Objective To evaluate the relation between carotid siphon calcification with the presence of TIA on non-enhanced CT images and carotid artery bifurcation stenosis(CABS) on MSCTA images. Methods This IRB-waived retrospective study included 84 consecutive patients suspected of TIA who underwent non-enhanced CT and MSCTA of the head and neck. CABS was rated on CTA as not present or present with non-significant (0-40%), moderate (50-69%), significant (70-99%) and occlusion (100%). And carotid siphon calcification was classified into 5 grades on non-enhanced CT images including grade 0 (no calcification), grade 1 (small spotty foci of calcification), grade 2 (a single calcification occupying <90°), grade 3 (90-270°), grade 4 (>270°). Furthermore, grade 0-1 were defined as low grade calcification, and grade 2-4 were defined as high grade calcification. Presence, shape of carotid siphon calcification were analyzed the relationship with CABS. Results The presence of CABS were as follows: left side, 43%; right side, 43%; bilateral sides, 58%. The presence of carotid siphon calcification and bigger extent of calcification resulted in odds ratios for having CABS, with a high sensibility (73%) and specificity (71%). Absence of calcification in carotid artery siphon has a high negative predictive value for CABS in patients (specificity of diagnosis=100%). However, siphon calcification is not a reliable indicator of moderate and significant carotid artery stenosis (sensibility of diagnosis=5.8%). Conclusion Presence and extent of calcification in carotid artery siphon can be indicators of CABS in the patients with TIA.