Objective To evaluate the diagnostic value of subtraction CT angiography in cerebral venous diseases.  Methods The image quality of subtraction of 20 cases of cerebral venous diseases

confirmed by DSA and/or surgically

by head or head-and-neck scanning with 64-row CT was analyzed

and the ability of conventional CT angiography and subtraction CT angiography to display focus was compared.  Results The focus displaying rate by subtraction CT angiography was 100%

including 4 cases of cerebral venous sinus thrombosis

8 venous malformation

5 tumor-involved sinus diseases

2 trauma-involved sinus diseases and 1 carotid-cavernous fistula

higher than conventional CT angiography. Image quality of subtraction was good and vessels were displayed clearly for 90% cases. But in a few cases

the cranium and skull base could not be completely removed due to slight motion of head

which did not influence the diagnosis after some postprocessing by volume rendering (VR)

maximum intensity projection (MIP) and multiplanar reconstruction (MPR).  Conclusion Subtraction CT angiography is reliable

effective and worthy of wide clinical application in diagnosis of cerebral venous diseases.