The Fate of Acute Lacunar Lesions in Terms of Shape and Size.

BACKGROUND: The description of lacunar infarcts on imaging is widely variable. In particular, there are fewer agreements on lacunar lesion size and the presence of cavitation. In this regard, we investigated the changes in size and shape of acute ischemic lesion that is possibly considered as small vessel occlusion on long-term follow-up.

METHODS: Patients with acute single subcortical ischemic lesion on penetrating arterial territories and without definite cause of cardioembolism and large vessel disease were included. Magnetic resonance imaging (MRI) was performed during an acute stroke period and approximately 1 year after the stroke. Maximal diameters on diffusion-weighted image and on follow-up (T2 or fluid attenuation inversion recovery) were measured. The change in lesion diameter over time was analyzed. Regarding the change in shape, lacunar lesions on follow-up were classified as either "disappeared," "cavitated," or "white matter lesion."

RESULTS: A total of 64 patients were included. The mean age was 64.94 ± 11.29 years and 32 patients were male. The mean time interval between initial and follow-up MR scan was 23.39 ± 14.88 months. The mean diameter of acute lacunar lesion was 14.11 ± 5.77 mm. On follow-up, the mean diameter reduced to 7.76 ± 5.19 mm. The mean percentage of final diameter over initial diameter was 53.57 ± 26.45%. All of the lesions were less than 15 mm on follow-up. Regarding the shape of the lesion on follow-up, the lesions of 33 (51.6%) patients remained cavitated, the lesions of 14 (21.9%) patients remained as white matter lesions, and the lesions of 17 (26.6%) patients disappeared. There were no differences on clinical characteristics between patients with cavitation and those without.

CONCLUSIONS: The diameter of acute lacunar lesions on initial diffusion-weighted MRI was markedly reduced on follow-up. In 52% of the patients, acute lacunar lesions were cavitated.