OBJECTIVE To assess the evolution of acute portal vein thrombosis by computed tomography (CT). METHODS Retrospective single-centre study (2005-2011) including 23 patients who had an initial CT scan and a CT scan during the first year. The analysis compared the last CT scan available with that of the initial CT scan. Neoplastic thrombosis, extrinsic compressions and cavernomas were excluded. All patients received anticoagulant treatment. RESULTS The causes included: cirrhoses (n = 6), blood disorders (n = 4), locoregional inflammations and infections (n = 8), abdominal surgery (n = 1). The thrombosis was idiopathic in 4 cases. After a mean follow-up of 7.7 months, 7 patients (30%) benefited from a restitutio ad integrum of the portal system, a stable or partially regressive thrombosis was noted in 12 patients (52%) and an aggravation of the thrombosis was noted in 4 patients (18%). In the sub-group of portal vein thrombosis, repermeabilisation was noted in 37.5% of the patients (6/16) and 6 cavernomas developed. CONCLUSIONS CT monitoring helps follow the evolution of an acute portal vein thrombosis and demonstrates complete repermeabilisation of the portal vein in 30% of the patients.