Imaging appearance of the symptomatic perforating artery in patients with lacunar infarction: occlusion or other vascular pathology?

Lacunar infarction is associated with distinct clinical features. It is thought to result from occlusion of a deep perforating artery in the basal ganglia, centrum semiovale, or brain stem. However, occluded perforating arteries have only rarely been observed at postmortem in patients with lacunar stroke and have not been noted previously on imaging despite the increasing sophistication of the techniques. We observed nine patients with lacunar stroke imaged with computed tomography and magnetic resonance imaging in whom we observed a linear structure with density or signal features consistent with an occluded (or at least abnormal) perforating artery associated with the relevant lacunar infarct. The appearance might also have been caused by a leak of blood and fluid into the perivascular space around the artery, as in several patients the width of the tubular vessel-like structure (>1 mm in diameter) was greater than the expected width of a perforating artery (<0.8 mm in diameter). This interpretation is supported by the fact that the area of infarction was usually around the abnormal vessel, not at the end of it. We describe the patients' clinical and imaging features, and discuss alternative explanations for the imaging appearance and the implications for gaining insights into the cause of lacunar infarction.