Table 2 The main distinguishing features between AIP and pancreatic cancer on cross-sectional imaging
From: Abdominal manifestations of IgG4-related disease: a pictorial review
AIP | Pancreatic cancer | |
|---|---|---|
CT | Peripancreatic hypoattenuating capsule (“halo”) present | Peripancreatic halo not present |
No upstream duct dilatation | Abrupt upstream duct dilatation often seen ± distal pancreatic atrophy | |
Pancreatic duct wall enhancement sometimes present | No pancreatic duct wall enhancement | |
Persistent enhancement in delayed phases | No delayed phase enhancement | |
Homogenous enhancement pattern | Ring-like enhancement pattern | |
MRI | Low T1/T2 signal peripancreatic capsule | No peripancreatic capsule |
Duct narrowing occurs over a relatively long segment | Duct narrowing occurs over a shorter segment | |
“Duct-penetrating sign” may be present | “Duct-penetrating sign” does not occur | |
Restricted diffusion with low ADC values | Restricted diffusion, but ADC values are not as low as AIP | |
PET/CT | Heterogeneous and diffuse FDG uptake | Focal nodular FDG uptake |
Increased FDG uptake at extrapancreatic sites of disease | No extrapancreatic FDG uptake (unless metastatic to nodes or distant organs) |