Quantifizierung des pulmonal-arteriellen Drucks im Truncus pulmonalis des Schweins. Methode: Künstliche Induktion einer pulmonalen Hypertonie mittels Thromboxan A2 in verschiedenen Schweregraden. Quantifizierung des Blutflusses anhand magnetresonanztomographischer Flussmessung im T.p., hieraus Bestimmung des zeitlichen Flussprofils und Akzelerationszeit (AT). Korrelation der AT mit den simultan erhobenen Daten einer invasiven Druckmessung (Pulmonalis-Katheter).

Purpose: To establish an estimate for the mean pulmonary arterial pressure (mPAP) derived from non-invasive data acquired with magnetic resonance velocity encoded sequences (MR). Material and Methods: In 7 sedated pigs synchronous catheter-based invasive pressure measurements (mPAPinv) and non-invasive MR were acquired in the main pulmonary artery (MPA) at different severities of pulmonary arterial hypertension (PAH) that were caused by infusion of thromboxane A2 (TxA2). The invasively measured mPAP was correlated with the non-invasive magnetic resonance velocity data and linear combination equations (LCE) were computed. Results: Intravenously applied TxA2 induced a dose dependent level of severity of PAH with an mPAP of up to 54 mmHg without systemic effects. The acceleration time (AT) measured with MR demonstrated the best correlation with the mPAPinv : (1) mPAPinv = 72 - 0.65 x AT, (r=0.87) The LCE with the highest correlation was found between mPAPinv on the one hand and mean flow velocity (MFV) and AT on the other: (2) mPAPinv = 72 - 0.50 x AT - 0.28 x MFV, (r=0.90). Conclusion: Applying the identified LCE allowed the estimation of the mPAP in an acute and resistance-based model of PAH with high accuracy using non-invasive magnetic resonance velocity encoded sequences.