The Application Of The Dual-source CT With Stellar Photon Detector In The Low-dose CTA Examination And The Follow-up After PCI

Part1Application of 70 kVp with 30ml Contrast Medium by Dual-source CT with Stellar Photon Detector Coronary AngiographyObjectiveTo investigate the value of prospectively electrocardiogram(ECG)-triggered high-pitch coronary computed tomography angiography at 70kVp and 30mL contrast medium with Stellar detector Dual-source CT.Methods60 patients with the BMI<24.9kg/m2were randomized into two groups:Group A(30cases)with the tube voltage of 70KV and 30ml contrast medium; Group B(30cases)with the tube voltage of 100KV and 50ml contrast medium.All the patients were performed with a Stellar detector Dual-source CT using a prospectively ECG triggered high-pitch spiral technique. The image of group A were reconstructed with SAFIRE technique, group B with FBP technique. The objective image quality includes CT attenuation, SNR、CNR. And radiation dose was calculated; The subjective was evaluated by 4-scale point.Independent sample t test was used.ResultsThere was no difference for subjective image quality between the groups, A: (3.38±0.942、B:(3.50±0.682), (t=-0.562, P>0.05).The CT attenuation of the 70KV group were higher than that of the 100KV group for all the segments (P<0.05). The SNR and the CNR have no statistically significant difference between the groups(P>0.05).Compared with the 100 kV group, the radiation dose of the 70 kV group was reduced by 76.5%(A:0.19±0.023mSv、B:0.81±0.101mSv, P<0.01)ConclusionUsing 70kVp with 30ml contrast medium in Stellar detector Dual-source CT Coronary Angiography for the patients with a normal BMI can obtain diagnostic image quality with low radiation dose and contrast medium.Part 2The Application of the dual-source CT with Stellar Photon Detector in the follow-up after PCIObjective:To investigate the value of Stellar detector Dual-source CT in the follow-up after PCI and evaluate its image quality and diagnostic accuracy of stent restenosis.Methods:200 patients with 302 stents after PCI who underwent coronary CTA in our hospital were enrolled. The image was reconstructed in two thickness:Group A with the thickness of 0.5mm and group B with 0.75mm. Image quality score was graded as follows:grade 0 for poor、nonevaluable、nondiagnostic image quality,grade 1 for moderate artifacts, acceptable for routine clinical diagnosis, grade 2 for minor artifacts, good diagnostic quality, and grade 3 for excellent image quality (noartifacts). Conventional coronary angiography was performed with 18 patients in the 200 cases with a standard technique. With coronary angiography as the gold standard, the diagnostic accuracy of in-stent restenosis(ISR) of coronary CTA was assessed in the two groups.ISR was defined as 50% lumen diameter reduction. Comparison between groups using independent sample t test.Results:The image quality of the 0.5mm group(2.46±0.664) were higher than that of the 0.75mm group(2.25±0.688) (P<0.05).16 cases were diagnosed with ISR. The ISR diagnosis accuracy of A group and B group are both 100%.Conclusion:It is superior in image quality of 0.5mm thickness to 0.75mm to show the lumen of the stent. A group and B group both have a high diagnostic accuracy and CCTA is an important means in the follow-up after PCI.