Magnetic resonance elastography and T1 mapping for early diagnosis and classification of chronic pancreatitis.

<bold>Background: </bold>Early detection and classification of chronic pancreatitis (CP) are both important and challenging.<bold>Purpose: </bold>To investigate the diagnostic performance of MR elastography (MRE) and T1 mapping of the pancreas for different stages of CP.<bold>Study Type: </bold>Retrospective.<bold>Subjects: </bold>Clinical and imaging records of 81 patients (from 5/2015 to 7/2017) with suspected CP were analyzed. Patients were categorized into the normal control (n = 35), mild CP (n = 30), and moderate/severe CP groups (n = 16) according to the Cambridge Classification based on concordant endoscopic retrograde cholangiopancreatography or ultrasound endoscopy findings.<bold>Field Strength/sequence: </bold>3T pancreatic MRI, which included MRE and T1 mapping.<bold>Assessment: </bold>T1 relaxation times, pancreatic stiffness values, the main pancreatic duct (MPD) diameter, and pancreatic thickness were measured in all patients. Statistical Tests: Cutoff values of T1 relaxation times and pancreatic stiffness values for diagnosis of CP were calculated using receiver operating characteristic analysis. Associations of imaging parameters with different stages of CP were assessed using logistic regression analysis.<bold>Results: </bold>Both T1 relaxation times (865 ± 220 msec vs. 1075 ± 221 msec vs. 1350 ± 139 msec) 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 msec) 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 time (>1131.6 msec) (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).<bold>Data Conclusion: </bold>Both MRE and T1 mapping are promising quantitative imaging methods for evaluation of CP; MRE slightly outperformed T1 mapping.<bold>Level Of Evidence: </bold>1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018. [ABSTRACT FROM AUTHOR]