Temel Tirkes MD, Presenter: Nothing to Disclose

Alex M. Aisen MD, Abstract Co-Author: Consultant, Repligen Corporation Research Grant, Repligen Corporation Consultant, Carestream Health, Inc

Fatih Akisik MD, Abstract Co-Author: Nothing to Disclose

Determine if pancreatic signal on T1-weighted fat-suppressed pre-contrast GRE image can be indicator of decreased exocrine function.

A retrospective analysis was performed on 42 suspected chronic pancreatitis (CP) patients who had both intraductal secretin stimulation test (IDST) and MRCP. IDST involves collection of fluid from the pancreatic duct after stimulation with intravenous secretin at the time of Endoscopic Retrograde Cholangiopancreatography (ERCP). Fluid is assessed for bicarbonate concentration (HCO3) as a measure of exocrine pancreatic function (HCO3 >105 is considered normal). There were 29 patients with normal and 13 patients with decreased exocrine function. By ERCP, 40 patients were categorized as normal and 2 patients as mild CP based on the Cambridge classification. MRCP was performed on 1.5T (n=34) or 3T (n=8) scanners. A volume interpolated 3D GRE sequence was used to acquire T1-weighted pre-contrast images using minimal TE, mean TR and flip angle of 5.01±0.32 ms and 12 for 1.5T and 4.33±0.32 ms and 9 for 3T scanners. Two reviewers independently performed region of interest (ROI) measurements (~1cm2) from the head, body and tail of the pancreas as well as the spleen. Signal intensity ratio (SIR) was calculated by dividing the average pancreas signal by the spleen. Pearson's correlation coefficient was calculated to assess the correlation between HC03 concentration and SIR. Analyses of covariance (ANCOVA) models were used to determine the differences in SIR between normal and decreased group as well as the variability of measurements between 1.5T and 3T scanners.

There was significant difference (p< 0.0001) in the SIR of the pancreas between the normal (mean 1.41, SD: 0.27) and decreased exocrine function group (mean 1.05, SD: 0.21). A significant positive correlation (p <0.0001) was found between pancreatic fluid HC03 level and SIR. Inter-observer correlation was excellent (kappa=0.90, p <0.0001). Similar results were found on both the 1.5T and 3T scanners (p=0.62).

There was significant correlation between the decreased exocrine function (measured by the IDST) and lower T1-weigthed signal on fat-suppressed pre-contrast GRE images.

Ratio of T1-weighted signal of the pancreas over spleen can be used as an indicator of decreased exocrine function in patients with suspected early chronic pancreatitis.

Tirkes, T, Aisen, A, Akisik, F, Prediction of Exocrine Dysfunction in Early Chronic Pancreatitis by T1-weighted Gradient Echo (GRE) Signal Intensity.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14003895.html