Magnetic Resonance Elastography And T1 Mapping For Early Diagnosis And Classification Of Chronic Pancreatitis

Objective: Chronic pancreatitis(CP)is characterized by progressive inflammation,pancreatic fibrosis,and impairment of both exocrine and endocrine function,but its diagnosis depends on postoperative pathology or endoscopic biopsy.Noninvasive imaging has developed rapidly in the diagnosis of pancreatic diseases,while MR elastography and T1 mapping imaging have not been reported in the field of chronic pancreatitis in China.This study aims to explore the diagnostic value of MRE and T1 mapping in the diagnosis of chronic pancreatitis staging,and then compare their diagnostic ability.Methods: This study was approved by the institutional review board with written informed consent.According to the patient's clinical and imaging information,a total of 81 patients underwent preoperative 3T MRE and T1 mapping imaging(35 normal cases,30 mild cases and 16 moderate to severe cases).MRE and T1 mapping imaging parameters(Stiffness,T1 relaxation time)were measured independently by two radiologists with 3 and 5 years of experience in abdominal imaging diagnosis.Using receiver operating characteristic curve(ROC)analysis to determine the diagnostic performance of MRE and T1 mapping parameters for staging chronic pancreatitis stages.Results:Both T1 relaxation times(865±220 ms vs 1075±221 ms vs 1350±139 ms)and pancreatic stiffness(1.21±0.13 kPa vs 1.50±0.15 kPa vs 1.90±0.16 kPa)differed significantly(P < 0.001)among the control,mild CP and moderate/severe CP groups.Pancreatic stiffness(>1.34 kPa)achieved significantly higher area under the curve(AUC)than T1 relaxation time(>908.4 ms)for detection of mild CP(AUC: 0.928 vs 0.751,P = 0.011).Pancreatic stiffness values(>1.61 kPa)also achieved significantly higher AUC than T1 relaxation times(>1,131.6 ms)(AUC: 0.981 vs 0.910,P = 0.033)for diagnosing moderate/severe CP from the other two groups.Multiple regression analysis showed that T1 relaxation time and stiffness were the independent factors associated with mild CP(P = 0.025 and <0.001,respectively).Conclusion: Both MRE and T1 mapping are promising quantitative imaging methods for evaluation of CP;MRE slightly outperformed T1 mapping.