RESUMO
BACKGROUND AND OBJECTIVES: Pure pontine infarct is defined as an infarct limited to the pons without the evidence of any other brainstem infarct. This study was designed to assess the etiology, lesion topography, and clinical characteristics of pure pontine infarcts. METHODS: Sixty-six patients with pure pontine infarcts, shown on magnetic resonance imaging, were divided into three groups(Group I(n=32) : unilateral lesion reaching the ventral surface of the pons(>1.5cm in size), Group II(n=27) : single or multiple lesions, separated from the surface(<1.5cm), Group III(n=7) : bilateral extensive lesion reaching the ventral surface). Clinical characteristics including the risk factors and the symptomotology were evaluated. Conventional or magnetic resonance angiography was performed in 37 patients(Group I ; 18/32, Group II ; 14/27, Group III ; 5/7). RESULTS: Pontine lesions in Group I(number of lesions = 36) were located longitudinally in the upper (8/36, 22.2%), middle(11/36, 30.6%), and lower(17/36, 47.2%) pons. Thirty-seven patients, in whom angiography was performed, were classified etiologically in each groups. In Group I, fourteen patients had basilar artery branch disease and four had large artery disease. In Group II, all had small artery disease. In Group III, three patients had large artery disease and two had basilar artery branch disease. The most frequent risk factor in pure pontine infarct was hypertension in all three groups. CONCLUSION: The lower region of pons is the most vulnerable site of pure pontine infarct. Basilar artery branch disease was the most common cause of the pure pontine infarct(43.2%). Small artery disease occupied 37.8% and large artery disease(18.9%) was less common.