Helical computed tomography in the diagnosis of portal vein invasion by pancreatic head carcinoma: usefulness for selecting surgical procedures and predicting the outcome.

OBJECTIVE To evaluate the use of helical computed tomography (CT) in diagnosing portal vein (PV) invasion by pancreatic head carcinoma and its usefulness in predicting outcome. DESIGN Validation cohort study. SETTING Tertiary care public hospital. PATIENTS Twenty-seven patients with carcinoma involving the pancreatic head were preoperatively studied with helical CT. All patients underwent resection. MAIN OUTCOME MEASURE By quantifying the contact between the tumor and PV on helical CT, the relationship between them was classified into 1 of 4 types: type 1, visible fat layer between PV and the tumor; type 2, with the total PV circumference defined as 360 degrees, contact between the tumor and PV was considered to be 90 degrees or less; type 3, contact ranged between 91 degrees and 180 degrees; and type 4, contact greater than 180 degrees. Helical CT results were compared with intraoperative observation, histological findings of the resected specimen, and postoperative course. RESULTS When helical CT showed type 3 or 4, the case was diagnosed as positive for PV invasion. Sensitivity, specificity, and overall accuracy were 83%, 100%, and 89% when compared with the intraoperative assessment, and 92%, 79%, and 85% with the histological assessment, respectively. One- and 2-year survival rates were 86% and 69% for type 1, 100% and 75% for type 2, and 33% and 12% for type 3, respectively. The survival rates of patients with types 1 and 2 were significantly higher than that of those with type 3 (P<.05). All 3 patients with type 4 died within 9 months. CONCLUSIONS Helical CT facilitates detection of PV invasion by pancreatic head carcinoma. The extent of PV involvement reflected the outcome after pancreatectomy.