DIGITAL TAPPING OF THE SUPERFICIAL TEMPORAL ARTERY - SIGNIFICANCE IN CAROTID DUPLEX SONOGRAPHY

To determine whether tapping on;he superficial temporal artery correct ly identifies the ECA during carotid sonography, prospective evaluatio n of the reflection of the temporal tap on the spectral waveform was r ecorded and graded as 3+, 2+, 1+, or 0 in each ECA, ICA, and CCA, with 3+ being the most brisk response in each carotid system (ipsilateral CCA, ICA, and ECA). The pattern of response was evaluated in patients with and without hemodynamically significant (> than 50% diameter) ste noses in CCA, ICA, and ECA. The most frequent pattern of response to t apping on the superficial temporal artery was 3+ in the ECA, 2+ in the CCA, and 1+ or 0 in the ICA. This pattern was found in 41% (82/200) o f systems overall. Whether or not stenoses were present in any branch of the extracranial carotid system, the strongest response (3+) was fo und in the ECA (58/200 [87%] with stenosis; 119/200 [89%] without sten osis, and lesser responses in the other arteries: 2+ in the CCA 31/200 [46%] with stenosis; 63/200 [47%] without stenosis, and 1+ or 0 in th e ICA 58/200 [87%] with stenosis and 103/200 [77%] without stenosis). This pattern was unaltered by the degree of stenosis in the ECA or in the ICA. In 92.5% of the systems interrogated, the response was greate r in the ECA than in the ICA. Tapping on the superficial temporal arte ry may be used as a reliable method of identifying the ipsilateral ECA even in instances of significant atherosclerotic disease in the ECA, CCA, or ICA.