Images of Note: An Emerging Use of 4-D CT
For structural assessment of bioprosthetic mitral valve function, 4-D CT can offer more than echo does — especially for distinguishing calcification from thrombosis. These images make the point.
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Echocardiography is the mainstay for assessing bioprosthetic mitral valve function, but when it comes to assessing structure, there’s an emerging role for four-dimensional (4-D) CT. That’s particularly the case when there’s a diagnostic question of whether the predominant pathology is calcification versus valve thrombosis.
The 4-D CT images above highlight this point. The top two images are from a patient with symptomatic bioprosthetic mitral valve stenosis. On the left, the reconstructed apical four-chamber view shows hyperattenuated bioprosthetic valve leaflets, representing severe calcification. On the right, the short-axis reconstruction also shows leaflet hyperattenuation, consistent with calcification.
In contrast, the bottom two images are from a case of subacute bioprosthetic valve thrombosis in a patient with symptomatic mitral stenosis. On the left, the apical four-chamber reconstruction shows layering hypoattenuation along the sewing ring, indicating thrombus. On the right, the short-axis reconstruction shows prominent hypoattenuation and increased leaflet thickness illustrating the extension of thrombus onto the leaflets.
Imaging calcium is a strength of CT and a relative weakness of echocardiography, despite the overall strength of echo to assess the severity of bioprosthetic mitral valve dysfunction. The above images highlight how helpful 4-D CT can be in evaluating structural causes of bioprosthetic mitral valve dysfunction, particularly for distinguishing between calcification and thrombus.
Dr. Cremer (email@example.com) is a cardiologist in Cleveland Clinic’s Section of Cardiovascular Imaging.