CT observations on the natural history of asymptomatic cerebral infarction following transient ischaemic attacks.

Two hundred and sixty-one neurologically asymptomatic patients were examined by computed tomography (CT) following a variable number of transient ischaemic attacks (TIAs) experienced over different time intervals. Cerebral infarcts were discovered in 101 patients. Dominant hemisphere infarcts were usually small, of recent origin and most often associated with less than 5 TIAs and a short history; whereas non-dominant hemisphere infarcts were found twice as frequently and were larger and older and correlated with repeated TIAs over many months. All infarcts, independent of size, were confined to a single vascular territory, suggesting haemodynamic rather than embolic causes. By comparing the age and size of the infarcts with the number of TIAs and their chronicity, the hypothesis emerged, suggesting that infarcts may occur early on and progressively enlarge with repeated attacks.