Revised Atlanta Classification
Interstitial edematous pancreatitis vs. necrotizing pancreatitis (parenchymal and/or peripancreatic necrosis). CT should be performed ≥48–72 hours after onset for accurate necrosis assessment.
Fluid Collection Types
| Collection | Timing | Definition |
|---|---|---|
| Acute peripancreatic fluid (APFC) | <4 weeks | Interstitial pancreatitis; no wall; homogeneous |
| Pseudocyst | >4 weeks | Encapsulated fluid; well-defined wall; from APFC |
| Acute necrotic collection (ANC) | <4 weeks | Necrotizing pancreatitis; contains heterogeneous debris |
| Walled-off necrosis (WON) | >4 weeks | Encapsulated necrosis; endoscopic/surgical drainage |
Balthazar Grade
| Grade | CT Finding | Score |
|---|---|---|
| A | Normal pancreas | 0 |
| B | Focal or diffuse pancreatic enlargement | 1 |
| C | Pancreatic inflammation with peripancreatic fat changes | 2 |
| D | Single peripancreatic fluid collection | 3 |
| E | ≥2 peripancreatic fluid collections or gas in/adjacent to pancreas | 4 |
CT Severity Index (CTSI)
CTSI = Balthazar score + Necrosis score (max 10)
| Necrosis | Score |
|---|---|
| None | 0 |
| <30% | 2 |
| 30–50% | 4 |
| >50% | 6 |
CTSI interpretation: 0–3 = Mild · 4–6 = Moderate · 7–10 = Severe
Higher CTSI correlates with increased morbidity and mortality.
Reporting Checklist
- Necrosis: extent (%) and location — head / body / tail
- Peripancreatic fluid collections: number, location, size (cm)
- Walled-off necrosis vs pseudocyst: wall thickness, complexity, >4 weeks duration
- Pancreatic duct: disruption / dilation (>3 mm body, >5 mm head) / disconnected duct
- Splenic vein thrombosis: present / absent
- Pseudoaneurysm: present / absent; vessel involved; size
- Biliary: CBD dilation (>8 mm) / choledocholithiasis / gallstones