Global left ventricular function parameters can be obtained with a high degree of accuracy and precision using the present semiautomated contour detection algorithm.

No abstract

After cardiac surgery, mild pulmonary oedema is relatively common, even in the absence of high filling pressures, and is mainly attributable to a low COP, irrespective of increased permeability in about one-half of patients. It may prolong mechanical ventilation at EVLW > 10 ml/kg. However, pulmonary radiographic and ventilatory abnormalities may result, at least in part, from atelectasis rather than increased permeability oedema.

Magnetic resonance tagging has proven a valuable tool in the quantification of myocardial deformation. However, time-consuming postprocessing has discouraged the use of this technique in clinical routine. Recently, the harmonic phase (HARP) technique was introduced for automatic calculation of myocardial strain maps from tagged images. In this study, a comparison was made between HARP instantaneous strain maps calculated from single tagged images (SPAMM) and those calculated from subtracted tagged images (CSPAMM). The performance was quantified using simulated images of an incompressible cylinder in the 'end-systolic' state with realistic image contrast and noise. The error in the second principal stretch ratio was 0.009 +/- 0.032 (mean +/- SD) for the SPAMM acquisition, and 0.007 +/- 0.016 for CSPAMM at identical contrast-to-noise ratio. Furthermore, differences between the methods were illustrated with in vivo strain maps. Those calculated from CSPAMM images showed fewer artifacts and were less sensitive to the choice of cut-off frequencies in the HARP band-pass filter. A prerequisite for the method to become practical is that the CSPAMM images should be acquired in a single breathhold.