title: [Comparison of two contrast agents for diagnosis of patent foramen ovale by contrast transcranial Doppler].
abstract: OBJECTIVE
  To compare agitated saline solution (AS) and the mixture of AS with blood (ASb) as the contrast agents in contrast transcranial Doppler (c-TCD) in the diagnosis of patent foramen ovale (PFO).
  
  
  METHODS
  We recruited 248 consecutive patients for c-TCD examination between November 2015 and January 2016, and the sequence of the use of AS (9 mL saline solution mixed with 1 mL air) and ASb (9 mL saline solution and a drop of the patient's blood mixed with 1 mL air) was determined by coin-tossing method. Before the examination, the contrast agent was injected with or without Valsalva maneuvers (VM), and the number of microbubbles within 25 s after the contrast agent injection and the time of first appearance of microbubbles were recorded by observing the TCD spectrum. Each injection was repeated twice and the interval between tests was at least 5 min. We classified PFO according to the number of microbubbles into negative (no microbubble), grade I (1-10 microbubbles), grade II (>10 microbubbles but no curtain), and grade III (with curtain).
  
  
  RESULTS
  s The positivity rates in diagnosis with AS without VM, AS with VM, ASb without VM, and ASb with VM tests were 10.9%, 23.8%, 12.1% and 25.8%, respectively. AS with VM test had a higher positive rate than AS without VM test (23.8% vs 10.9%, P=0.001), and ASb with VM test had a higher positive rate than ASb without VM test (25.8% vs 12.1%, P=0.001). The positive rates were similar between ASb without VM and AS without VM test (12.1% vs 10.9%, P=0.250) and between ASb with VM test and AS with VM test (25.8% vs 23.8%, P=0.125).
  
  
  CONCLUSIONS
  VM can improve the positive rate of PFO diagnosis in c-TCD examination, and the positive rates are comparable between examinations using the contrast agents AS and ASb.
authors: Department of Neurology, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710004, China. E-mail: 915344331@qq.com.
authors: Chao
authors: C
authors: Liu
authors: Ni-Na
authors: NN
authors: Zhai
authors: Ning
authors: N
authors: Bu
authors: Meng-Yi
authors: MY
authors: Chen
authors: Hai-Qin
authors: HQ
authors: Wu
mesh_terms: D003287:Contrast Media / Q000737:chemistry*; D054092:Foramen Ovale, Patent / Q000000981:diagnostic imaging*; D045423:Microbubbles; D012680:Sensitivity and Specificity; D012965:Sodium Chloride; D017585:Ultrasonography, Doppler, Transcranial; D014636:Valsalva Maneuver
chemical_list: D003287:Contrast Media; D012965:Sodium Chloride