256层螺旋CT两种扫描技术诊断Stanford A型主动脉夹层根部病变的对比研究

摘要

目的 评估256层螺旋CT前瞻性心电门控与非心电门控大螺距血管成像技术对Stanford A型主动脉夹层(AAD)根部病变成像的质量及诊断准确性.方法 采用回顾性研究方法,选择2015年8月至2017年7月在天津市第五中心医院就诊的68例CT血管造影(CTA)确诊AAD患者,依据扫描方式不同分为前瞻性心电门控CTA组(36例)和非心电门控大螺距CTA组(32例).以3分法评价主动脉窦、主动脉瓣交界区、冠状动脉(冠脉)开口图像质量,测量主动脉根部CT值和噪声值计算图像信噪比(SNR),并与术中探查对照,比较两组患者CTA成像质量及病变分型诊断的符合率.结果 所有主动脉CTA图像均能满足诊断要求,心电门控CTA组主动脉窦、主动脉瓣膜交界区、冠脉开口的图像质量评分均明显高于非心电门控大螺距CTA组〔主动脉窦(分):2.94±0.23比1.89±0.67,主动脉瓣膜交界区(分):2.94±0.23比1.83±0.70,冠脉开口(分):2.86±0.35比1.31±0.52,均P<0.01〕,心电门控CTA组和非心电门控大螺距CTA组客观评价指标主动脉CT值、主动脉噪声值、SNR比较无差异均无统计学意义〔CT值(HU):425.20±94.38比439.29±86.78,主动脉噪声值(HU):22.85±9.40比26.40±9.41,SNR:21.23±8.16比19.70±9.98,均P>0.05〕.心电门控CTA组诊断AAD根部病变与术中探查对照符合率明显高于非心电门控大螺距CTA组〔94.4%(34/36)比68.8%(22/32),P<0.01〕.结论 前瞻性心电门控CTA对AAD根部病变成像质量及诊断准确性明显高于非心电门控CTA.%Objective To evaluate and compare the imaging quality and diagnostic accuracy of two types of scanning techniques of 256-slice spiral CT angiography, prospective electrocardiogram(ECG)-gated sequence and non ECG-gated high-pitch sequence, used respectively for patients with Stanford type A aortic dissection (AAD) at the root of ascending aorta.Methods A retrospective study was conducted. Sixty-eight patients with AAD were definitely diagnosed by CT angiography were admitted to the Fifth Central Hospital of Tianjin from August 2015 to July 2017, and they were divided into two groups according to different scanning methods: 36 cases of AAD underwent prospective ECG-gated CT angiography (CTA) and 32 patients underwent non ECG-gated high-pitch CTA. A 3-grade scoring system was used to interpret the image quality of the aortic sinus, aortic valve junction zone and coronary artery opening. The CT value and noise value (SD) of aortic root were measured, the image signal to noise ratio (SNR) was calculated and compared with the discovery in exploratory operation; the patients' CTA imaging quality and the coincidence rate of lesion type diagnosis were compared between the two groups.Results All aortic CTA images could meet the diagnostic requirements. The imaging quality scores of aortic sinus, arotic valve junction zone and coronary artery opening images in ECG-gated CTA group were higher than those in non ECG-gated high-pitch CTA group (aortic sinus: 2.94±0.23 vs. 1.89±0.67, sinuscanal junction zone: 2.94±0.23 vs. 1.83±0.70, coronary artery opening images: 2.86±0.35 vs. 1.31±0.52, allP < 0.01); comparisons between the ECG-gated CTA group and non- ECG-gated CTA group in objective indexes, CT value, arotic SD value and SNR at the root of ascending aorta showed there were no statistically significant differences [the value of CT (HU): 425.20±94.38 vs. 439.29±86.78, the SD value of aorta (HU): 22.85±9.40 vs. 26.40±9.41, SNR: 21.23±8.16 vs. 19.70±9.98, allP > 0.05]. The coincidence rate between the diagnosis of AAD at the root of ascending aorta and the discovery in the exploratory operation in ECG-gated CTA group was higher than that in non ECG-gated CTA group [94.4% (34/36) vs. 68.8% (22/32),P < 0.01].Conclusion The diagnostic accuracy and image quality of AAD root of ascending aorta in prospective ECG-gated CTA group were significantly higher than those in non ECG-gated CTA group.