The diagnostic value of subtraction CT angiography(CTA) in the intracranial aneurysms

Objective:To evaluate the clinical value of subtraction CT angiography(CTA) in the intracranial aneurysms.Methods:33 cases were examined by CTA. The obtained images were 3D postdisposed with(method A) and without(method B) subtraction respectively.Two sets of the images were reconstructed using the techeniques of maximum intensity(MIP),shaded surface display(SSD) and volume rendering(VR).In evaluating all the images by two experienced neurologists and two radiologists,double blind method were adopted.Results:By the method A 36 intracranial aneurysms were detected in 33 cases,aneurysmal body and neck,parent artery and relationship to adjacent vessels were displayed clearly and exactly.While by method B only 29 aneurysms were detected,1 anterior cerebral artery anerrysm,2 anterior communication and artery carotis interna anerrysms were not displayed.The detecting rate of the aneurysm were 100%,with high ratio by method A than 86% by method B(χ~2=5.13,P0.05).Conclusion:The 3D subtraction CTA is superior to 3D CTA in the diagnosis of intracranial aneurysms.