Magnetic resonance velocity mapping of transtricuspid velocity profiles in dilated cardiomyopathy.

To investigate the velocity profiles and jet sizes of transtricuspid inflow by magnetic resonance imaging (MRI), we examined seven dilated cardiomyopathy (DCM) patients (mean age 37 +/- 15 years) and 20 normal subjects (mean age 32 +/- 7 years). We used a Siemens Magnetom Impact Expert (1.0 T) together with a surface receiver coil. Electrocardiographic gating, triggered by the R wave, was performed. Cine gradient echo images were obtained in the short axis of the right ventricle. Velocity mapping of right ventricular inflow was obtained at peak early diastolic filling. Velocity profile curves across the tricuspid inflow were obtained at 1-cm intervals from the tricuspid ring up to 3 cm into the cavity. Maximum/mean velocities in both groups were 1.1 +/- 0.1 at the ring level, unchanged at 1 cm from the tricuspid ring, and thereafter increased to 1.4 +/- 0.3 at 2 cm and 1.5 +/- 0.3 at 3 cm as peak velocity fell. Jet cross-sectional area was 10.4 +/- 2.1 cm2 at the ring level, and was unchanged at the 3-cm level in the normal subjects. However, in patients with DCM it was smaller than that in normals, and decreased in proportion to the distance from the tricuspid ring. Thus, tricuspid inflow velocity showed a relatively flat profile at the tricuspid ring and tip levels, becoming more dispersed at 2 and 3 cm from the ring. The cross-sectional area of the right ventricular inflow jet in the DCM patients was small and decreased in proportion to the distance from the tricuspid ring, although it appeared to be relatively constant in normal subjects.