Internal carotid artery occlusion: diagnostic inaccuracy of the ocular pneumoplethysmography

The diagnosis of internal carotid artery (ICA) occlusion has serious management and prognostic consequences. The accuracy of noninvasive techniques in this setting remains questionable, with the result that contrast arteriography remains the diagnostic method of choice in patients in whom ICA occlusion is suspected. Ocular pneumoplethysmography-Gee (OPG-Gee) is one of the noninvasive methods that is still utilized extensively in the evaluation of carotid artery disease. In order to determine the real utility of OPG-Gee, the authors conducted a retrospective comparison of the results of OPG-Gee and arteriography in 26 patients (52 internal carotid arteries) who had undergone both examinations. [table: see text] With the angiography results as the standard of comparison, 4 incorrect diagnoses were obtained by OPG-Gee, thus yielding an overall accuracy of 92 for this method. However, duplex ultrasonography, also performed in the same 26 patients, correctly identified the 2 ICA occlusions defined by angiography and further demonstrated patency in the 48 arteries so shown by angiography. The authors conclude from this experience that OPG-Gee is less reliable than duplex ultrasonography in the diagnosis of ICA occlusion. Furthermore, despite the 92% overall accuracy of their results with OPG-Gee, the occurrence of both false-positive and false-negative results renders this examination modality suspect in the diagnosis of ICA occlusion.