Noninvasive testing for carotid artery stenosis: II. Clinical application of accuracy assessments

Determination of the specificity, sensitivity, and accuracy of diagnostic tests usually identifies the value of the tests in isolation, but the clinical significance of the findings is less clear. In this study the accuracies of direct continuous wave color-coded Doppler imaging (DDI), periorbital directional Doppler ultrasonography (PDDU), and oculoplethysmography-carotid phonangiography (OPG-CPA) were calculated for each examination alone and in combination with others for 176 patients who had been studied by all three noninvasive methods for suspected extracranial carotid arterial disease. When evaluated alone, DDI yielded the highest accuracy, 94%. In 89% of the population, DDI agreed with at least one of the other two tests. When this occurred, the majority finding was correct 98%. When DDI disagreed with the other two tests (11% of cases), it was correct in only 50%. These findings suggest a clinical approach which would minimize testing while achieving a high accuracy for most patients and identifying those patients whose carotid status could not be discerned with these studies.