Small centrum ovale infarcts on diffusion-weighted magnetic resonance imaging.

BACKGROUND AND PURPOSE: A small centrum ovale infarct (SCOI), caused by occlusion of the white matter medullary arteries, is often equated with a lacunar infarct. We sought to clarify the clinical characteristics of a SCOI visualized by diffusion-weighted MRI (DWI) compared with those of a small basal ganglia infarct (SBGI).

METHODS: Patients with a SCOI (SCOI group; n=38) or SBGI (SBGI group; n=68) < or =15 mm in diameter on conventional MRI and DWI were selected from 582 consecutive patients with acute ischemic stroke. Sex, age, neurological symptoms, vascular risk factors, emboligenic heart disease, arterial occlusive disease in the ipsilateral carotid system, and recurrent stroke within the initial 30 days were compared between the 2 groups.

RESULTS: Only 47% of SCOIs but 87% of SBGIs could be identified with the use of conventional MRI, whereas DWI could detect them all. Age, sex, and vascular risk factors were not significantly different between the 2 groups. The SCOI group had more frequently an abrupt onset of symptoms (63% versus 26%; P=0.0002), emboligenic heart diseases (34% versus 12%; P=0.0054), occlusive carotid and/or middle cerebral artery diseases (53% versus 19%; P=0.0004), and recurrent stroke (13% versus 1%; P=0.0216) but less frequently a classic lacunar syndrome (50% versus 81%; P=0.0009) than the SBGI group. On a multivariate analysis, both arterial and heart diseases were independently associated with the SCOI group.

CONCLUSIONS: Symptomatic SCOIs detected by DWI may be associated with large-vessel and heart diseases and should be distinguished from lacunar infarcts.