title: Effect of inspiratory and expiratory breathhold on pulmonary perfusion: assessment by pulmonary perfusion magnetic resonance imaging.
abstract: OBJECTIVE
  The effect of breathholding on pulmonary perfusion remains largely unknown. The aim of this study was to assess the effect of inspiratory and expiratory breathhold on pulmonary perfusion using quantitative pulmonary perfusion magnetic resonance imaging (MRI).
  
  
  RESULTS
  Nine healthy volunteers (median age, 28 years; range, 20-45 years) were examined with contrast-enhanced time-resolved 3-dimensional pulmonary perfusion MRI (FLASH 3D, TR/TE: 1.9/0.8 ms; flip angle: 40 degrees; GRAPPA) during end-inspiratory and expiratory breathholds. The perfusion parameters pulmonary blood flow (PBF), pulmonary blood volume (PBV), and mean transit time (MTT) were calculated using the indicator dilution theory. As a reference method, end-inspiratory and expiratory phase-contrast (PC) MRI of the pulmonary arterial blood flow (PABF) was performed.
  
  
  RESULTS
  There was a statistically significant increase of the PBF (delta = 182 mL/100 mL/min), PBV (delta = 12 mL/100 mL), and PABF (delta = 0.5 L/min) between inspiratory and expiratory breathhold measurements (P < 0.0001). Also, the MTT was significantly shorter (delta = -0.5 sec) at expiratory breathhold (P = 0.03). Inspiratory PBF and PBV showed a moderate correlation (r = 0.72 and 0.61, P < or = 0.008) with inspiratory PABF.
  
  
  CONCLUSIONS
  Pulmonary perfusion during breathhold depends on the inspiratory level. Higher perfusion is observed at expiratory breathhold.
authors.affiliation: Department of Radiology, Deutsches Krebsforschungszentrum, Heidelberg, Germany. c.fink@dkfz.de
authors.forename: Christian
authors.initials: C
authors.lastname: Fink
authors.forename: Sebastian
authors.initials: S
authors.lastname: Ley
authors.forename: Frank
authors.initials: F
authors.lastname: Risse
authors.forename: Monika
authors.initials: M
authors.lastname: Eichinger
authors.forename: Julia
authors.initials: J
authors.lastname: Zaporozhan
authors.forename: Ralf
authors.initials: R
authors.lastname: Buhmann
authors.forename: Michael
authors.initials: M
authors.lastname: Puderbach
authors.forename: Christian
authors.initials: C
authors.lastname: Plathow
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Kauczor
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D001810:Blood Volume; D045853:Exhalation / Q000502:physiology*; D005260:Female; D006801:Humans; D001239:Inhalation / Q000502:physiology*; D008168:Lung / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011652:Pulmonary Circulation / Q000502:physiology*