Cross sectional imaging findings in pancreatic trauma
What cross sectional imaging findings may be encountered in pancreatic trauma?
Pancreatic injuries are uncommon but most commonly occur from penetrating trauma and less commonly occur from blunt trauma when there is severe compression of the pancreas against the spine during seat belt, deceleration, or handlebar compression injury. The pancreatic body is most commonly injured in the setting of blunt abdominal trauma, and overall, pancreatic injury has a mortality rate of up to 20%.
Currently, the most widely used CT grading system for pancreatic injury is based on the American Association for the Surgery of Trauma (AAST) scale. The spectrum of pancreatic injuries includes contusion, hematoma, laceration without or with ductal injury, and complete organ disruption. The most important factor that determines clinical outcome (and whether or not surgical intervention will be required) is the integrity or the pancreatic duct. Assessment of the pancreatic duct is difficult to perform on CT but is facilitated through use of MRCP or ERCP.
The pancreas, when injured, may sometimes appear normal on cross-sectional imaging.
Pancreatic hematomas appear as foci of nonenhancing high attenuation (30 to 70 HU) hemorrhagic fluid on CT. When active hemorrhage is present, one sees focal areas of increased attenuation on contrast-enhanced images similar to that of enhancing vessels that do not conform to known vascular structures and that persist or increase in size on more delayed phase acquisitions.
Pancreatic contusions appear as focal or more diffuse areas of hypoattenuation within the pancreas, although they may sometimes be isoattenuating relative to surrounding pancreatic parenchyma or hyperattenuating when there is associated hemorrhage. Associated pancreatic enlargement as well as peripancreatic fluid, hemorrhage, or fat stranding may also be seen.
Pancreatic lacerations appear as linear nonenhancing low attenuation parenchymal defects in the pancreas, often with adjacent areas of high attenuation hemorrhage.
Associated findings of pancreatitis or of fistula formation to adjacent organs may also be visualized.
