Study On Low Dose Scanning Technology And Low Concentrative Contrast Medium Used In Gemstone CT Contrast-enhanced Scan Of Rabbits

Objective:Appling the gemstone CT combined with the adaptive statistical iterative reconstruction(ASi R) technology to rabbits with CT contrast-enhanced scan of different radiation dose and concentration contrst medium, calculate and analyze the objective indicator(CNR, SNR, Noise)of Aorta descendens, and evaluate the subjective image quality.explore the feasibility of low-dose radiation scanning technology and low-dose contrast medium used in gemstone CT contrast-enhanced scan,and optimize the image quality of different percentage ASIR.Methods:Selected healthy 12 New Zealand white rabbits of either gender, weigh 2.8~3.9kg,according the noise index(NI) and concentration contrst medium, divided into A, B, C, D four groups. Group A is the normal group:concentration of contrast medium is350 mg I/ml,noise index is 9.Group B is the low dose and normal concentration group:concentration of contrast medium is 350 mg I/ml, noise index is 19. Group C is the normal dose and low concentration group: concentration of contrast medium is 270 mg I/ml, noise index is 9. Group D is the low dose and low concentration group: concentration of contrast medium is 270 mg I/ml, noise index is 19.All groups adopped Smart Prep technology to trigger scan, the injection speeed was 1ml/s, the injection parameters were 1ml/kg of injection volume. ASi R right were set to 30%、50%、70% to Group D. record the computer automatically generate data CT dose index volumes(CTDIvol), dose-length product(DLP),and calculate effective dose(ED), calculate and analyze the four groups’ objective indicators(CNR, SNR, Noise), and the four groups’ image quality were evaluated by three senior radiologists, all data above through the statistical analysis.Results:1.When the concentration of contrast medium was certain, the low dose(NI=17)comparing to the conventional dose(NI=9), ED、CNR、SNR decreased,while SD increased,There was a statistically significant difference in groups A、B and groups C、D about ED、CNR、SNR、SD(P <0.05).2. When the radiation dose was certain, low concentration of contrast medium(270mg I/ml) comparing to the conventional concentration of contrast medium(350mg I/ml), CT value of image and CNR、SNR decreased, the CNR、SNR、CT value in groups A、C and groups B、D were statistically significant((P <0.05),but the difference in ED and SD were not statistically significant(P> 0.05).3. Through “double low” scanning method combined with the different ASi R%(30%、50%、70%)technology, with the increasing of ASi R%, SD gradually decreased, while CNR,SNR increased, image quality score had reached a peak in the 50% ASi R.4. Image quality score: A,B,C,D four groups of image quality scores have no statistical difference(P>0.05).Conclusions:Based on the experimental analysis, appling the gemstone CT and using“double low”scanning mode with the angiography are feasible.