Postoperative pancreatic fistula is a relevant complication after pancreatoduodenectomy. Therefore, preoperative detection of high risk patients may be important. We evaluated preoperative CT-imaging by planimetry at the expected resection plane along the superior mesenteric vein and correlated the results with the incidence of postoperative pancreatic fistula. From 2009 to 2013, 123 patients with pancreatoduodenectomy underwent homogenous preoperative imaging and reconstruction of the pancreatojejunostomy. Planimetry was performed at a multiplanar reconstruction of the pancreatic transection plane (diameter, range, duct width, area) as well as the calculation of ratios (duct width/pancreatic diameter; D/P-ratio). The measured values were correlated with the incidence of postoperative pancreatic fistula. Planimetry showed a significant difference of the pancreatic transection plane in relation to the incidence of postoperative pancreatic fistula. A thick parenchyma and a tiny duct are significant risk factors. In 84 % or, respectively, 94 % of the patients with postoperative pancreatic fistula, a duct width of less than 20 % of the pancreatic diameter was observed (D/P ratio < 0.2; p < 0.01). The D/P ratio was the only independent risk factor in multivariate analysis. The incidence of postoperative pancreatic fistula correlates significantly with the morphology of the pancreatic transection plane. The risk increases significantly with a D/P ratio of < 0.2.