Magnetic resonance imaging analysis of left ventricular pressure-volume relations: validation with the conductance method at rest and during dobutamine stress.

The accuracy of magnetic resonance (MR) imaging was assessed for in vivo measurement of the ventricular end-systolic pressure-volume relation (ESPVR) and preload recruitable stroke work (PRSW). The conductance catheter was used as reference. In 10 pigs, ventricular volumes were measured with both methods under different loading conditions at two levels of contractility. Increased contractility resulted in a significant leftward shift of the ESPVR and PRSW for both methods. The magnitude of these shifts was on average similar for the two methods; MR imaging, 6.9 ml for ESPVR, 9.3 ml for PRSW; and the conductance catheter, 7.4 ml for ESPVR, 9.1 ml for PRSW. It was concluded that MR imaging may be used for in vivo analysis of pressure-volume relations, and that its sensitivity for detecting contractility changes is similar to that of the conductance catheter method.