0.05 ) . For diagnosis of intracranial aneurysms by VR , sensitivity , specificity, accuracy, positive predictive value and negative predictive value were 96.8%, 92.9%, 95.9%, 97.8% and 89.7% respectively,while sensitivity , specificity, accuracy, positive predictive value and negative predictive value of DSA was 97.9%, 96.3%, 97.5%, 98.9%, 92.9% respectively. Of all 94 aneurysms, 3D spacial relationship of neck, body and parent artery of aneurysms could well demonstrated by VR in 89,while by DSA only in 57(60.6%). Conclusion MS 3D-CTA VR is a very quick ,economical and effective method in diagnosis of intracranial aneurysms and has very high sensitivity , specificity and accuracy.