CT Imaging Features of Acute Pancreatitis

Acute pancreatitis is a common cause of acute abdominal pain and is generally classified into two main types: acute edematous pancreatitis and hemorrhagic necrotizing pancreatitis. Each type presents with distinct imaging characteristics on computed tomography (CT) scans.

Acute Edematous Pancreatitis:
In cases of acute edematous pancreatitis, CT scans typically reveal diffuse or localized enlargement of the pancreas due to inflammatory swelling and edema. The normal fat planes surrounding the pancreas may become obscured as a result of peripancreatic fluid accumulation. Additionally, increased density in the peripancreatic fat spaces is commonly observed due to inflammatory exudates. Thickening of the anterior renal fascia on the left side is also frequently noted.

Hemorrhagic Necrotizing Pancreatitis:
This more severe form of acute pancreatitis shows more pronounced features compared to the edematous type. On CT imaging, uneven pancreatic density is often seen, with areas of low attenuation indicating necrosis and high-density regions suggesting hemorrhage. The presence of focal low-attenuation areas within the pancreas is a hallmark sign of necrotizing pancreatitis. During contrast-enhanced CT scans, these necrotic regions fail to enhance, while the surrounding viable pancreatic tissue may show variable enhancement. Inflammatory exudates can extend beyond the pancreas into adjacent anatomical spaces such as the lesser omentum, perisplenic area, perigastric region, pre-renal space, paracolic gutters, mesentery, and even the pelvis. These changes are visualized as increased fat density or fluid-like density in affected areas. Complications such as pseudocyst formation or pancreatic abscess may also be detected on CT imaging.

Overall, CT plays a crucial role in the diagnosis, classification, and management of acute pancreatitis by providing detailed visualization of pancreatic morphology and associated complications.