title: Contrast transcranial Doppler can diagnose large patent foramen ovale.
abstract: BACKGROUND
  Contrast transesophageal echocardiography (c-TEE) and contrast transcranial Doppler (c-TCD) are useful diagnostic tools for detecting right-to-left shunts (RLS). However, the diagnostic accuracy of c-TCD for patent foramen ovale (PFO) remains uncertain. We investigated the relationship between the size of PFO determined by c-TEE and c-TCD findings and assessed the detectable rate of RLS by c-TCD.
  
  
  METHODS
  We assessed RLS three times using simultaneous c-TCD and c-TEE in 107 patients (321 examinations). We classified all of ultrasound examinations into three groups by size according to microbubbles on c-TEE, such as no PFO (0 microbubble), small PFO (1-29 microbubbles) and large PFO (>or=30 microbubbles). We also calculated the number of microembolic signals (MES) on c-TCD and evaluated the association between PFO size on c-TEE and MES count on c-TCD.
  
  
  RESULTS
  In the present study, c-TEE detected RLS in 105 (33%; small PFO, n = 78; large PFO, n = 27), and c-TCD detected RLS in 49 (15%) of 321 examinations. Among 78 examinations with small PFO, MES were found in only 19 (24%) on c-TCD. In contrast, of all 27 examinations with large PFO, MES were found on c-TCD. Also, c-TCD were able to detect MES in 3 of 216 examinations among the no-PFO group. When >or=2 MES on c-TCD was established as the cutoff to predict large PFO on c-TEE, the sensitivity, specificity and accuracy were 96.3, 96.8, and 96.9%, respectively.
  
  
  CONCLUSIONS
  When two or more MES were determined by c-TCD, large PFO could be accurately diagnosed.
authors.affiliation: Department of Stroke Medicine, Kawasaki Medical School, Matsushima, Kurashiki, Japan. k.koba@hotmail.co.jp
authors.forename: Kazuto
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Iguchi
authors.forename: Kazumi
authors.initials: K
authors.lastname: Kimura
authors.forename: Yoko
authors.initials: Y
authors.lastname: Okada
authors.forename: Yuka
authors.initials: Y
authors.lastname: Terasawa
authors.forename: Noriko
authors.initials: N
authors.lastname: Matsumoto
authors.forename: Kenichirou
authors.initials: K
authors.lastname: Sakai
authors.forename: Jyunya
authors.initials: J
authors.lastname: Aoki
authors.forename: Kensaku
authors.initials: K
authors.lastname: Shibazaki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D017548:Echocardiography, Transesophageal; D005260:Female; D054092:Foramen Ovale, Patent / Q000150:complications / Q000000981:diagnostic imaging*; D006801:Humans; D020766:Intracranial Embolism / Q000000981:diagnostic imaging* / Q000209:etiology; D008297:Male; D045423:Microbubbles; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017585:Ultrasonography, Doppler, Transcranial; D014636:Valsalva Maneuver
chemical_list: D003287:Contrast Media