Direct cardiac NMR imaging of heart wall and blood flow velocity.

Nuclear magnetic resonance (NMR) imaging is used to produce in the same scan both anatomical and functional information of the heart and great vessels. A method is described to generate velocity images by the use of phase shifts for moving spins induced by imaging gradients under electrocardiogram (ECG) synchronized imaging conditions. The influence of the different gradients is discussed together with methods to obtain velocity information for each gradient direction separately. The results, obtained with a 0.14 T resistive NMR scanner and normal volunteers, show the spatial velocity distribution in the aorta and heart walls in color scale images. The feasibility of velocity calculations is demonstrated and some applications are given. The present results indicate the possibility of quantitative flow and motion analysis with ECG synchronized NMR imaging.