Usefulness of “AcT ratio” in diagnosis of internal carotid artery stenosis: a multicenter, retrospective, observational study

The ratio of the internal carotid artery (ICA) to the common carotid artery (CCA), especially the “AcT ratio,” which is a modified measurement method of acceleration time, is useful for diagnosing ICA-origin stenosis. However, previous studies were single-center studies. Therefore, this multicenter, retrospective, cross-sectional study aimed to determine whether a method using the AcT ratio is useful for estimating stenosis rates. This study included 461 vessels subjected to carotid artery ultrasonography and evaluation for ICA-origin stenosis via NASCET at four hospitals. The duration from the steep rise point to the inflection point or the first peak was defined as AcT on pulsed wave Doppler. The AcT ratio was calculated as AcT of ICA/AcT of ipsilateral CCA. The AcT ratio and rate of ICA-origin stenosis were analyzed using Pearson's correlation coefficient, simple regression analysis, and ROC curve. A significant positive correlation was observed between the AcT ratio and NASCET stenosis. NASCET stenosis of ≥ 50