Radiology, Vol 157, 687-695, Copyright © 1985 by Radiological Society of North America
Blood flow imaging with MR: spin-phase phenomena
GK von Schulthess and CB Higgins
Blood flow phenomena occurring when flow is within the magnetic resonance
(MR) imaging plane were analyzed. In this situation, the signal intensity
of vascular lumina is predominantly determined by spin- phase change
phenomena, and section transition effects of moving spins can be neglected.
In this paper, we develop the concepts of in-plane flow, with emphasis on
the notion that the spatial variations in velocity and acceleration of
blood, which mainly occur along vessel walls, are important determinants of
intravascular signal loss in MR images. Flow patterns in the large
mediastinal arteries were qualitatively and quantitatively analyzed in six
healthy subjects and 14 patients with hemodynamic abnormalities using
multiple electrocardiograph-gated image acquisition; ungated studies of 30
patients were analyzed for venous flow effects. Intraluminal signal was
strongly dependent on the phase of the cardiac cycle and the echo number.
Signal loss was found to occur along vessel walls, in vascular bends, and
at bifurcations.
