Pancreatic extracellular volume fraction using T1 mapping in patients with impaired glucose intolerance

To evaluate pancreatic T1 mapping and extracellular volume (ECV) fraction's feasibility to assess impaired glucose tolerance (IGT) patients.

A total of 45 consecutive patients with known or suspected pancreatic disease underwent contrast-enhanced magnetic resonance (MR) imaging, including T1 mapping, using saturation recovery sequence. Patients were classified into three groups based on the American Diabetes Association criteria: no-diabetes subjects, HbA1c < 5.7%; pre-diabetes, 5.7% ≤ HbA1c < 6.5%; and type 2 diabetes mellitus (T2DM), HbA1c ≥ 6.5%. Pre-contrast pancreatic T1 value and ECV of the pancreas were computed, and then pre-contrast pancreatic T1 value, ECV and HbA1c values were compared. The present prospective study was approved by our institutional review board. Written informed consent was obtained from all patients.

A positive correlation between HbA1c values and both pre-contrast pancreatic T1 value and ECV (r = 0.79, P < 0.001 and r = 0.60, P < 0.001, respectively) were observed. The pre-contrast pancreatic T1 value and ECV were significantly higher in T2DM vs. no-diabetes subjects and pre-diabetes (P < 0.001). No significant difference between two qualitative values (P = 0.14) was found, however, the sensitivity, specificity, and area under the receiver-operating-characteristic curve differentiating no-diabetes subjects and pre-diabetes from T2DM were superior in ECV (100%, 93.5%, and 0.990) vs. pre-contrast pancreatic T1 values (84.6%, 96.8%, and 0.906).

The ECV of the pancreas could serve as a potential imaging biomarker for the assessment of pancreatic fibrosis leading to IGT.