Effects of postprandial state and mesenteric blood flow on the repeatability of MR elastography in asymptomatic subjects.

PURPOSE: To determine the repeatability of stiffness measurements in the liver using MR elastography (MRE) during the fasted and fed states. MRE has gained increased recognition as a noninvasive method to quantify fibrotic changes in the liver. It is well known that eating increases splanchnic blood flow, and fasting status of patients has been recognized as a factor that may affect hepatic stiffness measured with MRE.
MATERIALS AND METHODS: Hepatic MRE stiffness and flow through the superior mesenteric vein (SMV) were measured in 12 healthy subjects in fasted and fed states, and measurements were repeated 5 weeks later. A linear mixed effects model was used to estimate the sources of variability in the data, which included day (exams on different days) and subject. Sources were combined to calculate the overall standard deviation of a single MRE measurement.
RESULTS: The total within-subject standard deviation of an MRE exam is 8.5% (standard error [SE] = 1.7%) or 9.0% (SE = 1.8%) for fasted and fed states, respectively. No significant differences between fasted/fed state stiffness and no correlation between hepatic stiffness and SMV flow were observed.
CONCLUSION: As seen in this smaller population, healthy subjects scanned in a known fasted or fed state provide repeatable stiffness estimates with no relationship to SMV flow.