Investigation of annular pancreas through multiple detector spiral CT (MDCT) and MRI

Abstract

Background and purpose: To investigate annular pancreas in adults using imaging features displayed on computed tomography (CT) and magnetic resonance imaging (MRI). Methods: Retrospective review of annular pancreas in patients undergoing CT or MRI examinations. Two abdominal radiologists blindly reviewed the CT, MRI, and magnetic resonance cholangiopancreatography (MRCP) images from the Picture Archiving and Communication Systems (PACS). A Kruskal-Wallis test was performed to evaluate subjective scoring, with Mann-Whitney test for the comparison. A p-value less than 0.05 was considered statistically significant. Results: Eleven patients (45.8%) presented a complete ring of pancreatic tissue surrounding duodenum, displayed as circular, triangular, or sandwich sign configuration, the other 13 patients (54.2%) had incomplete annular pancreas which displayed a crocodile jaw appearance, pancreatic tissue extending in a posterolateral or anterolateral direction towards duodenum. When comparing CT images of each sequence, the arterial phase group had the highest score compared with the venous phase and the plain film group (χ 2 = 58.21, p < 0.05). When comparing MRI enhancement volumetric interpolated breathhold examination (VIBE) sequences, arterial phase group scores were the highest (χ 2 = 18.98, p < 0.05). Conclusions: Both CT and MRI could detect annular pancreas, with artery phase being the best sequence to diagnose annular pancreas.

Laparoscopic treatment for incomplete annular pancreas in neonates

“…Zhou Y, et al reported eleven patients (45.8%) presented a complete ring of pancreatic tissue surrounding duodenum, the other 13 patients (54.2%) had incomplete annular pancreas [11]. Totally 42 neonates with congenital annular pancreas were encountered in our institute during 10 years and 15 of the cases were partial annular pancreas with a ratio of 35.7%.…”

“…Most of the cases have been found in children. But with the improvement of clinical diagnostic techniques, such as ERCP, magnetic resonance cholangiopancreatography (MRCP) and CT scan, preoperative diagnosis has improved considerably in adults [11]. Complete annular pancreas has been estimated 5-15 cases per 100,000 adults according to autopsy reports [6].…”

Incidence and Clinical Implications of Anatomical Variations in the Pancreas and Its Ductal System: A Systematic Review and Meta-Analysis

“…In this study, eight types of morphological variants associated with the pancreas were found, which will be described below. Annular pancreas is a rare congenital anomaly characterized by the presence of a pancreatic tissue prolongation that surrounds the second portion of the duodenum [ 11 , 12 , 13 , 14 , 15 ] ( Figure 2 ). Ansa pancreatica is a rare variation of the pancreatic duct where the accessory pancreatic duct makes a sinuous curvature in its course before fusing with the main pancreatic duct due to an obliteration in the accessory duct [ 16 , 17 , 18 ] ( Figure 3 ).…”

“…Tree forest plots were carried out to see the prevalence of the variants of the ductal system of the pancreas, and a forest plot was also carried out to see the clinical correlation with PD. For the PD variant, 22 studies [ 7 , 12 , 14 , 16 , 29 , 34 , 36 , 40 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 57 , 61 , 64 , 65 ] presented a prevalence of 0.18 (0.15–0.21) and a heterogeneity of 99.52%. For the annular pancreas prevalence forest plot, 4 studies [ 11 , 15 , 24 , 66 ] were included, presenting a prevalence of 0.27 (0.01–0.5) and 97.18% heterogeneity.…”

“… Forest plot of prevalence of PD [ 7 , 12 , 14 , 16 , 29 , 34 , 36 , 40 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 57 , 61 , 64 , 65 ]. …”