The value of a combined study of carotid duplex ultrasound and oculopneumoplethysmography (OPG-Gee) in the diagnosis of carotid artery stenosis.

Two hundred consecutive carotid arteries were examined with the carotid duplex ultrasound and oculopneumoplethysmography (OPG-Gee) and compared with conventional arteriograms. The arteries were graded as normal, mildly stenotic (less than 50%), moderately stenotic (around 50%), severely stenotic (50% to 99%), or occluded. There was exact correlation between the duplex and the arteriogram as to disease severity in 70.5 per cent, good correlation in 25.5 per cent, and poor correlation in 4 per cent. When the carotid duplex was combined with an OPG-Gee, the exact correlation was 76.5 per cent, good correlation was 21 per cent, and poor correlation was 2.5 per cent. The diagnostic sensitivity of the carotid duplex alone was 95.6 per cent, diagnostic specificity was 84.3 per cent, false-positive rate was 16.2 per cent, false-negative rate was 4.2 per cent, and overall accuracy was 89.5 per cent. When the carotid duplex was combined with an OPG-Gee, the diagnostic sensitivity was 96.7 per cent, diagnostic specificity was 92.6 per cent, false-positive rate was 8.2 per cent, false-negative rate was 2.9 per cent, and overall accuracy rate was 94.5 per cent. In conclusion, when the carotid duplex was combined with an OPG-Gee, there was improvement in the exact correlation (70.5% to 76.5%), the overall accuracy (89.5% to 94.5%), and the diagnostic specificity (84.3% to 92%). The status of 15 arteries was also changed, either from moderate to mild stenosis or from possible occlusion to normal.