Formula used
Original CTSI = Balthazar inflammatory grade points + pancreatic necrosis points
The original score ranges from 0 to 10. Scores 0–3 are commonly grouped as mild, 4–6 as moderate, and 7–10 as severe radiological categories.
How to use this calculator
- Confirm that acute pancreatitis and CT findings have been assessed by qualified clinicians.
- Select the Balthazar grade matching the radiology report.
- Select the documented percentage of pancreatic necrosis.
- Enter contrast status and CT timing to receive relevant cautions.
- Enable the modified CTSI only when a separate comparison is needed.
- Review the full breakdown instead of relying on the total alone.
Scoring reference
| Grade | CT finding | Points |
|---|---|---|
| A | Normal pancreas. | 0 |
| B | Focal or diffuse pancreatic enlargement. | 1 |
| C | Pancreatic abnormality with peripancreatic inflammation. | 2 |
| D | One peripancreatic fluid collection. | 3 |
| E | Two or more fluid collections, or gas in or near the pancreas. | 4 |
| Necrosis | Points |
|---|---|
| No pancreatic necrosis | 0 |
| Less than 30% necrosis | 2 |
| 30% to 50% necrosis | 4 |
| More than 50% necrosis | 6 |
Worked example
| Example finding | Selection | Points |
|---|---|---|
| One peripancreatic fluid collection | Grade D | 3 |
| 30% to 50% pancreatic necrosis | 30%–50% | 4 |
| Total original CTSI | 7/10 | |
The example produces a severe radiological category. It does not independently define clinical severity or treatment.
Interpretation and limitations
The CTSI summarizes structural CT findings in acute pancreatitis. It does not include every clinical risk factor or organ failure measure. Clinical assessment remains essential throughout the illness.
Early CT may understate developing pancreatic necrosis. Contrast status also affects confidence in necrosis assessment. Use the timing and protocol warnings before interpreting results.
The modified CTSI changes the inflammation and necrosis categories. It also adds extrapancreatic complications. Therefore, its total must remain separate from the original index.
Frequently asked questions
What does the calculator measure?
It combines the Balthazar inflammatory grade and pancreatic necrosis extent into the original 0–10 CT Severity Index.
Can patients calculate the score themselves?
The selections require professional interpretation of CT findings. Patients should discuss imaging reports and clinical meaning with their treating team.
Does a severe score confirm severe clinical pancreatitis?
No. The result is a radiological category and does not replace organ failure assessment, laboratory data, examination, or clinical judgment.
Why does contrast status matter?
Contrast enhancement helps distinguish viable pancreatic tissue from nonenhancing necrotic tissue. Non-contrast studies can limit necrosis assessment.
Why does the calculator warn about early CT?
Necrosis can evolve and may not be fully visible during early imaging. Timing should be considered when interpreting the score.
What is the highest original CTSI score?
The maximum is 10 points. It combines four inflammation points and six necrosis points.
Is modified CTSI the same score?
No. Modified CTSI uses different categories and includes extrapancreatic complications. This page presents it only as a separate comparison.
Are case details stored?
No database storage is implemented in this file. Browser exports include the case identifier only when its privacy checkbox is enabled.
Can the result guide treatment?
No. It must not be used alone for admission, intervention, medication, surgery, or discharge decisions.
References
- Balthazar EJ, Robinson DL, Megibow AJ, Ranson JH. Acute pancreatitis: value of CT in establishing prognosis. Radiology. 1990.
- Mortele KJ, Wiesner W, Intriere L, et al. A modified CT severity index for evaluating acute pancreatitis. AJR. 2004.
- Royal College of Radiologists. Imaging of acute pancreatitis audit standard.
- Use current institutional protocols and specialist guidance for imaging indications and timing.