Balthasar score of acute pancreatitis on unenhanced CT scan, CT severity index, CTSI

The original Balthasar score was developed and published in 1985. Originally, the score was based on unehnaced CT scans. It was later extended with the necrosis score to reflect also necrotic changes of the pancreatic parenchyma on contrast enhanced CT and their prognostic relevance and named CT severity index (CTSI).

Balthasar score

Grade Description CTSI points
Grade A Normal CT 0
Grade B Focal or diffuse enlargement of the pancreas 1
Grade C Pancreatic gland abnormalities and peripancreatic inflammation 2
Grade D Fluid collection in a single location 3
Grade E Two or more fluid collections and/or gas bubbles in or adjacent to pancreas 4

Necrosis Score

Description - necrosis percentage CTSI points
No necrosis 0
0 - 30% necrosis 2
30 - 50% necrosis 4
>50% necrosis 6

CT severity index

CT severity index additively combines CTSI points from the Balthasar score and the necrosis score.
CTSI = Balthasar score + necrosis score


1. Balthazar EJ. Acute Pancreatitis: Assessment of Severity with Clinical and CT Evaluation1. Radiology. 2002 Jun 1;223(3):603–13.
2. Balthazar EJ, Robinson DL, Megibow AJ, Ranson JH. Acute pancreatitis: value of CT in establishing prognosis. Radiology. 1990 Feb;174(2):331–6

3. Balthazar EJ, Ranson JH, Naidich DP, Megibow AJ, Caccavale R, Cooper MM. Acute pancreatitis: prognostic value of CT. Radiology. 1985 Sep;156(3):767–72.