Csobay-Novák Csaba, Fontanini Daniele Mariastefano, Szilágyi Brigitta, Szeberin Zoltán, Kolossváry Márton, Maurovich-Horvat Pál, Hüttl Kálmán, Sótonyi Péter
Department of Vascular Surgery, Heart and Vascular Center, Semmelweis University, Budapest, Hungary.
Department of Vascular Surgery, Heart and Vascular Center, Semmelweis University, Budapest, Hungary.
Ann Vasc Surg. 2017 Jan;38:227-232. doi: 10.1016/j.avsg.2016.04.024. Epub 2016 Aug 12.
The introduction of electrocardiogram gating in computed tomography (CT) angiography imaging of aortic disease raised questions whether diameters measured on diastolic images can lead to the undersizing of aortic endografts. As previous studies suggested that young patients may have the highest risk of an unintended undersize, the aim of our study was to analyze the strain of the thoracic aorta in a young patient cohort.
We assessed the descending aorta of 52 patients (35 men, mean age 41.1 ± 7.3 years) who underwent coronary CT angiography (CCTA) with suspected coronary artery disease. To reduce radiation dose, native calcium score scans triggered on late systole were compared with diastolic phase CCTA images. Cross-section areas were measured, and effective diameters were derived at 3 levels of the visible segment of the descending aorta (P1, P2, and P3) in systole and diastole. Aortic pulsatility (mm, d-d) and strain (%, [d-d]/d) were calculated at each level. All measurements were performed 3 times by 2 independent readers to evaluate interreader and intrareader reproducibility.
A total of 936 measurements were performed. Significant differences were found between systolic and diastolic diameters at each location (all P < 0.001). Average aortic pulsatility was 1.5 ± 0.6 mm at P1, 1.6 ± 0.7 mm at P2, and 1.7 ± 0.7 mm at P3, with a corresponding aortic strain of 6.7 ± 3.1% at P1, 7.4 ± 3.5% at P2, and 8.1 ± 3.6% at P3. The differences between the strain of the measurement levels were not significant (P = 0.344). Aortic strain and pulsatility did not show significant correlation with pulse pressure (P = 0.693), patient age (P = 0.649), or other anamnestic data. Intraclass correlation coefficient was in the range of 0.95-0.96 for interobserver and in the range of 0.95-0.97 for intraobserver analysis.
This study shows that descending aortic strain can be measured precisely and reliably on images of routine CCTA examinations with native scans acquired during systole. We demonstrated that young adults have an aortic strain of 6.7-8.1%. As the average thoracic aortic strain was still lower than the recommended prosthesis oversize of 10%, routine use of systolic phase imaging cannot be recommended: it has no clinical benefit for the vast majority of the patients but increases the risk of motion artefacts. We also demonstrated that large interindividual differences are present in the scale of thoracic aortic strain, a phenomenon that needs further investigations to be fully understood.
在主动脉疾病的计算机断层扫描（CT）血管造影成像中引入心电图门控引发了一个问题，即舒张期图像上测量的直径是否会导致主动脉腔内移植物尺寸过小。由于先前的研究表明年轻患者可能面临意外尺寸过小的最高风险，我们研究的目的是分析年轻患者队列中胸主动脉的应变。
我们评估了52例患者（35名男性，平均年龄41.1±7.3岁）的降主动脉，这些患者因疑似冠状动脉疾病接受了冠状动脉CT血管造影（CCTA）。为了降低辐射剂量，将在收缩期末触发的平扫钙化积分扫描与舒张期CCTA图像进行比较。测量横截面面积，并在收缩期和舒张期的降主动脉可见段的3个水平（P1、P2和P3）得出有效直径。计算每个水平的主动脉搏动性（毫米，d - d）和应变（%，[d - d]/d）。所有测量由2名独立的阅片者进行3次，以评估阅片者间和阅片者内的可重复性。
共进行了936次测量。在每个位置，收缩期和舒张期直径之间均发现了显著差异（所有P < 0.001）。P1处的平均主动脉搏动性为1.5±0.6毫米，P2处为1.6±0.7毫米，P3处为1.7±0.7毫米，相应的主动脉应变在P1处为6.7±3.1%，P2处为7.4±3.5%，P3处为8.1±3.6%。测量水平之间的应变差异不显著（P = 0.344）。主动脉应变和搏动性与脉压（P = 0.693）、患者年龄（P = 0.649）或其他既往病史数据均无显著相关性。观察者间组内相关系数在0.95 - 0.96范围内，观察者内分析在0.95 - 0.97范围内。
本研究表明，在收缩期采集的平扫常规CCTA检查图像上，可以精确且可靠地测量降主动脉应变。我们证明年轻成年人的主动脉应变在6.7% - 8.1%之间。由于胸主动脉平均应变仍低于推荐的假体过大尺寸10%，因此不建议常规使用收缩期成像：它对绝大多数患者没有临床益处，但会增加运动伪影的风险。我们还证明，胸主动脉应变规模存在较大的个体差异，这一现象需要进一步研究才能完全理解。
