Time-course magnetic resonance imaging of rat pancreatic cyst after experimental pancreatitis.

Fast magnetic resonance (MR) imaging of the rat pancreas was carried out using a snapshot method to observe three-dimensional (3D) and temporal development of the pancreatic cyst after experimental pancreatitis. Acute pancreatitis was induced by a retrograde infusion of the trypsin-taurocholate solution into the pancreatic duct in 23 rats, of which seven survived for one month. Under 2% enflurane anesthesia, (1)H images of the rat abdomen were taken by a 4.7 T magnetic resonance spectrometer under spontaneous breathing. 3D images of the pancreas and cyst were reconstructed from the axial, sagittal and coronal images taken before, 24 h, 7 days, 14 days, 21 days and 28 days after the induction of pancreatitis. The 3D images reconstructed from different slice orientations at each time point showed good agreement with each other. The calculated volumes of the cyst on 7th, 14th, 21st, and 28th day were 0.3 +/- 0.1, 0.8 +/- 0.3, 2.1 +/- 0.6, 6.5 +/- 1.3 mL, respectively. The cystic fluid volume on 28th day was 6.4 +/- 1.4 mL, which confirmed reliability of volume measurement by MR imaging. Fast MR imaging (snapshot) together with 3D reconstruction allows us to understand the detailed chronological and spatial development of pancreatic cyst after acute pancreatitis in rats.