Maki Kiyonaga

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

PurposeTo 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.Materials and methodsFifty-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.ResultsInterobserver 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.ConclusionThe 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.

Extrahepatic Bile Duct Cancer: Invasion of the Posterior Hepatic Plexuses—Evaluation Using Multidetector CT

PURPOSE To assess the utility of axial and coronal reformatted multidetector computed tomographic (CT) images in the evaluation of the invasion of posterior hepatic plexuses by extrahepatic bile duct cancer. MATERIALS AND METHODS This retrospective study was approved by the institutional review board, and informed consent was waived. Forty-three patients (22 men, 21 women; age range, 40-80 years; mean age, 65 years) with surgically resected cancer involving the extrahepatic bile duct between December 2004 and September 2010 were included. Posterior hepatic plexus 1 runs from the superior and middle bile duct to the right celiac ganglion, and posterior hepatic plexus 2 runs between the lower bile duct and right celiac ganglion behind the portal vein. Invasion of the posterior hepatic plexuses was elucidated by using pathologic and postoperative multidetector CT findings. Three radiologists independently evaluated the preoperative axial and coronal reformatted images with a separate viewing session for the invasion of posterior hepatic plexuses that was detected on the basis of the presence of increased attenuation of fat tissue along the nerve routes. Receiver operating characteristic analysis was performed to compare the diagnostic performance of the two image interpretations. RESULTS Invasion of posterior hepatic plexus 1 and of posterior hepatic plexus 2 was recognized in 10 (23%) and nine (21%) of 43 patients, respectively. The diagnostic performance of coronal reformatted image interpretation was significantly greater than that for axial image interpretation (mean area under the curve, 0.99 vs 0.89, P = .04; mean accuracy, 95% vs 82%, P = .003). In all reviewers, one false-positive diagnosis of the invasion of posterior hepatic plexus occurred on axial and/or coronal image display types because of fibrosis and inflammatory cell infiltration along these plexus routes. CONCLUSION Coronal reformatted images can be useful for accurate diagnosis of the invasion of posterior hepatic plexuses and may facilitate surgical decision making in regard to the resection of celiac ganglion.

Perirenal lymphatic systems: Evaluation using spectral presaturation with inversion recovery T2 -weighted MR images with 3D volume isotropic turbo spin-echo acquisition at 3.0T.

To evaluate the normal anatomy of the perirenal lymphatics using spectral presaturation with inversion recovery (SPIR) T2‐weighted magnetic resonance imaging (MRI) with 3D volume isotropic turbo spin‐echo acquisition (VISTA) at 3.0T.

Fusion anomaly of the pancreatic tail and spleen: a case report

BackgroundSplenopancreatic fusion is a rare anomaly that is often associated with trisomy 13. Its diagnosis can be important in patients scheduled to undergo distal pancreatectomy or splenectomy, to avoid possible intraoperative or postoperative complications.Case presentationAn 82-year-old Japanese man was referred to our hospital for further evaluation and treatment for a solitary hepatocellular carcinoma based on liver cirrhosis. Triple-phase contrast-enhanced multidetector-row computed tomography and magnetic resonance imaging showed a splenopancreatic fusion as well as a solitary hepatocellular carcinoma in segment VIII of his liver.ConclusionsFusion of the pancreatic tail and spleen is a rare and asymptomatic anomaly. Its detection can be improved by the use of multidetector computed tomography or magnetic resonance imaging.

Beak-Like Extension of the Pancreatic Uncinate Process on MDCT: Is It Hyperplasia or Movement?

Objective We aimed to evaluate the pancreatic uncinate process with a beak-like extension (BLE) beyond the left border of the superior mesenteric artery, to define the cause of BLE, and to differentiate BLE from hyperplasia. Methods We retrospectively reviewed 1042 triple-phase contrast-enhanced multidetector-row computed tomography (3P-CE-MDCT) examinations of 500 patients. Finally, 38 patients (28 men, 10 women; mean age, 66 years) with 140 3P-CE-MDCT images showing BLE were studied regarding BLE size, contour, and cause. The superior mesenteric artery position was also evaluated. Results Beak-like extensions were found in 7.6% of patients. Most were caused by movement of the small bowel mesentery (n = 21, 55%), with deviation of mesenteric vessels or mass effect from expanded adjacent organs (n = 3, 8%). Seven patients (18.5%) had true hyperplasia. Conclusions Beak-like extension is caused by movement of the small bowel mesentery with deviation of mesenteric vessels or by adjacent organ expansion. Beak-like extension closely mimics other pathology on nonenhanced MDCT.

