Abstract: Abstract Objective: To explore the correlation of manifestations of multi-slice spiral CT (MSCT) and Balthazar CT classification in acute pancreatitis (AP) involved subperitoneal space of lesser omentum. Methods: MSCT images of fifty-eight patients with acute pancreatitis proved by surgery and/or clinical and laboratory findings were retrospectively analyzed. CT examinations were performed on a 64-MSCT scanner in 19 patients and on a 16-MSCT scanner in 16 patients. The automatic high pressure injector was used to inject contrast material through forearm vein. The scan scope was set between the level of diaphragm roof and pelvic floor. After multi-planar reconstruction, the MSCT findings of AP involved subperitoneal space of lesser omentum were observed and the Balthazar CT classification was recorded. Results:（1）In fifty-eight patients, four cases belonged to C grade, eighteen cases belonged to D grade and thirty-six cases belonged to E grade by Balthazar's criterion. Hepatoduodenal ligament was involved in forty-five cases, and hepatogastric ligament was involved in fifty cases.（2）The hepatoduodenal ligament and hepatogastric ligament involvement showed edema, thickening, fluid collection and density increasing.（3）There were significant difference between the incidence rate of hepatoduodenal ligament and hepatogastric ligament involvement and Balthazar CT classification (P<0. 05). Conclusion: MSCT can sufficiently demonstrate the details of acute pancreatitis involved subperitoneal space of the lesser omentum. The hepatoduodenal ligament and hepatogastric ligament involvement can reflect the severity of acute pancreatitis.

Key words: Acute pancreatitis, Lesser omentum, Subperitoneal space, Tomography, X-ray computed