Differential Lesion Patterns on T2WI and FLAIR Sequences in Cryptogenic Stroke Patients With Patent Foramen Ovale.

Objectives: The purpose of this study was to determine lesion patterns and stroke mechanisms in cryptogenic ischemic stroke patients with patent foramen ovale (PFO) on T2-weighted magnetic resonance imaging and fluid-attenuated inversion recovery sequences combined.

Participants And Methods: Twenty-nine patients with cryptogenic ischemic stroke and an isolated PFO (CS-PFO+ group) compared with 51 cryptogenic stroke patients without PFO (CS-PFO- group) were evaluated and the characteristics of their lesion patterns on T2-weighted and fluid-attenuated inversion recovery sequences combined were investigated. We compared the number, the size, and the distribution of ischemic lesions on magnetic resonance imaging between the 2 groups.

Results: Twenty-four of 29 patients had a total of 271 small ischemic lesions (diameter<1 cm) in the CS-PFO+ group against 24 of 51 patients with 156 small ischemic lesions in the CS-PFO- group, respectively; 11.29±8.14 and 6.36±4.33 ischemic lesions per person (P=0.015). Multiple small ischemic lesions occurred more frequently in the CS-PFO+ group (20/29, 69%) than in the CS-PFO- group (16/51, 31%, P=0.001). Subcortical frontal and parietal infarct lesions were more frequent in the CS-PFO+ group (19/29, 66%) than in the CS-PFO- group (18/51, 35%, P=0.009).

Conclusions: Multiple small ischemic lesions and subcortical frontal and parietal infarct lesions were significantly associated with cryptogenic stroke patients with PFO, which suggested that paradoxical embolism is the pathogenic mechanism in cryptogenic stroke patients with PFO.