Lymphatic pathway around the pancreatic head and extrahepatic bile duct: evaluation using MR imaging at 3.0-T

To evaluate the utility of spectral presaturation with inversion recovery (SPIR) T2-weighted images with 3-dimensional (3D) volume isotropic turbo spin echo acquisition (VISTA) at 3.0-T for the detection of the normal lymphatic systems located around the pancreatic head and extrahepatic bile duct. Fifty-six patients with suspected hepatic or pancreaticobiliary diseases and diagnosed as normal or benign pathologies were evaluated as having normal lymphatic systems. The protocol consisted of SPIR T2-weighted sequences with 3D-VISTA. The lymphatic systems were defined as fluid signal intensity structures and divided into eight portions and interobserver agreement was evaluated using weighted kappa statistics. Three readers graded the visualization of each portion using a five-point scale. The detectability of each portion was calculated by defining grades 1-2 as detectable and grades 3-5 as undetectable. Interobserver agreement regarding the visualization grades was moderate to almost perfect. All readers rated the detectability of the lymphatic systems of the superior and posterior portions of the pancreatic head, pericholedochal, right abdominoaortic, and interaorticovenous portions as 100%, and that of the anterior portion of the pancreatic head as 98.2%. For the inferior portion of the pancreatic head, the detectability was 100% for reader 2 and 96.4% for readers 1 and 3. The lymphatic systems located around the pancreatic head and extrahepatic bile duct could be sufficiently visualized on SPIR T2-weighted images with 3D-VISTA at 3.0-T.