Objective：To determine the consistency in the detection of basilar artery dolichoectasia（BD） by multi-slice spiral CT an－giography（MSCTA） using different post-processing techniques and to compare the diagnostic efficacy of various diagnostic methods. Methods：CT images of 125 patients who underwent head and neck MSCTA in the Radiology Department of our hospital were re－viewed. Of the 125 patients，17 were diagnosed with BD and 108 were diagnosed with non-BD，according to the results of multiplanar reformation（MPR），which is currently the accepted diagnostic method for CTA. The consistency between BD diagnosis results deter－mined by volume rendering（VR），vessel extraction（VE） and inspect & measure tool and MPR diagnosis results for the 125 patients was determined using the Kappa test. Evaluation indices of the VR and VE based diagnostic tests were determined using Medcalc software. Results：Among the 125 patients，12（9.60%） and 14（11.20%） cases of BD were diagnosed by the VR and VE methods，respectively. Consistency in BD diagnosis was moderate between the VR and MPR methods（?资=0.650，P=0.000），and good between the VE and MPR methods（?资=0.816，P=0.000）. The sensitivity（Se），specificity（Sp），positive predictive value（PPV），negative predic－tive value（NPV），and index of validity（IV） of the VR method for BD diagnosis were 58.82%，98.15%，83.33%，93.81%，and 0.928，respectively. The Se，Sp，PPV，NPV and IV of the VE method for BD diagnosis were 76.47%，99.07%，92.86%，96.40%，and 0.960，respectively. Conclusion：VE has higher Se，Sp，PPV，NPV，and IV than VR，and good consistency with MPR in the diagnosis of BD. Therefore，VE is a potential fully quantitative diagnostic method for MSCTA in the diagnosis of BD.