title: Patent foramen ovale and asymptomatic brain lesions in military fighter pilots.
abstract: OBJECTIVE
  Previous studies have reported higher incidence of white matter lesions (WMLs) in military pilots. The anti-gravity straining maneuver, which fighter military pilots perform numerously during a flight is identical to the valsalva maneuver. We sought to investigate the prevalence of right-to-left shunt (RLS) associated with WMLs in military pilots.
  
  
  METHODS
  A prospective study was performed involving military pilots who visited the Airomedical Center. The pilots underwent brain magnetic resonance imaging (MRI) scan and transcranial Doppler (TCD) with intravenous injection of agitated saline solution for the detection of RLS. Periventricular WMLs (PVWMLs) on MRI were graded using Fazeka's scale, and deep WMLs (DWMLs) were graded using Scheltens's scale.
  
  
  RESULTS
  This study included 81 military pilots. RLS on TCD was observed less frequently in non-fighter pilots than in fighter pilots (35.5% vs. 64.5%, p=0.011). Fighter pilot was an independently associated factor with RLS on the TCD. DWMLs were independently associated with RLSs through a patent foramen ovale (PFO) (OR 3.507, 95% CI 1.223-10.055, p=0.02).
  
  
  CONCLUSIONS
  The results suggest that DWMLs in military pilots may significantly be associated with RLS via PFO. Additional investigations are warranted.
authors: Department of Neurology, Cerebrovascular Center, Chonnam National University Hospital, Gwangju, South Korea; Department of Neurology, Aerospace Medical Center, Republic of Korea Air Force, Choongbuk, South Korea.
authors: Kyung Wook
authors: KW
authors: Kang
authors: Department of Neurology, Cerebrovascular Center, Chonnam National University Hospital, Gwangju, South Korea. Electronic address: alldelight2@jnu.ac.kr.
authors: Joon-Tae
authors: JT
authors: Kim
authors: Department of Cardiology, Cardiovascular Center, Han Heart Hospital, Changwon, South Korea.
authors: Won-Ho
authors: WH
authors: Choi
authors: Department of Occupational and Environmental Medicine, Chonnam National University Hwasun Hospital, Hwasun, South Korea.
authors: Won-Ju
authors: WJ
authors: Park
authors: Department of Orthopaedic Surgery, Aerospace Medical Center, Republic of Korea Air Force, Choongbuk, South Korea.
authors: Young Ho
authors: YH
authors: Shin
authors: Department of Neurology, Cerebrovascular Center, Chonnam National University Hospital, Gwangju, South Korea.
authors: Kang-Ho
authors: KH
authors: Choi
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D001930:Brain Injuries / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D054092:Foramen Ovale, Patent / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D008889:Military Personnel / Q000706:statistics & numerical data*; D015995:Prevalence; D011446:Prospective Studies; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods; D055815:Young Adult
keywords: Patent foramen ovale; Pilot; Right-to-left shunt; White matter lesion