The Revised Sonographic NASCET Index: A New Hemodynamic Parameter for the Assessment ofA InternalA Carotid Artery Stenosis

G. Hathout, N. Nayak, A. Abdulla, J. Huang

Research output: Contribution to journalArticlepeer-review


Purpose: A previously described Doppler parameter, the sonographic NASCET index (SNI), was derived to be more directly analogous to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) methodology for assessing carotid artery stenosis. However, this index does not account for complex changes affecting the Doppler waveform. We propose a revised SNI (rSNI) in an effort to improve predicting carotid stenosis. Materials and Methods: 25 carotid bifurcations with stenoses ranging from 40-92 were analyzed. For each vessel, the rSNI and original SNI were calculated. The peak systolic velocity (PSV), rSNI, and original SNI were correlated with angiography using linear regression analysis and relative accuracies were compared at two thresholds. Results: A correlation between rSNI and angiography was found to be significantly better than that between PSV or internal carotid artery-common carotid artery (ICA-CCA) peak velocity ratio and angiography (r=0.47 vs. 0.22; r=0.47 vs. 0.16). The accuracy of PSV in predicting high-grade stenosis was 68 and 72, compared with 80 and 88 for rSNI, at each of two thresholds. The original SNI better correlated with angiography compared to the rSNI (r=0.55 vs. 0.47), but with slightly lower accuracy in predicting high-grade stenosis (76 vs. 80). Conclusion: The revised SNI correlates more closely with angiographic stenosis than either the PSV or the ICA-CCA ratio, and is more accurate in predicting high-grade stenosis. However, it is overall comparable to the original SNI, suggesting that the previously unaccounted for effects over the remainder of the cardiac cycle do not significantly improve the ability to sonographically predict significant stenosis.

Original languageEnglish (US)
Pages (from-to)362-368
Number of pages7
JournalUltraschall in der Medizin
Issue number4
StatePublished - Aug 6 2015
Externally publishedYes


  • angiography
  • carotid arteries
  • ultrasound Doppler
  • ultrasound spectral Doppler
  • vascular

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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