors(such as the brain, prostate, et al.) to assess the efficacy of treatment.Microscopic changes in the molecular structure of DWI sequence earlier than the change of general mass alignment. In this paper,The multi-article b value of DWI sequence can reflect changes in the value of the measurement area ADC before and after radiotherapy, and can be used to evaluate the efficacy of early pancreatic cancer radiotherapy and provide a reference for clinical treatment programs continue or change.If the ADC values have no significant changes before radiotherapy, indicating that the cells apoptosis have no significant, namely tumor infiltration therapy or not. If the ADC values gradual increase, namely tumor cells gradually apoptosis, suggesting that treatment is effective.At the same time,it can be applied to the entire follow-up of patients with pancreatic cancer radiotherapy process,and provide better individualized treatment.However,due to various limiting factors, Such as sample size, ADC error,patient physical fitness, researchers subjective conditions et al,further research is needed.