Differentiation of pancreatic head ductal adenocarcinoma from inflammatory pancreatic pseudomass by MR cholangio-pancreatography: utility of the duct-interrupted, corona, and attraction signs.

Abstract

To determine sensitivity and specificity of the "duct-interrupted," "corona," and "attraction" signs on MR cholangio-pancreatography (MRCP) in distinguishing pancreatic head ductal adenocarcinoma (PDAC) from inflammatory pancreatic pseudomass (IPP). This study included 53 adults (33 men and 20 women, mean age, 55 years; range, 17-87 years) with a pancreatic head mass who underwent MRCP. Three blinded radiologists independently reviewed each MRCP exam and three signs were assessed: (1) the "duct-interrupted" sign, deemed positive for PDAC if the duct within the mass demonstrated complete interruption with upstream dilation; (2) the "corona" sign, considered positive for PDAC if dilated side-branches were located exclusively outside the mass; and (3) the "attraction" sign, deemed positive for IPP if the dilated common bile duct showed attraction and angulation towards the mass. Sensitivity, specificity, and positive and negative predictive values of the signs were calculated, as well as interobserver agreement. Out of 53 masses, 17 (32%) were PDAC and 36 (68%) were IPP. Sensitivity, specificity, and positive and negative predictive values of the "duct-interrupted" sign to differentiate between PDAC from IPP for the three readers were 29-53%, 89-95%, 56-82% and 73-81%, respectively (κ = 0.41); for the "corona" sign, they were 29-53%, 81-100%, 56-100%, and 75-78%, respectively (κ = 0.4), and for the "attraction" sign, they were 20-25%, 71-82%, 64-75%, and 31-34%, respectively (κ = 0.54). The "duct-interrupted" and "corona" MRCP signs have high specificity for diagnosing PDAC, while the "attraction" sign has good specificity for identifying IPP.