Peggy Nguyen, MD

The lacune, often used interchangeably with the definition of a stroke of small vessel atherosclerotic etiology, is traditionally based on a size definition of no greater than 15 mm. It is a classic feature of cerebral small vessel disease. However, despite its prolific use in the stroke literature, the exact characteristics and morphological features of a lacune are not well defined. Here, the authors analyzed the shape of incident lacunes in CADASIL, a genetically inherited small vessel arteriopathy, to better define the lacune’s morphological features.

Fifty-seven CADASIL patients with incident lacunes were included in the study, encompassing 88 incident lacunes, only 18 of which were associated with symptoms. The most common locations for lacunes were in the centrum semiovale (n=30) and the basal ganglia (n=27). In spectral shape analysis, elongation and planarity were found to be the primary determinants of lacune shape and tended to align along perforating arteries. Although 15 mm is traditionally used as the upper size limit of a lacune, about 10% of lacunes, particularly when evaluated in planes other than axial, exceeded this size, whereas only 1 lacune was larger than 15 mm in the axial plane.

Not all lacunes are created the same, but there are certainly similarities, and this may have to do with the mechanisms by which they develop. The findings in this study confirm some generalizations of lacunes, such as the common locations, but also refutes some others, for instance, the size of lacunes, particularly when viewed in non-axial planes. These findings are also suggestive of a mechanism in which lacunes of chronic small vessel diseases develop secondary to factors related to vascular anatomy, rather than tract degeneration.