Objective:To investigate the influence of scanning parameters(including mA

kV

slice thickness and pitch)on image quality and radiation dose of volume computed tomographic digital subtraction angiography(VCTDSA).Methods:VCTDSA were performed on a skull specimen.Scans were obtained with different scanning parameters

including current of 100

85

75

65

50

25 and 10 mA

synchronic voltage modification of 140

120

100 and 80 k V

non-synchronic voltage modification of 120~140

100~140

80~140

100~120

80~120 and 80~100 kV

slice thickness of 0.625

1.25

2.5

3.75 and 5 mm

and pitch of 0.531

0.969.CT numbers of the overall view were measured on subtraction images obtained from Add/Sub software.The image quality of subtraction images were analyzed

which were reformatted and displayed with 3D volume rendering(3D VR).Results:Except subtracted image qualitys were evaluated gradeⅢ(100%)with non-synchronic pitch

other subtracted image qualitys were evaluated grade Ⅰ(100%)undergoing different scanning parameters(mA

kV

slice thickness and synchronic pitch).With the decrease of mA

kV

slice thickness and the increase of pitch

CT numbers and imaging noise increased

and imaging quality after subtraction decreased.Image quality was improved and noise was reduced by dual energy subtraction.With the increase of k V

CT numbers increased.Conclusion:Image quality was improved and radiation dose was reduced by dual energy subtraction technique

thick collection and reconstruction in thin slice

decreasing mA and increasing pitch.