Thirty seven patients suffering from acute pancreatitis were explored using contrast-enhanced computed tomography (CT). The authors found a good concordance between the extension of the lesions on the initial CT examination, prognostic criteria on admission and the course of the disease. In addition, a new prognostic CT sign was reported in the early phase of parenchymal contrast perfusion, i.e. the lack of contrast-enhancement in a limited portion of the pancreas. This sign was present in 8 patients, all with severe clinical symptoms. These 8 patients showed the highest morbidity rate in the series with abscess-type complications occurring in all, compared with 24 p. 100 among the 29 other patients who did not exhibit this CT sign. Moreover, these 8 patients showed the highest mortality rate (25 p. 100 compared with 3.5 p. 100 among the other patients). An histological analysis of partial pancreatectomy specimens was performed in 7 out of the 8 patients. Devitalized pancreatic tissue, at the site of the parenchymal abnormalities on CT scan, was found in all cases. One false negative case was reported. Contrast-enhanced CT scan seems to be the most reliable method for diagnosing pancreatic necrosis during acute severe pancreatitis. It appears to be an useful prognostic predictor of morbidity. It can improve the outcome of the disease by depicting and guiding needle aspiration of a fluid collection, and/or surgery in case of clinical findings suggesting abscess formation.