Long-term low-dose warfarin therapy is highly effective in preventing stroke in patients with non-rheumatic atrial fibrillation, and can be quite safe with careful monitoring.

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Proton nuclear magnetic resonance (NMR) imaging was performed on normal volunteers and patients with various types of clinical strokes. True three-dimensional volumetric data were obtained for subsequent reconstruction of images at various orientations, including transverse, coronal, and sagittal, and for specific matching to x-ray computed tomographic planes. A variety of radiofrequency pulse sequences was used to generate images weighted by the NMR parameters spin density (p) and spin-lattice (T1) and spin-spin (T2) relaxation times. Quantitative T1 data and qualitative T2 information were obtained from appropriate sequences. Proton NMR images embodying T1 information provided adequate delineation of normal intracranial anatomical structure and a high level of gray matter-white matter contrast; high lesion detection sensitivity in various clinical forms of stroke was seen in images providing both T1 and T2 information. T1 and T2 relaxation times were prolonged in embolic, thrombotic, and watershed infarctions as well as in lacunae; shortening of T1 and T2 was found in hematomas. Serpiginous vessels in an arteriovenous malformation were seen that had particular pulse sequences.

Spectral phonoangiography, a noninvasive method for measurement of the residual-lumen diameter of carotid stenosis by bruit analysis, was compared with x-ray angiography and direct measurement of the pathological specimen at carotid endarterectomy in 39 bifurcations from 36 patients. In six studies, the bruit was too faint to analyze. In 31 of the other 33 studies, the phonoangiogram predicted the residual-lumen diameter to within 0.5 mm of the measured value. Of the 39 contrast angiograms, 35 showed residual lumens within 0.5 mm of the value measured in the specimen, two showed lumens between 0.5 and 1 mm, and the sizes of two could not be estimated because of vessel overlap in all planes. Spectral phonoangiography and contrast angiography are both accurate methods for evaluation of carotid stenosis. Since phonoangiography is noninvasive, it may be of particular value in determining the natural history in patients with carotid bruits.