Objective: To evaluate the clinical significance and radiographic characteristics of acunar strokes. Methods: Forty-seven patients with acute schemic strokes between Sepember 2005 and January 2006 were included. The criteria of the TOAST (Trial of Org 10172 in Acute Stroke Treatment) classification were used to determine the stroke subtype. Routine radiographic evaluations included brain MRI(magnetic resonance angiography), post-contrast neck MRA, and transthoracic rchocardiography (TTE). Results: There were 30 men and 17 women (mean age, 69 years). Regarding stroke subtypes, stroke of undetermined etiology (SOU) was the most common (20 aptients, 42.6%), followed by small-vessel occlusion (SVO) initially, only 14 patients turned out to fulfill the criteria of SVO finally. Twelve patients who had been classified into SVO initially turned out  have significant marrowing of large arerty or probale source of cardioembolism(CE).  Conclusion: A thorough investgation by using various radingraphic modalities is required to  aboid erroneous classification of schemic strokes. We should keep in mind that patients with lacunar strokes may also have LAA or probable source of CE.