We investigated the diffusion weighted magnetic resonance imaging (DWI) features of 76 very elderly patients aged 90 years or above with
acute ischemic stroke.
Stroke subtypes were classified into five types according to the Trial of
Org 10172 in
Acute Stroke Treatment (TOAST) and the Japanese
Stroke Databank. The incidence rates of atherothrombotic
brain infarction (ATBI), atherothrombotic
brain embolism (ATBE),
lacunar infarction (LI), cardiogenic
brain embolism (CBE) and undetermined type of
brain infarction (UTBI) were 2.6%, 17.1%, 10.5%, 50.0% and 19.8%, respectively. We estimated that the incidence of
acute ischemic stroke in women was 3.5-fold higher than that in men. This is likely because survival rate of females is higher than that of males in populations aged 90 years or above. The prevalence of
atrial fibrillation (AF) was 46.1% in patients with
brain infarctions, and 92.1% in patients with CBE. The frequency of multiple
infarctions is 52.6% and that of single
infarction is 47.4%. In DWI of lesions, the frequencies of territorial
infarction in the cerebral hemisphere, borderzone
infarction, and vertebrobasilar
infarction were 85.5%, 13.2% and 17.1%, respectively. The frequencies of massive territorial
infarction and cerebellar
infarction were 23.7% and 13.2%, respectively. With regard to the relationship between DWI lesion topography and
stroke subtypes, superficial
infarctions in the cerebral hemisphere were seen in patients with ATBE, CBE and UTBI. Single
infarctions deep in the cerebral hemisphere were seen in all patients with any of the five
stroke subtypes. Massive territorial
infarctions with
infarctions in other sites of the cerebral hemisphere or vertebrobasilar region were seen only in patients with CBE, and single pontine
infarction was seen only in patients with LI. (Received November 19, 2015; Accepted July 3, 2017; Published November 1, 2017).