The benefits of computed tomography carotid angiography (CTA) in terms of evaluating the anatomical structure of the carotid arteries, surgical planning, and evaluating possible risks were reported in previous studies. This study aimed to calculate the predictive value of internal carotid wall thickness in CTA that can predict whether a modified carotid eversion endarterectomy (MCEE) will result in a successful or not. This study was designed in a retrospective cross-sectional format. Consecutive 83 symptomatic carotid surgery patients who were operated in our hospital and had CTA were included in this study. The wall thickness of the internal carotid artery (ICA) 20mm distal from the carotid bifurcation was calculated in axial sections using a three-dimensional imaging technique. In addition, all patients' characteristics and laboratory findings were recorded. Patients who failed MCEE and required classical carotid endarterectomy were compared with patients who had successful MCEE. MCEE technique was applied to 62 patients. In 21 patients, the MCEE technique failed and the classical endarterectomy technique was required. Preoperative clinical and laboratory characteristics were similar in both groups. The mean ICA wall thickness was 0.65mm 20mm distal to from the carotid bifurcation and it was lower in the group with successful MCEE (1.03 ± 0.21mm vs. 0.56 ± 0.08mm) (p < 0.001). The critical ICA wall thickness was calculated as 0.76mm in the group that MCEE failed and classical carotid endarterectomy was required. Cut-off analysis of ICA wall thickness was calculated as 0.755mm in ROC analysis (p < 0.001), (95% confidence interval, curve area; 0.985). Successful carotid endarterectomy with the MCEE method is associated with distal ICA wall thickness and distal extension of the atheroma plate. The use of ICA wall thickness 20mm distal to from the bifurcation as a predictive value for the success of the MCEE technique is beneficial to avoid serious complications.