Comparison of magnetic resonance imaging with echocardiography and radionuclide angiography in assessing cardiac function and anatomy following Mustard's operation for transposition of the great arteries.

The Mustard operation in infancy and childhood has successfully palliated many patients with transposition of the great arteries who have now survived to adulthood. Right ventricular dysfunction and tricuspid regurgitation are important determinants of late morbidity and mortality. The value of noninvasive magnetic resonance imaging (MRI) in the assessment of cardiac function and anatomy 9 to 20 years after this procedure has been investigated, and compared with findings on echocardiography, radionuclide ventriculography and angiography in 17 adult patients. Ejection fractions measured by MRI were higher compared with radionuclide ventriculography. The correlation for the left ventricle was closer (r = 0.75) than for the right ventricle (r = 0.49). Tricuspid regurgitation was assessed by Doppler echocardiography and by MRI using the right/left ventricular stroke volume ratio. The mean stroke volume ratio in those with Doppler evidence of tricuspid regurgitation was 1.6:1 compared to 1.1:1 in those without, and this difference reached significance (p less than 0.01). The anatomy of the great arteries was clearly visible in all patients. Five patients had a residual ventricular septal defect which, with the exception of 1 small defect, was easily visualized. The intraatrial baffle was best seen in transverse slices, and the systemic venous connection showed as a relatively narrow channel lying in the posterior part of the cavity. In general, baffle anatomy was easier to assess on 2-dimensional echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)