The Research Of Sinogram Affirmed Iterative Reconstruction (Safire) On Image Quality And Radiation Dose Of Coronary Computed Tomography Angiography

PART1The relevance research on image quality of coronarycomputed tomography angiography and reconstructionalgorithm by using the chinese anthropomorphic chestphantom on new DSCTObjective：The purpose of this study was to investigate the imagequality differences of coronary computed tomography angiography（CCTA）between iterative reconstructions which based on the original data andfiltered back projection.Materials and methods: A Chinese anthropomorphic chest phantomwith simulated coronary arteries undergoing CCTA by different scanparameters(tube voltage100kV and tube voltage120kV).The CCTA scandata sets of two groups were reconstructed with Sinogram Affirmed IterativeReconstruction (SAFIRE, Siemens) and filtered back projection (FBP).Indicators of image quality (SNR,CNR, SD) in each group were comparedby Dunnett t-test. The paired t-test was conducted to analyze the imagequality of the same tube voltage of different reconstruction algorithms and the same reconstruction algorithms of different tube voltage by SAFIRE.Results: The image quality of group by SAFIRE reconstruction washigher than FBP reconstruction whether tube voltage high or low. With theincrease of tube current from200mA to360mA, it shows the characteristicsof linear tendency. when it comes to340mA or more, the image qualitycome up to be stable. Statistical significance between the two groups(100kV,120kV)of SNR,CNR and SD by SAFIRE was existed (t=5.36、t=2.49,t=21.82,p＜0.05）p＜0.05).Conclusion: With the increased scan parameters the image qualities inthe two groups(FBP&SAFIRE) were corresponding higher, when it comesto340mA or more, the image quality come up to be stable. The SAFIREalgorithm have no effect on CT values.Using SAFIRE can significantlyimprove the image quality under the same scanning conditions PART2The effect of sinogram affirmed iterativereconstruction (SAFIRE) on different tube voltage andradiation dose of coronary computed tomographyangiography: a China Sichuan anthropomorphic phantomstudyObjective: The purpose of this study was to investigate thedifferences in image quality between SAFIRE and FBP in coronarycomputed tomography angiography (CCTA) by using the Chineseanthropomorphic chest phantom, and evaluation of different tube voltagesof the radiation dose in dual-source computed tomography (DSCT)Materials and methods: A Chinese anthropomorphic chest phantomwith thermoluminescent dosimeters (TLD) and simulated coronary arterieswas used for CCTA with different scan parameters (tube voltages100kVand120kV). The CCTA scan data sets of two groups were reconstructedwith sinogram affirmed iterative reconstruction (SAFIRE, Siemens) andFBP. The CT attenuation was measured and converted to contrast-to-noiseratio (CNR), signal-to-noise ratio (SNR) and CT value standard deviation(image noise). The organic radiation doses were recorded and wereconverted into effective doses. The image quality for each group wascompared by the Dunnett t-test. The paired t-test was conducted to analyzethe image quality at120kV/340mA and100kV/340mA.Results:1)The image quality of SAFIRE reconstruction was higher than that of FBP reconstruction at the different tube voltages. There werestatistically significant differences between the two groups (100kV,120kV) in SNR, CNR, image noise and CT attenuation (p<0.05). The imagequality of SAFIRE were similar to FBP reconstruction in group of360mAwhereas the radiation dose were higher in group of FBP/360mA than groupof SAFIRE/280mA.2) Both effective doses and organic radiation doseswere increased by the scan parameters from80kV to120kV. The effectivedose convert from test of TLD was higher than that of CT affiliated.Conclusion: The new SAFIRE reconstruction algorithm cansignificantly reduce radiation and improve the image quality under thesame scan parameters. The effective doses and organic radiation dosescorrespondingly increased with increasing tube voltage under anappropriate tube voltage range for CCTA. PART3The comparative study on image quality of coronarycomputed tomography angiography by iterativereconstructions and filtered back projectionObjective: The purpose of this clinical study was to investigate theimage quality and image noise in second-generation coronary computedtomography angiography（CCTA）with iterative reconstructions whichbased on the original dataMaterials and methods: Between March2012and April2012, weenrolled80patients with CCTA. For the CCTA scan (SOMATOMDefinition Flash, Siemens), data sets were reconstructed with SinogramAffirmed Iterative Reconstruction (SAFIRE) and filtered backprojection(FBP). We also recorded height, weight, gender and heart rate.Mann–Whitney-U-test and t-test were used for statistical analysisResults: There was no significant statistic difference for the scoring ofsubjective image assessment. However, the quantity of high mark(4) with Awas higher than B. The mean SNR significantly lower with protocol A thanB(p<0.01).the mean CNR was significantly lower with protocol A than B((p<0.01). the mean image noise was significantly higher with protocol Athan B((p<0.01). The coronary attenuation were not significantlystatisticallyConclusion: Compared with standard FBP reconstruction, SAFIRE improves image quality and has the potential to decrease radiation dose.