Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Nov 1995
Phase-contrast echo-planar MR imaging: real-time quantification of flow and velocity patterns in the thoracic vessels induced by Valsalva's maneuver.
Although the clinical manifestations of Valsalva's maneuver are well known, the associated hemodynamic changes in the great vessels have not been extensively studied and documented. In each of six healthy subjects, we evaluated three "quasi-steady-state" phases of Valsalva's maneuver: (1) during normal respiration, (2) during late strain, and (3) 4 seconds after strain release. ⋯ MR velocity measurements agreed with echocardiographic data and supplied additional information on flow and morphology. EPI showed a reduction in venous return during Valsalva's maneuver by simultaneously assessing flow, velocity, and vessel morphology; this technique appears to be useful in the analysis of flow dynamics of the great vessels.