Pancreatic stiffness response to an oral glucose load in obese adults measured by magnetic resonance elastography

Abstract

BackgroundTo test the feasibility of magnetic resonance elastography (MRE) for assessing changes in pancreatic stiffness of obese adults administered an oral glucose load. MethodsMRE scans were performed on 21 asymptomatic obese volunteers (BMI ≥ 27 kg/m2) before and after receiving a 75-g oral glucose load, and repeated in 7 days without a glucose load. Shear waves at 40 and 60 Hz were introduced into the upper abdomen by a pneumatic drum driver (diameter of 12 cm). Two radiologists subjectively graded the overall quality of the wave images of the pancreas using a scale from 1 to 4, in which suboptimal image quality was considered to be scores of 1 and 2. ResultsGood inter-observer agreement was found for image quality at both frequencies (kappa = 0.805 for 40 Hz and 0.762 for 60 Hz). The median overall image quality score was significantly higher in 40 Hz than that of 60 Hz (4 versus 2). At 40 Hz, pancreatic stiffness in response to oral glucose had a decrease of 6.7% (pre vs post: 1.17 ± 0.13 kPa vs 1.08 ± 0.12 kPa; P < 0.001), whereas the change in stiffness was not significant at 60 Hz (pre vs post: 2.01 ± 0.21 kPa vs 2.02 ± 0.24 kPa; P = 0.695). Excellent intersession agreement was found for MRE acquisitions at 40 Hz with an overall intraclass correlation coefficient = 0.947 (95% confidence interval: 0.913–0.967). ConclusionMRE at 40 Hz provides good-quality wave images and high sensitivity to changes in the mechanical properties of pancreatic tissue in obese volunteers after an oral glucose load.