Diffusion-weighted Imaging Features In Cryptogenic Stroke Patients Attributable To Patent Foramen Ovale

A most of those young patients were diagnosed with cryptogenic stroke, which is unclear of the etiology and pathogenesis. Therefore, it is very important to study the causes and pathogenesis of cryptogenic stroke, then to prevent and treat the cryptogenic stroke in adults. Recently, the medical imaging is rapid developed, detection rate of ischemic stroke in clinical increased. According to the different feature of infarcts in imaging can provide important clues of the etiology. And lots of researches and clinical practices showed that MRI, especially diffusion-weighted imaging(DWI) has a high specificity and sensitivity of the acute, ischemic stroke.Present studies raise that cryptogenic stroke was related with many factors,such as,patent foramen ovale(PFO), artery dissection, arrhythmia, Fabry’s disease and obstructive sleep apnea etc. The patent foramen ovale have attracted the most researchers’ attentions,and many authors conceived through study the features of infarcts on MRI or DWI to detect the the etiology of CS. But the features of infarcts which related with patent foramen ovale are not unified and controversial.This study sought to analyze the different neuro-imaging features between cryptogenicstroke patients with and without PFO, and to study the relationship between the size of PFO and the severity of stroke in patients with patent foramen ovale infarcts. At last we will detect whether it is that degree of right-to-left shunting(RLS) can influence the distribution of infarct on DWI.Experiment 1 Diffusion-weighted imaging features in cryptogenic stroke patients with to patent foramen ovaleBackground and Purpose: The patterns and mechanisms of special lesion in cryptogenic stroke(CS) patients with patent foramen ovale(PFO) are unclear and widely controversial.This study sought to analyze the different neuro-imaging features between cryptogenic stroke patients with and without PFO.Methods: We respective analysised 8218 patients who with acute ischemic cerebral infarction in xijng hospital.At last,there were 218 cryptogenic patients were included in this study and classified into two groups, CS-PFO(+) and CS-PFO(-), between which the distribution of ischemic lesions on diffusion-weighted imaging(DWI) were compared.Moreover, the association between the PFO size and NIHSS score, the volume of infarction and the degree of right-to-left shunting(RLS) were measured in the CS-PFO(+)group.Results: The cases of the CS-PFO(+) group(n=142, 65.1%) were approximately twice that of the CS-PFO(-) group(n=76, 34.9%). There were more sub-cortical single infarcts that were larger than 15 mm, which primarily involved the anterior circulation, in the CS-PFO(+) group(44 of 142 patients, 31.0%) than in the CS-PFO(-) group(10 of 76 patients, 13.2%, P<0.01). Meanwhile, in the CS-PFO(+) group, the degree of RLS in the large PFO group was more serious than in the small group(P<0.05). Finally, the distribution of infarcts on DWI did not differ depending on the magnitude of RLS.Conclusions: A sub-cortical single lesion larger than 15 mm was more likely to be associated with cryptogenic stroke patients with PFO, which indicated that paradoxical embolism is the mechanism of PFO-related cryptogenic stroke. There was no association between DWI features of infarcts and the degree of RLS.Experiment 2 The Association of Patent Foramen Ovale size and the Diffusion-weighted imaging features of InfarctBackground and Purpose:Patent foramen ovale(PFO) has long been regarded as the important pathogenesis of cryptogenic stroke, which include paradoxical embolism and direct embolism of thrombi form. This study evaluated the relationship between the morphological and functional size of the PFO by transesophageal echocardiography(TEE)compared with NIHSS score, cerebral infarct volume measured on DWI and the distribution characteristics of lesions on DWI.Methods: Tansesophageal echocardiogram was used to exam PFO measurements. DWI was used to diagnose the acute ischemic stroke and measure the lesions volume. At last,142 cryptogenic patients were checked with PFO at same in the first experiment. And,according to the morphological and functional size of PFO to classify all patients into two groups:large PFO group and small PFO group. Then, to detect the association between the PFO size and NIHSS score, the volume of infarction and the degree of right-to-left shunting(RLS).Results: In the large PFO group, the degree of RLS in the large PFO group was more serious than in the small group,and we found there is a positive correlation was revealed between the degree of RLS and the size of the PFO(P<0.05). Finally, the distribution of infarcts on DWI did not differ depending on the magnitude of RLS.Conclusions: There was no association between DWI features of infarcts and the degree of RLS.