MRI beats echo for accuracy of mitral regurgitation assessment

Echocardiography may be cost-effective and widely available, but a comparison of echo and MRI found only a modest accord in assessing mitral regurgitation. And between them, MRI had greater accuracy in evaluating regurgitation volume.

The multicenter trial assessed 103 patients with MRI and echocardiography for regurgitation severity. Following assessment, 38 patients underwent mitral valve surgery. Twenty-six patients had further MRI follow-up at five to seven months.

Seth Uretsky, MD, of Morristown Medical Center in Morristown, N.J., and colleagues found that between MRI and echocardiography, overall severity estimates of mitral regurgitation were modest. Among all patients, MRI and echocardiography agreed on severity assessment of regurgitation in only 36 percent.

In 34 percent of patients with severe regurgitation according to echocardiography, MRI reported only mild regurgitation. Only 20 percent of patients were characterized as having severe mitral regurgitation on both echocardiography and MI.

However, Uretsky et al wrote that changes in left ventricle volume were seen among patients who had surgery, with more significant differences among those who had been considered most severe on MRI. Patients with severe regurgitation according to MRI assessment had reduced left ventricular end-diastolic (LVED) volume by 140 ml; LVED volume dropped by 55 ml among those deemed moderate by MRI and 31 ml among those who MRI deemed mild.

The researchers noted that not only was MRI assessment more accurate, it also was highly reproducible across observers, which echocardiography assessment was not. One major difference in how mitral regurgitation was assessed via MRI was through the use of a flow measurement calculation that included left ventricular stroke volume and forward flow.

These findings have major impacts in the clinical realm. According to guidelines, patients with severe mitral regurgitation according to echocardiographic assessment are recommended surgery, regardless of symptoms. However, if MRI provides a more accurate picture, fewer patients would require intervention.

In an editorial, Saibal Kar, MD, and Rahul Sharma, MD, of Cedars-Sinai Medical Center in Los Angeles wrote that perhaps both methods could complement one another when used for a second opinion. As noted by Uretsky, only among mild regurgitation did MRI and echocardiography have the most concurrence and there were no patients where MRI determined regurgitation to be severe that echocardiography called mild. “In those patients with moderate or severe [mitral regurgitation], particularly asymptomatic patients, MRI may be indicated to confirm the degree of severity before subjecting the patient to invasive therapy,” wrote Kar and Sharma.

Kar and Sharma added that in future guidelines, perhaps a better means of classifying regurgitation would be a continuous variable instead of categories like mild, moderate or severe.

The article appeared in the March 24 issue of Journal of the American College of Cardiology.