Computed tomographic patterns of proven embolic brain infarctions.

To define patterns of infarction on computed tomography that are characteristic of embolism, as opposed to hemodynamically or microangiopathically induced brain lesions, a consecutive series of 60 patients with acute brain embolism were studied. Strokes were embolic in origin; that is, hemodynamic and in situ thrombotic stroke mechanisms had been excluded. Embolically active, cardiac disease was proved in 42 and was clinically evident in 13 patients. Five patients had suffered a stroke due to catheter-related embolism. Computed tomography revealed pial artery territorial infarction in 55 patients (92%). In 5, the infarction had the size or location (or both) characteristic of lacunes, although shape and lack of multiplicity raised questions about this interpretation. No patient showed a low-flow type of infarction pattern. These findings strongly support the view that (1) except for in situ thrombosis, pial artery territorial infarctions are indicative of an embolic mechanism, and (2) that the mechanism underlying lacunes is hardly, if ever, embolic.