智能期相联合SSF技术改善冠状动脉CTA图像运动伪影

目的:评价智能期相选择(Smart phase)和自动追踪冻结(Snap-Shot-Freeze, SSF)技术联合应用在前门控冠状动脉CT血管成像(Coronary CT angiography, CCTA)改善图像运动伪影中的价值。方法:94例疑似心血管疾病的患者行CCTA检查。所有患者图像均采用smart phase、SSF及smart phase+SSF两种技术联合进行后处理。将原始图像(A组)、smart phase图像(B组)、SSF图像(C组)和smart phase+SSF图像(D组)导入GE AW4.6工作站。对四组患者冠状动脉三大分支(右冠状动脉、左前降支及左旋支)图像质量进行主观评价(5分法)和测量每组图像主动脉根部及前胸壁肌肉CT值和标准差,并计算图像的噪声(Noise,N)、信噪比(Signal-to-noise ratio,SNR)和对比噪声比(Contrast-to-noise ratio,CNR)和比较。结果:经smart phase处理后,A组冠状动脉三大分支图像评分均得到了明显提高(P<0.05)。经SSF矫正的A组和B组冠状动脉三大分支图像质量评分均得到明显提高(P<0.05)。Smart Phase联合SSF技术得到的图像评分在所有组中评分最高,与其他组均存在显著差异(P<0.05)。结论:Smart phase联合SSF技术可明显改善前门控CCTA图像运动伪影,值得临床推广应用。

Combination of Smart Phase and Snap-Shot-Freeze Technique Can Correct Image Motion Artifact for Prospectively Gated Coronary CT Angiography

ABSTRACT Objective: To evaluate value of combination of smart phase and snap-shot-freeze (SSF) techniques in improvement of image motion artifacts in prospectively gated coronary CT angiography(CCTA) by using a 256-row CT scanner. Methods: Coronary CT angiography was performed in 94 patients with suspected cardiovascular disease by using a 256-row revolution CT scanner. All patients'' original images were reconstructed by using smart phase, SSF, smart phase and SSF, respectively. The original image (Group A), smart phase image (Group B), SSF image (Group C), smart phase and SSF image (Group D) were imported into the GE AW4.6 workstation. Then image quality of right coronary artery(RCA), left anterior descending artery(LAD) and left circumflex artery(LCx) were evaluated by two experienced readers on GE AW4.6 workstation. Subjective evaluation of the image quality were performed using 5-point scale method in four groups. The CT attenuations and standard deviations of aortic root and anterior chest wall muscle were measured, and then SNR and CNR were calculated and analyzed. Results: The scores of the RCA, LAD and LCx of the coronary artery in group A were significantly improved after the smart phase processing(P<0.05). The image quality scores of the three branches of coronary artery in group A and group B were obviously improved after motion correction using SSF technique(P<0.05). The image scores obtained by smart phase combined with SSF technique were the highest in all groups, and there were significant differences between the other groups(P<0.05). Conclusion: Smart phase combined with SSF technique can significantly improve the motion artifacts of prospectively gated CCTA by using revolution CT, which is worthy of widely clinical application.