Pancreatitis

Pathology

• Pancreas is edematous and is enlarged.
• Pancreas can show acute inflammation, suppuration hemorrhage and or extensive necrosis, .
• There can be extensive peripancreatic inflammation.
• Fluid can accumulate in lesser sac and pleural space, and paracolic gutters.
• Neutrophils infiltrate the edge of the necrotic areas and extend into the adjacent lobules of fat and produce fat necrosis.
• Calcification can be seen in chronic pancreatitis.

Calcification in pancreas.

Potential complications

• Abscess/pseudocyst
  • As liquefaction of necrotic pancreatic tissue progresses, it will gradually take on the appearance of localized fluid collection - pseudocyst.
  • This may be in the region of the pancreas or extend beyond the pancreatic region.
• Pancreatic rupture/hemorrhage
• Obstructive jaundice
• Pulmonary complications in severely ill patients - ARDS
• GI obstruction
• Acute renal failure 

What are the useful imaging procedures to evaluate patients suspected to have pancreatitis?

• Plain film is non-specific.
• CT scan is diagnostic and sensitive in the diagnosis of acute pancreatitis and its complications.
• Ultrasound is rarely used in the diagnosis of acute pancreatitis due to overlying ileus. 

What are the imaging findings of pancreatitis in plain radiographs?

Abdominal x-ray is not diagnostic, but may show:

• Calcification in the pancreas
• Mass from a pseudocyst
• Ileus
  • Sentinel loop: a single dilated jejunal loop in the upper abdomen
  • Colon cut off: dilated colon to the mid-transverse colon with no air seen beyond the splenic flexure. This is due to extension of inflammation along mesocolon.
  • Diffuse ileus (smalll bowel dilatation) is most common
• Pleural effusion - left

Acute Pancreatitis Findings: Cut off sign

Acute Pancreatitis Cut off sign and Ileus White arrowpoints to Transeverse colon cut off at Splenic flexure. No air in descending colon. TC: Transverse colon I: Represents small bowel loops with air suggestive of Ileus

What are the imaging findings of pancreatitis in ultrasound?

• Edematous pancreas
• Gallstones
• Dilated common bile duct
• Pseudocyst
• Due to ileus pancreas Is poorly defined in acute pancreatitis

What are the imaging findings of pancreatitis in CT?

Contrast-enhanced CT of the pancreas is diagnostic and can show:

• Enlargement of pancreas due to edema
• Peripancreatic inflammation: linear strands in the peripancreatic fat
• Phlegmon
• Fluid in the paracolic gutters
• Necrosis: On contrast enhanced phases the necrotic pancreatic parenchyma will show decreased or no enhancement when compared with normally enhancing viable tissue
• Fluid collections: A simple peripancreatic fluid collection will not have a well-defined capsule
• Pseudocysts: As liquefaction of necrotic pancreatic tissue progresses it will gradually take on the appearance of localized fluid collection - pseudocyst
• Abscesses: Diffusely enlarged pancreas with air pockets
• Hemorrhagic: Enlarged pancreas with increased density due to hemorrhage

Acute Pancreatitis CT Findings: Post Contrast Diffusely enlarged pancreas with low density from edema C: Colon St: Stomach P: Pancreas

Acute Pancreatitis Phlegmon / Inflammatory mass White arrowheads: Phlegmon Black arrowhead: Pancreatic calcification Large Arrow: Peripancreatic fascial infiltration St: Stomach

Acute Pancreatitis / Pancreatic necrosis Arrow: No enhancement of pancreas with IV contrast Arrowheads: Normal enhancement in the tail of Pancreas. St: Stomach

Acute Hemorrhagic pancreatitis Enlarged tail of pancreas White arrow: Increased density in the enlarged tail of pancreas due to blood Fascial changes adjacent to tail of Pancreas due to inflammation

What are the imaging findings of chronic pancreatitis?

• Calcifications in the pancreas
• Pseudocysts
  • As necrotic pancreatic tissue liquefies, it forms a "pseudocyst".
  • This may be in the region of the pancreas or extend beyond the pancreatic region.

Chronic Pancreatitis Arrowheads point to extensive pancreatic calcification.

Pancreatitis with Pseudocyst and calcifications Mass density in pancreas White arrow: Psudocyst Black arrow: Calcifications

Which is the imaging procedure of choice in a suspected case of pancreatitis?

• If the pancreas is necrotic, CT with PO and bolus IV contrast has a sensitivity and specificity of 100 and 100%.
• For drainable collections (like a large pseudocyst), options include - CT, US
  • Transabdominal ultrasound (S/S = 54/88)
  • CT with PO and bolus IV contrast (S/S = 100/25)