The outcome of cerebral venous sinus thrombosis (CVST) depends on rapid diagnosis and initiation of effective anticoagulation. We report seven cases of a subgroup with deep cerebral venous sinus thrombosis (DCVST) treated in our institution since 1990. Six of our seven patients presented with early neuropsychological deficits (mental obtundation, bradyphrenia or apathia). This clinical presentation, in combination with headache, and focal neurological deficits, aids the early diagnosis of DCVST. Thalamic hyperintensities on T2-weighted MRI images, previously considered infarctions, were fully reversible during treatment with heparin. This indicates that early in the course of the disease they correspond to vasogenic oedema.