Introduction

T2 mapping plays an important role in diagnosis of diseases[1] due to its quantitative ability. So far, the application of T2 mapping has been applied to heart, nerve, bone joints and so on, however, seldom work has been reported about its application in pancreatic diseases. Therefore, this study aims to explore the application of T2mapping quantitative imaging in pancreatic changes after benign and malignant bile duct obstruction.

Material and methods

Malignant group with 6 cases and benign group with 7 cases were enrolled in this retrospective study. The study was performed on a 3.0T MR scanner (Ingenia 3.0T CX; Philips Healthcare, Best, the Netherlands) with a 32-channel abdominal array coil.Scanning sequences: axial T2-weighted imaging (T2WI),T2 mapping And Diffusion-weighted imaging (DWI). Scanning parameters: T2WI: TR/TE= 4900/85ms, FOV=240x 240x 119mm3, voxel size 0.7x0.7x4mm3, scan time=2min48s;T2 mapping: TR/TE=1157/20ms, FOV=400 x319 x70mm3, voxel size 2.1 x2.62 x7mm3, scan time=1min58s;DWI: TR/TE= 3900/60ms, FOV=240x240x119 mm3, voxel size 3.0x3.0x4mm3, scan time=1 min 46s. All data were transferred to the IntelliSpace Portal, (Philips Healthcare). Two physicians with 3 years and 6 years of MRI diagnosis experience were employed to drawregion of interest(ROI) in the uniform areas of parenchymal signals in the head, body, and tail of the pancreas with dilated pancreatic ducts avoided.(Figure 1). The value of ROI drawn by the senior physician was taken as statistical analysis,and averagevalue of ROI for three times was taken as the follow-up statistical analysis. Intra-group correlation coefficient (ICC) was used to test the consistency of the measurement results of the two observers.The difference of parameters between the two groupswere performed by Mann-Whitney U test.

Results

The consistency of data measured by two observers was good (ICC>0.75)( Table 1).T2 mapping value of pancreatic changes caused by malignant low biliary tract obstruction was higher than that of benign group with statistical difference (P<0.05)( Table 2). T2 mapping value were 90.065 as the differential diagnosis thresholds, the corresponding diagnostic sensitivity and specificity were 83.3% and 100%, and the AUC value were 0.857(Figure2).

Discussion and Conclusion

In this study we illustrate the feasibility of T2 mapping in evaluating the parenchymal changes of the pancreascaused by benign and malignant low biliary tract obstruction.. Results shows that T2 value in malignat groupis significantly higher than that inthe benign group, which indicates that T2 mapping may be an effective tool fordiagnosis ofsuch pancreatic diseases.

Acknowledgements

no acknowledgements founds

References

[1]Hamlin SA, Henry TS, Little BP, et al. Mapping the future of cardiac MR imaging: case-based review of T1 and T2 mapping techniques. Radiograohics. 2014;34(6):1594-1611.