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Cardiac magnetic resonance imaging.

All four cardiac valves can be imaged using MRI. Gradient-echo imaging is the preferred mode of imaging. Valvular regurgitation seen as an area of signal loss in the more proximal chamber can be diagnosed with a high degree of accuracy when compared with 2-D Doppler echocardiography and catheterization angiography. Aortic and mitral stenosis can be semiquantitatively diagnosed, but no method for determining valve areas is currently available. Cardiac prosthetic valves can be imaged but appear only as localized signal loss. Prosthetic valve regurgitation can be diagnosed in the same way as native valve regurgitation. At present, MRI, though not a widely used modality, can contribute significantly to the diagnosis of cardiac valve disorders. With the addition of fast magnetic resonance scanning, which can eliminate the need for electrocardiographic gating, it will be possible for patients with cardiac rhythm irregularities to be scanned, thus broadening the base of patients with valve disease who can be diagnosed.