1666

Differentiation of Pancreatic Head Ductal Adenocarcinoma from Inflammatory Pancreatic Pseudomass by MR Cholangio-pancreatography: Utility of the Duct-interrupted, Corona and Attraction Signs
Alejandro Garces-Descovich1, Kevin Beker1, Leo Tsai1, Karen Lee1, Tarek Hegazi1, Alexander Brook2, Adrian Jaramillo-Cardoso1, and Koenraad Mortele1

1Division of Body MRI, Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States, 2Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States

Synopsis

To properly treat and determine a truthful prognosis, accurate pancreatic head mass differentiation is fundamental. Pancreatic ductal adenocarcinoma (PDAC) of the head and inflammatory pancreatic pseudomass (IPP) simulate significantly to each other in clinical imaging. We proposed the use of three radiological signs ("duct-interrupted”, “corona”, and “attrition” signs) on magnetic resonance cholangio-pancreatography (MRCP). The proposed signs were assessed by three blinded radiologist, demonstrating high specificity for diagnosing PDAC by the “duct-interrupted” and “corona” signs, while good specificity of the “attraction” sign to identify IPP.

Introduction

Accurate differentiation between inflammatory pancreatic pseudomasses (IPP) and pancreatic ductal adenocarcinoma (PDAC) is fundamental to a patient’s management and prognosis. Radiologists may often encounter lesions that distort the normal contour of the pancreatic head, simulating the appearance of pancreatic cancer, but without any of the pathognomonic features to confirm the diagnosis. In the absence of or prior to histopathological confirmation, differentiation between IPP and PDAC by imaging diagnosis may play a significant role in the management of these patients, especially since the treatment choice may range from invasive surgical resection for PDAC to pharmacological management for IPP [1, 2]. Although magnetic resonance cholangio-pancreatography (MRCP), in the setting of pancreatic mass evaluation is already widely used, only few studies have shown the utility and specificity of MRCP in this context [3-5].Therefore, the purpose of our study is to determine the utility of three MRCP signs, the “duct-interrupted”, “corona” and “attraction” signs for the differentiation of PDAC from IPP in the pancreatic head.

Materials and Methods

This HIPAA-compliant, institutional review board-approved retrospective study with written consent waived included 53 adults (33 men and 20 women, mean age, 55 years; range, 17-87 years) with a pancreatic head mass who underwent MRCP. Final diagnosis was established by means of histopathology, serum IgG4 levels, and/or reduction of at least 50% of size/complete resolution of mass at follow-up. 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 in differentiating between IPP and PDAC were calculated, as well as the degree of interobserver agreement, using the chance-corrected κ statistic.

Results

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).

Conclusion

The “duct-interrupted” and “corona” MRCP signs have high specificity for diagnosing PDAC while the “attraction” sign has good specificity for identifying IPP.

Acknowledgements

No acknowledgement found.

References

1. Abraham Susan,Wilentz Robb, Yeo Charles, Sohn Taylos, Cameron John, Boitnott John HR. Pancreaticoduodenectomy (Whipple Resections) in Patients Without Malignancy Are They All “Chronic Pancreatitis”? [Internet]. American Journal of Surgical Patholology. 2003 [cited 2018 Jan 10]. p. 110–20.

2. Kennedy T, Preczewski L, Stocker SJ, Rao SM, Parsons WG, Wayne JD, et al. Incidence of benign inflammatory disease in patients undergoing Whipple procedure for clinically suspected carcinoma: a single-institution experience. [cited 2018 Jan 10]

3. Neff CC, Simeone JF, Wittenberg J, Mueller PR, Joseph Ferrucci IT. Inflammatory Pancreatic Masses Problems in Differentiating Focal Pancreatitis from Carcinoma’. [cited 2018 Jan 10]

4. Lammer J, Herlinger H, Zalaudek G, Hofler H. Pseudotumorous Pancreatitis. Gastrointest Radiol [Internet]. 1985 [cited 2018 Jan 10];10:59–67

5. Kim HJ, Kim YK, Jeong WK, Lee WJ, Choi D. Pancreatic duct “Icicle sign” on MRI for distinguishing autoimmune pancreatitis from pancreatic ductal adenocarcinoma in the proximal pancreas. Eur Radiol. 2015;25(6):1551–60.

Figures

Figure 1. PDAC with positive “duct-interrupted” sign in a 69-year-old man (a) Axial fat suppressed T1-weighted post-contrast image shows hypointense mass at the head of the pancreas (arrows). (b) Coronal thick slab single-shot fast spin-echo MRCP image shows main pancreatic duct interruption at the level of the mass (arrow) with upstream dilation.

Figure 2. PDAC with positive “corona” sign in an 88-year-old man. (a) Axial 3D GRE post-contrast T1-weighted image shows hypointense mass at the head of the pancreas (arrows). (b) Coronal T2-weighted single-shot fast spin-echo image shows hyperintense mass at the head of the pancreas (arrows). (c) Coronal thick slab single-shot fast spin-echo MRCP image shows hypointense mass (arrows) (d) Coronal thin section MRCP image shows hypointense mass in the head of the pancreas with dilated side-branches outside of the underlying mass (arrows).

Figure 3. Inflammatory pancreatic pseudomass with positive “attraction” sign in a 54-year-old man (a) Axial T1-weighted 3D dual-echo image shows hypointense mass (arrows). (b) Axial T2-weighted single-shot fast spin-echo image shows mass to be mildly hyperintense (arrows). (c) Coronal thick slab single-shot fast spin-echo MRCP image shows dilation of the common bile duct with attraction to the underlying mass, demonstrated by angulation and formation of a vertex (arrowhead) pointing to the underlying mass. Also note ductal strictures along the main pancreatic duct and small cystic changes in the pancreatic head.

Proc. Intl. Soc. Mag. Reson. Med. 27 (2019)
1666