Imaging characteristics of ischemic strokes related to patent foramen ovale

Subclinical atrial fibrillation (AF) and patent foramen ovale (PFO) are the major causes of cryptogenic stroke, and neuroimaging may help distinguish the cause. We compared the imaging characteristics of ischemic stroke caused by PFO (PFO-stroke) and AF (AF-stroke).

We recruited 117 patients with PFO-stroke and 358 patients with AF-stroke after excluding other causes. The lesion patterns were classified according to number, location, size, and pertinent vascular territory and were compared between the 2 groups. Occlusion of the corresponding artery and its recanalization rate were also investigated.

The lesion pattern of a PFO-stroke was more frequently observed as a single cortical infarction (34.2% versus 3.1%; P<0.001) or multiple small (<15 mm) scattered lesions (23.1% versus 5.9%; P<0.001) and in the vertebrobasilar artery territory (44.4% versus 22.9%; P<0.001). By contrast, AF-stroke was more frequently observed as a large cortico-subcortical infarction or confluent lesion (>15 mm) with additional lesions in multicirculatory territories. For a PFO-stroke, occlusion of the corresponding vessel on angiography was less frequent (34.2% versus 71.5%; P<0.001), and the neurological deficit evaluated by the National Institutes of Health Stroke Scale was mild (3.48±4.16 versus 9.15±7.35; P<0.001). The recanalization rate was also lower (57.1% versus 78.3%; P=0.007).

A PFO-stroke usually appears as a single cortical or multiple small ischemic lesions in the vertebrobasilar circulation without any visible vessel occlusion on angiography. The recanalization rate is significantly lower than in AF-stroke. These imaging characteristics of PFO-stroke may help to diagnose the mechanism and determine the treatment strategy.