🩻 CT Severity Index (CTSI, Balthazar)
Grade acute pancreatitis severity on CT with the Balthazar CT Severity Index.
Clinical takeaway
Assess contrast-enhanced CT > 72 h after onset to avoid underestimating necrosis.
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When to use
Assess prognosis in acute pancreatitis from imaging.
How it works
CTSI = Balthazar grade (A–E = 0–4) + necrosis extent (0/2/4/6), total 0–10. 0–3 mild, 4–6 moderate, 7–10 severe.
Key points
- Assess contrast-enhanced CT > 72 h after onset to avoid underestimating necrosis.
- Higher scores carry higher complication and mortality rates.
- The modified CTSI (Mortele) adds extrapancreatic complications.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Balthazar CT grade | A (0): normal pancreas |
|---|---|
| Extent of pancreatic necrosis | No necrosis (0) |
→CTSI0/10
- Band：0 → Mild (0–3 mild, 4–6 moderate, 7–10 severe); higher scores carry higher complication and mortality rates
- Timing：Contrast-enhanced CT is best assessed > 72 h after symptom onset (earlier underestimates necrosis); necrosis requires contrast-enhanced CT (reduced enhancement)
- Note：The modified CTSI (Mortele) simplifies necrosis grading and adds extrapancreatic complications (+2); this tool uses the classic Balthazar CTSI (grade 0–4 + necrosis 0/2/4/6)
| Balthazar CT grade | E (4): ≥ 2 collections or retroperitoneal gas |
|---|---|
| Extent of pancreatic necrosis | > 50% (6) |
→CTSI10/10
- Band：10 → Severe (0–3 mild, 4–6 moderate, 7–10 severe); higher scores carry higher complication and mortality rates
- Timing：Contrast-enhanced CT is best assessed > 72 h after symptom onset (earlier underestimates necrosis); necrosis requires contrast-enhanced CT (reduced enhancement)
- Note：The modified CTSI (Mortele) simplifies necrosis grading and adds extrapancreatic complications (+2); this tool uses the classic Balthazar CTSI (grade 0–4 + necrosis 0/2/4/6)
Frequently asked questions
- What is CT Severity Index (CTSI, Balthazar)?
- Grade acute pancreatitis severity on CT with the Balthazar CT Severity Index.
- How is CT Severity Index (CTSI, Balthazar) calculated? What is the core formula?
- CTSI = Balthazar grade (A–E = 0–4) + necrosis extent (0/2/4/6), total 0–10. 0–3 mild, 4–6 moderate, 7–10 severe.
- When is CT Severity Index (CTSI, Balthazar) used?
- Assess prognosis in acute pancreatitis from imaging.
- What are the key clinical points for CT Severity Index (CTSI, Balthazar)?
- Assess contrast-enhanced CT > 72 h after onset to avoid underestimating necrosis. Higher scores carry higher complication and mortality rates. The modified CTSI (Mortele) adds extrapancreatic complications.
- What are the limits and cautions when using CT Severity Index (CTSI, Balthazar)?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is CT Severity Index (CTSI, Balthazar) calculated in practice? Can you show a worked example?
- Inputs: Balthazar CT grade A (0): normal pancreas, Extent of pancreatic necrosis No necrosis (0) → Result: CTSI 0 /10（Band: 0 → Mild (0–3 mild, 4–6 moderate, 7–10 severe); higher scores carry higher complication and mortality rates, Timing: Contrast-enhanced CT is best assessed > 72 h after symptom onset (earlier underestimates necrosis); necrosis requires contrast-enhanced CT (reduced enhancement), Note: The modified CTSI (Mortele) simplifies necrosis grading and adds extrapancreatic complications (+2); this tool uses the classic Balthazar CTSI (grade 0–4 + necrosis 0/2/4/6)） Inputs: Balthazar CT grade E (4): ≥ 2 collections or retroperitoneal gas, Extent of pancreatic necrosis > 50% (6) → Result: CTSI 10 /10（Band: 10 → Severe (0–3 mild, 4–6 moderate, 7–10 severe); higher scores carry higher complication and mortality rates, Timing: Contrast-enhanced CT is best assessed > 72 h after symptom onset (earlier underestimates necrosis); necrosis requires contrast-enhanced CT (reduced enhancement), Note: The modified CTSI (Mortele) simplifies necrosis grading and adds extrapancreatic complications (+2); this tool uses the classic Balthazar CTSI (grade 0–4 + necrosis 0/2/4/6)）