Differential lesion patterns on T2-weighted magnetic resonance imaging and fluid-attenuated inversion recovery sequences in cryptogenic stroke patients with patent foramen ovale.

BACKGROUND The present study aimed to determine lesion patterns and the stroke mechanisms in cryptogenic ischemic stroke patients with patent foramen ovale (PFO) on T2-weighted magnetic resonance imaging (T2WI) and fluid-attenuated inversion recovery (FLAIR) sequences combined. METHODS In this retrospective study, 38 patients with cryptogenic stroke and an isolated PFO compared with 51 cryptogenic stroke patients without PFO were evaluated and their characteristics of lesion patterns on T2WI and FLAIR sequences combined were investigated. The number, distribution of small ischemic lesions, and the frequency of multiple small ischemic lesions were analyzed between the 2 groups. RESULTS Thirty-two of 38 patients had a total of 341 small ischemic lesions in cryptogenic stroke patients with PFO versus 24 of 51 patients with 156 small ischemic lesions in patients without PFO, and, 8.97±7.91 and 3.19±4.82 ischemic lesions per person, respectively. Multiple small ischemic lesions occurred more frequently in cryptogenic stroke patients with PFO (25 of 38 patients, 66%) than in patients without PFO (16 of 51 patients, 31%; P=.001). Subcortical frontal and parietal small lesions were more frequent in cryptogenic stroke patients with PFO (28 of 38 patients, 74%) than in patients without PFO (18 of 51 patients, 35%; P<.0001). CONCLUSIONS Multiple small ischemic lesions and subcortical frontal and parietal small lesions were significantly associated with cryptogenic stroke patients with PFO, suggesting that paradoxical embolism may be the mechanism of PFO-associated cryptogenic stroke patients.