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).
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°; 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.
There was a statistically significant increase of the PBF (Δ = 182 mL/100mL/min), PBV (Δ = 12 mL/100 mL), and PABF (Δ = 0.5 L/min) between inspiratory and expiratory breathhold measurements (P <0.0001). Also, the MTT was significantly shorter (Δ = −0.5 sec) at expiratory breathhold (P = 0.03). Inspiratory PBF and PBV showed a moderate correlation (r = 0.72 and 0.61, P ≤0.008) with inspiratory PABF.
Pulmonary perfusion during breathhold depends on the inspiratory level. Higher perfusion is observed at expiratory breathhold.
From the *Departments of Radiology and †Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany; and the ‡Department of Radiology, University of Mainz, Mainz, Germany.
Received June 23, 2004 and accepted for publication, after revision, October 3, 2004.
Reprints: Christian Fink, MD, Deutsches Krebsforschungszentrum (DKFZ), Abteilung Radiologie E010, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany. E-mail: firstname.lastname@example.org.