Value of Free-Breathing Diffusion-Weighted MR Imaging with Background Suppression by Inversion Recovery at 3.0T for the Diagnosis of Solid Pancreatic Masses

Objective:To assess the value of free-breathing diffusion-weighted MR imaging with background suppression by inversion recovery at 3.0T for the differential diagnosis of solid pancreatic masses.Methods:A total of 58 patients with solid pancreatic masses have been enrolled,including 30 cases of pancreatic cancer,9 cases of mass-like pancreatitis,9 cases of solid pseudopapillary tumor of pancreas(SPTP) and 10 cases of pancreatic neuroendocrine tumor(PET).Fifteen healthy volunteers have also been enrolled as control group.All of them underwent T1WI,T2WI,MRCP,DWI,non-enhanced LAVA and enhanced LAVA.Free-breathing diffusion-weighted MR imaging with background suppression by inversion recovery was done.SE-EPI sequence and b values were 0 and 600.Apparent diffusion coefficient values(ADC) in tissues from different groups have been compared,and receiver operating characteristic(ROC) curves were used to analyze the efficiency.Results: ADC value was the highest in the control group,which was followed by PET,pancreatic cancer,mass-like pancreatitis and SPTP.Significant differences in ADC values were found among different groups by analysis of variance(ANOVA)(P0.001).LSD test showed that there were significant differences in ADC values among pancreatic cancer,mass-like pancreatitis and normal pancreas(P0.001).Sensitivity,specificity,positive predictive value and negative predictive value were 86.7%,88.9%,96.3% and 66.7%,respectively,when ADC≥ 0.00133 mm2/s was used as cutoff value for differential diagnosis of pancreatic cancer from mass-like pancreatitis.They were 77.8%,100%,100% and 83.3%,respectively,when ADC≤ 0.00125 mm2/s was used as cutoff value for differential diagnosis of SPTP from PET.Conclusions: ADC values in free-breathing diffusion-weighted MR imaging with background suppression by inversion recovery at 3.0T can reflect histopathological patterns of normal pancreas and pancreatic lesions,which is useful in the differential diagnosis of pancreatic masses.