NMR Microscopy of Blood Flow at the Carotid Bifurcation

We have found a blood flow pattern "signature" in sup 1 H NMR microimages of the rat carotid artery near the bifurcation. This "signature," sensitive to stenoses in the vessels of the neck, is seen by using a short TE spin-echo sequence to observe slices approximately 3 mm below the carotid artery bifurcation. Depending on the point in the heart cycle at which the image is gated, the signature appears in magnitude images as three lobes of different intensity within the artery (Figure 1). The source of this "signature" is understood by calculating the phase-angle image from the spin echo data, producing a velocity profile of blood flow in the vessel (Figure 2). The appearance of the "signature" can be altered by placing a stenosis in either carotid.