Pulsed Doppler: a classification of results of diameter, velocity and volume flow measurement in diseased common carotid arteries.

Arterial diameter, mean velocity and mean volume flow was measured in 580 common carotid arteries of 290 patients. These patients were undergoing investigations for carotid artery disease and selection for arterial surgery. A pulsed Doppler velocimeter with an adjustable range gated time system and a double transducer probe was used. The results were classified using each of the parameters to determine which would give the most reliable method of subgrouping from normal range values through mild, moderate and severe reduction. Subgrouping by mean volume was found to be the most satisfactory method of expressing the results. Disturbance in the sonogram was observed in all examinations and the distribution of changes was not affected by the method of subgrouping used. The findings in this study suggest that interpretation of results from either diameter or velocity alone should be approached with caution.