Application of pixel shine algorithm at 80 kVp in direct CT venography of the lower extremities

Abstract:

Objective：To evaluate the radiation dose and image quality of pixel shine（PS） algorithm at 80 kVp in direct computed to－mography（CT） venography of the lower extremities. Methods：Forty-one patients who were clinically diagnosed with lower extremity varices and underwent direct CT venography of the lower extremities were randomly assigned to experimental group（80 kV） and con－trol group（100 kV）. Filtered back projection（FBP） and PS algorithm were used for reconstruction in the control group and the exper－imental group，respectively. The volume CT dose index（CTDIvol） and the dose-length product（DLP） were compared between the two imaging techniques. The images of the fifth lumbar vertebra，the femoral head，and the popliteal fossa were selected. Two radiologists gave subjective scores for quality and noise of the above images. Venous vessel CT value，image noise，signal-to-noise ratio（SNR），and contrast-to-noise ratio（CNR） were measured and calculated. Results：The experimental group had significantly lower CTDIvol and DLP than the control group（t=-89.95，P<0.01；t=-35.83，P<0.01）. The two radiologists achieved a high consistency in subjective evaluation of image quality（?资=0.78，P<0.01）. There were no significant differences in the subjective scores for image quality of the infe－rior vena cava，the femoral vein，or the popliteal vein between the two groups（P=0.17，P=0.92，and P=0.75）. There was no difference in image noise between the two groups. However，the experimental group had significantly higher vessel CT value，SNR，and CNR than the control group（all P<0.01）. Conclusion：PS algorithm at 80 kVp can be routinely used in direct CT venography of the lower extremities to reduce radiation dose and improve vessel CT value，SNR，and CNR.