Two axial slices of a contrast-enhanced computed tomography (CT) scan of the abdomen demonstrate severe acute pancreatitis with extensive complications. The imaging shows a large, heterogeneous fluid collection in the left retroperitoneal space and left paracolic gutter, characterized by significant inflammatory fat stranding around the pancreas. Key findings include the presence of multiple air bubbles within the necrotic collections, suggestive of an emphysematous infection or secondary infected necrosis. Additionally, there is evidence of a colonic fistula involving the descending colon. The slices further reveal gallbladder stones without biliary tree dilatation. The findings are consistent with Balthazar Grade E acute pancreatitis, showcasing advanced local complications including walled-off necrosis, infection, and hollow viscus fistulization.

This clinical imaging series comprises three non-contrast axial CT scans (a, b, and c) of the upper abdomen, illustrating the temporal progression and resolution of acute pancreatitis (AP) in a post-transplant patient. Image 'a' demonstrates acute pancreatitis findings consistent with Balthazar Grade D, characterized by diffuse pancreatic swelling (edema) and prominent peripancreatic fluid collections/exudative effusions. No obvious necrosis is visualized in this non-contrast phase. Image 'b' represents a follow-up scan 14 days after the cessation of the suspected causative agent (tigecycline), showing a significant reduction in pancreatic volume and the resolution of surrounding fluid, returning toward a baseline morphology. Image 'c' is a further follow-up scan at 58 days, confirming the complete resolution of inflammatory changes and a normal pancreatic appearance. This series serves as an educational example of drug-induced acute pancreatitis and its radiographic recovery following the withdrawal of the offending medication. Key structures visible include the liver, spleen, kidneys, and vertebrae, providing anatomical context for the central pancreatic pathology.

This diagnostic image is an axial contrast-enhanced abdominal computerized tomography (CT) scan focusing on the upper abdominal organs. The scan demonstrates clinical signs of acute pancreatitis. Key findings include visible infiltration and stranding of the peripancreatic fat, particularly noted as increased attenuation in the interpancréatico-duodenal region. The pancreas itself shows signs of inflammatory densification. Notably, the biliary system appears normal; the main bile duct (common bile duct) is not distended, the intra- and extra-hepatic bile ducts are fine, and the pancreatic duct (canal of Wirsung) is not dilated. Other visible landmarks include the liver, spleen, both kidneys, and a cross-section of the lumbar vertebra and aorta. This imaging is characteristic of Balthazar Grade B/C pancreatitis, illustrating the absence of significant fluid collections or biliary obstruction while highlighting localized fat-plane effacement indicative of acute inflammation.

This composite diagnostic image features four axial abdominal CT scans demonstrating the spectrum of acute pancreatitis (AP) severity. Panels (a) and (b) represent mild acute pancreatitis (MAP), characterized by the pancreas showing focal or patchy low-density, non-enhancing areas. The peripancreatic fat planes remain relatively preserved with minimal fluid accumulation. In contrast, panels (c) and (d) illustrate severe acute pancreatitis (SAP). These scans reveal extensive pathology, including large, patchy peripancreatic effusion shadows and significant fluid collections in the retroperitoneal space (RPS) and anterior pararenal space (APS). The pancreatic parenchyma in SAP shows more pronounced density changes and irregular borders, reflecting higher degrees of inflammatory infiltration and potential necrosis. These images serve as educational examples for the Computed Tomography Severity Index (CTSI), highlighting the radiological differences between mild interstitial inflammation and severe exudative or necrotizing processes in the abdominal cavity.

**Imaging Modality:** Contrast-enhanced computed tomography (CECT) of the abdomen. **Anatomical Region:** Axial section at the level of the upper abdomen, showing the pancreas, liver, spleen, and kidneys. **Observed Pathology:** The image demonstrates findings consistent with acute pancreatitis. There is significant inflammatory changes and edema involving the pancreatic parenchyma. A prominent, low-attenuation peripancreatic fluid collection is visible (indicated by the yellow arrow). **Characteristic Visual Features:** * **Pancreas:** Diffuse enlargement with ill-defined borders and heterogeneous enhancement. * **Fluid Collection:** An acute peripancreatic fluid collection (APFC) is noted in the anterior pararenal space, extending laterally into the splenorenal space. * **Fat Stranding:** Increased density and "dirty" appearance of the peripancreatic fat, indicating active inflammation. * **Adjacent Structures:** The collection is bordered by the tail of the pancreas and the medial aspect of the spleen. **Key Diagnostic Features:** The combination of pancreatic swelling, heterogeneous contrast enhancement, and organized peripancreatic fluid in the splenorenal space are characteristic radiologic markers for grading the severity of acute pancreatitis using the Balthazar or CT Severity Index (CTSI) criteria.