Medial pathway patterns of the right retromesenteric plane: anatomical investigation using MDCT in patients with acute pancreatitis and pyelonephritis

OBJECTIVE To investigate the medial pathways of the right retromesenteric plane by reviewing multidetector CT (MDCT) findings in patients with acute pancreatitis and pyelonephritis. METHODS 112 patients with acute pancreatitis and 114 patients with pyelonephritis underwent MDCT scans. 64 of the 112 patients with acute pancreatitis and 34 of the 114 patients with pyelonephritis had right retromesenteric plane thickening because of inflammatory extensions. The medial pathways of the right retromesenteric plane were evaluated by two radiologists in consensus. RESULTS In 18 (28%) of the 64 patients with acute pancreatitis and 10 (29%) of the 34 patients with pyelonephritis, the right retromesenteric plane continued to the central retroperitoneum behind the descending duodenum and pancreatic head (Type 1 pathway). The right retromesenteric plane extended to the right wall of the descending duodenum (Type 2 pathway) in 46 patients (72%) with acute pancreatitis and 24 patients (71%) with pyelonephritis. There was no significant difference in the pathway patterns of the right retromesenteric plane between the acute pancreatitis group and the pyelonephritis group (Type 1 pathway, p = 0.89; Type 2 pathway, p = 0.76). CONCLUSION Two patterns were confirmed regarding the medial pathways of the right retromesenteric plane; this anatomical knowledge is important for evaluating the extension of retroperitoneal diseases. ADVANCES IN KNOWLEDGE Medial aspect of the right retromesenteric plane is thought to have two pathways. The right retromesenteric plane continuing to the right duodenal wall is a common type. Knowledge of these variations is important when evaluating the retroperitoneal diseases.

Diagnostic Utility of Reduced Radiation Dose Non-Contrast-Enhanced CT with Iterative Reconstruction for Screening in High-Risk Individuals with Pancreatic Cancer: An Anthropomorphic Phantom Study

Background: Previous studies showed that the dilated main pancreatic duct (MPD) and pancreatic cysts were the important predictors of the subsequent development of pancreatic cancer. The purpose of this study was to reveal the utility of non-contrast reduced radiation dose CT with iterative reconstruction for screening in high risk pancreatic cancer individuals by assessing the dilated MPD and cysts by using abdominal phantoms. Materials and methods: Two phantoms with normal and abnormal pancreas with dilated MPD (5 mm) and cysts (5 mm, 10 mm and 15 mm) were constructed. Each phantom was scanned by ten images using following three protocols: 120 kVp and 120mA with filtered back projection (FBP) algorithm (120 kVp-FBP), 80 kVp and 168mA with FBP algorithm (80 kVp-FBP), and 80 kVp and 168mA with sinogram affirmed iterative reconstruction (SAFIRE) (80 kVp-SAFIRE). The image noise and contrast-to-noise ratio (CNR) of the 15mm cyst were assessed. The radiation dose was assessed with the volume CT dose index (CTDIvol). Two radiologists scored the image quality and conspicuity of the dilated MPD and cysts. Results: Mean image noise significantly decreased from 80 kVp-FBP images to 80 kVp-SAFIRE and 120 kVp-FBP images (p < 0.001). The CNR significantly increased from 80 kVp-FBP images to 120 kVp-FBP and 80 kVp-SAFIRE images (p < 0.05). Image quality was significantly lower in the 80 kVp-FBP images than in 120 kVp-FBP and 80 kVp- SAFIRE images in both readers (p < 0.05). The conspicuity point for the dilated MPD and three cysts was higher in 80 kVp-SAFIRE images than in 80 kVp-FBP and 120 kVp-FBP images. CTDIvol was reduced by 60 % at 80 kVp protocol. Conclusion: Non-contrast 80 kVp-SAFIRE CT protocol allowed for higher conspicuity of dilated MPD and cysts at a reduced radiation dose compared with 120 kVp-FBP protocols.

Pancreatic Neuroendocrine Tumor with Extensive Intraductal Invasion of the Main Pancreatic Duct: A Case Report

CONTEXT Pancreatic neuroendocrine tumors account for only 1-3% of all pancreatic neoplasms and the intraductal invasion of the main pancreatic duct (MPD) is rare. CASE REPORT We report a case of a 26-year-old woman with an endocrine tumor of the pancreas extensively invading into the MPD. She presented abdominal pain and her laboratory data showed abnormal liver function. Contrast-enhanced computed tomography demonstrated a well-enhanced mass on the arterial dominant phase in the head of the pancreas. The mass grew within the lumen of the MPD in the body of the pancreas, with dilatation of the upstream MPD. The contrast-enhancement pattern between the main tumor of the head and the intraductal lesion of the body was different. On T2-weighted magnetic resonance (MR) imaging, the pancreatic head lesion showed non homogeneously low signal intensity, while the intraductal lesion of the pancreatic body showed high signal intensity. MR cholangiopancreatography showed obstruction of the MPD in the pancreatic head to body, with dilatation of the upstream MPD. An endocrine tumor or acinar cell carcinoma of the pancreas was considered as preoperative diagnosis, and pancreaticoduodenectomy was performed. As a result, pancreatic endocrine tumor (G2) was confirmed pathologically. CONCLUSION A rare case of pancreatic neuroendocrine tumor with extensive growth within the MPD was presented. The intraductal extension is a unique growth pattern of nonfunctioning pancreatic neuroendocrine tumor, and the desmoplastic reaction in this tumor may reflect the increased invasiveness.