Different B Values Application Of MR Diffusion -Weighted Imaging In Pancreatic Carcinoma

Objective:To describe different b-valued solid tumor and cystic neoplasm of the pancreas diffusion-weighted imaging (DWI) performance and measurement apparent diffusion coefficient (ADC values), So as to investigate the ADC values scope and threshold between solid tumors and between cystic neoplasm of the pancreas in different b-valued.Materials and Methods:Respectively to 51 pancreatic solid tumor:(including 12 cases of benign tumor,6 cases of solid pseudopapillary tumors SPT,33 cases of pancreatic cancer) and 38 cases of pancreatic cystic neoplasm (including 21 cases of nonneoplastic cysts,17 cases of neoplastic cysts) by cervical disc compression were examined by MRI and magnetic resonance imaging (DWI) diffusion weighted scan, DWI and ADC map findings were reviewed,observe the differences of different b-valued tumor respectively, and do signal statistical analyses;The ADC values of lesions were measured in the different b values (b=50,350,400,450,700,1100 s/mm2), And then analyze the ADC values range and threshold of between solid tumor and between cystic neoplasm in different b-valued group by statistical analysis.Results:(1) Pancreatic solid tumor:①the DWI signal of pancreatic benign tumor declined orderly, however, there was no significant change for solid pseudopapillary tumors of pancreas and pancreatic cancer as b values increased with b factors of 700 s/mm2. Signal strength of pancreatic cancer and solid pseudopapillary tumors of pancreas were> signal strength of pancreatic benign tumor, which there was statistical difference (P<0.05);①There was statistical difference between the ADC value of solid pseudopapillary tumors of pancreas,pancreatic cancer and pancreatic benign tumor with b factors of 700 s/mm2. Yet three were no statistical significance between the there with b factors of 50,350,400,450,1100 s/mm2.③Using the the ADC values with the b=700 s/mm2 group for ROC curve analysis, the diagnosis threshold was 1.420×10-3mm2/s, with the sensitivity in differentiating pancreatic cancer was 71.4%, the specificity was 96.3%。(2) Pancreatic cystic neoplasm:①the DWI signal of pancreatic nonneoplastic cysts declined orderly, however, there was no significant change for pancreatic neoplastic cysts as b values increased with b factors of 700 s/mm2. Signal strength of pancreatic neoplastic cysts> signal strength of pancreatic nonneoplastic cysts, which there was statistical difference (P<0.05);③Using the the ADC values with the b=700 s/mm2 group for ROC curve analysis, the diagnosis threshold was 2.9122×10-3mm2/s, with the sensitivity in differentiating pancreatic neoplastic cysts was 73.7%, the specificity was 84.6%。Conclusion:(1) MR DWI can give quantitative information for pathological changes in pancreatic solid tumor and pancreatic cystic neoplasm. (2) MR DWI map can well display cancer of pancreas location and area. All pancreatic cancer lesions were hyperintense on DWI, the DWI value was lower in cancerous tissue than that in solid pseudopapillary tumors of pancreas and in the tissue of pancreatic benign tumor. DWI value can be used to differentiate diagnosis,and to prevention of early pancreatic cancer; All pancreatic neoplastic cysts lesions were higher signal on DWI, the DWI value was lower in pancreatic neoplastic cysts tissue than that in pancreatic nonneoplastic cysts. DWI value can be used to differentiate diagnosis,and to prevention of early pancreatic neoplastic cysts. (3) DWI, ADC value of combining conventional T1WI,T2WI, can improve the diagnosis of pancreatic cancer and the accuracy of diagnosis.