title: Association of right-to-left shunt with frontal white matter lesions in T2-weighted MR imaging of stroke patients.
abstract: BACKGROUND
  Cardiac right-to-left shunt (RLS), mainly due to patent foramen ovale (PFO), is a risk factor for paradoxical embolism and stroke. Results of studies about brain lesions in diffusion-weighted imaging (DWI) in PFO patients were controversial. DWI only detects acute ischemic lesions. We assessed the hypothesis that, in T2-weighted magnetic resonance imaging (T2WI) of stroke patients, RLS is associated with a typical distribution of small white matter lesions.
  
  
  METHODS
  In this retrospective case-control study, T2WI images of 162 stroke patients were evaluated. From stroke patients admitted between 1999 and 2003, 81 stroke patients with RLS were identified with contrast-enhanced transcranial Doppler (bubble test). Controls were 81 age-matched stroke patients without RLS (negative bubble test). In T2WI images, small lesions (<2 cm) were categorized depending on their location in subcortical white matter, peritrigonal white matter, deep and paraventricular white matter, and basal ganglia. Additionally, larger territorial infarcts were rated.
  
  
  RESULTS
  In T2WI frontal or predominantly frontal-located subcortical small white matter, lesions are significantly associated with RLS (p < 0.0001, chi-square test). Forty-three patients with RLS (53%) and only 19 control patients (23%) showed this frontal dominance. Odds ratio is 3.7 (95% confidence interval = 1.9-7.1) for having a RLS when T2WI shows this lesion pattern in a stroke patient. No patient of the RLS group and 6% of the control group had parietal dominance. Distribution of small lesions in other locations like basal ganglia or deep white matter showed no significant difference for the groups.
  
  
  CONCLUSIONS
  A distribution of mainly frontal subcortical small white matter lesions in T2WI is significantly associated with RLS in stroke patients.
authors.affiliation: Department of Neurology, The Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, People's Republic of China.
authors.forename: Jian-Ren
authors.initials: JR
authors.lastname: Liu
authors.forename: Björn-Moritz
authors.initials: BM
authors.lastname: Plötz
authors.forename: Axel
authors.initials: A
authors.lastname: Rohr
authors.forename: Robert
authors.initials: R
authors.lastname: Stingele
authors.forename: Olav
authors.initials: O
authors.lastname: Jansen
authors.forename: Karsten
authors.initials: K
authors.lastname: Alfke
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D005260:Female; D054092:Foramen Ovale, Patent / Q000175:diagnosis* / Q000453:epidemiology*; D005858:Germany / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D020521:Stroke / Q000175:diagnosis* / Q000453:epidemiology*; D055815:Young Adult