Purpose
Autoimmune pancreatitis (AIP) is a unique form of pancreatitis in which autoimmune mechanisms are suspected to be involved in the pathogenesis [1].
The histopathological characteristics are periductal lymphoplasmacytic infiltrate with obliterative phlebitis and storiform fibrosis,
and/or lymphoplasmacytic infiltrate with storiform fibrosis showing abundant IgG4-positive cells [2,3].
We previously reported that AIP occasionally demonstrated the main pancreatic duct wall enhancement on computed tomography (CT) examination,
which might reflect the histopathological periductal fibrotic change and/or thickening of the infiltrated duct wall by fibrosis [4].
And we call...
Methods and Materials
<Patients>
● We retrospectively recruited consecutive patients with AIP in multiphase contrast enhanced CT database from July 2003 to May 2010.
The consecutive patients with pancreatic carcinoma and usual chronic pancreatitis were also selected in adjustment with the same ratio of the CT systems (16- or 64-slice multisection CT) in the same period.
In recruiting these patients,
sex and age were not considered.
● The present study examined 55 patients with AIP (5 female and 50 male; age range 24-86 years,
mean age 64 years),...
Results
● The finding of “enhanced MPD sign” was most frequently observed in AIP (AIP; 37/55,
67 %; carcinoma; 5/50,
10 %; and chronic pancreatitis; 0/50,
0 %; P<0.01)(Figure.1).
The level of interobserver agreement was good (k=0.64; P < 0.001).
● Sensitivity,
specificity and accuracy of the enhanced MPD sign in the diagnosis of AIP were 0.67,
0.95 and 0.85,
respectively.
● The result of the further assessment among “enhanced MPD sign” positive cases are as below.
(a) Location of the enhanced MPD
Enhanced MPD sign...
Conclusion
The CT finding of “enhanced MPD sign” was useful for diagnosing and differentiating AIP from pancreatic carcinoma and usual chronic pancreatitis.
Especially,
enhanced MPD sign with surrounding abnormal contrast enhanced pancreatic parenchyma,
and/or completely unvisible of the MPD lumen was specific finding of AIP.
References
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A...