Objective To evaluate the clinical application of regulating bone removal ratio in dual-energy cerebral subtraction angiography.Methods A total of 45 patients who underwent two phases dual-energy CT angiography (CTA) were recruited and divided into several groups by the value of bone removal ratio,as follows: group A (Ratio=1.6), group B (Ratio=1.7), group C (Ratio=1.8) and group D (Ratio=1.9,default), as well as group E (100kV Neuro-DSA).The image quality of dual-energy CTA was evaluated by double blind method according to bone suppression and integrity of the vessel lumen (1-5 points, 1=poor, 5=excellent, 3-5=satisfactory).The bone removal ratio dependence of the image quality was analyzed using the self-control method.Moreover,the signal-to-noise ratio (SNR),contrast-to-noise ratio (CNR) and image scores were compared with the Neuro-DSA subtraction among these groups.Results The overall satisfaction of basis cranii images that were executed by dual-energy CTA with different bone removal ratios was listed as below: group A 73.33%, group B 91.11%, group C 78.52%, group D 70.37%.The satisfaction of siphon segment and petrous segment reached the maximum when the value of ratio was 1.7,and with significantly difference (P<0.05).The SNR and CNR were not significantly different among group B, group D, and group E (P>0.05).Conclusion With optimal bone removal ratio,the single enhanced dual-energy subtraction image quality with flash dual-source CT is consistent well with that of conventional 100 kV Neuro-DSA subtraction.Thus,this method is recommended in clinical emergency cerebrovascular examination for the improved image quality,which can compensate the shortage of vascular defect in basis cranill.

130 mg/dl). Conclusions The fibrinogen level may reduce to 40～130 mg/dl treated with Batroxobin in patients with acute cerebral infarct, but whether it could be regarded as a target level need more studies.