Lacunar infarcts: Clinical, neuroimaging and prognostic features

Sammanfattning: The thesis investigated clinical, neuroimaging and prognostic features in lacunar infarction. The studies were based on a series of 100 consequtive patients with a first-ever stroke and a lacunar syndrome investigated with CT, Gd-DTPA enhanced MRI, and with respect to large vessel disease and cardioembolic sources. the patients were followed for a mean of 4 years. MRI was repeated one year after stroke onset and in case of a recurrent stroke. The majority of patients had MRI findings compatible with lacunar infarction, and no other cause than small vessel diseae to account for their symptoms. However, other causes were also found, indicating the necessity of performing neuroimaging studies as well as tests for cardiac and large vessel disease in patients with lacunar syndromes. Enhanced MRI facilitated the identification of the symptomatic infarct. MRI at 1 year showed a reduction of the infarct size, and signal abnormalities typical of central cavitation and pyramidal tract degeneration had developed. New "silent" infarcts were more frequently encountered than recurrent strokes. Quantitative thermal testing confirmed an involvement of spinothalamic pathways in lacunar infarcts causing pure sensory and sensorimotor stroke, and revealed a subclinical sensory impairment in patient with pure motor stroke. Infarcts causing pure motor stroke and sensorimotor stroke were mainly lenticulocapsular, while those causing pure sensory strokes were thalamic. New, lacunar infarcts were the most common type of recurrent stroke, but other pathogenetic mechanisms were found in about one third of cases. Functional outcome regarding physical independcence was favourable. Poor outcome was predicted by the degree of hemiparesis and the severity of white matter abnormalities at MRI.