title: Intracranial embolism characteristics in PFO patients: a comparison between positive and negative PFO by transesophageal echocardiography: the rule of nine.
abstract: OBJECTIVE
  Patent foramen ovale (PFO) can be diagnosed by contrast-enhanced transcranial Doppler (cTCD), but no definitive criteria exist to correlate the results obtained from cTCD with diagnoses of PFO obtained by contrast-enhanced transesophageal echocardiography (cTEE). The aim of the present study was to analyze markers in the positive RLS by cTCD that confirm the PFO by cTEE.
  
  
  METHODS
  Twenty-six stroke patients who had previously submitted to cTEE, 16 with PFO (PFO group) and 10 without PFO (no-PFO group), were evaluated for three markers based on a positive cTCD test. The number of microembolic signs (MES), the latency time (LT) to the first MES and the duration time (DT) of MES were evaluated to look for a difference between the PFO and no-PFO group.
  
  
  RESULTS
  The PFO group had higher MES (80.9+/-124.5 vs. 10.2+/-25.6, p<0.001), shorter LT (12.5+/-6.6 vs. 16.2+/-5.1, p=0.02) and longer DT (21.4+/-17.4 vs. 11.7+/-12.5, p=0.013) compared with the no-PFO group. Considering only MCA tests with more than 9 MES and LT shorter than 9s, 30% of patients from the PFO group had positive tests compared with no patients from the no-PFO group. This cutoff demonstrates a specificity and positive predictive value of 100%.
  
  
  CONCLUSIONS
  The rule of nine (>9 MES and LT <9s) for cTCD can be considered a marker for PFO diagnosis by cTEE.
authors.affiliation: Neurology Division, Internal Medicine Department, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brazil. lange@ufpr.br
authors.forename: Marcos Christiano
authors.initials: MC
authors.lastname: Lange
authors.forename: Viviane Flumignan
authors.initials: VF
authors.lastname: Zétola
authors.forename: Admar Moraes
authors.initials: AM
authors.lastname: deSouza
authors.forename: Felipe Matos
authors.initials: FM
authors.lastname: Novak
authors.forename: Elcio Juliato
authors.initials: EJ
authors.lastname: Piovesan
authors.forename: Lineu César
authors.initials: LC
authors.lastname: Werneck
mesh_terms: D000328:Adult; D015150:Echocardiography, Doppler; D004947:Esophagus / Q000000981:diagnostic imaging*; D005260:Female; D054092:Foramen Ovale, Patent / Q000150:complications*; D006801:Humans; D007089:Image Enhancement; D020766:Intracranial Embolism / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011859:Radiography