A novel ultrasonography measurement of internal carotid artery stenosis: comparison with the North American Symptomatic Carotid Endarterectomy Trial angiographic method

Internal carotid artery (ICA) stenosis is a cause of stroke. ICA stenosis is generally measured using the North American Symptomatic Carotid Endarterectomy Trial (NASCET) angiography method, though ultrasonography (US) is often used in practice. This study aimed to identify the correlation between ultrasonographic and angiographic findings in the calculation of ICA stenosis degree using the NASCET method. US and angiography were performed in 42 patients. The ICA stenosis grades calculated using the angiographic NASCET method were compared to those from ultrasonographic findings of longitudinal views (Longitudinal axis NASCET method), transverse views (Transverse axis NASCET method), and the peak systolic velocity (PSV method). The values obtained on the Transverse axis NASCET method (r = 0.80, p < 0.01), the Longitudinal axis NASCET method (r = 0.74, p < 0.01), and the PSV method (r = 0.75, p < 0.01) significantly correlated with the percent stenosis measured by the angiographic NASCET method. The error of the Transverse axis NASCET method was significantly lower than that of the Longitudinal axis NASCET method (p = 0.022). The Transverse axis NASCET method is more closely correlated with the angiographic NASCET than the Longitudinal axis NASCET or PSV methods.