MR elastography of pancreatic masses: preliminary results

Abstract

Objective To investigate the feasibility of spin-echo echo-planar imaging(SE-EPI) of magnetic resonance elastography (MRE) for the diagnosis of pancreatic mass and to evaluate the difference of stiffness value in different pancreatic mass. Methods In a retrospective study, MRE was performed in 20 healthy volunteer (control group) and 62 patients with surgery-proved pancreatic masses, including pancreatic cystadenoma in 5 cases and solid masses of pancreas in 57 cases (39 with malignant mass and 18 with benign mass) using 3.0 T MRE. The differences of stiffness between two groups were evaluated using non-parametric Mann-Whitney U test. ROC was used to assess the diagnostic ability of elastogram for the detection of pancreatic masses, and to evaluate MRE-determined stiffness for the differentiation of masses from healthy pancreas, and malignancy from benign solid masses. Results The total detection rate of elastogram was 91.9% (57/62),with false positive rate of 5.0% (1/20) and false negative rate of 8.1% (5/62). The median stiffness value in the control group vs patient group were 1.18 kPa (interquantile range:1.15 to 1.30) kPa and 2.43 kPa (interquantile range:1.94 to 3.64 kPa) respectively, with statistically significant differences (Z=-5.967,P<0.01). The sensitivity and specificity of stiffness (≥1.36 kPa) to differentiate pancreatic mass from healthy pancreas was 93.6% and 100.0%, respectively, and to differentiate benign and malignant solid masses (≥2.17 kPa) was 82.1% and 83.3%, respectively. Conclusion MRE is a promising method in detecting and distinguishing different pancreatic masses. Key words: Pancreas; Magnetic resonance imaging; Stiffness